Connecting rod big end sizing issue

[bevans6]

Now, i am NOT the expert here, just listening and learning. Is angle cutting the cap considered a legit fix, or something that's ok up to a point? Is it better to have the hole round with this method, leave the cap as is with a bigger diameter at the part line, or spend $250 for a new rod?

I have left the parting line a little big when having blocks line honed when I didn't want to move the crank up too far, feeling that if 95% of the hole was perfect, the 5% at the parting line didn't matter. I would have thought the same would hold for the rods. Coincidentally, that's on 1275 A-series engines too... These aren't high horsepower engines, mostly about 100 - 110 HP per litre and 7500 rpm, mine anyway.

Brian

[hapfp]

Awesomebill, sounds like you are as anal as me, and I guess in this business, anal is good Brain, yeah I would say you can't go crazy with angle cutting, I would think if you cut too much you woauld start having a fair about of side pressure on the rod bolt and misalignment problems.

As for as the point of being a lower horsepower engine, what's that got to do with anything, it double it stock horsepower, this prep level is FP SCCA, so about 140-145 HP at 8100 rpm and the occasional venture up to 9000 rpm, and as a road race engine it will have higher revs for a longer periods of time when compared to a short track or drag engine.

[Darin Morgan]

Maybe you guys can clarify some thing for me. I have read this thread about three times but cant find anywhere where a tolerance was given for the amount of clearance at the parting line. It seems that many here look at this as a bad thing. If you think that parting line clearance is a bad thing, your wrong. My step father Kip Martin raced a 352FE for many years and in order to even get the engine to turn 8000rpm, you have to oval the rods about .007 to .008. If you didn't, you wouldn't make it to the 1/8 mile mark by the time the rods would be laying out on the track. Literally! We do not put an engine together hear at Reher Morrison unless the rods have at least .003 to .005 on aluminum and about .003 to .004 on steal. Some rods require more and some less it just depends on the loads, design and structure of the rod itself. There was a Titanium rod manufacture that will go nameless that gave rods to some companies to try. Due to the modulus of elasticity of Titanium, they would flex a great deal. They shipped them perfectly round or with no more than .001 clearance at the parting line. They also grabbed the bearing and blew up peoples engines on the first pull on the dyno! We knew better because we where taught to give rods a little more clearance at the parting line than we thought they would need because a little to much wont hurt anything but to little will destroy the engine. My brother Brad gave them .006. Guess what, That was not enough. They grabbed the bearing. The second time we tried them brad gave them .0085 and they ran all year with no problems. We had people calling us from all over the country asking us how we got away with running them because everyone else blew up there engine on the first dyno pull when they tried to us them! Brad told them that they have to coat the threads on the bolts, use grease instead of molly and give them .008 to .009 clearance at the parting line. They never had any more problems after that and the bearings looked brand new on tear down.



We wont put an engine together with out adequate clearance at the parting line and a little to much is not going to hurt you just so long as the housing bore is not tapered or bell mouthed. There is nothing wrong with clearance at the parting line. There are however right and wrong ways to do it!!!! We do NOT use angle cutting or over honing ( hone big and cut caps down to clearance) to set parting line clearance. If you use the over hone proceadure, you minimize the load bearing area and problems can result. We use Vise grips. Set the pressure on the vise grips to a predefined amount of out of roundness and hone them normally. This way the housing bore is a true OVAL and not just a massive amount of clearance all at once at the parting line.

The rods you referring to are probably junk and not reparable. If this operation is done incorrectly, the rod is junk, plane and simple.

[Wolfplace]

Maybe you guys can clarify some thing for me. I have read this thread about three times but cant find anywhere where a tolerance was given for the amount of clearance at the parting line. It seems that many here look at this as a bad thing.

If you think that parting line clearance is a bad thing, your wrong. !
We do not put an engine together hear at Reher Morrison unless the rods have at least .003 to .005 on aluminum and about .003 to .004 on steal. Some rods require more and some less it just depends on the loads, design and structure of the rod itself.

We wont put an engine together with out adequate clearance at the parting line and a little to much is not going to hurt you just so long as the housing bore is not tapered or bell mouthed.

There is nothing wrong with clearance at the parting line. There are however right and wrong ways to do it!!!! We do NOT use angle cutting or over honing ( hone big and cut caps down to clearance) to set parting line clearance. If you use the over hone proceadure, you minimize the load bearing area and problems can result. We use Vise grips. Set the pressure on the vise grips to a predefined amount of out of roundness and hone them normally. This way the housing bore is a true OVAL and not just a massive amount of clearance all at once at the parting line..

Darin,
Excellent post
I was doing this 30 years ago to a 482" BB I ran in a Vega
Basically stock L88 type rods with the good Boron bolt.
This was shifted at about 8500 & went through the traps at about the same.
If you tried to use a "round" rod bore it would kill it.
We tried pins like an aluminum rod, more clearance,,, all kinds of crap
Learned how to hone stock rods with a C clamp from a Super Stock guy to make them live.
I never lost a bearing after this.

I do not concern myself with more clearance at the parting line on anything I do anymore if it is within reason.

When I was doing stock stuff for some other shops this is the only time I concerned myself with "angle cutting" & it was purely for cosmetic reasons.
If I left a small shadow at the parting line some would tell me I did not know what I was doing.
So,, we made them round & purdy

[Baprace]

I think you guy's are missing the point on this rod rebuild spec, I have done many set's and have found that GM rods are generaly round BUT I have never had a Ford rod round ( even new ) they are always wide at the parting line, most bearing are wide at the parting line, just read the posts, the guy's are saying look at the old bearing pattern, I personaly think OEM rod manufacturers are trying to stop the bearing from turning and with an elongated hole the bearing can not spin, I always do the vertical clearance correct and if the part line is wider so be it , I have had 0 failures and I also respect the other engine builders on here, it's sorta like you want to go to Chicago, there are many ways to get there but in the end we are all ending up at the same address, I have noticed a lot of good bearing manufacturers have the parting wider also, Vandervell was always this way if memory serves me right. Rod side clearance is probably the most overlooked area in an engine, that is where the problems usually start. Now when I get new Crower rods they are always dead on and yet you buy a new Ford rod the elongation is always there , ( go figure ) if you can cheat the parting line on your rod cap cutter I would do it BUT if the rod is over a couple of thou on the part line I would not try to angle grind and shorten the rod because it will have no effect on the bearing crush ( this last statement is without getting into an argument with a machinist ) they are the worst .

[awesomebill]

Wow. I really don't know what to say other than do what you would like here. Here are a couple of points to think about.
1. I have used GRODEN, BME, GRP. Manley, C&A, Fowler, and even SS rods for blower engines that make well over 2000 hp and never seen one of these so called rods enlongated or oval.
2. Every rod from Lunati, Crower, Manley, Eagle, Cat, Scat, Ohio, C&A, and so on, have never come with the wide parting line theory.
My Statement is, if what Darin says is true then why don't the Rod manufactures tell us when we reach a certain RPM or HP you need more Horizontal clearance at the parting line! They do not tell us this because it is not true.
The reason this got started was years ago, engine builders were having problems with bearings using stock style very inadequate rods to push their engines father than what they could stand. So a bandaid was invented. I was told by one machinest, put a piece of writing paper under the cap and torque it down and then remove that paper after the rod was honed and this would make it work better. Wow, his engines blew up one after another and just about ruined his business.
The mere fact was there was not enough cap area, or material strength to keep the rod from stretching and doing this.
HP as nothing to do with this happening. The rod is pretty much being forced in a downward motion and if anything on this cycle the rod would tend to get even wider when this happens not closer.
The method of angle cutting which only make matters worst, because now you have the rod bolt mis alined as well as you now have thinner rods after truing the sides up to make it 90. Thus causing less material and making the rod bolt seating area bend the rod as it is tightened. JUNK
The horizontal clearance is built into the bearing and the bearing clearance is set buy what the engine builder prefers, not what you come up with buy making this not to well thought out plan to fix a rod that will not stand the negative G's on the intake stroke.
We have much better material now than we did even 10 years ago and along with the CNC, we can produce Billet rods, steel or aluminum, and get a very high quality rod that does not need someone changing the parting line distance to correct a bearing problem that does not exist.

The ability of the rod to stay round to keep the bearing crush in tact is way more critical than you may think. The bearing clearance allows a certain amount of coushin from the oil to keep the bearing off the crank. If the crank touches the bearing at any point in the cycle, or if the resistance of the oil being heated and now clingy, the only thing you do here is lower the bearings ability to not spin in the bore. Even if those parisitic drags you get with rubbing two agents together increase 20% and you have now decreased your rod bearing area of crush by 30% you now have a spun bearing. you got problems that will manifest in a way everyone will see. Its called the window effect.

The rod jouranl does not flex or change shape, the crank is not supposed to flex or change any amount that will cause a binding affect on the rod journal or main journal for that matter, unless severe detonation happens. So why would we think the rod has to be opened up to .0085 and for that matter for how far we should take this clearance issue into the rod. Whenever we open this measurement up, we take away from the crush effect and the ability to keep the round bearing in place. Did you ever think that the more you opened it up the worst it got? I don't hear to many engine builders claiming this at all. As a matter of fact, a pretty well know Rod Manufacture who runs top fuel says its a no no.
I will admit that I have seen super stock hemi guys do this to stock steel rods but it is because they only think they have to. A good bolt when properely stretched yeilds a clamping load that will hold pretty much keep any rod cap to the rod without having to enlongate the parting line.
I think it would be more important to have an oil that has the proper ingrediants with the proper high pressure and anti wear agents than to make a rod out of round to make it work.

Zinc- is an anti wear agent as well as phosferous

Sulfur and boron are extreme pressure agents.

Oil in its self is nothing but a carrier of these compounds along with parifin, cal, mag, and other chemicals for neutralizing and longevity and keeping things clean.
All the engines with liquid plastic for fillers or thickening agents, AKA polamer, have problems with ring seating, increased detonation, oil rings getting stuck etc. Liquid plastic has no ability what so ever to help the oil protect the 2 mating surfaces from touching. We have learned this just from the 10w10 weight racing oil now used in just about every Pro style series engines on the market.

These compounds are what keeps the crank from digging into the bearing not some formula for adjusting enlongation at the parting line. If the crank comes into contact at any time with the bearing, it is not will it break, it is only when.

The part about a Ford rod having to be this way may of been true only because journals that are spread apart have a much harder time staying round just because the areas have increased and the flat style design of the stock series rods. The rod nor engine knows its a Ford, Chevy, or Dodge. That is nonsense.
But, the journal width does feel the stress factor because of the width and weight and rpm and its ability to withstand those forces. Exceed it and boom.
Granted, the old Ford rods as well as the Pontiacs, Olds, Rambler, were very limited in strength and always had problems over 5500 20 years ago. We were racing junk.
But now inject a new billet rod into the equasion and the cap strength and rigidity of the rods with raised areas and radius's and you have a rod now capable of withstanding the loads required to live for the area requested.

What is the rod journal on the Pro stock Rod at this point? 1.855? If this is even close, the reason it stays together is because the area is so small,it can not make it enlongate even at 10,000 rpm plus with good 3/8 bolts. Not 7/16 as you would think. Why is that? The bobweights are very light and the stoke is very short and piston speeds are not as fast as you would think. Now take a 4.75" crank at spin it 10,000 rpm with a 6.75" rod and I don't care whats in it, it will only last as long as the material is capable of withstanding the critical tension points. That would be about 8800.

So in all fairness, the next time I get a new set of rods and check the big ends and they are .008 out at the parting line, I will just ignore that and hope for the best?
You know very well round is round and we can control that. Oval is not a controlled shaped and has to be at the best guessed at. So we should just forget about bearing crush and parting line distances and only worry about vertical measurements or at best at the X.
I don't think I could get Warren to consider that one for sure. If they, the rod compaines wanted rods to be made oval, they would have an oval section in the rod area of all the compaines catologs. I will be waiting patiently for that one.
I prefer anal when it comes to my rods and my aline bore and my customers faith in me to purchase a quality engine.
You may never have a problem with your way to get to Chicago, but I think I will choose what all the map makers say. ROUND. If this oval shape was good then why don't we make the bores oval to better fit the piston when it gets out of shape and make up for the distorations in the cylinder walls. We spend a lot of time to make the rods as round and perfect as when they were knew. I will yeild to the fact that 1/4" down is all I will allow for the parting line to be out and this will lower the crush by about 10%

The only reason this would matter is if I had all 8 rods previously done this way. I know it will run and last this way. But, If I had 1 rod like this or 2, I would yeild to the safe side and install 2 new ones. Because of this factor alone.

My customer takes it to the other engine builder and he puts the rods on the gauge and says, "Wow this guy is an idiot, look at this big end, this is exactly why your engine broke."
Now we have a big problem of me explaining this to my customer why I left his parting line area way to big. Not for me!

[Hardcore]

The additional clearance across the parting line on a resized rod will have no negative effect on the engine's performance. As for the bearing's, they all have extra clearance built in across the parting. Regardless whether or not the bores are round or oval. The bearings are oval shaped when installed. If possible keep the finished bore on the low, it will help with some slight additional crush. Factory Ford rods were notorius for this problem years ago, mostly on the FE motors. Angle grinding is not an option, you'll just be stressing the bolts. This doesn't apply to previously spun rods, only decent used ones.
Bill

[Wolfplace]

Wow. I really don't know what to say other than do what you would like here. Here are a couple of points to think about.
1. I have used GRODEN, BME, GRP. Manley, C&A, Fowler, and even SS rods for blower engines that make well over 2000 hp and never seen one of these so called rods enlongated or oval.
2. Every rod from Lunati, Crower, Manley, Eagle, Cat, Scat, Ohio, C&A, and so on, have never come with the wide parting line theory.
My Statement is, if what Darin says is true then why don't the Rod manufactures tell us when we reach a certain RPM or HP you need more Horizontal clearance at the parting line! They do not tell us this because it is not true.
The reason this got started was years ago, engine builders were having problems with bearings using stock style very inadequate rods to push their engines father than what they could stand. So a bandaid was invented. I was told by one machinest, put a piece of writing paper under the cap and torque it down and then remove that paper after the rod was honed and this would make it work better. Wow, his engines blew up one after another and just about ruined his business.
The mere fact was there was not enough cap area, or material strength to keep the rod from stretching and doing this.
HP as nothing to do with this happening. The rod is pretty much being forced in a downward motion and if anything on this cycle the rod would tend to get even wider when this happens not closer.
The method of angle cutting which only make matters worst, because now you have the rod bolt mis alined as well as you now have thinner rods after truing the sides up to make it 90. Thus causing less material and making the rod bolt seating area bend the rod as it is tightened. JUNK
The horizontal clearance is built into the bearing and the bearing clearance is set buy what the engine builder prefers, not what you come up with buy making this not to well thought out plan to fix a rod that will not stand the negative G's on the intake stroke.
We have much better material now than we did even 10 years ago and along with the CNC, we can produce Billet rods, steel or aluminum, and get a very high quality rod that does not need someone changing the parting line distance to correct a bearing problem that does not exist.

The ability of the rod to stay round to keep the bearing crush in tact is way more critical than you may think. The bearing clearance allows a certain amount of coushin from the oil to keep the bearing off the crank. If the crank touches the bearing at any point in the cycle, or if the resistance of the oil being heated and now clingy, the only thing you do here is lower the bearings ability to not spin in the bore. Even if those parisitic drags you get with rubbing two agents together increase 20% and you have now decreased your rod bearing area of crush by 30% you now have a spun bearing. you got problems that will manifest in a way everyone will see. Its called the window effect.

The rod jouranl does not flex or change shape, the crank is not supposed to flex or change any amount that will cause a binding affect on the rod journal or main journal for that matter, unless severe detonation happens. So why would we think the rod has to be opened up to .0085 and for that matter for how far we should take this clearance issue into the rod. Whenever we open this measurement up, we take away from the crush effect and the ability to keep the round bearing in place. Did you ever think that the more you opened it up the worst it got? I don't hear to many engine builders claiming this at all. As a matter of fact, a pretty well know Rod Manufacture who runs top fuel says its a no no.
I will admit that I have seen super stock hemi guys do this to stock steel rods but it is because they only think they have to. A good bolt when properely stretched yeilds a clamping load that will hold pretty much keep any rod cap to the rod without having to enlongate the parting line.
I think it would be more important to have an oil that has the proper ingrediants with the proper high pressure and anti wear agents than to make a rod out of round to make it work.

Zinc- is an anti wear agent as well as phosferous

Sulfur and boron are extreme pressure agents.

Oil in its self is nothing but a carrier of these compounds along with parifin, cal, mag, and other chemicals for neutralizing and longevity and keeping things clean.
All the engines with liquid plastic for fillers or thickening agents, AKA polamer, have problems with ring seating, increased detonation, oil rings getting stuck etc. Liquid plastic has no ability what so ever to help the oil protect the 2 mating surfaces from touching. We have learned this just from the 10w10 weight racing oil now used in just about every Pro style series engines on the market.

These compounds are what keeps the crank from digging into the bearing not some formula for adjusting enlongation at the parting line. If the crank comes into contact at any time with the bearing, it is not will it break, it is only when.

The part about a Ford rod having to be this way may of been true only because journals that are spread apart have a much harder time staying round just because the areas have increased and the flat style design of the stock series rods. The rod nor engine knows its a Ford, Chevy, or Dodge. That is nonsense.
But, the journal width does feel the stress factor because of the width and weight and rpm and its ability to withstand those forces. Exceed it and boom.
Granted, the old Ford rods as well as the Pontiacs, Olds, Rambler, were very limited in strength and always had problems over 5500 20 years ago. We were racing junk.
But now inject a new billet rod into the equasion and the cap strength and rigidity of the rods with raised areas and radius's and you have a rod now capable of withstanding the loads required to live for the area requested.

What is the rod journal on the Pro stock Rod at this point? 1.855? If this is even close, the reason it stays together is because the area is so small,it can not make it enlongate even at 10,000 rpm plus with good 3/8 bolts. Not 7/16 as you would think. Why is that? The bobweights are very light and the stoke is very short and piston speeds are not as fast as you would think. Now take a 4.75" crank at spin it 10,000 rpm with a 6.75" rod and I don't care whats in it, it will only last as long as the material is capable of withstanding the critical tension points. That would be about 8800.

So in all fairness, the next time I get a new set of rods and check the big ends and they are .008 out at the parting line, I will just ignore that and hope for the best?
You know very well round is round and we can control that. Oval is not a controlled shaped and has to be at the best guessed at. So we should just forget about bearing crush and parting line distances and only worry about vertical measurements or at best at the X.
I don't think I could get Warren to consider that one for sure. If they, the rod compaines wanted rods to be made oval, they would have an oval section in the rod area of all the compaines catologs. I will be waiting patiently for that one.
I prefer anal when it comes to my rods and my aline bore and my customers faith in me to purchase a quality engine.
You may never have a problem with your way to get to Chicago, but I think I will choose what all the map makers say. ROUND. If this oval shape was good then why don't we make the bores oval to better fit the piston when it gets out of shape and make up for the distorations in the cylinder walls. We spend a lot of time to make the rods as round and perfect as when they were knew. I will yeild to the fact that 1/4" down is all I will allow for the parting line to be out and this will lower the crush by about 10%

The only reason this would matter is if I had all 8 rods previously done this way. I know it will run and last this way. But, If I had 1 rod like this or 2, I would yeild to the safe side and install 2 new ones. Because of this factor alone.

My customer takes it to the other engine builder and he puts the rods on the gauge and says, "Wow this guy is an idiot, look at this big end, this is exactly why your engine broke."
Now we have a big problem of me explaining this to my customer why I left his parting line area way to big. Not for me!

=
Bill,
You do like to wander off a bit don't you
I don't quite understand what the oil additives have to do with anything if you lose clearance.
Don't care what you use for oil, if the film is destroyed you are going to have a problem

And no one said "anal" wasn't good when it comes to machine work.
What you seem to miss is one size does not fit all & your way is not the only "correct" way.

There are others of us out here that have been doing this stuff for a long time too & have found over the years things that work & things that seem not to.
I am not saying I make my new rods oval any longer, I for one learn every day, am not stuck with "what worked 30 years ago" & am willing to listen to the opinion of what others I respect have to say.
(this includes you too by the way,,, )

Darin & RM may "ovalize" their rods & if it works for RM I certainly would not be the one to tell them what they are doing is wrong, Their results speak for themselves.

In my case I no longer do this with the rods of today but that is me.
What I said was with the stock rods a round hole did not live 30 years ago at higher RPM.
What I said was I do not concern myself with a rod that is wider at the parting line within reason. or a "shadow" left here meaning it did not clean up perfectly.
This was referring to rods that are resized, not new rods

And the only time I angle cut was with stock type rods for other shops that didn't understand what they were looking at.
This does not mean I would take a junk rod that was two or three or more out & try to fix it, it means slight "adjustments" & never to anything I was using myself or for a performance deal with good rods.

Also, gotta ask but how exactly does a shadow of 1/4" at the parting line yield a 10% reduction in crush?
Don't think I agree with this.

If this part in my case is .0005-.0015 big I do not throw the rod away & I do not concern myself with it.
And here I am talking about a small area at the parting line not an oval shape that was a necessity in years gone by in some applications when we did not have access to the rods of today.

In my opinion the only reason in life for this part of the bearing area is to support the part that does the work which is about 60-80% of the "circle"
along with leaving extra space for the beginning of the "wedging" process that must take place to protect the parts.

This part of the rod has nothing to do with how the oil supports the loads any more than oil pressure does
If you have enough pressure more is not necessarily good
All that happens with a rod that is larger at the parting line is you have more oil to form the hydrodynamic wedge that is actually what protects the crank & bearing
When I used to see contact any where near the parting area I know for a fact that the rod is changing shape too much.
If you don't think rods change shape in tension you are living in a different world than I.
Either you change this shape or you use a different bearing if possible.

Ask any bearing manufacturer why they make bearings with differing amounts of concentricity.
I will assume you know the answer.
Are you saying that raising the concentricity of the bearing & adding more clearance & oil at the parting area is detrimental to how the load is carried in either compression or tension?

As for crush, I won't disagree that it may go down a little but I have never had this cause a problem & know of many top shops that open the rod & main bore sizing to adjust bearing clearance.
This includes some of the top cup shops & I consider them to be some of the best of the best.
I have personally seen engines that came out of that environment with main bore sizes that were what I considered well over the "high limit"
& can only assume they did it for clearance as the oil clearance was right where I prefer for this type of engine,, tight
As it seemed to work just fine for them I don't have a problem adjusting my bearing clearance with this method now.

This is getting way too long,,,

[Darin Morgan]

So in all fairness, the next time I get a new set of rods and check the big ends and they are .008 out at the parting line, I will just ignore that and hope for the best? You know very well round is round and we can control that. Oval is not a controlled shaped and has to be at the best guessed at. So we should just forget about bearing crush and parting line distances and only worry about vertical measurements or at best at the X.

The reason the rod manufactures don't tell you is because they don't have to and often don't even know about it. Why do manifold manufactures not tell you to port your manifolds for more power? Why do crank manufactures not tell you that you have to balance the crank. They don't have to that's why. If I where you, I would ask Warren if he ovals rods and make sure to ask him if he has ever our is currently ovaling the mains. The answer might surprise you. When you push things to the limits and don't use rods that look like tree trunks, a little added clearance is a necessity and will save your butt in the case of over rev or a limiter that didn't work. I have seen 12000rpm on the tach because of a missed shift and a failed limiter. We replaced the rods but they didn't break and they didn't grip the crank. These rods are not tree trunks either. They are very light and on the edge. Is it always necessary? No its not but if done correctly it wont hurt a thing and like I said, it will save your butt when the customer tries to see if the tach needle will go a full 360 degrees! Why do you think that bearing manufactures make bearings with added parting line clearance? Do you think they always did this? Every single thing is important. You still have to have adequate crush and over all clearance and the housing bore must be perfect in regard to taper or bell mouth and I never stated other wise. The way you talk, you would think I am throwing caution to the wind and letting anything slide. I take insult at that and any other professional machinist would feel the same way. When you say that an oval is not repeatable, this comes from someone who has never done it so I will educate you in the fact that it is accurate within a tenth or less! If it where not, it would be a useless operation. You know as I do that repeatability is paramount and can not be taken lightly.

The only reason this would matter is if I had all 8 rods previously done this way. I know it will run and last this way. But, If I had 1 rod like this or 2, I would yeild to the safe side and install 2 new ones. Because of this factor alone.

My customer takes it to the other engine builder and he puts the rods on the gauge and says, "Wow this guy is an idiot, look at this big end, this is exactly why your engine broke."
Now we have a big problem of me explaining this to my customer why I left his parting line area way to big. Not for me!

Your right on both counts and I would not try and convince you other wise. Again I feel you are misconstruing what I have said or at best, tried to say.

If you have a rod that is out of spec, then chunk it. I never said to use a rod that was wrong just because it had extra parting line clearance. Again I say.
IT HAS TO BE DONE CORRECTLY
you cant use just any old procedure and have it work.

Yes your correct about people coming back on you but, I feel its worth the efforts to explain to them the benefits of the procedure. I can also see why someone would want nothing to do with it so they don't have to explain it. If they want round rods we sell them to them, no problem. I have had some customers come back and ask me or outright demand there money back. Either way I don't have a problem. We just use the rods in our Super Series engines and give them some we have not ovate honed.


My brother and I as well as others have been utilizing the ovate honing procedure for decades and have never, not once, seen it have negatives effects, when done correctly. I have however seen it save my butt and many hundreds of thousands of dollars in time and components.

On this paricular topic, I can not be swayed. I do know that the rods of today are much stronger but I excersise caution and continue to ovate hone.

[#84Dave]

Wow..... this thread got me wondering so much I scooted out to the shop, before the start of the Indy Cup race, and measured some lower end parts on my 358" Chev(564HP) paved oval Super Late Model I'm putting together. Lunati 6.125" rods (don't know who actually manufactures the rod) with 7/16" cap-screw bolts that stretch-to-spec(.006") @ 75# torque. The I.D. of the rod, without the bearing, is perfectly round. The Calico/ACL rod bearing is .00125" thinner on each end than the middle. For a total of .0025" wider at the parting line across the journal. This regimen has caused no failures up to 8500 and leaves 1/8"-3/16" 'untouched' bearing surface on each half at the parting line. Maybe the lower HP doesn't beat up on parts as much as the 'on the edge' drag-racing assemblies?

Dave

[Darin Morgan]

Wow..... this thread got me wondering so much I scooted out to the shop, before the start of the Indy Cup race, and measured some lower end parts on my 358" Chev(564HP) paved oval Super Late Model I'm putting together. Lunati 6.125" rods (don't know who actually manufactures the rod) with 7/16" cap-screw bolts that stretch-to-spec(.006") @ 75# torque. The I.D. of the rod, without the bearing, is perfectly round. The Calico/ACL rod bearing is .00125" thinner on each end than the middle. For a total of .0025" wider at the parting line across the journal. This regimen has caused no failures up to 8500 and leaves 1/8"-3/16" 'untouched' bearing surface on each half at the parting line. Maybe the lower HP doesn't beat up on parts as much as the 'on the edge' drag-racing assemblies?

Dave

Its not the amount of power. Its the kinetic energies exerted on the rod in proportion to the strength of the metal and the rods design. If you have a really strong rod and have .0025 at the parting line at 8000rpm your probably just fine. Now cut the rods weight by 40% and turn it 9500rpm and see how much more clearance you need. Now, cut the rods weight by 70%, thin the bearing up by 25%, make it out of aluminum, use 3/8 bolts and twist it 10200rpm.


If your not having problems then you dont have anyhting to worry about.

[#84Dave]

Thanks, Darin. I like the first part of your answer. Don't believe I'll tread into the last two parts! Although your point is well taken regarding trying to reduce the reciprocating mass and the necessity to adjust the mechanical parts accordingly. I assume the worst case for those energies exerted on the rod/bolts takes place when the crank jerks the piston/pin/rod down the bore from TDC on cam overlap at high rpm, with no force on the piston top?

Dave

[MadBill]

The worst case is actually a closed throttle decel from peak RPM. Not only is there maybe a 25"Hg. vacuum pulling up on the piston at the same time the crank is yanking it down, there is also no counteracting pressure from compression/combustion.
Certain engines, e.g. inline 6 cylinder racing Jaguars, were renown for blowing up upon lifting the throttle at the end of a straight...

[ClassKing]

QUOTE: " I assume the worst case for those energies exerted on the rod/bolts takes place when the crank jerks the piston/pin/rod down the bore from TDC on cam overlap at high rpm, with no force on the piston top?"

yes - it's the extensive load. Trying to extend the length of the rod.

[awesomebill]

Maybe you guys can clarify some thing for me. I have read this thread about three times but cant find anywhere where a tolerance was given for the amount of clearance at the parting line. It seems that many here look at this as a bad thing. If you think that parting line clearance is a bad thing, your wrong. My step father Kip Martin raced a 352FE for many years and in order to even get the engine to turn 8000rpm, you have to oval the rods about .007 to .008. If you didn't, you wouldn't make it to the 1/8 mile mark by the time the rods would be laying out on the track. Literally! We do not put an engine together hear at Reher Morrison unless the rods have at least .003 to .005 on aluminum and about .003 to .004 on steal. Some rods require more and some less it just depends on the loads, design and structure of the rod itself. There was a Titanium rod manufacture that will go nameless that gave rods to some companies to try. Due to the modulus of elasticity of Titanium, they would flex a great deal. They shipped them perfectly round or with no more than .001 clearance at the parting line. They also grabbed the bearing and blew up peoples engines on the first pull on the dyno! We knew better because we where taught to give rods a little more clearance at the parting line than we thought they would need because a little to much wont hurt anything but to little will destroy the engine. My brother Brad gave them .006. Guess what, That was not enough. They grabbed the bearing. The second time we tried them brad gave them .0085 and they ran all year with no problems. We had people calling us from all over the country asking us how we got away with running them because everyone else blew up there engine on the first dyno pull when they tried to us them! Brad told them that they have to coat the threads on the bolts, use grease instead of molly and give them .008 to .009 clearance at the parting line. They never had any more problems after that and the bearings looked brand new on tear down.



We wont put an engine together with out adequate clearance at the parting line and a little to much is not going to hurt you just so long as the housing bore is not tapered or bell mouthed. There is nothing wrong with clearance at the parting line. There are however right and wrong ways to do it!!!! We do NOT use angle cutting or over honing ( hone big and cut caps down to clearance) to set parting line clearance. If you use the over hone proceadure, you minimize the load bearing area and problems can result. We use Vise grips. Set the pressure on the vise grips to a predefined amount of out of roundness and hone them normally. This way the housing bore is a true OVAL and not just a massive amount of clearance all at once at the parting line.

The rods you referring to are probably junk and not reparable. If this operation is done incorrectly, the rod is junk, plane and simple.

The gentlemans question was how come he can't get the big ends to come in. Now we have pro stock rod theroy injected into our every day racing bracket engines that have little to none to do with every day Racing. In pro stock, you have to do what you have learned works and stay with it if its not biting your butt. That point is conceaded. You obviously have to do things to make them live. But even given up that, aluminum is 1/2 the strenght of steel, thats why it must be twice as big. Now if your using an aluminum rod that is the same physical size of steel, I guess you have to do what you must. But this brings up the point again about rod bolts not being the weak link.

But I stll have to wonder why the rod hole of a rod needs to be oval when the crush is what holds the rod bearing in place for our normal e.t bracket engines with good racing rods, not super lite stuff. The oval part of the rod bearing is made in the I.D. of the bearing not the O.D. of the bearing. I thought all of us new this. If your talking .008 or .0085 on the parting line added for whatever amount needed into the radius of the rod for the amount of enlongation needed for your pro stock engines, thats like playing with a loaded gun and the safety off.

I do not see any reason to use any thing other than what Crower, Carrillo, Lunati, Manley all recommend for the bore of the rods. Now if your talking about the small chamfer right at the parting line 45 to the cap, that is exceptalbe. That is not what the post was about. Some rod companies put the small chamfer in their rods. We do that ourselves sometimes for different applications. The clearance as stated for the parting line is made in the i.d of the bearing. Throw pro stock out the window. I find we always use this as the bible of drag racing. I am very sure if you use rods as light as you say and also throw in aluminum you have to do things that we are not privy to. But for bracket racing, the clearance made in the bearing is more than really needed to use in anything we build.

Now if you meant .0008-.00085, that is a different story. I have and use the .0003 on the high or low side of spec and have never spun a rod bearing from the bearing getting pinched. And even the 10ths are ridiculous to think that they would make a difference in a bracket racing engine making 1000 at 7500 rpm. Its not needed when the rod clearance is .0025 to .0030.

Parting line chamfer and parting line being out .008 as far as the X reading is not recommended by anyone. A customer of mine purchased a JOHN FORCE ALUMINUM CONNECTING ROD from the Keystone race. I asked him if I could see it. He brought it into the shop and the first thing I did was torque it to 100 for a basic reading. I checked the rod 360 and found the rod to be out on one side only .0005 tight. This was very shocking to say the least. The parting line was as consistant as the entire diameter of the housing bore. Now I know this is not pro stock but, these rods have handled 7000 rpm and over 6000+ hp and no one knows what type of abuse with the limiters they have on the engines now. I wonder why their rod was still round but yet threw it away or sold it at 25% of the cost of new?

With all this being said, I agree with everyone who does this and it works. I am not saying that anyone is wrong in how they do it. What I am saying is I do it like the rod companies have always told us to do and we experience no failures on the dyno nor the track if the engine is not abused with detonation.

As far as using stock FE rods, thats a scary thought now just thinking about having to go back to that. Any rod journa over 2.2, your on your own when you go over 7500 rpm so what you had to do to make it live, you done it for a reason.

As far as the compounds used to keep the bearing from coming into contact with the crank, theres a subject worth beating. I listed most the stuff in oil that is used for keeping these 2 metals from touching. If the extreme pressure agents that are placed in oil fails to keep the 2 parts from touching, I don't care how much taper is there, it will fail. It has too.

Does anyone know that oil by itself is not really much good for engines? Ask P Long what they used for their special secret ingrediant to protect your engine. Not to mention it rusted and ate the bearings right out of the motor. It for certain was not the oil but the additive. But with that being said, that compound has a great protection factor. They just did not use enough neutralizer!. The next time your oil additive salesmen comes around and he has his little wheel with the 6 plates and he adds his oil and it sits there with 6 plates and spins good, tell him to clean it off really good, take a battery into the bathroom with you, take your finger if you want to and get some fluid from the battery and put a drop of this on the bearing surface to be tested. It will run there forever. He will say man what is that, tell em you took a leak on you finger. Now tell me why? Not one drop of oil, just plain old battery acid. If you think that the fluid or oil you put in your engine is all the same then keep using those high content polamere oils with your low tension or even standard tension oil rings and see what happens

The lubricants have way more to do with the running conditions between the 2 metals than any .0008-.00085 ovals in rod afaia concerned. I bet pro stock does not use syn oil in their engines either. most I have talked to and would say were 10w10 and that oil is killer stuff. Also with a few other engine builders who make killer power in pro mod.

Don't get me wrong with this post, if it works and is not broke for you, then keep on doing it. But with that said, we produce a few engines ourselves and its works for us the way we do it so why would that be wrong? Just another way to get to Chicago. As far as anyone getting upset over this post, in know way is anything ever meant to cause those feelings. We are all here to kick this around so lets do it without having the ego factor thrown in there.