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Cold lash after 500 miles, yikes!

General engine tech -- Drag Racing to Circle Track

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gmrocket
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Re: Cold lash after 500 miles, yikes!

Post by gmrocket » Wed Sep 12, 2018 9:48 pm

CamKing wrote:
Mon Sep 10, 2018 11:40 am
randy331 wrote:
Sun Sep 09, 2018 4:12 pm
F-BIRD'88 wrote:
Sun Sep 09, 2018 12:44 pm
When you do it the right way, instead of all the incorrect alternative methods. It is quick easy and accurate and pain free. (And your lifters live too.)
I can't believe my lifters survive cause I set them at TDC.

Well,.. just maybe my cams aren't "racey" enough !!

Randy
With 95+% of the cams out there, setting the lash at TDC is perfectly fine. It takes a pretty long duration cam, to still be on the lash ramp, at TDC.

I just looked at a Pro-Stock exhaust lobe I designed. It's 310@.050" with .530" Lobe Lift. If it was on a 122 Exhaust centerline, it would be on the base circle at TDC, but only by 1.25 degrees. Not a lot of guys running over 310@.050", or wider then a 122 ECL.
That makes sense..and at that point your not on speedtalk asking how to set lash.

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Re: Cold lash after 500 miles, yikes!

Post by F-BIRD'88 » Wed Sep 12, 2018 10:20 pm

If it is all about how it idles and drives you probably need
A milder cam. Seems like you drive it around more than race it.

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Re: Cold lash after 500 miles, yikes!

Post by Bishop540 » Wed Sep 12, 2018 10:31 pm

F-BIRD'88 wrote:
Wed Sep 12, 2018 10:20 pm
If it is all about how it idles and drives you probably need
A milder cam. Seems like you drive it around more than race it.
Not sure what shipping costs are from Canada but I can give you my new cam specs and you can surprise me for Christmas. :D
Eric

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Re: Cold lash after 500 miles, yikes!

Post by Bishop540 » Wed Sep 04, 2019 7:06 pm

Its been about a year since my last post on this topic...I have been checking lash periodically and have noticed that my intakes (1.8 ratio) are the ones that keep loosing lash. Now let me remind you that I have PRW 1.8/1.7 stainless rockers. I figured they would be alright since DV uses them on his engines in his books. But it looks as if the extra lash is coming from the rockers wearing out. They were a bit sloppy the last time I checked lash at 1250 miles. I called PRW and they said they dont even have a replacement for the 1.8 anymore. He did everything except admit they were junk. I told them my spring pressure is 250 seat and 600-ish open. He said that was within their range.....so it looks like I will be changing rockers soon and since i will have to buy pushrods again I may just go with 1.7/1.7. Crower said his stainless rockers would be good, 1.8 or 1.7. I'm not looking forward to setting the adjustable guideplates on my AFR (the old "s" series. Since 2014 they now have a "v2" head) heads. That was a job last time....I guess my question would be: what stud mount (or shaft -but its not in my budget) would fit the "S" AFR heads the best, in your experience? Thanks!
Eric

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Re: Cold lash after 500 miles, yikes!

Post by prairiehotrodder » Wed Sep 04, 2019 7:18 pm

I've been using comp gold rockers on my 555 with AFR 335 heads for a number of years now. One needed a little clearancing near the front top drivers side valve cover bolt depending on what valve covers you have.

I'm also currently running 1.8 scorpion race series rockers on my intake valves. If you have the solid guideplates you will likely have to cut and weld them to get them in the right spot.
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Re: Cold lash after 500 miles, yikes!

Post by Malvn » Wed Sep 04, 2019 7:37 pm

MadBill Wrote
There used to be (still is?) a tool or tools available that positioned a dial indicator on the valve end of the rocker.


You mean this one ??
https://www.precisionmeasure.com/product/valve-gapper/

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Re: Cold lash after 500 miles, yikes!

Post by Cobra720 » Wed Sep 04, 2019 8:17 pm

Since everyone is in on this I'll give my 2 cents. Just put a new 408w Dart SHP block Brodix aluminum heads together TLSR. EO IC method every 90* in firing order I cold lashed them at .010 ran the motor and checked them hot. .016 .016 right on the money. Cooled the motor down overnight and checked them cold again .010 +/- .002 . Ran the motor for 200 miles checked the lash cold all less than .004 looser. Ran the motor for a total of 400 miles cold lash stabilized at .010 +/- .001. I think between the Bushed lifters, lash caps and the rocker needles (crower SS) that's where the few thousands comes. I think and hope i'll be good for a long time. Time will tell.

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Re: Cold lash after 500 miles, yikes!

Post by MadBill » Wed Sep 04, 2019 8:42 pm

Bishop540 wrote:
Wed Sep 04, 2019 7:06 pm
Its been about a year since my last post on this topic...I have been checking lash periodically and have noticed that my intakes (1.8 ratio) are the ones that keep loosing lash. Now let me remind you that I have PRW 1.8/1.7 stainless rockers. I figured they would be alright since DV uses them on his engines in his books. But it looks as if the extra lash is coming from the rockers wearing out. They were a bit sloppy the last time I checked lash at 1250 miles...
As mentioned, new parts sometimes loosen up a bit at first. How many thous have yours opened up in total? Is it the rollers or the trunnions that are wearing? Is rebuilding an option? Eccentric rollers* (I've seen up to 0.005") can confuse the issue... *Speaking of which, with feelers, it's easy to detect and compensate for any roller eccentricity (yeah, I know it should be 0.000", but sometimes it's not...) but with a dial indicator not so much. (Also, per the link above, the Valve Gapper is similar to but not exactly as I remember from 40 plus years back.)
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

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Re: Cold lash after 500 miles, yikes!

Post by Bishop540 » Wed Sep 04, 2019 11:12 pm

MadBill wrote:
Wed Sep 04, 2019 8:42 pm
Bishop540 wrote:
Wed Sep 04, 2019 7:06 pm
Its been about a year since my last post on this topic...I have been checking lash periodically and have noticed that my intakes (1.8 ratio) are the ones that keep loosing lash. Now let me remind you that I have PRW 1.8/1.7 stainless rockers. I figured they would be alright since DV uses them on his engines in his books. But it looks as if the extra lash is coming from the rockers wearing out. They were a bit sloppy the last time I checked lash at 1250 miles...
As mentioned, new parts sometimes loosen up a bit at first. How many thous have yours opened up in total?
Initially when I first started this thread at 500 miles they were all .020 or so too loose. Hence the "yikes". Since I have checked the 1st time (twice in the last 700 miles) they have been .003 to .005 for each time I checked. Or .006 to .010 since my 1st check.

Thats why I think the wear is coming from the Stainless Steel rocker's trunnion area (they feel a little sloppy) and not my roller LIFTERS..... My idle speed is set at 1200 rpm's for good oil flow.
Eric

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Re: Cold lash after 500 miles, yikes!

Post by rustbucket79 » Wed Sep 04, 2019 11:59 pm

You have a year on the engine, you need to change the rockers anyways, so my suggestion is to pull your intake and check all your lifters for a roller that feels crunchy to roll or has noticeable clearance. No point in replacing rockers only to have the possibility that one of your lifters was 10 miles away from failing. Check the pushrod ends as well for wear.

Don’t feel bad, you’re not the first person to be burned by lower quality rockers. Comp, Crower, etc all make decent rockers.

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Re: Cold lash after 500 miles, yikes!

Post by Cobra720 » Thu Sep 05, 2019 4:14 pm

To answer one of your questions. The Crower Stainless Steel rockers are some of the very best in the industry ( and good clearance for retainers and Push rods. Compared to the PRW stainless Steel they are $400.00 more expensive. You get what you pay for.

I did a back to back to back comparison with Scorpion 1.6, Jim Miller 1.6 and Crower 1.6 as I was having difficulty finding a rocker arm that would give me good 90* geometry at half lift on both sides of the rocker arm and position the rocker tip on the valve stem in the center. That isn't easy to achieve. Ive been at this for a few years and even had Comps aluminum 1.6 rockers and Crower .050 backset rockers a few years back.

I have +.100 5/32 valves which can pose a problem on 17* ford heads. The converging axises of the stud and valve was becoming a problem in the world of one rocker arm fits all. The lash cap gives me more area and protects the stem but add to the length. The quest was interesting.

The Millers ended up with cracks along the stud bore in 8 trunnions (knock off Chinese junk the trunnion thickness was thin, I heard there were good ones out there but I did not have them). The geometry was good on both sides of the rocker arm and the witness mark was not bad but still on the outer part of the valve tip.

The Scorpion 1.6 are thick and strong, good trunnions, but at half lift the push rod cup was over arched while the roller tip was at 90* to the valve and the witness mark was on the outer edge of the valve tip. (the push rod cup was too high in the rocker arm body for what I was looking for.

The Crower Small Block Chevy 1.6 have a very large trunnion, a good amount of metal and plenty of room for retainers and push rod angle. The distance from trunnion axis to roller tip is about .060 shorter than a SBF. The geometry on both sides of the rocker at half lift was 90* and my witness mark on my valve tip was in the center.

BINGO I had a winner after several years of trying. For me it was worth it, the whole rocker arm geometry had become an obsession and I was going to find an answer. The funny thing is I had to use a SBC rocker arm on my SBF to get there.

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Re: Cold lash after 500 miles, yikes!

Post by BigBlocksOnTop2 » Thu Sep 05, 2019 7:58 pm

Pull the Intake and see if you can remove a lifter by hand.

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Re: Cold lash after 500 miles, yikes!

Post by Bishop540 » Mon Sep 09, 2019 11:13 am

The reason I settled on the PRW's was the extra lift they gave and I got a decent witness mark. I tried all other brand Stainless Steel, even Crower, and their offset design, and never got a good sweep.

I am looking for someone who has the AFR 325/335 -pre2013- "s" heads. I would like to compare notes.

When I bought my heads from Jegs they already had a spring that was close to what I needed for my solid roller cam, just a little on the higher side of spring pressure. At that time in -2012- that head was priced right with a very good spring so I couldn't pass up the deal. But shortly thereafter, AFR redesigned the valve angle a couple degrees. It was probably in an effort to help with the geometry mess at the intake valve (if I quoted correctly what Tony told me in those days).
Eric

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Re: Cold lash after 500 miles, yikes!

Post by Bishop540 » Mon Sep 09, 2019 11:20 am

prairiehotrodder wrote:
Wed Sep 04, 2019 7:18 pm
I've been using comp gold rockers on my 555 with AFR 335 heads for a number of years now. One needed a little clearancing near the front top drivers side valve cover bolt depending on what valve covers you have.

I'm also currently running 1.8 scorpion race series rockers on my intake valves. If you have the solid guideplates you will likely have to cut and weld them to get them in the right spot.
Thanks for the info. I may try the aluminum rockers. Just not sure that design would fit on my "stock looking" aluminum valve covers, as my stainless steel rockers do fit -with a small modification.

Did you say the 1.8 Scorpions are on your AFR 335's? And I do have adjustable guide plates. A must on a BBC. :D
Eric

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Re: Cold lash after 500 miles, yikes!

Post by prairiehotrodder » Mon Sep 09, 2019 2:50 pm

i have the 1.8 scorpion race rockers on the intake valves. Last winter when the heads were off i ground a little metal out of the inside of the guideplate because those rockers move the pushrod closer to the stud. I'm using the AFR 335 heads.
Brian
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