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Main Bearing Question

General engine tech -- Drag Racing to Circle Track

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earlymopar
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Main Bearing Question

Post by earlymopar » Sat Aug 01, 2020 7:47 am

In the process of checking my short block assembly over, I discovered an important soft plug was missing which forced me to remove the rear main cap. I got the plug installed and started to reassemble and noticed the pattern shown below. This is just from hand-rotating the crankshaft to check the cam dial-in. There is no depth to the wear mark / contact area but is this what you would expect from an engine that has been align-honed?
Main Bearing.jpg
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67satellite
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Re: Main Bearing Question

Post by 67satellite » Sat Aug 01, 2020 8:11 am

Not good. That and the missing plug would be enough for me to want to check-EVERYTHING- in the engine. Was it seated properly/completely in the block? Trash or a burr between bearing &cap? Here's one place a hunk of plastigauge might be helpful.

earlymopar
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Re: Main Bearing Question

Post by earlymopar » Sat Aug 01, 2020 8:14 am

Yes, This was found as I was in the process of checking over everything I asked them to do.

- EM

norm
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Re: Main Bearing Question

Post by norm » Sat Aug 01, 2020 8:34 am

The rear main seal ends appear to be sticking out quite a ways.

If the other half is sticking out that much also it might have caused distortion.

On BBF's at least, the crush on the rear main seal needs to be set on assembly

earlymopar
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Re: Main Bearing Question

Post by earlymopar » Sat Aug 01, 2020 10:38 am

Thanks Norm. The main seal is actually flush, it just looks proud in the picture.

BillK
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Re: Main Bearing Question

Post by BillK » Sat Aug 01, 2020 1:08 pm

What engine is it ? Which plug was missing ? I would take that bearing out and make sure there is not a piece of dirt under it. Also I would have to pull the crank and see if it was ground straight. Have you pulled any other caps to see what the other bearings look like ?
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earlymopar
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Re: Main Bearing Question

Post by earlymopar » Sat Aug 01, 2020 2:49 pm

Bill:

This is a Mopar small block "A" series and for the most part, the "A" and the later "LA" blocks are very similar. There is a soft plug under the rear main cap that if absent doesn't divert oil to the filter and also causes a serious lack of oil pressure. Hopefully the (blurry) picture gets the point across. I have not pulled any other caps. Yes, I've also wondered about the crank being re-ground correctly, the align hone being done at all or correctly if done, poor assembly practices, etc. I'm not happy.

- EM
Soft Plug under Rear Main.JPG
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pdq67
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Re: Main Bearing Question

Post by pdq67 » Sat Aug 01, 2020 3:09 pm

Who put together the short block?

I ask because my Buddy Doc's step sons rebuilt a little 6-banger 1st Gen. Mustang engine and the guy that did the cleaning, machine work, and checking, and stuff didn't give them back the cam hold-down plate and 2 bolts.

If I had not have been there and caught this, they would not have known that they needed this plate, put it together and toasted an engine.

I figure the guy was screwing them because he didn't get to charge for putting it back together for them.

I told then NOT to go back to him.

Another old, "pdq67", story!

Years and years ago, I took my old junkyard -461 big valve heads to a Machine Shop up in South Bend, IN to be rebuilt.

I told the guy that they were real, "fuelie", heads and he looked at me kind a strange and said, "Sure they are!!".

Anyway, I picked them up and he came over to me and sheepishly said, "You are right, they are real, "fuelie", heads"!!

pdq67

earlymopar
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Re: Main Bearing Question

Post by earlymopar » Sat Aug 01, 2020 4:12 pm

The same shop that did the machine work....

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Re: Main Bearing Question

Post by BillK » Sat Aug 01, 2020 4:45 pm

pdq67 wrote:
Sat Aug 01, 2020 3:09 pm
didn't give them back the cam hold-down plate and 2 bolts.

I figure the guy was screwing them because he didn't get to charge for putting it back together for them.
Paul,
I dont think that is very fair. I have had a bunch of parts in the tank and forgotten a small part like that before. Does that make me a crook ??? It was probably an honest mistake.
pdq67 wrote:
Sat Aug 01, 2020 3:09 pm
If I had not have been there and caught this, they would not have known that they needed this plate, put it together and toasted an engine.
Who disassembled the engine ?? Did they have a service manual like they should have had to reassemble it ?? Bottom line the person assembling the engine has the final responsibility to make sure it is done correctly, period.

I don't know of a single machine shop owner anywhere that would do this intentionally to "screw" a customer.
Bill Koustenis
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Waldorf Md

www.enginerepairshop.com

BillK
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Re: Main Bearing Question

Post by BillK » Sat Aug 01, 2020 4:54 pm

earlymopar wrote:
Sat Aug 01, 2020 2:49 pm
There is a soft plug under the rear main cap that if absent doesn't divert oil to the filter and also causes a serious lack of oil pressure.
Yeah, same as a small block Chevy but on those it doesnt affect oil pressure in any way. Just keeps the oil from getting filtered.

Not sure what to tell you about your bearing. Its going to be hard to really check it properly without taking the crank out.
Bill Koustenis
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Waldorf Md

www.enginerepairshop.com

earlymopar
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Re: Main Bearing Question

Post by earlymopar » Sat Aug 01, 2020 5:19 pm

Thanks for your replies fellas. I'm not going to take it any further myself but plan to call the owner of the shop on Monday and explain what I found and see what he says. I have the original list of parts I supplied to him and the machining process steps I requested when I dropped off my block and parts. I also have his receipt. It did bother me that his invoice didn't itemize things like my list did so at the time I should have pulled out my list to double confirm everything rather than assuming. My hope is that he'll stand behind his work like any reputable business would.

- EM

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Re: Main Bearing Question

Post by pdq67 » Sat Aug 01, 2020 6:21 pm

BillK wrote:
Sat Aug 01, 2020 4:45 pm
pdq67 wrote:
Sat Aug 01, 2020 3:09 pm
didn't give them back the cam hold-down plate and 2 bolts.

I figure the guy was screwing them because he didn't get to charge for putting it back together for them.
Paul,
I dont think that is very fair. I have had a bunch of parts in the tank and forgotten a small part like that before. Does that make me a crook ??? It was probably an honest mistake.
pdq67 wrote:
Sat Aug 01, 2020 3:09 pm
If I had not have been there and caught this, they would not have known that they needed this plate, put it together and toasted an engine.
Who disassembled the engine ?? Did they have a service manual like they should have had to reassemble it ?? Bottom line the person assembling the engine has the final responsibility to make sure it is done correctly, period.

I don't know of a single machine shop owner anywhere that would do this intentionally to "screw" a customer.
The boys said that when they asked him for the parts, he went over and pulled them off a shelf. He knew just exactly where they were!

Take it for what you think it is?

pdq67

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Re: Main Bearing Question

Post by racear2865 » Sat Aug 01, 2020 6:26 pm

Just my two cents worth from the casual observation. If there was no crap under the bearing and the line hone is good, then you must check the crankshaft for size. That marks indicates less than zero clearance at that point. So u got a big problem
reed

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Re: Main Bearing Question

Post by BillK » Sat Aug 01, 2020 6:44 pm

pdq67 wrote:
Sat Aug 01, 2020 6:21 pm

The boys said that when they asked him for the parts, he went over and pulled them off a shelf. He knew just exactly where they were!

Take it for what you think it is?

pdq67
And I have done exactly the same thing. I have a shelf that I put cleaned parts on in boxes with customers names on them. I have simply forgotten to give somebody one of the boxes. Usually happens when five people come in at the same time to pick stuff up and you simply forget. Usually notice it the next day or when the customer calls looking for it. But I suppose you have never forgotten anything ??

Sorry, I simply cannot believe that someone would do it on purpose and like I said before it is the engine builders responsibility to know what they are doing and check everything.
Bill Koustenis
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Waldorf Md

www.enginerepairshop.com

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