Billet Main Cap Torque?

mtocrs1

Mtocrs1
If an engine has billet main caps with studs is the torque value different?
I need to replace the rear main seal on this engine and it has a billet rear main cap.
Engine builder is unknown so I can't ask what torque was used during the line bore process. What do you guys think?
048457588da4ce9f8afb01bb95051dc5.jpg



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Ttype6

Well-Known Member
The only way to be sure is to remove the crank and install the main caps and bearings and measure with a bore gauge then measure the main journals of the crank to see what the clearances are.
 

mtocrs1

Mtocrs1
The only way to be sure is to remove the crank and install the main caps and bearings and measure with a bore gauge then measure the main journals of the crank to see what the clearances are.

And your saying tighten to 100lb-ft measure and then try at 110 etc?


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Ttype6

Well-Known Member
I would think the fastener would dictate the torque value.
The mains were torqued to a certain value from 85 to 120,then it was honed. If it was honed at 85 and he wants 120,it might tighten the bearing clearances to much at 120.
 

Ttype6

Well-Known Member
The studs can handle 120. If you have good clearance at 120 you should do it to take advantage of the extra clamping force.
 

ek02

Well-Known Member
ARP specs call for 110 ft. lbs. using their Ultra Torque lube and 95 ft. lbs. with their no longer available moly lube, or 130 ft. lbs. with 30 wt motor oil. Kind of hard to tell what was used originally. Removing the crank to check the main bores at different torque settings would be the correct way. 120 would be a good compromise if you are not measuring the bores since it looks like motor oil on the nuts and washers in the photo.
 

mtocrs1

Mtocrs1
Before I removed the nuts I marked them with a paint pen and in increments of 5 ft/lbs tightened them. First movement was 110 on my torque wrench.
Amazingly enough the threads under the nuts and contact areas of the washer still had whatever grey lube was used.
Right or wrong this is why I chose 105.
As always, thanks for the feedback.


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Ttype6

Well-Known Member
Before I removed the nuts I marked them with a paint pen and in increments of 5 ft/lbs tightened them. First movement was 110 on my torque wrench.
Amazingly enough the threads under the nuts and contact areas of the washer still had whatever grey lube was used.
Right or wrong this is why I chose 105.
As always, thanks for the feedback.


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You're guessing,so there was no need to ask for advise. You're just as comfortable doing it wrong as you are doing it right. You'll very likely be OK,but your caps will have a greater chance of moving around with less clamping force.
 

Ttype6

Well-Known Member
Since your nuts have the grey goo on them,it's logical to assume that they were torqued to at least 110 because that is what ARP recommends.
 

mtocrs1

Mtocrs1
You're guessing,so there was no need to ask for advise. You're just as comfortable doing it wrong as you are doing it right. You'll very likely be OK,but your caps will have a greater chance of moving around with less clamping force.

There was plenty of reason to ask for advise i just chose not to use yours. I appreciate you providing your advice but in the end I researched more and chose to do what I did.


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mtocrs1

Mtocrs1
There was plenty of reason to ask for advise i just chose not to use yours. I appreciate you providing your advice but in the end I researched more and chose to do what I did.


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But again I do appreciate it, that didn't sound the way I thought it would after I posted it.


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Ttype6

Well-Known Member
There was plenty of reason to ask for advise i just chose not to use yours. I appreciate you providing your advice but in the end I researched more and chose to do what I did.


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I understand that you don't want to disassemble. Since you want to guess,I think 110 is a better guess since that is what ARP recommends. You'll be fine either way.
 

mtocrs1

Mtocrs1
I understand that you don't want to disassemble. Since you want to guess,I think 110 is a better guess since that is what ARP recommends. You'll be fine either way.

That is correct, I don't want to disassemble. I'll go to 110.
This will probably come back to bite me anyway. The cap was really stubborn going back in. I'm sure something is jacked up...
If it doesn't leak I'll be amazed.


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