Mains to tight?

[Drewster]

I've been trying to search the value but can't find and someone may know off hand.
I'm doing final assembly with a new internal balanced forged crank. I just installed crank and it seems to be difficult to get it to start to turn over by hand. Is there a "OK" turn over torque?
For now I'm guessing the moly paste I used is to blame and causing the drag.
The no rods installed yet just mains torqued down
My clearances are .002-.0025 and thrust is .006
Using M107 bearings. Rear seal installed.
What torque is ok. Like 5-10ft lbs?


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[gunzandgearz]

You should have just used a good quality engine oil on bearings, your clearance is good and you should be able to turn crank by hand its always a little tough to start by hand but you should still be able to. don't know about any paste on bearings but you shouldnt be having any issues turning .End play is good too so might try taking back apart ind using oil,by the way don't forget to offset your new neoprene rear seal so it wont leak.

 

[fastblackracing]

Things that I have learned over the years that make a difference between a successful rebuild and a not so successful one are paying attention to details like you are doing......when something seems wrong stop and find the issue, the crank is telling you something is wrong......you need to put a dial indicator on the cranks inboard main journals to measure run out.....TIR on a new crank should be very near zero and no more than .0005 imo, and you have to remove the center two main caps to do this...good assembly practice is to install the bearings without the rear seal and use a thin oil [5w 30] only on the bearings, then install the caps but only snug the caps down.....at this point the crank should spin very freely rotating on its own 1-2 revolutions after you give it a fast hand snap if that makes sense.....now at this point I would torque the thrust main to 20 ft lb after centering the thrust flanges......check for binding it should still be free....then torque another cap to 20....recheck then another cap to 20 and so on ...... up the torque 20 ft lb at a time until you reach your ending torque setting......if the crank starts to drag at any point you will have an idea where the issue is.......when torqued all the way down with no seal and a good clean oil coating on the bearings the crank should still spin freely......if not one or more of the following is wrong, crank has tir runout, line bore is off on the block, or you do not have the bearing clearance you think you have......this slower methodical checking will help you find issues......and just use a good heavy oil or something like lucas assembly lube at final assembly, the moly paste is more for bolt threads and camshaft lube.

 

[Chuck Leeper]

.and just use a good heavy oil or something like lucas assembly lube at final assembly, the moly paste is more for bolt threads and camshaft lube

^^^^^^^^^^
Also, excessive amts of moly paste can/will cause issues w/ oil flow thru the filter.

 

[toomanymodz]

I've used assembly lube during builds and the crank always can turn by hand. I'd measure crank runout, and I would check your line bore.

 

[gunzandgearz]

This is how I do it and I know there is more than one way to skin a cat so that being said when I start a new engine build very first thing I ALWAYS do is torque the main caps down with oil on the threads and under the head of bolt,also with no inserts {bearings} in the block.Start with the center cap first and work your way outboard,the last two caps to be tightened will be the #1 and thrust,and do this in three different torque steps. Now measure your clearances 90 degrees from parting line, if they are in tolerance we go to step two if not time to align hone.Step two as fastblack said time to check crank runout, how I learned to do this when I was building aircraft recip engines is to put crank in two v blocks, one at each end of crank one on frst main and the other on the last main most people don't have v blocks so just use your engine.Install the front main bearing in the block and the last main bearing in the block (thrust), oil bearing and set crank in block, use dial indicator on center main journal an check runout, if it checks good time for step three if not time to get crank straightend or new crank.Step three pull crank out install all the bearings, oil bearings set crank in engine with no rear main seal yet,I personally like to check my end play several different times and this is one of them

 

[gunzandgearz]

Sorry hit wrong button any way torque down rear main and check end play reading again if good now we can install rest of main caps and check for end play reading and that crank spins freely.If all is good up to this point we can pull crank out, install rear seal in block and cap and offset the seal about an eighth of an inch in other words don't install seal whereparting line of seal lines up with parting line of cap this will help cut down on leaks.Now for the final step a little oil on seal and beasrings install rear main cap torque down smack crank back and forth with deadblow hammer and check end play once more, if good install #1 cap and torque down check check end play if all good install rest of caps oil on threads and under head of bolt and one last time check end play if all is good your done.Now I know this is a lot of steps and some guys might do it a little differently, and that's fine but ive always had pretty good luck doing it this way, but if you get a sequence like this you will find that if your going to have a problem you will catch it before you get to the end and go where is my problem. good luck with your build.

 

[gunzandgearz]

By the way before some guys start hollering at me I want apologize for the Chevrolet in me because the rear main on most of the other gm engines I build the thrust is the rear main cap. just thought I should clear this up before I get thrown into the fire. Everything else still applies just remember the number 1 reason for post is get a sequence whether its mine or someone elses and follow it to a t on every build and youll come out ahead of the game.

 

[turbodave231]

Some tips I picked up from David Reher,

• Always check crank TIR before install
• Place the crank in the block with all the upper bearings in place.
• Set up dial indicator on the end of the crank
• Measure and record end play
• Install the caps and bearings
• Set the thrust bearing by tapping crank rearward and forward
• Torque thrust bearing cap
• Recheck endplay (if it changed, that bearing/journal has a problem)
• Rotate crank, is it OK? Yes....proceed!
• Torque remaining caps one at a time rechecking end play and rotation each time.

If you run into a problem, it was the last cap/bearing you tightened

 

[Drewster]

Thanks for all your input. Just to clarify I can turn it over by hand but it's tough to get it going.
I'll get rid of the paste and start over check in slower steps checking run out first


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[Steve V]

it's tough to get it going.



Drewster on Tapatalk

That's a no go right there. Check it out. You'll find it and be happy in the end.

 

[FASTV6HENRY]

So what happened? Did you clean the paste and apply assembly lube or oil? how does it spin now?

 

[Drewster]

It might be a month or so before I get to it. Just had ACL knee surgery and will have to stay off of it for a month.


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[steve hughes]

If everything checks out ok and you still have drag on the crank check that the edges of the bearings are not rubbing the radiuses on the crank.

 

[Mike Licht]

Set the thrust, I bet that will fix it

 

[Drewster]

[emoji106]


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