Think I over torqued the rod bearing caps

[SmokeyGST]

Well the engine rebuild started off smoothly everything came apart quick. and then got hung up on the head being the wrong one. I turned the crank around and it gave alot of resistance. I figure this is just because the walls have no oil and the rings are brand new. I got to turn the crank again 2 days later and it won't move, so i think oh no its siezed? so i loosen the rod caps so i can take the pistons out and when they are all lose i try to turn the crank again to see if the crank will move away enough to hammer the piston when suddenly it turns somewhat freely(no where near as free as before the pistons came out) Now i am figuring that the rod caps were over torqued and kept the crank from moving which seems pretty correct. THe chiltons said exact print "1990-1994(plus and additional 1/4 turn) 14.5ft/lbs
What that means to me is the torque wrench clicks and then i turn another 90 degrees, so this is what i did. I know have a rather large inkling that i have severely overtorqued the rod bearing caps, and would like some opinions on how bad what i have just done really is?

Cliff notes: Chiltons book told me to torque rod caps to around 75ft. lbs. Mayhem ensues.

 

[Cesar]

1992 Eagle Talon Chrysler repair manual.

Connecting rod bearing cap. 50-53NM or 37-38Ft-lbs.

Seems like you went quite a bit over. I don't think this would cause it to seize. I don't think it's the end of the world, you didn't say you ran the motor like that did you?

Disassemble it and recheck all clearances...Assembly lube is a must. The crank should easily rotate with no head on.

 

[SmokeyGST]

Well i just wondering if i had to replace the bearings themselves kinda worried they could be crushed.

 

[OverboostXS]

I talked to SBR and Eagle INC. for my 7 bolt it was 52lbs arp bolts federal mogul bearings. I can't see the 6 bolt being drastically different.

 

[half-cocked]

Are you using stock rod bolts? ARP rod bolts, which I was under the inpressing are the rebuild standard, are torqued to 40 ft/lbs.

 

[SmokeyGST]

yes just reusing the stock ones.

 

[Batty200]

yes just reusing the stock ones.

Order new bolts since they are prob fatiqued and then just torque them properly. Also you did keep each rod cap with each rod correct? I once mixed two up and the motor wouldnt turn when I torqued the rods and I swapped them back and it was fine.


Later

 

[86MCSS]

Assembley lube is our friend

 

[VR-4Galant767]

I use Lucas for all my rebuilds. Its really thick and sticky, apply liberally.

 

[gimmie11s]

you have some rod caps misplaced on the wrong rods.


it is crucial that they are reassembled with EXACTLY the same rod as they came apart with.

 

[92tealTSI]

If you torqued them to 75 ft/lbs, then order some ARP rod bolts and new rod bearings then torque them to what ever the ARP sheet says and you will be fine.

 

[jetdriven]

If you change the rod bolts you must have the big end of the rods resized. No way around that. Number stamp them so when you get them back they are matched.

 

[myblack98gst]

I recently had this same problem while helping a friend rebuild his starion motor. we were using federal Mogul bearings. standard size. put one rod on toqued it down, you couldn't budge the crank.. loosen the rods it turned free.

We called the parts house and gave them the part number they said they are standard size. the back of the bearing was marked .050 std. I busted out the caliber they measured .070!!!!

WTF. the bearing were stamped boxed and everything else as standards when they were .020 oversized.. this woul dhave caused SERIOUS issues if I hadn't tried turning it and we just finished assembling and installed.

so from now on I measure the thickness of the bearings before I install them

 

[espinelli]

On a 2G w/ stock rods and bolts, it should be 14.5lbs then a 90-100* turn, you'll need to lube things up with motor oil.

I used ARPs on my rebuild w/ federal mogul rod bearings and the torque specs by ARP are 43lbs w/Moly Lube. I'm pretty sure there is a different torque setting when using 30 weight oil vs. moly lube.

 

[1fast97gsx]

On a 2G w/ stock rods and bolts, it should be 14.5lbs then a 90-100* turn, you'll need to lube things up with motor oil.

I used ARPs on my rebuild w/ federal mogul rod bearings and the torque specs by ARP are 43lbs w/Moly Lube. I'm pretty sure there is a different torque setting when using 30 weight oil vs. moly lube.

yea 43 with the arp lube is correct ... with oil its usually more however I do not have the exact number in front of me.

 

[Jankenshank]

sorry about the zombie thread......

but im in the same boat....
after i torque the main caps the crank wont budge! this is the second time i have assembled it, and i seem to remember being able to turn the crank on the first build...
i torque each cap separately from center out(snugging the bolts first), 18ftlbs then 90'(quarter turn)

i have plasti-guage'd top and bottom of the bearing's four times and got .002" on all five journals.


i completely confused, please enlighten me....is it just my imagination?

 

[4g64fiero]

Are you using assembly lube?

 

[Jankenshank]

a crap ton of it.....

wiseman?

 

[Jankenshank]

can anyone with experience please point me in the right direction!

im ready to put this together but i don't want to backtrack!

some input please?

 

[slowgsr]

may need a linehone.

 

[Jankenshank]

but do i have the right torque specs?

and is the crank meant to move when torqued down?

 

[slowgsr]

Yes the crank must turn, It will turn over easily.

I used ARP's there not torqued to yield. This is why you do that 1/4 turn extra. Im unsure of the exact spec's, however, from what you are using im am certain, that the spec's won't cause any issues with the crank not turning.

Something may be distorted. I suggest you take the block/crank, caps.. bearings etc to a trusted local machine shop and ask them to diagnose the problem. (get a written quote first!).

Goodluck, sorry I can't be of more help.

 

[Jankenshank]

Yes the crank must turn, It will turn over easily.

this is what i needed to hear, confirms my thought that my crank did in fact turn last time, thanks gsr.

im going to do a physical check one more time......
snug each cap, then torque each cap independently correct?

 

[donniekak]

With the main caps torqued to spec, and assembly lube on the bearings, with no rods bolted to the crank the cranks should turn really easy. If not, the bearings are the wrong size, the main bores are not straight from a warped block, or mismatched caps, or the crank is bent.

 

[Jankenshank]

With the main caps torqued to spec, and assembly lube on the bearings, with no rods bolted to the crank the cranks should turn really easy. If not, the bearings are the wrong size, the main bores are not straight from a warped block, or mismatched caps, or the crank is bent.

i sure hope its not a bent crank, its bloody brand new, only got 7miles on it.