VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 torque specs

I need torque specs for rods and main bearings on 8-6-30 -835501 and is .002 proper clearance on both

Try these values it is best to use the lower value if original bolts as they are soft and can be streeeaaached. If when applying torque the resistance does not continue to get greater STOP! You are streaching the bolt and it will break with more force.

Piston pin bolt, torque 25 - 30 ft-lbs.

Main bearing, torque 75 - 80 ft-lbs.
Rod bearing, torque 25 - 35 ft-lbs.
Oil pan bolts (corner), torque 12 1/2 - 15 ft-lbs.
(flange) 6 - 7 1/2 ft-lbs. Timing gear cover torque 6 - 8 ft-lbs.

Cylinder head bolt torque 60 - 70 ft-lbs.
Rocker arm bolt torque 25 - 30 ft-lbs.
Spark plug torque 20 - 25 ft-lbs.

Flywheel bolt torque 50 - 60 ft-lbs.

thanks so much Chipper-tried finding everywhere even advanced search-may have approached 40 ft.lb on couple of rods to get cotter pins in-hope I'm ok-didn,t feel like they were streching-even tried backing off to previous hole but didn,t seem tight enough-using plastiguage and getting .oo2 on rods-will do mains today-as I value your knowledge any clearance info will be greatly appreciated-was going to replace oil pump (that I can't afford)but did search and noted that you've had no problem with vane type-project is getting expensive but don't want to cut corners in wrong places as this will be my daily driver

Use the procedure in the repair manual to set the tolerance on rod and main bearings. Yes a properly operating vane pump is more than enought oil.

.002" on the rods is too loose.

As JYD said, .002 is too loose. Factory setting is a half of one thousands. I think thats typed as .0015

At .002" your rods will knock like a Woodpecker.

.0015 is one and one half thousand (aka 15 ten-thousands). .0005 is one half of one thousand, or 5 ten-thousands.

are babbit rods held to much tighter specs than inserts?

On modern engines GM specifies production 6 cyl clearances of rods to be .001 - .0026.

.0005 seems awfully tight for a good oil film to be present

Yep.

For the 194 cubic inch engine, the rods should be from .0005" to .001".

that goes against everything I've been taught or studied. .0015 being the minimum for proper oil film retention. I would think .0005 would be just asking to smear the babbit, especially on a non pressure feed.

If the rods are set at .0015" to .002" they will knock. Been there and done that. I have even experienced mains knocking at .002".

As a side note, the 1932 Chevrolet Repair Manual states that "connecting rod bearings should be burnished so that rod may be tapped slightly back and forth with a peen end of a light machine hammer."

Another source states to use an 8 ounce hammer. Yet, another shop manual states that if the rod can be moved by hand it is too loose.

And, finally, a 1931-36 Chevrolet shop manual that I have states that "no perceptible clearance is required with the dip or splash type of lubrication system used on these models."

Thats right. Thanks for that correction!

seems like I started quite a controversy here-I took Chippers advice and put plastigage aside and followed 80yr old book and lo and behold although gage said I had clearance I couldn,t turn crank or move back and forth-reinstalled 1 shim of 2 and still tight so installed remaining shim and now seems ok-don't understand-was plastigage not for use on babbit bearings and how are you determining clearances-with micrometers?-one tool I don't have is inside mic.-seems like it would take guessing out of equation and also tell out of round-bearings look like they have a ton of "meat" left with deep oil grooves but most shims are gone so I can't do as book says-really don't know what to do-running out of funds but don't want to "shelve" project as it's the dream that keeps me going-any future advise will be greatly appreciated

Seems strange becouse plasti-guage has been used succesfully for years without a problem. Not to depress you and you say you are running low on funds (trust me i've been there before) So i have an idea what your feeling, but if plasti-guage is not working for you then your crank MIGHT not be true if your using proper torque.

I have always plasti-guaged cranks in atleast two difirent spots in 4 diferent positions. Just guaging in one spot in one or two positions will give false reading making the plasti-guage look defective as a method of finding clearance but usually thats operator or crank faulty-ness there.

Again, always check the crank in two spots of the crank pin, one to the left and one two the right, and in four positions of the crank, one check at the 9:00 12:00 3:00 and 6:00 position. Upon torquing the cap down with plasti-guage, DO-NOT move the crank or rod as the plasti-guage will smudge and that will give false reading.

I agree and thats why I'm confused as I've used plastigage for over 30yrs but only checked in 2 places-I'll try four and see what happens-if I have to I'll pull crank and measure journals and bores and if results aren't good I'll have to reconsider entire project but being disabled this is a dream I've wanted to enjoy before I move on-thanks for responding