babbah

Changing rear main seal on friends 427 with 2 bolt mains. Its a 67. What is the main bolt cap torque in ft/lbs for 2 bolt rear main bearing cap bolts??

And same question for oil pump bolt?

Thanks Guys!

magicv8

torque chart link near the bottom of my web page at http://www.corvetteforum.net/classics/magicmachine

JohnZ

Main cap is 95, oil pump bolt is 65.

babbah

Thanks Guys!

rongold

Just remember, you have to follow a special procedure to align the rear thrust surface of the upper and lower bearing halves. Big Block rear main caps DO NOT have dowel pins to align the cap. Snug the bolts by hand, and then using a large screwdriver, push the crank rearwards to force the cap backwards. Then reverse the direction--force the crank forwards and while a second person holds the screwdriver (or if you are able to jam it without a second person) tighten the main cap bolts. This assures that the crank thrust flange will hit both halves of the bearing when you push on your clutch pedal. If you do not follow this procedure, it is possible that the crank thrust flange will only hit 1/2 of the bearing flange (upper OR lower)depending how far backward or forward the cap is.

RON

babbah

Hi Ron, The engine is in the car on a lift, just pulling the pan to clean pan and replace the rear main seal. I have done this many times before and never did any aligning, simply removed the oil pump and main cap, replaced the seal and repaced the main cap, oil pump and pan......fini...Since the crank has not been touched do I need to do what you are speaking of? Thanks!

rongold

I would think so, because if the lower half of the main bearing is let's say forward of the upper half, when you push on the clutch pedal the crank flange will ONLY be against the upper half of the bearing and will eventually burn it out. It's easy to align it even in the car. Just hand tighten the bolts, force the crank rearward to square up the cap, and then force it forward and tighten the bolts. I've done it--not that hard--one person can do it. Just jam a BIG screwdriver between the block webbing and a crank counterweight.

RON

babbah

It's unusual that the chassis manual says nothing of this procedure as well. When I do this the clutch is engaged in 1st gear, as always when I park it and on lift, so is this procedure really required? I have had my 67 since new and the engine is original and bearings are also, nothing has burned out........I ask cause this is the first I have ever heard of this so now I'm real curious....????? Also is it as easy as you say to "move the crank back and forward with a screwdriver with entire engine assembled in car??

Has anyone else ever heard of this procedure when replacing the main rear seal??

Joel 67

I know it is mentioned in the "How to Rebuild Big Block Chevy Engines" book



I'm not saying that book is the gospel but it does cover the basics.

babbah

Ill check it out

JohnZ

See the '67 Chassis Overhaul Manual, page 6-5, Assembly, item 1(f).

babbah

Thanks John!!
I have the chassis service manual - page 6-22 "Oil Seal" Rear Main, says nothing of the procedure above. What is the 67 Chassis Overhaul Manual? Where can I get that?

JohnZ

Many of the vendors have the Chassis Overhaul Manual, and it's also available from the NCRS on-line store at www.ncrs.org.

babbah

I bought it on CD, Thanks John - Procedure seems simple enough. Should I have the trans in neutral when doing this?

JohnZ

Doesn't matter which gear it's in - there's no pressure on the crank unless the clutch pedal is pushed down.