ohiovet

My Motors Manual calls out the main bearing cap torque to be from 60 to 70 ft pounds. Engine is a 64 327 250 HP PG.
Can someone please confirm this?
Thanks,
Bruce B

ILBMF

I've seen the mains listed anywhere from 65 to 75 ft lbs. I would do it in steps like 30, then 50, then 70 or 75

ILBMF

And make sure to run a tap into the block on each hole and add engine oil to the threads of the bolts.

1restoman1

My 1965 Chevrolet service manual also states 60-70 ft. lbs.

63split63

I would not run a tap in any bolt holes unless there is a problem with the thread . A tap will cut metal out and loosen the thread .
JMO Bill

ILBMF

I'll have to respectfully disagree.

63split63

No problem .

Bill32

Yep, I NEVER use a tap unless I'm cutting new threads, especially on the race motors.

However, every hole in the block has a thread chaser run thru it and is cleaned and blown out with air.

Thread chasers will straighten out slightly bent threads, taps will usually screw them up.

A decent set of thread chasers runs about fifty bucks, you'll be surprised how often you use them.

Dr L-88

100%

ILBMF

I do agree a thread chaser is a better choice. Most people don't have them, but a better choice. Ultimately, if you can take the bolt and run it in by hand to it's limit without effort you're good to go...just oil the bolt threads. I recently assembled a modular Ford aluminum V8 stroker engine and needed to install ARP head studs and did not have a long metric thread chaser and didn't hesitate to run a long tap. I remember distinctly feeling a burr in one hole and just being glad I had the tap.

Westlotorn

And just as important as putting oil on the bolt threads a drop on the underside of the bolt head is necessary also.
I have an old Federal-Mogul Engine Bearing catalog from the 80's. These were the bearing bible for engine builders for years.
It says
Rods 30-35 ft pounds
Mains 60-70 ft pounds
Head Bolts 60-70 ft pounds
Boy, things were simple back then.

tbarb

From my memory the rod bolts for the 327 small journal crankshaft has a 11/32 bolt and I believe the torque is 20-25ftlbs. The 30-35 spec is for the later rods with 3/8 bolts.

DUB

And I ASSUME that those here KNOW that when using an oil on the threads of a bolt...depending on its grade...DOES effect the torque. Which is why in many factory service manuals you may see that when the wheel is being put back on a the car they specifically write: 'DRY threads'.

http://www.engineeringtoolbox.com/to...ts-d_1693.html

http://www.enerpac.com/en-us/torque-tightening

DUB