How to torque head bolts G148B (480B)

RC Brooks · Oct 27, 2013

I've got a 480B with the gas motor. I haven't pulled this motor apart before. How do you torque the distributor side head bolts that sit under the top lip of the head? A very cumbersome setup to say the least. I'd rather not use a u-joint as it can do funny stuff to torque settings.

Thanks for any advice!

-RC

Joe (Wa) · Oct 27, 2013

The original tool was an offset extension (pic). Note that the offset on both ends is the same length so there is no leverage to screw up the torque as would be the case using a universal.

This extension fits the G148 engine (and others) that was superseded by the G148B, 1/2" drive x 11/16" box end. Snap-on p/n S8663B, I don"t think they are available anymore from Snap-on.

George Md posted a pic of some torque extensions made up of welded wrench pieces awhile back that would work just fine. The key is to get the offset on both ends the same length for an accurate torque.

Joe

Alan K · Oct 28, 2013

Im looking for that style wrench for the MM heads in 15/16" size....

Joe (Wa) · Oct 28, 2013

This is George Md"s pic from the archives.

Joe

RC Brooks · Oct 28, 2013

Just as a piece of information to add here, I did discover that if while using a crows foot, you keep the wrench at a 90 degree angle to the crows foot you will not need to compensate. I should have realized that, but still... I may try to fab one up. It"ll be a few days before the new gasket comes in anyhow.

Joe (Wa) · Oct 28, 2013

RC, that is not true. The distance from the center of the crowsfoot square drive to the center of the fastener is lateral leverage and must be compensated with an equal distance offset at the center of the drive on the torque wrench.

On a vertical fastener the center of the torque wrench drive must be perfectly perpendicular to the center of the fastener for accurate torque.

If you want to use the crowsfoot w/o an equal offset you need to calculate the leverage. There are several sites that have basic calculations for that, do a goggle search.

Joe

RC Brooks · Oct 28, 2013

Yes, now maybe I read wrong, but what many of those sites said was that by turning it 90 degrees (making an L out of the crows foot), you are keeping "L" (Lever Arm) the same for purposes of torque calculation. So rather than adding "x" number of inches to the lever arm, by turning it 90 degrees, you're adding 0 inches to the centerline of the lever arm.

But, I could be misreading/misunderstanding and quite possible that the sites could be mistaken.

Joe (Wa) · Oct 29, 2013

Ok RC, I am going to have to eat some crow on having the crowfoot at 90 degs.

Here is a site that proves you are right by using the calculator.

I am old but I can still learn if you beat on my head hard enough.

Joe
Crowfoot torque

RC Brooks · Oct 29, 2013

OK, well I value experience more than I do websites. The physics of it I understand, but there are always things I may leave out, so I appreciate corrections as needed.

How to torque head bolts G148B (480B)

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