Torquing ALUMINUM cylinder heads.....

[Spitfire8]

Hello all: I'm curious what final torque values are used on ALUMINUM cylinder heads from 1930s-era vehicles. I realize there may be some variation among different makes, but am wondering what final values have proved successful.

I have a '36 Studebaker President with aluminum head, and there is no shop manual information on this topic. A period Motors Manual says "83 lbs." which I feel is WAY too tight for this motor. So I'm hoping to get a general sense for final torque values from those who have successfully torqued other makes' aluminum heads from this time period.

Thanks in advance for any wisdom here. Bill.

[JACK M]

I would think that there should be some flat washers under the bolt heads. The torque value would be determined by the bolt size.

[c49er]

Probably fine thread studs and washers were used back in the 30's- not course thread head bolts. So that means less torque used with fine thread studs and nuts. Maybe around 50-55lbs of torque if thats the case.

[Curti]

I restore 1934-1936 Auburns which have aluminum cylinder heads. The head gaskets are copper 'crush'. It is recommended to never torque the head more than 50 pounds I do it in 3 steps . Yes there needs to be a washer under the bolt head. torqueing greater than 50 will result in two things:

The gasket will fail.

The head bolt will spin in the block.

[Spitfire8]

Thanks to those who responded. I've decided to max at 45 lbs., torqued in 5 lb. intervals, to hopefully avoid stressing the aluminum. After the first several short drives, I'll retorque each time, when cold, again to 45 lbs. With a newly-decked block and surfaced head, I also decided to not apply any coatings on the copper gasket. I want that copper to "bite" into the adjoining metals without any compound in between. We'll see how it goes!

[Gary_Ash]

I bought a set of engine gaskets for a 1937 President block with aluminum head from Sandy Olson at Olson's Gaskets when we were at the Studebaker International Meet in Colorado Springs this past summer. Sandy provided a copper gasket for the head. He said to paint it with aluminum paint before installing it so that it doesn't stick to the head permanently. Torque in 50-60 lb-ft range sounds right. Torque wrenches weren't commercially available before 1938, hence no specs in the manuals.