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Head torque


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There were no torque specs for any engine prior to about 1938 (the commercialization of the torque wrench). The 1939 Studebaker shop manual for the 250 cu in straight 8 says 1000 in-lb (62.5 ft-lb), but they were using 1/2-13 studs/bolts by then. Yours are probably 7/16-14. About 40-50 ft-lbs for lubricated threads should be about right for 7/16", about 50-55 ft-lbs for dry threads. This is the value for studs/bolts of about Grade 5 quality. The 1939 shop manual says to tighten the head bolts, drive 500 miles, and re-tighten.

The 167032 head was probably 4.5-5:1 compression, 168022 head was 5.5:1 compression, the 168411 head was 6.5:1, so you don't need to go overboard on bolt torque. Err on the low side.

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What Gary says. Go down to TomB's post here regarding main bearing torque specs and read my response. That old time mechanic never used a torque wrench even on engines that had torque specs available (late 1960's). He challenged me one day to put a torque wrench on a Chev 265 after he had just installed the cylinder heads. Using a dial type torque wrench, he was within 3-5 pounds on all of them! I have always remembered that. As a 20 year old and new owner of my 27 Dictator, I spent a considerable amount of time in his back alley shop between 1966-70. What he could do with the minimum of equipment blew me away.

We moved from the area in 1970 and I have often wondered what happened to old Ernie. He was in his 80's at that time.

Terry

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Guest frshcatch

That is very useful information. I have to soon install a '29 Commander head. I have found a source for an aluminum head, but it is expensive. Does anyone know where there might be a salvaged head or an OEM head?

I was wondering if there is a particular order in which you tighten the bolts. I may be installing an aluminum head and don't want to break it. Also, it looks like the original head bolts were securing the head. What do forum members recommend regarding replacement of bolts, type of bolts, helicoils, preparation of bolt holes, use of lubricants or locking agents, etc.?

Thanks,

H.B.

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That is very useful information. I have to soon install a '29 Commander head. I have found a source for an aluminum head, but it is expensive. Does anyone know where there might be a salvaged head or an OEM head?

I was wondering if there is a particular order in which you tighten the bolts. I may be installing an aluminum head and don't want to break it. Also, it looks like the original head bolts were securing the head. What do forum members recommend regarding replacement of bolts, type of bolts, helicoils, preparation of bolt holes, use of lubricants or locking agents, etc.?

Thanks,

H.B.

Here are some of the procedures/sequences to tighten head bolts/nuts....click on the image a few times to enlarge.

post-37352-143142794193_thumb.jpg

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