225 slant head torque
- Thread starter Thumpower
- Start date
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76Scamp
Well-Known Member
I've never had a slant six opened up like that, but for the Chevy engines I've worked on, I've never done anything to the head bolts. Always put in dry and torqued to spec. The 350 is just a run-around truck that gets driven maybe once or twice a week, the 4.3L, although a daily driven work truck that I have driven 250 miles a day a few times with 196K miles on it, generally gets beat like it owes me money and it has never let me down. I've heard it's a good thing to do it, but even though I haven't, it may be a good thing to do so just as a precaution. I've never opened up anything this old (yet) so I never really thought about it and everything that I've worked on is generally junk and it didn't matter if anything broke.
nm9stheham
Well-Known Member
All the older stock engines I ever worked on were to be torqued with dry threads. I only ran into lubed threads the first time I used ARP bolts.
BTW, my '62 FSM for the /6 says to torque to 65 ft-lbs in sequence. Then retorque by first loosening each bolt (does not say how much) and then torque it again to 65 ft-lbs, and do that in the same sequence for each bolt. That was in the days when the original steel shim head gakset was used. You may not need to to that with a newer composite head gasket. I would still re-torque after a few heat cycles since these are not torque-to-yield head bolts.
BTW, my '62 FSM for the /6 says to torque to 65 ft-lbs in sequence. Then retorque by first loosening each bolt (does not say how much) and then torque it again to 65 ft-lbs, and do that in the same sequence for each bolt. That was in the days when the original steel shim head gakset was used. You may not need to to that with a newer composite head gasket. I would still re-torque after a few heat cycles since these are not torque-to-yield head bolts.
moe7404
moe7404
my 1967 factory dart coronet manual. for slant six. says 65 ft lbs 9/16-14 thread. valve cover bolts 40 in lbs 1/4-20 thread.
BillGrissom
Well-Known Member
In my day job (aerospace), bolt torques are critical. I recall a study that found putting oil on the threads and under the bolt head does not change the tension you get at a given torque, but it does make it more reproducible. Thus, a little oil is good. Do not pour oil down the bolt holes or you risk "hydro-locking" and getting a wrong torque. Coating the threads with a high-pressure dry lubricant like molybdenum disulfide decreases the torque needed get the same tension by about half. Thus, don't grease the threads, especially w/ moly grease or you might yield the bolt trying to get the desired torque. Also smart to chase all the threads w/ a tap and blow out the holes. You can spray WD-40 down the holes if you blow most of the liquid out. You want to get rid of any rust.
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