head retorque after 1st start

My opinion is wait until cool - that's how I always retorque.

On a re-torque where the bolts haven't worked loose it's not that important to follow the torque sequence UNLESS you loosen all bolts then torque back down. If all the bolts are already relatively tight it's safe to loosen then re-torque one at a time in any sequence. One or two slightly loose bolts won't warp the head. When you're doing a routine re-torque on one of these (should do it every other year at a minimum, or every time the valve cover is off for adjusting the valves) just loosen and tighten each bolt one at a time. The TSM says to check torque every 8K miles, but I've been able to run 12-14K miles with no problems. I just wouldn't push it past 15K. If you do have problems the head warps and usually cracks due to their age, and good ones are hard to find now.


Edited by farna - Jun/23/2011 at 10:51am

I didnt know there was a re-tork maintanace interval for the early 196, is that the aluminum block?

YES -- the re-torque interval is in the TSM and the early owners manuals (pre 63, might be pre 63... I know all the tune-up and maintenance info is in the 61 and earlier American owners manuals. The TSM says to "check head bolt torque" at 8K intervals. The only way to check is to loosen and re-torque as far as I know. I suppose you could put a wrench on the bolt and "check" without loosening, but may as well loosen then torque it back down.The bolt could be stuck, which would give a false torque reading.

THIS IS ESPECIALLY IMPORTANT FOR THE ALUMINUM ENGINE!! The tops of the cylinder walls are only supported by contact with the head in the AL block. The liners are firmly anchored at the bottom (cast into place) and are siamesed, but are more likely to shift when the engine blows a head gasket due to overheating because of loose head bolts. The head design is identical to the cast iron block head, just a bit wider for the AL engine. The head bolts loosen over time because the rather massive head expands and contracts by about 0.020" every heat/cooling cycle (every time it's fully warmed up then cools down to ambient temperature). It can expand and contract up to half that much just with regular weather changes. I've run the CI block engine as much as 15K miles between re-torques, but more commonly ran it 10-12K (averaged 5-6K a year, re-torqued every other year). I re-torqued it and adjusted valves every other year regardless of miles put on, but it was a daily driver at the time, with some "rest" when I was able to ride my motorcycle to work and for errands. I put 5-6K on the car AND 5-6K on the bike every year in my younger days, no need to drive so much anymore (I was military away from home, that included a couple trips back home most years, and a long distance trip to an AMC car show). If the car is only a fair weather hobby car, you can probably go 3-4 years between re-torques and valve adjustments, but keep a record so you don't forget, and don't go over 10K miles. Like I said, normal temp changes will expand/contract the head just a little.




Edited by farna - Jun/27/2011 at 8:56am

I always torqued mine cold. The bolts do expand slightly hot, but not enough to make much difference. Never had a problem over 14 years of driving. I bet modern torque wrenches are more accurate too, which makes a difference.

I went back and edited my post... I somehow overlooked the Tune-Up section in the early TSMs. I don't mind being corrected, everyone makes mistakes, but I don't want to accidentally mislead anyone.


Edited by farna - Jun/27/2011 at 8:57am