I am to the point of installing my "Z" head and can't remember for the life of me what to the head bolt torque specs are!
How many ft-lbs should I torque the head bolts down too?
I think if I remember right it says in the box your head came in 45-50 lbs.
That is what I thought....but I wasn't sure.
...45, 50 lbs just sounds low though. I would think it was more like 65 lbs, but that is why I am asking..
I use 50 to 55 for both flat heads and overhead valve heads. Works for me. I haven't stripped the threads in the process nor had any leaks. I do make sure the head and block surfaces are clean and flat.
I just put a Z head on. Pete Zajicek's Documentation calls for 45-50 lb-ft, I went to 50. It also says to use a copper gasket with copper coat. Also with the aluminum to head run 50% antifreeze. And as I have learned, from the forum don't use the long life antifreeze, use the green stuff. I guessed right when I put mine together and used the old style formula before the posts on the forum.
Walt,
That sounds right...50 lbs it is! The head and block are flat for sure, so we shouldn't have a problem there.
John,
I am doing the same, copper coat and all. I have never used the "long life" stuff either...just the good old green stuff
I decked my block and with the new head at 50 and a couple of runs on it it started to leak I think ???I had remembered many times to retorque the head but never did it. I drove it home very easy let it cool and retorqued it and added a few drops of dish soap and it is doing fine now.
Guys - I've heard 50 ft lbs max too, but in regard to the very real possibility of stripping the threads out of the engine block, I've heard that the earlier blocks are much more suceptible to this than the later blocks. Specific years of the earlier engine blocks to be most careful ref max torque is what I'm not sure of. Maybe just the later "improved" Model T blocks are the tougher ones least likely for the threads to strip out, but again, I'm not sure. (???)
If you are going to torque MORE than 45 -50 ft/lbs be sure to invest in some heli-coils and the installation kit to put them in. You will have them on hand when you need them. Also learn how to remove the broken head bolt when it is below the surface of the block.
Clayton,
Be sure to retorque the head after 10 - 20 miles. You'll find they've settled in at about 35 ft-lbs. Failure to retorque will result in a leak and ruined head gasket. I'm a slow learner, it's happened to me twice.
I lucked out and didn't waste my gasket.
I would recomend a few cooldown cycles then retorque again before your big trip yo lucky dog
Jerry,
A very good point, however it is not something I would forget I did that the last time and that the bolts did settle in at about 35 lbs as you mentioned.
Never had my "Z" head loosen up on me.
Reading this whole thread has prompted a question or two; I suppose some internet or other research could produce answers to my dumb questions, but then I'm curious as to specifically Model guys opinions:
I certainly believe that head bolts should be retorqued after the first couple heating/cooling cycles on a newly installed head.
My question is, should that be done on a cold engine, or hot? Or, maybe retorque hot immediately after a run, and then retorque again when the engine has cooled down?
Overkill,......(???)
Re-torque should be done on a cold engine.
Thanks John.....guess I should have known that, but then if I ever did know, it's one of many things I seem to be forgetting due to what I'll call,.....ahhhh,....."advancing age"!
I bring engines up to operating temperature two separate times, re-torqueing to 47-50 lbs. after each complete cool down.
Did you get your engine placed in yet, Harold ?
Seems like my sore shoulder has gotten about as good as it's going to get Steve, so I'm going to tackle that job starting in the morning.
1926 blocks strip just as easily as early ones in my experience. i've even stripped helicoils out of the block...