torque specs for cyl head

I am finally getting back to my DK8 project and I need to know the cylinder head torque specs. The engine runs fine, but I need to re-tighten the head. I knew the number of foot pounds once upon a time.....but that was then, and this is now.

Larry

Larry...I'm about to put the head back on my '32 DL and I was going to use 60-65 ft-lbs...which is what's spec'd for the '28-'32 Plymouth. I'm assuming that's close enough for both of ours, but if someone has different info, I hope they'll chime in for both of us.

Thanks Phil. I kept thinking it might be 85 ft-lbs, I don't want to overstress or break anything!. I'll use 65, it should be at least that much i'd think.

Larry

Larry...I'm about to put the head back on my '32 DL and I was going to use 60-65 ft-lbs...which is what's spec'd for the '28-'32 Plymouth. I'm assuming that's close enough for both of ours, but if someone has different info, I hope they'll chime in for both of us.

Hi Larry,

My Family have a 30' DeSoto CF8 sedan, previously we have over tightened the head studs and stripped the studs out of the block! I believe we were around 90 lb ft when they stripped. Heli-coiling the block was a very unpleasant experience.

Currently we have ours down at about 55-60lb ft. I have previously had a very small amount of water climbing the studs which I solved using Irontite / chemi weld with great success.

Cheers

Stewart

Larry...I'm about to put the head back on my '32 DL and I was going to use 60-65 ft-lbs...which is what's spec'd for the '28-'32 Plymouth. I'm assuming that's close enough for both of ours, but if someone has different info, I hope they'll chime in for both of us.

Where did you find the specs for the four cylinder Plymouths? All the stuff that early that I've found don't mention torque values at all just things like "first run all the nuts down snug with a speed wrench. Next, tighten them fairly snug with a head nut wrench in the same order and finally go over them a third time drawing them down securely."

For what it is worth, the early Plymouth L-6 engines specified 55 to 60 ft. lbs. for stud nuts. When they went to head bolts that changed to 65 to 70 ft. lbs. Don't know if that would be the correct value for the Dodge in question.

We have Often worked from a 52 Plymouth service manual. The engineering didn't change a huge amount between 1929 and the 1950's.

Also just as a side note, my car is studs and has nuts.

Cheers

Stewart

Where did you find the specs for the four cylinder Plymouths?

I was looking for just the same thing this morning.

It is the system I used just expanded out for an 8 cylinder.

OK, thanks to each and everyone who took the time to respond. I will follow the 60-65 lb recommendation, all my studs are new, but I don't want to risk tearing the engine down. I will be following the tightening sequence for an 8 cyl. 1930's Chrysler.

Larry

No worries mate,

If god forbid the worst happens and you do bust a stud out of the block, shoot me a PM and I will give you all the details on how we fixed it, you can do it with the engine in the car.

You can probably check maximum tensions based on recommend torque for the size and metal grade of the studs and nuts or bolts you are using. If using cap nuts and they bottom, you might break the stud before reaching the desired torque.

I expect your studs are similar in size to Stooy's CF8 studs. They stripped at 90 lb.ft. So you are at 2/3 of yield of the block at 60 lb.ft.

MOTOR's Auto Repair Manual for 1947 covers cars 1935 onwards. For Chryslers, it recommends 52.5 to 57.5 lb.ft on cylinder head nuts; 65 to 70 on plain head cap screws; and 67.5 to 72.5 lb.ft on cupped head cap screws, with no difference for model or year. The lower limit is for clean, oily threads, the upper is for clean and dry threads. The same text is used for De Soto.

The same text is used for Dodge and there is also a table of torque wrench settings, which says 65 to 70 lb.ft for cylinder head cap screws.

My notes tell me I did my '30 DC head up to 70 lb.ft dry.

Wow...I just have plain nuts, no washers....I never thought about how many threads might be left, but again these are new studs, the builder was good, and we went to a lot of trouble to get the right length studs, so I imagine I have enough threads left since this is only a re-torque of the rebuilt engine, with the engine hot - so it looks more like 53 - 58 lbs for mine. It's probably only going to take a few clicks anyway.

Larry

Larry

I finished torqueing the cylinder head and I quit at 54 ft-lbs. I did not want to take it any further. I started at 40 and went around again at 45, then 50 stopping at 54. It brought up about 2 more threads on the studs, a little more on few - less on others. Thanks again for the help!

Larry