Peerless 8U Engine Torque Specs

[mil*man]

Does anyone know the cylinder head torque specs for the Peerless Continental 8U engine  used in the 6-80 cars?

[JV Puleo]

I don't think "torque specs" were invented until well after Peerless was out of business. They are a relatively modern development.

Google "torque spec chart" and you'll get info on generic torque figures depending on the size, thread, and material of the bolt. If using the original bolts, er on the side of caution and presume they are soft. Or, find a 1920s copy of the SAE handbook and look up the specs for different bolts. That will generally identify the material although there may not be readily apparent modern equivalent.

 

[Guest]

You could use these as a guide.   My Pontiac manual suggests tight enough so it does not leak but not tight enough to break the bolt.

Edited April 15, 2018 by Guest (see edit history)

[Carsnz123]

As a slight giggle the "torque spec" for the 30s Bentley 3 1/2 and 4 1/4 cars is "An experienced technician with a 6 inch bar."  yup, torque specs weren't really a thing in the old days. 

[Curti]

Auburn never supplied a torque spec. the last one was built in 1936. Newbies like to torque the head bolts to 90-100 lbs and they frequently pull up the threads in the low chromium cast iron block. 

[Gunsmoke]

Cracking the block, particularly for bolts near the edge of the block, is a real risk. A friend's 6cyl flathead '27 Pontiac block was ruined by over torquing the head, 2 edge bolt holes cracked, a near impossible repair. Reinforces the importance of using a new high quality headgasket and any other additional measures to eliminate leaks rather than over-tightening bolts.

[JV Puleo]

The maximum torque rating varies according to the diameter of the bolt, the threads, the material and whether it is dry or lubricated. If you are going for "as tight as you can get it" you cannot use just any figures... you have to figure out what it probably should be. If there is any chance the bolt was overtightened in the past, it is probably stretched and you should probably replace it. It isn't rocket science, but you can't "wing it" either.

 

Phantom I RRs were - "a strong man with a wrench no longer than 6".

[mike6024]

If it was common to specify a wrench or bar no longer than 6 inches it suggests it wasn't that high. I would think 60 pounds of force would be pulling quite hard, and if at the end of a 6 inch wrench that would only be 30 foot-pounds.

 

[C Carl]

I use 50 - 55 for my ‘20s  Cadillacs.   -    Carl

[Guest]

With a standard 1/2" ratchet I tightened my head bolts using my lower arm, not my whole body for many years.  When I bought a torque wrench I found that on average my bolts had been tightened to 50 ft/ lbs.  So that is how I tighten them now 40 then 45 then 50 even when reusing a gasket for the second or third time.  I never had a problem with leaks and only broke one head bolt removing it.  At that point I replaced all the head bolts.

Edited April 15, 2018 by Guest (see edit history)

[Spinneyhill]

Use the value for Grade 2 bolts in generic torque charts, referenced above. Just remember, if you replace the bolts with high strength bolts, you are still putting them into old low grade cast iron, so continue to use the Grade 2 values.