TR4/4A Any tips on re-torquing TR4a head now that 500 are on the rebuild

[tdskip]

Any tips on re-torquing TR4a head now that 500 miles are on the rebuild

Hi guys - hope everyone is doing well.

Any tips or things to be aware of on doing the re-torque of my head now that I am at 500 miles on the rebuild?

Engine should be warm?

Anything else to be aware of?

Thanks!

 

[trrdster2000]

Hi, As you are going for the full monty, 104 Ft lbs and I'm guessing an extension bar on the handle. Try to use just the socket on the wrench, no extension there. If you did not replace the studs there is a good chance on stripping the threads at this tight a torque.
Best advise, if it feels funny, STOP!!!! live with what you got.

Wayne

 

[tdskip]

Hi Wayne.

New studs, but concerned about the comment of the likelihood of stripping them. Not a fun thought....

 

[poolboy]

Are you going to loosen the nuts about a quarter to half (one at a time) before final tightening ?
As far as the temperature, I've done both ways without harmful consequences so I don't know if there is a 'right or wrong' way of doing it.

 

[Merlin63Tr4]

I usually do the re-torquing like poolboy does, except I only do a re-torque with the engine cold.
1/4 turn de-torque and then re-torque, one nut at a time in the workshop torquing order.

M.

 

[TR3driver]

TR3 manual says to do the nuts hot, but I couldn't find that line in the TR4 manual. I doubt it makes much difference on an iron/iron engine. I did, however, find a note that says to wait (or do it again) until 1000 miles.

As Ken says, you should loosen each nut slightly before retightening, then get the torque reading while the nut is still moving. This avoids the sticktion (aka static friction) effect.

Book says 100-105 ftlb, which I interpret as 102.5 ftlb plus or minus 2.5%. In other words, the range is to allow for inaccuracy in your torque wrench (and your reading of it). Shoot for the middle, not the top.

There is a lot more strain on those studs & nuts when the engine is running, than when you retorque the nuts. So IMO if something feels "funny", it's best to find and fix the problem now, rather than having a leak later on. That said, I have never had a head stud on a TR3 give me any problem (although I have found a few that were stretched from over-tightening).

 

[tdskip]

Thanks guys - will give this a go later today.

 

[Geo Hahn]

One other thing I like to do before loosening for a re-torque is put a dab of paint (I use a yellow paint pen) at the same spot on each nut - say, at the forward edge. That way I can see after I'm done just how much more each nut moved to achieve correct torque.

Really, no idea how to use that info - I am just curious as to how much a of correction was needed.