• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR2/3/3A Torqueing heads after startup.

Share this page

J

John_Progess

Jedi Warrior
Country flag
Offline
When you re-torque the heads after startup, do you loosen the head bolts then go through the proper sequence to torque them to the required setting or do you just check each head bolt to see if it is still at the proper setting. My concern is the piston liners and loosing the figure 8 seal if I loosen the head bolts. Is there a chance of loosing the seal and water getting into the oil system or am I concerned for nothing. Thanks and have a good day!

John
 
The way I was taught to do it (and always have) is to loosen each nut/bolt one at a time, then turn it back to the correct torque before doing the next one. Do that in the recommended sequence, but don't loosen them all at once.

However, I think there is very little chance of losing the fig 8 seal even if you do take them all loose. I've had the head off more times than I can count, and never had a problem with Fig 8 gaskets. The workshop manual even gives the procedure. In theory, you should clamp the liners in position if you are going to turn the engine with the head off (for fear the liners might move with the pistons), but I've even gotten away with not doing that.
 
Do not loosen the nuts. Apply the torque to the high side of the recommended torque. If they break loose, then turn until you reach the recommended torque. If they do not break loose, then do not exceed the high side recommendation.
 
I'll go +1 to Randall's method. If you do not loosen them, it will take additional force to overcome the static friction (just as it will take more force to loosen them than it did to tighten). At least that's what my mentors taught me.
Tom
 
TomMull said:
I'll go +1 to Randall's method. If you do not loosen them, it will take additional force to overcome the static friction (just as it will take more force to loosen them than it did to tighten). At least that's what my mentors taught me.
Tom
Click to expand...

That's why there is a range for torque. I was taught (while learning a BS in mechanical engineering...from PHD engineers) to torque with lube to the low value. When checking, bring it to the high value because of the "static" friction you are talking about. Never loosen a torqued bolt unless you plan to remove it.

I'm sure everyone wondered why there is always a range of torque...now you know.
 
I use Randall's method (which does not mean it is best) and put a dot of paint on the stud and nut to mark their starting position. Then I can see when I am done what moved as a result of the re-torque.
 
CJD said:
Do not loosen the nuts. Apply the torque to the high side of the recommended torque. If they break loose, then turn until you reach the recommended torque. If they do not break loose, then do not exceed the high side recommendation.
Click to expand...

No PHD engineers in my background and probably quite a few without even a H.S. diploma. I'll still go with them, though.
Tom
 
Back
Top