tr7triumph.com

Hi folks. Here's a quickie:

I have been following the sequence in the Haynes Manual, however a graphic on this forum shows a completely different sequence - scroll towards the bottom. https://www.triumphexp.com/forum/tr7-and-tr8-forum.3/potential-head-gasket-replacement.1262254/

Any thoughts?

Thanks

John

I think this may complicate things further instead of clarifying,

There’s this factory bulletin from back in the day which changes the tightening sequence...
https://www.triumphwedgeowners.org/uplo ... 79-a-1.pdf

Rimmers have this video on YouTube with their take on the Stag incarnation of the cylinder head. About 11 minutes in.
https://www.youtube.com/watch?v=-kgrCMIZVqI&t=247s

Certainly different from normal cylinder heads...

Yikes, that really does confuse things, doesn't it?! That's three different sequences for fitting the head.

John

The BL Slant Four Training booklet has this picture in the Appendix as the new sequence to be followed.

dursleyman wrote:The BL Slant Four Training booklet has this picture in the Appendix as the new sequence to be followed.

That one gets my vote too. The Triumph engineers should know I'd say.
I have built a few engines over the years and always used that sequence.
Never had a head gasket fail on one of these engines (knock on wood ).

johnnyj wrote: ... Any thoughts? ...

I wouldn't use that sequence!
There must be a good reason why they changed it

That's the same sequence as in the Haynes Manual. It is the one I have been following - phew!
The only remaining question is about the torque settings - 50 lb/ft (as per the above) or 55 as per Roger Williams' book?


John

Start with the lower setting

It's more important that the torque settings are the same across the head than any particular torque setting, unless you have a properly calibrated torque wrench (and have it's calibration checked regularly) it wont matter much if it's 50 ft/lb or 55 ft/lb as your wrench is probably inaccurate anyway.
Use the torque values as a guide, start at a lower value..... say @ 30 ft/lb, follow the tightening sequence..
Then go around again checking they are all 30 ft/lb.
Now readjust the torque wrench to @ 40 ft/lb and do as above.
Finally go though it all again @ the value you choose 50 or 55 ft/lb.
It wont matter if your torque wrench is a bit out of calibration as all the bolts will be torqued the same.

Another point about the use of torque wrenches is the use of an extension will throw out the torque setting as it will act as a torsion spring.......this wont matter if the same extension is used on all the head bolts as the tension will be the same value applied across the head. Never use the extension on some of the head bolts and not on the others or change extensions for some......this will result in uneven torque across the head!

Thanks guys, really interesting. The point about using an extension is really useful, as that's what I have done (i.e. used an extension on some, but not on others). Having torqued my head, is it acceptable to "un-torque" it and effectively start again? And can the studs be re-used? Mine were new at this installation.

The reason for the post, by the way, is because I have a lingering doubt that my new HG is not doing its job correctly, possibly due to yours truly not torquing it correctly as above.

Thanks

John

If you want to re-torque the head use the torque sequence.
Than undo the first bolt by a quarter turn and re-torque to the set figure.
Repeat for all other bolts and studs.