GT6 mk3 with Triumph 2000 engine cyl head torque?

[garypowell]

Hi all, I recently had my head gasket go on my GT6 that has a 2000 engine instead of an original GT6. I used the engine number to buy the correct head set and bought a payen gasket. After a good clean and light inlet matching and cleaning job I've now got the head back on but a bit stuck for head nut torques. My book is  GT6 & Vitesse and has 3 different torques for them models. It seems the 6 cylinder engine configs all have different torques but I'm struggling to find the correct torque anywhere on the net. Is it possible anyone can help please? The head nut and rocker cam nut torques would be really helpful. Next job will be to convert lb foot to Newtons.

[Pete Lewis]

Mk2 has 7/16"  studs   the torque is  ot always obvious amd can be a bit over the page from the general torque showing the   3/8" mk1 first

Mk1    3/8" unf   42 to 46 lbft

All mk2  7/16" dia  65 to 70 lbft

Dosnt matter if its vit gt6 or 2000 saloon , In all cases you must use heavy duty nuts and washers, std will strip at these torques and soft washers will and do deform undermthe load and this looses torqure and clamp force in time amd subsequent re failure

The figures in the gt6  vitesse manual for mk2 are beyond the body section 

Alloy Pedestals are 22 to 26 lbft  for all 3/8" unf pedestal studs what ever engine  (  ie lower than a std 3/8 bolt at 29/31)

Pete

[garypowell]

Peter, it's been a while since I posted and I remember how helpful you were when I got the car a couple of years ago, your'e a life saver, many thanks.

[Pete Lewis]

  there are many  not just me ,          some  say   im here to help........or hinder ..............just tripped over my halo  !!!!

some manuals are a hash of clues all shuffled about or  missing the one important obvious bit   just  when you need it 

Pete

[Algy]

Convertion for lb/ft to Nm multipy the lb/ft by 1.356.

 

[garypowell]

Cheers, I got help on that from my mate Google.

 

[haggis]

Hi Gary, I’m mentioned this before, but so annoyed I’ve got to take my head off again to do it, don’t forget the little bit of instant gasket around the oil feed hole to the head and Put some around the big slot holes where the push rods go. 

Not too much mind you. 

Hag 

[Pete Lewis]

Hag,  think i would do a retorque before you remove it, nothing to loose

back each nut 1/2 turn and retighten  might juts nip up your oil leaks 

Pete

[Algy]

It depends on the gasket you use the pressed metal ones I would use “Hylotyte Red”, not instant gasket or “Loctite 574”; for a compound gasket there should be no need, provided both head and block are flat! If retorquing undo all the nuts ½ a turn, in the opposite order to the tightening sequence then retorque run engine up to temp and retorque again.

[garypowell]

Thanks for the extra tips guys, I opted to pay extra for a Payen gasket and presumed there would be no need for anything extra to help makes seal, after flushing the old oil and running for a hundred or so miles I'll re torque and check for oil seepage rate than remove the head against this stage. I am grateful for the advice.

[haggis]

Hi all, I used a payan gasket and both head and block were skimmed and still seeps/leaks, down the side of the engine. Re-torqued head twice now, reduced leak slightly but still there. Wish I’d used a tiny bit of instant gasket! 

Hag 

[Algy]

Sorry to hear that Haggis, but I still would not use an instant gesket, standard or even high temp silicone sealants are not good in thist type of application from  my experiance. Hylotyte Red has worked very well for me.

The thing is the oilway is so small and even at over 100 psi should not have enough pressure to escape, unless blown out by combustion pressure across faces (in you situation were both block and head are flat). The most likley cause of that is washer bow, the only other thing I can think of is an out of cal torque wrench. You say you retorqued your head, did you undo the nuts and retorque and do it with a hot engine? I ask as just torquing can in some cases not allow the head to settle but as the oil way is at the end of the block even that is unlikely.

As for around the pushrod holes there should be very little pressure there to force oil out, even if your engine breather system is faulty, the problem with using added sealants is that you reduce the crush pressure some were else ( learned that to my cost with copper head gaskets, for vintage race engines, with those it was coat the whole thing or use nothing).

[thescrapman]

I always understood that there was a flaw in the block castings which is why they all leak at the back, so slimming etc makes no difference, by sealant does.

cheers, colin

[haggis]

Hi algy, I did post this about a year ago and I believed the general consensus was to put a thin layer (I had assumed instant gasket) in the two places mentioned, I was thinking loctite SI5980 as this has worked really well in my engine rebuild, no leaks to date anywhere Except at the Head/block of course. It has reduced to a minor seepage now, which is annoying but it’s easier to wipe it off than go through removing the head and doing it again!

Head & block both skimmed, torqued cold & hot, initially the head wouldn’t torque down as the washers(as you mention) were rubbish, so replaced with new and r torqued again twice. 

Not sure how to add the previous post. 

Hag 

[Algy]

Hi Haggis,

It is one of those things, I can only go with my experiance from the old cars I have had to deal with and what has worked for me. I don't know how well SI5980 would work. It sounds like you are doing all the right things, the thing is with the hot retorque is not to drive the car hard until it is done, or the gasket damage is done and in the case of these engines and Jag's not to rev the engine to produce an oil pressure of over 100psi for any time until the retorque is carried out or they can blow oil onto the gasket face (even with sealant) and the seep can not be sorted if it starts.

I am with you all the way a cloth saves a lot of time and cost and a seep is not major. My old British bikes all leak and as I have been told by so many "If it isn't leaking fill it up quick". I did get one not to leak from engine casings (only from the seals) by using aircraft sealants after remachining the faces, I would hate to strip it again though!