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Mk2 Engine Rebuild going into a Mk1 GT6 by a novice!


AidanT

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1 hour ago, AidanT said:

Probably already know the answer to this but it's worth checking

Can cylinder head studs be re-used??

 

On our cars certainly as they are not stretched. Some modern cars use bolts/studs that are single use as they are designed to stretch when torqued. Ours are just simple studs so no issue so long as, as Doug says they are not damaged.

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They were taken out with a stud remover so three vertical lines on the top thread but none of them were massively difficult to remove. I will run the old nuts up and down the threads to make sure there's no problem with the threads, but should they still be OK?  If so that saves a good few Quid!

 

Thanks

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They ought to be OK.  I'm not a fan of stud removers, preferring the old 'double nut' technique.  Just lock two nuts together and undo the lower one with a spanner.

I never changed any head studs until I was about 45, and then only due to damage.  The oldest vehicle I've worked on with bolts was my '67 Series 2A petrol Land Rover, which had bolts rather than studs.  I think there were either 15 or 18, can't remember... it was only a four-pot, which seemed rather overkill to me, as they were pretty thick too. The CR was only 7:1.

Bolts or studs, if you're painting the head be sure to clean any paint off the surface under the bolt heads or nuts on the top of the head.  If there's any left under it's surprising how it can affect the torque settings of the bolts/nuts, don't ask how I know.  A lesson learnt many moons ago with a quite expensive head gasket.

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Double-nutting puts enormous stress on a small area of thread, and just where you want it to be working well!    If you have to resort to double nutting, and you often will if you aim to do a proper job on the block face, then consider a new set of studs.  They aren't costly.

I don't know why they are always so well stuck in, it must be age, as they should be installed no more than finger tight!

John

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I tried double nutting on mine, didn't work. even Pete Lewis's "Never been known to fail!" Impact Driver couldn't shift them. In the end the combined brute strength of Lewis & Brown on a 3 foot breaker bar sorted them. And, no rust involved, they'd just been put in by a gorilla. As John says they should be "finger tight!"

Don't forget, new nuts and hardened washers.

Doug

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1 hour ago, JohnD said:

I don't know why they are always so well stuck in, it must be age, as they should be installed no more than finger tight!

Is that right John?  Maybe my ignorance but surely if you are torqueing the nuts down, does that not impact on the tightness of the studs? (Not sure of the logic / physics behind this)

Aidan

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I think that might be the key: when putting the nuts on hold the stud to ensure it doesnt tighten up fully. Then when torqueing down the correct torque should be reached before the stud can screw itself in enough to come to the end of its thread and jam... 

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Believe me, that is correct!     Some texts tell otherwise, and I ruined a block once by using a toque wrench that was out by 25%.   It cracked the block (that one close to the edge) and opened the water jacket - instant boat anchor!

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6 hours ago, AidanT said:

They were taken out with a stud remover so three vertical lines on the top thread but none of them were massively difficult to remove.

Lucky you!! This one wouldn't play at all a while back, the stud pullers actually wore all the threads off. It just laughed at heat so I had to drill it out. The rest were okay but any that even look slightly suspect especially round the threads will be replaced, about 50% of them. For all they cost I don't want to have to redo it all again. Nuts are always new; I'm using the uprated Mini versions on the current rebuild.

DSCF7338.jpg.61e7de9f6114a54a6ed63b56c8ff6742.jpg

 

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19 hours ago, Colin Lindsay said:

I'm using the uprated Mini versions on the current rebuild.

Yes, good quality nuts and hardened washers are essential as the torque settings are on the limit for 3/8” UNF. Or use the flanged nuts (no washers needed) from Minispares. Superior to anything I’ve found from Triumph suppliers. 
 

Nick

 

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Roger / Nick

Any idea on what torque they are suitable for? We're you able to torque them up to 70 lbft?

Mini spares didn't know their torque capacity only that they were fine on minis @ 50 lbft

Thanks

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2 hours ago, Nick Jones said:

Yes, good quality nuts and hardened washers are essential as the torque settings are on the limit for 3/8” UNF. Or use the flanged nuts (no washers needed) from Minispares. Superior to anything I’ve found from Triumph suppliers. 
 

Nick

 

Nick

We're you able to torque these nuts up to 70 lbft?

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So looking once more 

16148004048031250881729433229873.thumb.jpg.fdabb674aa975e48136d394bcda37c73.jpg

And yes I read it wrong but 

Cylinder Head stud middle section at the bottom 65 to 70??? Is that right? From the conversations above it can't be  

Am I misunderstanding ????

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