Head stud question

[TVR Beaver]

I was thinking of cleaning the heads up and may be removing the engine this winter to do a few jobs....

The question is, do i re-fit the heads with stretch bolts?

or... Do I use the head studs???

And if I use studs... can you then get the heads off in the car (without removing the studs?... and do you have to re-torque after a few miles to nip it all down? (as this is the reason for stretch bolts in the first place)

If anyone could comment... Cheers

[spend]

You should be able to slide the heads off the studs in-situ, doesn't really matter though the studs have hex key removal/insertion.

The studs can be torqued up & not touched, but its not a big deal to check them ~ I'd say that choice of process is pretty much down to what gaskets you use & personal preference.

[haircutmike]

John, having done mine in situ once, I would use new stretch bolts as there isn't much room. The also block has locating dowels for easy alignment.

[spend]

haircutmike said:

John, having done mine in situ once, I would use new stretch bolts as there isn't much room. The also block has locating dowels for easy alignment.

If, as I suspect, you are commenting on experience with a Chim not a Griff - the bulkhead clearance is totally different (it varies on Chim evolutions as well BTW).

[haircutmike]

spend said:

haircutmike said:

John, having done mine in situ once, I would use new stretch bolts as there isn't much room. The also block has locating dowels for easy alignment.

If, as I suspect, you are commenting on experience with a Chim not a Griff - the bulkhead clearance is totally different (it varies on Chim evolutions as well BTW).

You learn something every day .

[TVR Beaver]

So bolts or studs?.. which way to go??..... the gasket on a 99 would be the composite one so may need a re-torque after 300 miles or so.. no great issue (if you can get on all the bolts??)... or the stretchies.. don't like doing these?.. no reason why.. but just don't feel right somehow........

BTH Dave.. did you get my mail on Springs???...

[carsy]

I went with studs. Like you i dont like the idea of those stretch bolts or normal bolts stressing the block threads. The studs can also be re used time and again, should the need arise. As for re torqueing, as Spend says it is not necessary. You cant get on the outer bolts any way without taking exhaust manifolds off.

For me i would always go with studs.

[TVR Beaver]

Yes.. I guess thats the issue.. you should actualy re-torque down after a few hundered miles... but if you can't get at them without removing the exhaust.. it become a right pain!!

[gavgavgav]

A quick side question - do you have to remove the exhaust heders to access the head bolts?

[TVR Beaver]

carsy said:

You cant get on the outer bolts any way without taking exhaust manifolds off.

For me i would always go with studs.

as it says above...

[v8 racing]

Just my two pence worth, All IMHO of course, Stretch bolts are the work of the devil in an alloy block, and i would certainly never entertain fitting them, personally i believe this is one of the big issues with the 4.6/4.0 blocks going pourous, the recommended way of fitting these bolts is 30nm, then 90 degress and then another 90 degrees, i have done this with a torque wrench just to see what kind of torque you are putting on the block, now alloy head alloy block composite gasket there is no nead to go anymore than 70ftlb of torque, my torque wrench goes to 250ftlb and that is maxing out when checking the stretch bolts!!! also because the bolt has the washer built in when tightening down it is actually chewing the head away! i have seen lots of threads pull out months after the engine has been built due to the torque on the alloy, sorry not for me at all, studs or aftermarket bolts torqued to a sensible rating

[TVR Beaver]

Hi Rob... ''Stretch bolts are the work of the devil''... okay.. get the feeling your not keen then... I did once do an Ali engine that had stretch bolts in.. and when you checked the block for flatness, you could see localised mounds around the thread holes where I guess the bolt had pulled up the Ali over time... and as you say, may be started to split it apart? ... studs or normal bolts it is... do you ever re-torque them afterwards? I would have thought with the compression we see you'd need to do it after the composite gasket had squished down a bit??
.
YHM anyway over a few other parts I may need,,,

cheers...

Edited by TVR Beaver on Monday 31st October 21:36

[Simon says]

v8 racing said:

Just my two pence worth, All IMHO of course, Stretch bolts are the work of the devil in an alloy block, and i would certainly never entertain fitting them, personally i believe this is one of the big issues with the 4.6/4.0 blocks going pourous, the recommended way of fitting these bolts is 30nm, then 90 degress and then another 90 degrees, i have done this with a torque wrench just to see what kind of torque you are putting on the block, now alloy head alloy block composite gasket there is no nead to go anymore than 70ftlb of torque, my torque wrench goes to 250ftlb and that is maxing out when checking the stretch bolts!!! also because the bolt has the washer built in when tightening down it is actually chewing the head away! i have seen lots of threads pull out months after the engine has been built due to the torque on the alloy, sorry not for me at all, studs or aftermarket bolts torqued to a sensible rating

I totally agree with this being on the spanners on engines other than the RV8 ie euro boxes i checked the torque on a peugeot diesel cylinder head once and came up with the same conclusion an obscene amount of clamping force that in my opinion is not neccesary,at least the block was cast iron,i have also seen the evidence of the bolt holes on alloy blocks raised as mentioned already from from the pulling stress of yield bolts.

[gavgavgav]

TVR Beaver said:

carsy said:

You cant get on the outer bolts any way without taking exhaust manifolds off.

For me i would always go with studs.

as it says above...

ta .... ahh bo**ox, that was how I was going to get to a couple of stuck manifold bolts.