Exhaust header bolts
Discussion
Spending that sort of money on a 17 year old car is definitely not pleasant, but it's transformed the car in the same way having the arms/bushes/top mounts done 2 years ago did.
I had a couple of small cracks in the headers, and the back boxes were splitting on the seams. The car was VERY loud, ran roughly through the mid range, popped/banged on overrun when cold, and had struggled to pass emissions last 2 MOT's.
Post the exhaust work, it's like someone's given it another 50bhp... for a 163k mile car, it now whips round the rev counter. It's also a lot quieter... a bit too quiet... so I fitted a Helmholz bypass, but I think I might still need a bit more volume at the top of the rev rannge.
The joys of owning a high mileage car!
I had a couple of small cracks in the headers, and the back boxes were splitting on the seams. The car was VERY loud, ran roughly through the mid range, popped/banged on overrun when cold, and had struggled to pass emissions last 2 MOT's.
Post the exhaust work, it's like someone's given it another 50bhp... for a 163k mile car, it now whips round the rev counter. It's also a lot quieter... a bit too quiet... so I fitted a Helmholz bypass, but I think I might still need a bit more volume at the top of the rev rannge.
The joys of owning a high mileage car!
I thought the 10 hours I spent dealing with the studs at the exhaust (rather than cylinder head) end of the manifolds/headers on my Cayman a few years ago was bad enough! I had heard horror stories about the bolts into the head shearing so decided to leave well alone.
There is a jig (Stomski jig?) that can be used as a drilling guide/template to drill broken bolts out of the heads but I don't think it's cheap and not sure which Porsche models it fits. A couple of specialists I spoke with previously said they have local thread "doctors" they call in to deal with these.
There is a jig (Stomski jig?) that can be used as a drilling guide/template to drill broken bolts out of the heads but I don't think it's cheap and not sure which Porsche models it fits. A couple of specialists I spoke with previously said they have local thread "doctors" they call in to deal with these.
anonymous said:
[redacted]
It's highly unusual not to strip everything off the head when doing a rebuild, but technically you could leave the manifold in place as it doesn't prevent access to anything. One would hope that they stripped the head, stuck it through the parts washer & then replaced the valve stem seals at the very least...ETA: With the head off, any studs that need to be drilled are much easier to deal with because you can use a pillar drill to ensure you drill straight & true.
Edited by nxi20 on Thursday 27th April 07:44
If the rebuild was under Warranty, no betterment would be implemented - heads and assemblies are not stripped unless the failure dictates as the work doesn't affect the repair.
On rebuilds I do, I ask the customer if they want to add anything while I am there - the new parts then have a 2yr parts and labour Warranty which is worth having.
On rebuilds I do, I ask the customer if they want to add anything while I am there - the new parts then have a 2yr parts and labour Warranty which is worth having.
Unless I am missing something, I would have thought it would be difficult to put your cylinder heads back onto the new block with the manifolds attached. Mainly because getting the head square to the block and torqued up corrected with weight of the manifold hanging off the side. If this is not done right, a cylinder head gasket failure will occur.
Workshop Manual for 987 states Manifolds removed for cam removal; if you have the repair invoice are the bolts/gaskets listed?
If you ping me the VIN I could check the list?
To be fair, the manifolds on a 987 are better protected being in front of the rear wheels and partially covered by the rear undertray - we have far more issues with 996/7 fixings.
If you ping me the VIN I could check the list?
To be fair, the manifolds on a 987 are better protected being in front of the rear wheels and partially covered by the rear undertray - we have far more issues with 996/7 fixings.
gsewell said:
Unless I am missing something, I would have thought it would be difficult to put your cylinder heads back onto the new block with the manifolds attached. Mainly because getting the head square to the block and torqued up corrected with weight of the manifold hanging off the side. If this is not done right, a cylinder head gasket failure will occur.
If you are removing the head with the engine on the removal bed the whole thing is on its side??996 heads can be removed with engine in; again its effectively on its side - the joy of flat engines!!
DRH986 said:
I thought the 10 hours I spent dealing with the studs at the exhaust (rather than cylinder head) end of the manifolds/headers on my Cayman a few years ago was bad enough! I had heard horror stories about the bolts into the head shearing so decided to leave well alone.
There is a jig (Stomski jig?) that can be used as a drilling guide/template to drill broken bolts out of the heads but I don't think it's cheap and not sure which Porsche models it fits. A couple of specialists I spoke with previously said they have local thread "doctors" they call in to deal with these.
Just grind the pipes off an old manifold and use that as a jig. Bush the bolt holes.There is a jig (Stomski jig?) that can be used as a drilling guide/template to drill broken bolts out of the heads but I don't think it's cheap and not sure which Porsche models it fits. A couple of specialists I spoke with previously said they have local thread "doctors" they call in to deal with these.
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