Manifold studs stuck :(

[Wobba]

As you all know by now, I have the head off the engine, but I am having a big problem getting the exhaust manifold off. It's partly off, with just two stod bolts remaining, but I think one of them is jammed and wont come off.

I am worried as both the bolts wobble when I wiggle the manifold, and I am fearing they have at some stage saused some damage to the soft alloy head as they wouldnt wobble if their holes were not damaged.

I will probably send the head off for a refurb soon but dont want to get charged more for someone having to take it off for me....I have heard these can be a problem and need some advice...I dont want to rip them out!

[Justin..]

like you say , wobbling is no a good sign. worst case you can get the threads repaired with a helicoil else you need the hole drill and tapped for bigger studs which may not fit the manifold

[Wobba]

oh noes :(

[drsmith1979]

personally i would just buy a fully built head to replace it, will save you time. there are some companies that sell a fully refurbed head... but you could always try a 2.0 conversion?

[Wobba]

One of the studs wobbles a fair bit, must have either been like that for a long time or I did it while removing the head from the bay or trying to take the manifold off :(

I am sure it is fixable, I'll ask the reconditioners tomorrow. But can I be arsed? I'll sleep on it.

As for 2.0. I could do that but again it's time and money. I need the car to be functioning soon and although I am sure taking the block out wouldnt be that hard with the head off, it's another list of things to buy and sort out, which doing solo, and having never even looked inside an engine before is quite a task!

[drsmith1979]

you are doing great to be fair and hats off for having the balls to do it!

it probably is savable, but its one of those 'chasing faults' issues, you get the studs fixed, then it needs a new valve or some other modification, would be easier in the long run to get a new reconned head and fit it as a whole?

the 2litre surely cant be too hard compared to what you have already done!

[MicKPM]

I've seen this on a few high mileage F7P's now and what usually happens when the manifold gets "Stuck" to the head is the exhaust gasket fails on one or more ports. Either it gets wet or is just old... either way, the gasket seems to react with the cast manifold and starts to weld itself to the aluminium of the cylinder head. It's for this reason Renault fitted an aluminium heat sheild between the gasket and manifold mating face on the Megane F7R as it stops the reaction occuring.

You will need to be carefull removing it or else you can rip the studs from the cylinder head meaning you'll need the head retapping with a helicoil set. Just give it LOADS of WD40'n sessions (Allowing it to soak in) and hitting the manifold with a hammer. Don't wollap the arse out of it cos it's only cast and will break! Given time the vibration and WD will break down the crud. DON'T use heat on the head though... resist!

[Wobba]

you are doing great to be fair and hats off for having the balls to do it!

it probably is savable, but its one of those 'chasing faults' issues, you get the studs fixed, then it needs a new valve or some other modification, would be easier in the long run to get a new reconned head and fit it as a whole?

the 2litre surely cant be too hard compared to what you have already done!

Thanks drsmith! I am asking people about their heads and seeing if one could be suitable and easy to get to me as we speak.

Mick: thanks for that info. I am pretty sure the hole in the head has become damaged already :( the stud should not woble up and down while still in the head. I will not unscrew or come away from the manifold at all, so is stripping the threads as I have tried to seperate the mani and head.

Bugger.

[MicKPM]

I take it the manifold is free on all bar 1 or 2 studs then? If so, try some mole grips and unscrewing the studs. If you shaft them it doesn't really matter as they're already gonna need replacing so no harm no foul - Just get the head threads checked!

You could always replace the studs with cap heads to if you wanted... just be carefull not to overtighten them ;)

[Wobba]

I take it the manifold is free on all bar 1 or 2 studs then?

Yes thats right. the other came out with the nuts as I undid them. On two the nuts unscrewed with the studs still in the head and they are the problem ones. I thik one is okay the other isn't.

I'll try undoing them with mole grips. I need to buy some.