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Wobba
21-02-2008, 23:04
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..
21-02-2008, 23:47
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
22-02-2008, 00:09
oh noes :(

drsmith1979
22-02-2008, 00:39
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
22-02-2008, 01:13
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
22-02-2008, 07:44
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
22-02-2008, 09:34
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
22-02-2008, 10:40
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
22-02-2008, 10:50
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
22-02-2008, 11:03
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.

u33db
22-02-2008, 11:10
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!

Can you get an angle grinder in there?

Try cutting the studs down as far as they'll go then drill them outof the manifold.

MicKPM
22-02-2008, 11:14
Don't drill them out the manifold mate... it leaves less than no material to grip when removing the remaining stud from the head!

I bet it's the left hand port (As you look at it head on) that's giving you the grief?

alex_blue16v
22-02-2008, 13:07
i had a similar problem when i was removing my head mate where my manifold had sort of welded itself to the last stud. I couldnt get my head off either as my downpipe bolts were rounded as well.

i tried all sorts but in the end a big breaker bar and hammer was the only way but with quite significant damage to the head :(

have you tired heating it up with a blowtorch to expand the manifold?although i imagine you would need quite alot f heat :?

Wobba
22-02-2008, 14:23
It's the far left bolt yet, and the one on the far right too, though I dont think it's as bad as the left one. Bloody cars.

I dotn want to heat it up, and only have a cogarette lighter anyway hehe!

MicKPM
23-02-2008, 10:02
Just persever mate. The 1.8 engine i'm stripping today for rebuilding has exactly the same problem... loads of WD40 and gentle applications of Mr Hammer (Dance - Can't touch this) and you'll be rate :wink: