Exhaust Manifold Removal 1.9i 8V.

Post by **Tim Leech** » Sun Mar 04, 2012 9:12 pm

Since I bought the TZI it had a very slight blow from the exhaust manifold, which all but disappeared when it got warm, however the 200 mile round trip in all weathers on Monday seems to have made it worse, so much so its quite noticeable now under acceleration.

I imagine it hasn't been off since new (1991), so it is repairable in situ with some exhaust gunk (if I can find the crack) or will it need to come off and be welded or replaced.

The frontpipe has been off in the past few months so shouldnt present much problems.

I just fear snapped studs and bolts etc meaning the head has to come off etc

Thanks

Post by **mat_fenwick** » Sun Mar 04, 2012 11:28 pm

I think the chances of it being fixable with gunk are slim to none I'm afraid. The manifold sees such temperature changes that it will flake away in no time. Is it a cast iron manifold? If so it's technically not supposed to be weldeable unless by specialist means, but I've had some success using stainless steel wiring wire (with mild steel wire the carbon from the cast iron diffuses into it and turn it into the same sort of steel you make tools out of i.e. hard and brittle so can crack easily.

I wouldn't have thought a replacement will be difficult to find if it has cracked. I think you'd be unlucky to shear off a stud - in my experience if the nut is rusted to the stud the whole thing will just unscrew from the head.

Mike E (uk) · Post by **Mike E (uk)** » Mon Mar 05, 2012 12:40 am

I replaced my manifold on the GTI many years ago when it cracked.

I had the head off at the time, so it was easy.

But it is possible to replace the 16V manifold with the head in place, so I expect the 8V is also do-able, if you can get under the car with a pit or lift.

Remember the Pug 405 and I expect other PSA cars used the same engine, so check them as a source for manifolds too.

Mike

Post by **Tim Leech** » Mon Mar 05, 2012 8:54 am

Cheers

The manfifold does looks reasonably accessable wit the downpipe removed, but its more the case of snapped studs etc which concerns me.

mds141 · Post by **mds141** » Mon Mar 05, 2012 6:04 pm

Tim, if you remember when I got the valver it had a blowing manifold. Dave Ashworth in Blackpool advised welding in situ, as the studs would most likely shear. It was welded near 18 months now and is still fine.

JayW · Post by **JayW** » Mon Mar 05, 2012 6:40 pm

The studs just don't snap, as Mat said above, if the nut won't undo then the stud will just unscrew from the head. Then, once off you can either replace the studs or wind the nuts off with proprietry tools.

Dollywobbler · Post by **Dollywobbler** » Mon Mar 05, 2012 7:08 pm

I can't speak from experience with BXs, but with 2CVs (also alloy head). I have had the stud snap when trying to remove the bolts. It's pretty common as the thread tends to seize in the head - due to the two different metals, so if the nut won't go around, there's no way that the stud will spin. I think heat would probably help, so I'd be tempted to try and free off the nuts when the engine is hot - more scope for burning yourself, but hopefully less for that horrible sudden looseness that suggests a snapped bit of metal. It's not a nice feeling!

JayW · Post by **JayW** » Mon Mar 05, 2012 7:41 pm

Each to their own i suppose

Having removed god-knows how many heads & manifolds i've obviously been lucky to NEVER have one snap. As the alloy isn't ferrous they don't tend to grip the steel as would steel on steel (which is the same reason the nuts stick on the studs).

Granted it's possible to strip the thread out of the head but i've also never known that whilst undoing a bolt, only when tightening.

Ironically, i've never had any success with pre-heating the engine. Asside from being bloody hard to work around a roasting hot manifold it's probably that the manifold also expands when hot pulling on the bolts even harder and effectively making them tighter as the metal between nut and head expands.

Shotguns ready boys!

Dollywobbler · Post by **Dollywobbler** » Mon Mar 05, 2012 8:15 pm

No shotguns here - just reporting mine and others' experiences with a non-BX engine. You never know how it's going to go. When I did a 'stat change on my Alfa 164 V6, there were many tales of woe about snapped bolts. No problem at all.

JayW · Post by **JayW** » Mon Mar 05, 2012 8:40 pm

Dollywobbler wrote: You never know how it's going to go. .

This is true

Expect the worst, hope for the best

Post by **Tim Leech** » Mon Mar 05, 2012 11:03 pm

Okidokey, I will have a looky this weekend (3 days off to see if I can see where the blow is etc).

Dollywobbler · Post by **Dollywobbler** » Tue Mar 06, 2012 9:34 am

Is the car at home Tim? I'd give the nuts a soak in good penetrating oil (not just WD40) daily until the weekend.

JayW · Post by **JayW** » Tue Mar 06, 2012 10:59 am

I swear i read "your nuts" not "the nuts"

Jayboy · Post by **Jayboy** » Fri Mar 09, 2012 9:25 pm

Lol. It's almost compulsory for 2CV exhaust manifold studs to snap! That's if there's even enough of the nut left for tools to grip....

Post by **Tim Leech** » Fri Mar 09, 2012 9:29 pm

Dollywobbler wrote:Is the car at home Tim? I'd give the nuts a soak in good penetrating oil (not just WD40) daily until the weekend.

Yes its in one of the two garages. Hve 3 days of this weekend for some BX realted spannering!