Alfa Romeo Owners Club of Australia Forum

Technical => 116 Series (Alfetta Sedan/GT/GTV & Giulietta Sedan) => Topic started by: poohbah on December 17, 2016, 07:06:56 PM

Title: GTV exhaust manifold gaskets
Post by: poohbah on December 17, 2016, 07:06:56 PM
I guess I knew it was too good to last - just ticked over a year with no dramas of note on the GTV. Went on a long drive two weekends ago, but got stuck in inexplicable congestion at 3pm on a Sunday (30min to travel 2km) on way home, after which the car sounded like a tractor (though it wasn't running hot, still pulled and revved fine).

Looking at it up close, it appears that the exhaust manifold gasket on cylinder No3 maybe leaking (I can see crappy carbon buildup all round it).

I'm a bit surprised, given I had the manifolds replaced a year ago. Am I wrong to think its unusual, or is it the sort of thing that can go anytime?

Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on December 18, 2016, 10:23:00 AM
Good tip sportiva, I'll check the nuts.
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on December 18, 2016, 08:36:40 PM
I've identified the problem, and it is as simple as it is bizarre.  After wrestling the heat shielding out (what a pain that was), I was able to get a good view of both manifolds.

The two bolts which fasten the 1- 4 manifold to the exhaust downpipe seem to have undone themselves and done a runner. No wonder it's making a racket.

Question I have now is - any useful tips on how to insert and tighten two replacement bolts? I don't have axle stands or a lift, so haven't got access from beneath, but it seems impossible to get to from above, mainly because the manifolds themselves get in the darn way.

Is there a trick to gaining access from above? Or am I just going to have to get some axle stands and (assuming I can get the bolts in and nuts on) find a friend to hold while I tighten?



Title: Re: GTV exhaust manifold gaskets
Post by: aggie57 on December 19, 2016, 07:16:45 AM
Quote from: poohbah on December 18, 2016, 08:36:40 PM
I've identified the problem, and it is as simple as it is bizarre.  After wrestling the heat shielding out (what a pain that was), I was able to get a good view of both manifolds.

The two bolts which fasten the 1- 4 manifold to the exhaust downpipe seem to have undone themselves and done a runner. No wonder it's making a racket.

Question I have now is - any useful tips on how to insert and tighten two replacement bolts? I don't have axle stands or a lift, so haven't got access from beneath, but it seems impossible to get to from above, mainly because the manifolds themselves get in the darn way.

Is there a trick to gaining access from above? Or am I just going to have to get some axle stands and (assuming I can get the bolts in and nuts on) find a friend to hold while I tighten?

Nope, you're going to have to get access from below. 
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on December 19, 2016, 08:56:18 AM
Thanks, that's what I thought.
Title: Re: GTV exhaust manifold gaskets
Post by: Duk on December 19, 2016, 09:38:57 AM
Can you build a stack of planks to drive the car onto?
Even jack the car up and put planks or bricks under the left front wheel?
Obviously anything you do must be solid and the car totally sure footed.

Using some ancient memory, I'm thinking I use to do the nuts for the secondary pipes from above and used a crows foot spanner to do so................ But that was a long time ago.
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on December 19, 2016, 10:26:59 AM
Cheers Duk. I have got a set of ramps, so can at least get front off ground. Will see if I can get enough space under car using them, and try to do do it over Xmas.

I assume there is a gasket that fits between manifold and downpipe?
Title: Re: GTV exhaust manifold gaskets
Post by: Duk on December 19, 2016, 11:05:26 AM
Yes there's a gasket between the parts.
If it's still there it's probably a bit eroded from the gasses squeezing out the gap. Some exhaust sealant on both faces of the gasket could give it a new lease on life.
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on December 19, 2016, 11:53:11 AM
Good tip, thanks Duk.
Title: Re: GTV exhaust manifold gaskets
Post by: GTVeloce on December 19, 2016, 01:50:31 PM
Lie on your back under the car with a 13mm socket on a 200mm extension bar and try not to get anything into your eyes! Depending on the type of bolt used, you may need a second person to hold the bolt head from the engine bay. And put copper grease on the threads so they come of easily again later!
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on December 19, 2016, 02:07:45 PM
Another good tip!
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on December 19, 2016, 03:16:39 PM
Cheers guys for all the tips, lots of good advice.
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on December 19, 2016, 03:33:41 PM
Also, what is the correct size bolt?
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on January 06, 2017, 05:41:12 PM
Update.

Yes you can replace the flange gasket, nuts and bolts on your own without having to get under the car.

"All" it took was about two hours, lots of swearing, a selection of different length socket extensions, and some extreme dexterity...

Of course I only had to replace the rearmost flange gasket and bolts. God help me if I had to replace them on the front manifold.
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on January 07, 2017, 01:49:05 PM
Maybe. More the need for triple jointed wrists. And fair to say I left a fair bit of skin on the manifold...
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on April 30, 2017, 07:07:38 PM
What a joy. Having replaced the bolts and nuts on joining the rear exhaust manifold to the flange a couple of months ago, the nuts on the front manifold undid themselves yesterday. And they are an even bigger faff to get to.

Two hours, a layer of skin and the use of every four letter word in The Swearing Bastard's Dictionary later, I got the new nuts on and tightened up from the topside.

Question - does anyone else have heat shielding fitted to cover the left hand side engine mount (the one closest to the exhaust manifolds)?

Mine does, and it really gets in the way and tends to rattle as its only attached in two places. If its not really needed, I'm tempted to rip it out.

Title: Re: GTV exhaust manifold gaskets
Post by: Neil Choi on April 30, 2017, 07:19:58 PM
Yep, check exhaust nuts regularly.  Heat and vibration will loosen them, access is difficult, better with extractors.

Yep, remove and discard that heat shield if originality is not important, wrap mount with exhaust heat cloth tape and wire on to secure.  Standard race car mod.
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on April 30, 2017, 07:26:37 PM
Cheers Neil.
Title: Re: GTV exhaust manifold gaskets
Post by: carlo rossi on May 05, 2017, 10:21:27 AM
I noticed the other day that the nut on the end on one that hadnt fallen off was Copper
maybe this is the secret you can tighten the copper without fear of cracking the exhaust
dont know but it was interesting
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on May 05, 2017, 11:20:24 AM
Good tip Carlo. Next time they fall off I will try copper - I can't face the prospect of removing the nuts I've just fitted right now!
Title: Re: GTV exhaust manifold gaskets
Post by: poohbah on May 06, 2017, 02:24:16 PM
Cheers Glen, that is a handy reference, especially seeing the original had a squared end to lock it in place while you tighten the nut.