a4944

I recently purchased a 1986 944 Turbo and the shop that did the inspection stated there is a leak in the exhaust manifold. It is making a noise and I do smell the exhaust fumes but I can't make out where it's coming from.

What's the best way to isolate the exhaust leak? It has the standard heat shields. I plan on taking the exhaust manifold off this weekend and could really use some advice before I get started. Do I have to take the heat shields off?

Thanks,
Mark

RedS2

I have a similar problem on my re-done Turbo S. I suspect the interface between the exhaust maniold and the collector. I am going to try using an air pressure fitting and a large rubber cork at the exhaust pipe.

Perhaps someone here has a better way.

This minor exhaust leak is about the last problem I have.

Dave E

When my '86 manifold was cracked, it was the 2-3 header and you could see the crack from the hole at the collector end. I ended up removing the heat shields to weld the cracks. Non-visible cracks can be found with the basic pressure test RedS2 proposes, block up the holes and add some air and listen for leaks. I'll be doing this on my car sometime soon...Be careful with the insulation under the shields, it might be asbestos.

a4944

I'm new to exhaust systems and I have limited tools. I don't have an air compressor besides a basic air tank that you fill at a gas station and some cheap $20 compressor pumps that you plug into the cigarette lighter socket in the car to fill tires.

Is there any special fittings that can be used for the pressure test? What's a good technique for getting the pressure in the headers? I assume I'll hear the leak once I have it pressurized.

I think I'm going to learn alot with this car! I'm having fun with it so far.

Thanks,
Mark

Dave E

I think what I'll do is get two of those rubber plugs that expand in diameter when you tighten the screw that goes through the middle, and then make up another cover (wood or steel) with a hole in the middle to fit a schrader valve cut from a bicycle tube(with some extra rubber around the sides as a flange and seal) and use some bolts through the header flange holes to tighten it down and try to make a seal. Then fill with air by whatever method( I did buy a compressor when my last cars motor went and I decided to do the work myself) and voila, a setup for leak testing! The cracks were so large on my '86 header that it wouldn't have held air for long, I mean even a few seconds would have been pushing it. I just went ahead and removed the shields when I saw the cracks. I drilled out the spot welds with a sharp drill bit and got a sharpened 1" putty knife in between the sheet metal and broke the welds that way. Always an adventure, Porsche ownership...

a4944

I may try and use duct tape and a brake pressure bleeder that I made a while back with one of those garden spray pumps. I'll just duct tape the openings and insert the tubing from the pressure bleeder. I can then pump in the air pressure and see what happens.

Thanks,
Mark

jimbo1111

You dont need air. There is two parts to the headers. Both are 2 into 1. cover the outlet with duct tape. Stand them up and fill them with water. Your leaks will show up. You will have to take the shields off though.

a4944

I'm assuming that once I take the heat shields off that they are off for good. I was hoping to avoid taking the heat shields off just to test. Is there any negative implication of taking the heat shields off and leaving them off?

Thanks,
Mark

Dave E

Exrta heat under the hood, cooling of exhaust and its susequent loss of enrgy, energy that you want to have to turn the turbo. You should be able to put them back on if you a re reasonably careful when you take them off. I'm sure you could find a shop with a spot welder to reinstall them.

DangerIsland

You might also think about wrapping the headers while they're off. $50 in wrap and clips from summitracing.com and you'll reduce heat quite a bit and won't have to worrk about the heat shields so much.

Wachuko

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by DangerIsland:
<strong>You might also think about wrapping the headers while they're off. $50 in wrap and clips from summitracing.com and you'll reduce heat quite a bit and won't have to worrk about the heat shields so much.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Ditto... <img src="http://groups.msn.com/_Secure/0RgAAAFEVO*mn8xR3XlUWcnvd9ef4yfhU*q2nnnKEqCBN5lm*I0MxePnXNx0vqp5ODNvCrs1 V8F*BWofVZMpbXQBQS5V2otruaCeiK5p*fzM/engine-2.jpg?" alt=" - " />