OTish - can use use dumdum for sealing exhausts and manifolds?

No. And most silicone sealant won't stand exhaust temperatures either. There is a good reason why that horrible stuff you refer to is still on the market - none of the possible 'nicer' alternatives will stand the conditions.

JD

Have you any idea how hot an exhaust manifold can get ???? Either learn to weld better, or use the exhaust seal stuff. Could I mill you some seals in copper sheet perhaps ?

Steve

its only an n/a. it cant get that hot can it? i've use silicone on my turbo (joint between turbo and downpipe) and that worked!

Its not leaking round the bits ive welded! :p - its the head-manifold joint and the manifold-downpipe flanges.

the old gasket was the funny metallic sandwich stuff.

I thought that 'proper' silicone should be able to take the heat?

It can get to just below "red" heat without too much effort,even NA - so that's close to 600 C.

Steve

In my experience Firegum only works in conjunction with the correct gaskets - it doesn't stick well enough to work on its own, unless the seal is nearly perfect without it.

High temperature silicone will work further down the exhaust, but can't cope with the heat at the manifold end.

Which any decent motor factors should have in stock. It's not too hard to cut gaskets from it if you can obtain a sheet.

As an interim solution it works. I've had more luck using the intumescent fireproofing s**te used to seal round pipes through fire rated walls in buildings (despite it not being designed for exhausts). Nige might be able to point you at something like that - I expect he uses it to seal round alarm cabling.

I have a Rimmer's SS system on my SD1 and after many years use one of the heatshields for the gearbox broke off. There's an excellent SS exhaust fabricator nearby and he kindly TIG welded it back on for not much money. He had to remove that downpipe to do this. The downpipe to manifold gaskets are sort of composite copper O rings and he didn't have any so used his favourite silicone. Didn't last. It was blowing like a good 'un after a few days. To be fair he did say this might happen. I have a stock of the O rings so fixed it myself. Anything after the downpipes seems to be ok with silicone, though.

Bastard thing.

Have taken the manifolds off the engine. No signs of any blows at any joints. Reassembled with 2 gaskets after i scoured my stash of gasket sets (it has a heat shield between the head and manifold so you can fit a gasket either side) It still ticks.

Tom Woods uttered summat worrerz funny about:

Spark plug?

Head Gasket?

Saab?

:-)

Lee D

they are all tight ad sparking and not very old. not taken them out to check further.

Hmm. its all of 2000 miles old. might pull the plugs and do a compression test while im at it

yep

On or around 4 Nov 2007 21:43:01 GMT, Tom Woods enlightened us thusly:

what sort of seal? The turbo transit Di doesn't have manifold-to-head gaskets, it's sealed with sealer. Someone told me to use loctite.

well, looks like it isnt the exhaust manifold!

compression test says ive got 150psi on 3 pots and zero on no 1. Its got a spark

Oil and water are fine though and it doesnt seem to be pressurised so i'm guessing it could be a valve spring or valve and the noise is the cylinder contents going back into the inlet manifold or somthing?.

Saab engines are definately built well - i've done about 50 miles today seemingly on 3 cylinders and it is only a little bit slower than it should be (though the idle leaves a lot to be desired!). Getting my best ever mpg too! ;)

Not having much luck with bloody engines are you Tom !

Steve

The 101 engine is fine! Its just a shame its dashboard lights and swivel seals arnt as good (it looses everything out of the swivel in one day!). Gonna fix the dash lights tommorrow and stock up on ep90 and drive in style for a while (since im fixed at one work place for the next 4 days so dont have to worry about parking it)

Did you put new seals in ?

Fit a drip tray !

Steve

not yet but i have em ready to do so.

im not worried about leaking in the work carpark ;) - its just bloody tricky squeezing a 101 ambi in there (and getting it out again!) unless you get there first thing! This isnt a problem when im at one site all day (as i am now for a while) but is when im doing 50+ miles going to 3 or 4 places.

On or around 6 Nov 2007 22:46:52 GMT, Tom Woods enlightened us thusly:

can you use one-shot grease in the 101? Might stay in there a bit longer.

Also, check yer swivel bearings, 'cos swivel leaks can be caused by slack swivel bearings, although you've probably done that.

The biggest argument I've heard against one-shot is on vehicles with railko bushes on the top swivel.