as the motor is out due to the broken crank its time to fix a few other things also. The Perry LCB actually has a flang gasket. I didn't think it would be easy to find one which fitted and as expected no luck. One exhaust place said to use plain silicon as they use it on most cars. I didn't like the sound of silicon. But while at Burson i noticed they a heat resistant Copper Silicon so Ill see how it goes.

But what are your experiences with just silicon for exhaust gaskets

_________________
Stop Licking the Dog...I Don't Care Who Started It

Silicone sealant is good for about 400° or so.
But where that flange is (bottom of the 2 downpipes) it'll get to near red heat.
It might survive... but I doubt it. Try it and see.
I reckon you are going to need a flange gasket. Or, coating the 2 flanges with muffler putty then bolting together might work.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

We used roof and gutter to seal pretty much any gap on our fear car, it did backfire though and got sucked through the inlet and stopped a spark plug. then it killed the lambda sensor too. so it takes he heat bt destroys electrics.

_________________
Simplify and add lightness

I like the loctite hi temp red silicone for jobs like this.
If the flanges are really flat it should be fine. I used it to seal the combustion chamber to the turbine housing on my turbojet engine, it ran red hot and held up fine.

_________________
Dean Hutton's first car was a Mini.

I usually use Maniseal on exhaust joints.

For those wondering, Gaf's manifold is a Perry (or similar) LCB that some enterprising individual has cut the downpipes at the slip joint, and fitted mating double flanges... then bolted it together.
It had a gasket, but it's knackered.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Most exhaust places carry the stock flange gaskets.

Yep interesting one this one, I even had to show Greg @ Karcraft as he had never seen a Perry with a flang which fits under the back brace of the front subframe. Ill take a pic tomorrow for you all. I tried 5 different exhaust place in total an came up with zip and two offered to find and order in but were unable to get a match close to it. So I'm going to test out Permatex Ultra copper High Temp RTV Silicone. It's not cheap at $20 for a 85G tube but ill also use it further down the system to see how it goes with the temp

_________________
Stop Licking the Dog...I Don't Care Who Started It

Some one did remind me about this today. Considering I was looking for the gasket for the flange. I reluctantly went with this high temp silicon. Todate I could not complain and nor has my wife.
Must admit I really clean the surfaces and layed it on thick then bolt it up..Perfect and I would recommend it

_________________
Stop Licking the Dog...I Don't Care Who Started It

Glad to hear that you have had such good success with what could have been a headache - in more way than one!

_________________

we used silicon on both racecars, never had any problems.
One was a 350 chev , the other was a rotary. Both speedway super sedans running at max revs. the rx7s exhaust glowed from the extractor back to the muffler.

_________________
cheap work is not good, good work is not cheap