The V8 Owners Forum -

What would anyone recommend for sealing my collector to my primaries?
Tried using a regular exhaust paste but that wouldn't let me fit the collector. After 2 hours of tapping the primaries there was still an 25 mm to go!
I though of using a high temp grease like copper slip. Anyone use this with success?



tom

That's all I use & it makes getting it apart at a later date easy.

Regards Ged

Hello Tom, I has a similar problem when fitting my SS tubular exhaust to my STP Vitesse way back in 1994. The paste just binded everything so tight - impossible - so I came up with a cute workaround because if its that tight it must be a pretty good fit from the get-go.

First off - a question - does the collector fit on the output of the primaries without any paste? Of course it does - slapped wrist for me!

So, if you very slightly bell the end of the female part and fit the male as far in as it will go, then slip it out (say) 10-15 mm.

Now paint a mixture of your exhaust paste well amalgamated with some silicon grease all around the circumference of the withdrawn section and tap the fitments back together, you will get some friction free effect from the silicon, but the paste particles will also enter the void and when the almagum dries out it will leave the paste in situ to seal as required

It does not take very much paste to seal an obviously good fit.

Thanks guys,
Yes it has been assembled in the past. I've changed the engine and had quite a job taking my exhaust apart. Originally i used an exhaust paste which was a pain to fit but this time round i didn't want to know. The paste had already started going hard even though i tried fitting it straight after applying the paste. Crap!
It is a good fit so I'll have a play with the paste and try a concoction, or I'll try copperslip
Tom

I just use grease. It lets it all slip together nicely and the grease carbons off at heat to form a seal, but doesn't seem to burn on hard.
Not done it on a car yet, but have done so a few times on my bike.

Hi Temp copper based silicone might work.

But it's basically down to the design of that collector.

You could have a proper merge collector made where the collector pipes would actutally seat against the collector and would not leak by virtue of design.

One will cost over £200 though, but they are work of art.

Thanks for the sugestions.

Last night I thought i'd measure the diameters of the collector and the primaries to see how much clearance I had then I would pick a sealing method to suit.

Well the ID for the 4x collector inlet measured about 41.5mm, 3 of the primaries measured 41.4mm OD which is great, nice fit BUT one measured 41.8mm so no wonder I could only get it on about 5mm. Don't know how this happened, It used to fit, pre-new engine. I had the primaries pollished but I can't see how they would have 'squashed' the end of one? maybe they 'nipped' it in a vice?

First off - a question - does the collector fit on the output of the primaries without any paste? Of course it does - slapped wrist for me!

Thanks Ramon, seems things aren't always as you left them!!

Anyway tonight i will 'nip' it in the oposite direction to make it round then have ago at re-fitting the exhaust. I'll be sure to measure the other side before I spend 2 hours sweating trying to fit it

Tom.

had a similair issue with my westfield exhaust.

Took mine down to a local exhaust manufacturer/supplier

Who expanded each exhaust/matching pipe to be a nice snug fit.

Now its a nice fit i dont need to put any sealant in...and it doesnt leak any gas.

Cost me £20 to do all 8 ports on the exhaust.

Much better job than sealant or clamps.

If you match them, get them to make a nice tight but useable fit.

job done.

scott