Plenum, Trumpet base and manifold.

CastleMGBV8 · Post by **CastleMGBV8** » Thu Dec 11, 2008 9:25 am

Just thinking forward a bit, I have an injection system off a 4.0 Gems engine which I intend using in the near future on my new 4.35 engine although I will have to swap the plenum for a earlier 3.9/4.2 because of height issues.

On inspection having split the three items there does not appear to be any form of gaskets or sealing between the manifold, trumpet base and plenum and wonder if this is normal.

I did see a Thor manifold and this had some form of rubber or neoprane gasket between the manifold and trumpet base, can anyone enlighten me?

Kevin.

bodger · Post by **bodger** » Thu Dec 11, 2008 10:38 am

Hi Kevin , i think they do a gasket that goers between the trumpet base and manifold as an after market item
http://cgi.ebay.co.uk/ROVER-V8-DISCOVER ... 240%3A1318
but as std it's just gasket gooo

i have a trumpet base sitting here you more than wlecome to it if you want , it's off a 3.5 but i think they are the same

CastleMGBV8 · Post by **CastleMGBV8** » Thu Dec 11, 2008 12:23 pm

Keith,

Thanks for the link, yes thats what i saw on the later manifold, I think I have also seen an isolator (heat) somewhere, dont know how effective they are but gathering info at the moment as won't be doing anything serious about the EFI til next year.

Thank for the offer of the trumpet base, but I already have the one that came off the 4.0 engine with the manifold fuel rail and injectors.

I will need a hotwire plenum from a 3.9 or 4.2 which I've been told will fit the later trumpet base as they are the same as the earlier hotwire ones and that will give me a bit more clearance under the bonnet.

I'll still need an EFI pump, swirl pot, ECU, poss megasquirt not decide yet, which all adds up to another £400+

Kevin.

bodger · Post by **bodger** » Thu Dec 11, 2008 12:41 pm

no porbs Kevin ...

Eliot · Post by **Eliot** » Thu Dec 11, 2008 1:58 pm

I use blue hylomar on them.

CastleMGBV8 · Post by **CastleMGBV8** » Thu Dec 11, 2008 5:58 pm

Eliot wrote:I use blue hylomar on them.

Thanks Eliot, just a light smear I presume.

Kevin

Seight-V8 · Post by **Seight-V8** » Fri Dec 12, 2008 2:47 pm

hiya,

I've always used unipart RTV compound silicone.

Basically its instant gasket....

A light smear on both parts the torque the bolts up....

Never had a leak...in over 10 years...

No running a tuffnol isolator and use it on both sides...still no leaks and works a treat.

Most automotive motor factors will have some form of RTV silicone.

scott

CastleMGBV8 · Post by **CastleMGBV8** » Fri Dec 12, 2008 3:29 pm

Scott,

Thanks, tell me more about the Tufnol isolater and how thick is it, as I have height problems in the MGB even with an RV8 bonnet with bulge for EFI.

Kevin.

Seight-V8 · Post by **Seight-V8** » Sun Jan 11, 2009 6:35 pm

kevin,

its basically 4mm thick tufnol sheet with the 8off inlet holes cut into it.

You can buy them for £65, but get the tufnol off ebay for £6 and make your own.

I also had 4mm machined of the bottom of the trumpet base, to keep the heights and inlet runners the same length.

Some rtv both sides and runs a treat.

Think they recon you can get 9-12bhp by using one, as the plenum runs very cool.

When mines running at operating temp, the plenum just feels luke warm.

Worth the money for me, but its up to you.

Got some pics somewhere if you want me to mail them over to you.

scott

CastleMGBV8 · Post by **CastleMGBV8** » Sun Jan 11, 2009 9:16 pm

Scott,

That's interesting 9 -12 BHP I suppose with a cooler denser inlet charge. that may just be possible.

Where did you get yours from?

Kevin.

bodger · Post by **bodger** » Mon Jan 12, 2009 3:24 pm

Hi Kevin , i was looking at those things the other day , if you want o go halfs a on a sheet on ebay

i don't mind ordering it if you wish , i have just measured the trumpet base and it's 300mm x 100mm approx so a sheet that they are selling would do 2 ???

and i would imagine that MODERN SCREWS in bexley would do the longer bolts needed

http://cgi.ebay.co.uk/5mm-CARP-SRBF-TUF ... 240%3A1318

chodjinn · Post by **chodjinn** » Mon Jan 12, 2009 4:51 pm

thirds anyone?! Anything for a few cheap bhp on an RV8 is gotta be worth it!

CastleMGBV8 · Post by **CastleMGBV8** » Mon Jan 12, 2009 10:05 pm

bodger wrote:Hi Kevin , i was looking at those things the other day , if you want o go halfs a on a sheet on ebay

i don't mind ordering it if you wish , i have just measured the trumpet base and it's 300mm x 100mm approx so a sheet that they are selling would do 2 ???

and i would imagine that MODERN SCREWS in bexley would do the longer bolts needed

http://cgi.ebay.co.uk/5mm-CARP-SRBF-TUF ... 240%3A1318

Keith,

Nice idea but I wouldn't have a clue how to make it unless we could persuade Eliot to make up a batch?

Kevin.

Wotland · Post by **Wotland** » Tue Jan 13, 2009 7:49 am

SC Power sells an trumpet base insulator gasket for 15GBP+VAT and 3GBP for delivery.

Aviaible for 38mm and 45mm trumpets.

CastleMGBV8 · Post by **CastleMGBV8** » Tue Jan 13, 2009 2:46 pm

Dimitri.

Thanks, for that money it's hardly worth trying to make one.

Kevin.