just been welding my manifold up (thanks Jason at short track )

is there anything i can use on the insides of the tubes to smear round to smooth out the airflow (round tube, and the intake ports on the head aren't round, you get the idea)

would need to be something soft that won't ruin the engine and valves if it fell in, and petrol resistant.

or an i worrying about nothing, will it not make much difference if there's a few bumps in there?

I used chemical metal.

i thought of using that, wasn't sure if it would cause a problem if bits broke off and fell in?
bent valves etc?

Epoxy resin, its even used inside cylinder heads to build up ports.

Just make sure whatever you use is petrol resistant and has a good key so it grips well/cannot fall out.

Regards Mark

well, I hope it wont fall off.

I have so far only driven around 80mi to SVA and back, and the manifold is still as designed.

It is petrol resistant and can handle the temps.

You can smooth it nicely with some sandpaper as well.

I would have thought that if it affected by heat/petrol it would slowly wear away rather than break off.

i'll certainly be looking at epoxy resin and chemical metal tomorrow then

lars, i was thinking perhaps vibation might take its toll, butr if the surface is keyed it should be fairly secure

the inside of mine's not too bad, but i did manage to blow a hole in one of the tubes right at the last bit annoyed to say the least. managed to build the weld up on the outside to fill the hole so not all lost, but its left a bit of a hole inside

I attached round 2" pipe onto a zetec manifold plate. THis meant that I actually used a fair bit of chemical metal. So I am not sure that even if it broke loose that it would actually make it to the valves.

(In the worst case I fit my spare engine.)

is chemical metal the same as epoxy resin?

Hi,

Hope I'm not hijacking the post, but on the same subject.....

Is there any reason that silicon cannot be used to seal holes in the TB's?

I am fitting GSXR 600 TB's to the ST170 manifold. I am going to mount the injectors in the manifold and therefore need to block the old injector holes in the TB's. A 1p piece fits in the hole perfectly, so what is to stop me fixing the 1p in place with silicon. Also, the holes in the TB sides where I have removed the secondry butterflies need filling. I propose to fit cut down cap heads into the holes from the outside and again fix with silicon. This way there is no danger of anything breaking away and being drawn into the engine.

Is there any reason I cannot do it this way?

TIA,

Mart.

lol no hijacking going on my manifold's done

if using silicone to fill an area the size of a 1p, i think the vacume created might pull the silicone out.

small peice of metal to cover the hole with a small overlap, then cover with 'chemical metal' maybe a better option?

I usedJB weld to build up the inside of a manifold ive worked on before, this smoothed out well. i wouldnt use silicon. I joined my carbs to manifold using silicon hose and it went mushy. i also know you shouldnt use silicon anywhere near a fuel tank so will probs be bad news in the manifold.

Doesnt silicon take out lambda sensors too in FI systems?

Cheers Guys, JB Weld it is then.

I just wondered about silicon because when I was racing karts about 20 years ago (blimey, am I that old!) we used to use silicon to seal the head gaskets on the Villiers engines.

Blake82, sorry, I wasn't very clear. There's a lip inside the injector hole and a 1p sits inside the hole and rests on the lip perfectly. I was going to fix the 1p in place with silicon rather than fill the entire hole with silicon.

Cheers,

Martin.

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