Calling all triple carb experts

[Nigel1943]

Thanks for the help Nigel, Just to clairifiy what exactly do you mean by The "ear" should be just resting against the needle valve during this operation? Does that mean right as it touches the round head but no compressing the spring??

Correct!

[NismoZ]

OK, i got everything installed started it up and what do i hear? my Z that sounds like a Subaru and a SQUEAK SQUEAK to go along with it . I got a vacuum leak at the intake manifold... how reliable is the surface on a TWM intake manifold? do they need to be surfaced prior to installation. any suggestions?

Edited February 24, 2010 by NismoZ

[Lazeum]

Are you sure it is a leak? Use a hose with one tip close to you ear and the other one where you beleive you might have a leak to make sure about it.

Other solution is to spray some carb cleaner and check how engine react (if it revs, you have a leak)

You should also have some gasket there. You might want to try to tighten up a little the studs. If it is between carbs and manifold, try to turn bolt by half a turn (do not compress them completely if you don't want to crush the o-rings you most likely have in between)

How is your timing though?

[jmortensen]

OK, i got everything installed started it up and what do i hear? my Z that sounds like a Subaru and a SQUEAK SQUEAK to go along with it . I got a vacuum leak at the intake manifold... how reliable is the surface on a TWM intake manifold? do they need to be surfaced prior to installation. any suggestions?

A friend of mine had a leak like that on 44 Mikunis, sounded like a mouse or a bird was under the hood. Turned out to be a leaky throttle shaft. He didn't care because his was a race car and it's WOT most of the time.

If you're sure it's at the manifold, put a thin layer of silicone on each side of the insulators and that should prevent it. You could lay a straight edge on the manifold and see if it's warped, but the TWM stuff is usually pretty good from what I've seen.

[NismoZ]

A friend of mine had a leak like that on 44 Mikunis, sounded like a mouse or a bird was under the hood. Turned out to be a leaky throttle shaft. He didn't care because his was a race car and it's WOT most of the time.

If you're sure it's at the manifold, put a thin layer of silicone on each side of the insulators and that should prevent it. You could lay a straight edge on the manifold and see if it's warped, but the TWM stuff is usually pretty good from what I've seen.

Crap I hope its not the throttle shaft... all the carbs have been rebuilt so they should be good.. what I did notice was as the car was running i could see it was a little wet in between # 1 and 2 on the intake gasket. do most people use silicon seal along with the gasket or is just the gasket usually enough?

[jmortensen]

Gasket is usually enough. I used silicone on the exhaust ports to seal a header. It would probably work on the intake side as well.

[NismoZ]

Gasket is usually enough. I used silicone on the exhaust ports to seal a header. It would probably work on the intake side as well.

is there any particular kind i should use?

[jmortensen]

I would use ultra grey on the intake ports, copper on the exhaust ports if you need it. What I did with the copper was to put a really thin layer around the port and then hang the gasket up for an hour or two to dry and then bolt it up. Verify that your leak is really there first though with the carb cleaner.

[NismoZ]

I would use ultra grey on the intake ports, copper on the exhaust ports if you need it. What I did with the copper was to put a really thin layer around the port and then hang the gasket up for an hour or two to dry and then bolt it up. Verify that your leak is really there first though with the carb cleaner.

Well I already pulled the carbs off, I couldn't really get it to idle long enough to spray carb cleaner since they are not even tuned yet.. I did notice that it has wet spots on the gasket around the intake ports on #1 and 2 ... is that a good indicator of where the problem lies? i also ran a straight edge across the manifold and they seem to very a little but not much maybe a hair.

[jmortensen]

Well I already pulled the carbs off, I couldn't really get it to idle long enough to spray carb cleaner since they are not even tuned yet.. I did notice that it has wet spots on the gasket around the intake ports on #1 and 2 ... is that a good indicator of where the problem lies? i also ran a straight edge across the manifold and they seem to very a little but not much maybe a hair.

I wouldn't be able to make a good assessment as to whether the wet spots indicate a leak. If it's a brand new TWM manifold I think a leak where the manifold bolts to the head is relatively unlikely, but if you stick a straight edge across the whole manifold you can look to see if there is a gap between the middle runners. If that's what you did and they varied just a hair, I doubt the problem is at the head.

Using a graphite gasket, or a paper gasket? I had nothing but bad luck with the paper manifold gaskets.

[NismoZ]

I wouldn't be able to make a good assessment as to whether the wet spots indicate a leak. If it's a brand new TWM manifold I think a leak where the manifold bolts to the head is relatively unlikely, but if you stick a straight edge across the whole manifold you can look to see if there is a gap between the middle runners. If that's what you did and they varied just a hair, I doubt the problem is at the head.

Using a graphite gasket, or a paper gasket? I had nothing but bad luck with the paper manifold gaskets.

Its the MSA header Gasket, Im going to take a closer look at it. Since I have the n47 head the MSA gasket only had holes for the fuel injection manifold not the carb. So maybe when I made the the new holes it caused the gasket to not be flat like it is suppose to be.. its the only thing i can think of. Everything from the manifold back is new or rebuilt including spacers.

Maybe I should have tried reusing the previous MSA header gasket.

Edited February 24, 2010 by NismoZ

[jmortensen]

If it's the white paper MSA header gasket that I had, it sucks. Get a graphite gasket, it's compressible and will seal better and won't crack and cause an exhaust leak like mine did a couple thousand miles after I installed it. That's my opinion anyway, others may differ.