Carburetor Gasket Sealent

[f2502011]

Yes I know typically a no-no, but if you have to use a sealant what would you recommend? Gasgacinch, permatex high tack gasket sealant, Indian head shellac or?

 

[doran4x]

Why are you wanting to put sealant on gasket?


Sent from my iPhone using Tapatalk

 

[f2502011]

To see if it will seal an air leak that I haven’t been able to seal otherwise through different gaskets, machining etc.

 

[gnpenning]

What carb are you using??

Throttle shafts have been known to wear and create vacuum leaks.

Remove all linkage and springs and try wiggling the shaft. Quick and free.

 

[DirtDonk]

If I were going to use a sealant, I would try the Permatex spray on copper.
You can get a nice thin layer without creating something thick enough to squeeze out.

But ditto on the shaft.
And also make sure that the gaskets match the manifold and carburetor. Some manifolds have a very thin rail on at least one side of the carburetor, and it’s hard to get a good seal there.

 

[73azbronco]

yeah, no sealant on carb anything

 

[m_m70]

In the past I've had luck with doubling up on gaskets. Never tried sealant.

I see you tried machining?? We would check for warpage with a file on the bottom of the carb base and then the mounting surface of the manifold. That usually would fix things if there was a leak between the two surfaces.

Are you sure it's leaking at the gasket?

 

[f2502011]

It’s a Holley 4 barrel on a Ford Performance over the counter intake for a small block.

The leak just started and I’m not exactly sure where it’s coming from but vacuum leaks at the carb have been an issue in the past. It just also got cold here and I’m not sure if that’s a factor.

I don’t have enough clearance to double up on gaskets.

 

[f2502011]

What carb are you using??

Throttle shafts have been known to wear and create vacuum leaks.

Remove all linkage and springs and try wiggling the shaft. Quick and free.

Wiggle which way and what would I be looking for?

 

[m_m70]

I don’t have enough clearance to double up on gaskets.

What size/thickness gasket are you using????

 

[SteveL]

Have you tried spraying the base of the carb with carb cleaner(while running)? That should help find the leak. If you have access to another carb swap out the holley.

 

[gnpenning]

Wiggle which way and what would I be looking for?

Side to side and up and down. Pretty much any direction. In and out shouldn't cause a leak.

Have you started to use oil? The intake manifold even on the inside of the lifter valley can cause vacuum leaks.

What are the symptoms that you have noticed?

Can you hear the leak?

 

[Broncobowsher]

If I had to use something, I would use some grease. Yes, grease the gasket. It will seal a leak. If the leak is really bad you will see the blow trail in the grease as you take it apart.

 

[f2502011]

What size/thickness gasket are you using????

I have to use one on the thinner side otherwise the air cleaner and hood rub. Some stumbling and inconsistent throttle response. Probably been like this a while but yesterday was the first time I actually heard it. Minimal vacuum lines on the vehicle checked all of those. Has to be at the carb because it’s done it before. I’m going to try the grease. Done that before on other gaskets with some success. Any particular type? I’ve also used Indian head shellac before on other cars and seemed to fix it. What about a thin layer of that or some Gasgacinch? Or I could do gasgacinch on the intake side and grease on the carb side?

 

[f2502011]

Side to side and up and down. Pretty much any direction. In and out shouldn't cause a leak.

Have you started to use oil? The intake manifold even on the inside of the lifter valley can cause vacuum leaks.

What are the symptoms that you have noticed?

Can you hear the leak?

Should have absolutely no movement or minimal?

 

[m_m70]

I have to use one on the thinner side otherwise the air cleaner and hood rub

Gotcha......The carb gaskets I've always used have only been like .020 to .030 thick. I do run a phenolic spacer but that has gaskets on both manifold and carb sides.

I also use a VERY thin coat of grease on carb gaskets. Been doing that since the '60s........

 

[DirtDonk]

I have to use one on the thinner side otherwise the air cleaner and hood rub.

Is this a 351? Or are you using a taller intake than normal?
Or are your body bushings sagged out?
I’ve used the stock air cleaners and the super thick, insulating gaskets before, with no trouble.
Do you have any kind of a spacer under the carburetor?
Just curious what is causing your clearance issue.

Some stumbling and inconsistent throttle response. Probably been like this a while but yesterday was the first time I actually heard it.

Do you have any vacuum caps blocking unused ports? They often fail far too quickly and you can’t always see the leaks, except in the thick rubber ones where they show the cracks.
Definitely worth checking any caps.

 

[f2502011]

It’s a 302. Has an intake like Shelby would have used so it is higher than normal. The shafts have minimal to no movement and are essentially the same in all directions.

 

[gnpenning]

This is a process of elimination. You have some good ideas given on things to check. Keep crossing them off your list. Every time you are one step closer.

Keep in mind new doesn't equate to good. Just did a bunch of work on my plow truck. 2 of the "new" items were bad out of the box. The ps pump was a rebuild and I knew better than to trust a rebuild . First time I've had a voltage regulator bad out of the box even though others have it happen.

Do you by chance have vacuum brakes?

 

[f2502011]

This is a process of elimination. You have some good ideas given on things to check. Keep crossing them off your list. Every time you are one step closer.

Keep in mind new doesn't equate to good. Just did a bunch of work on my plow truck. 2 of the "new" items were bad out of the box. The ps pump was a rebuild and I knew better than to trust a rebuild . First time I've had a voltage regulator bad out of the box even though others have it happen.

Do you by chance have vacuum brakes?

Brakes are manual. Only thing using a port on the vac block is the trans modulator. Other port is capped.