Quadrajet Question ----

[Bill C.]

Hey all ....

Is there another way to seal the well-plugs in the base of the body, other than the epoxy that carb rebuilders are currently using?

It seems that with intrduction of 10-15% ethanol - the epoxy degrades after about 9 months or so and causes issues.

This is the 2nd time in the last 2.5 years I have had issues. I am almost crazy enough to have them tig welded permantly closed.

[Clem Z.]

Re: Quadrajet Question ----

any Qjet built after 1969 should not have a leakage problem as the aluminum plugs are "spun" into the main body.

[Joe L.]

Re: Quadrajet Question ----

Hey all ....

Is there another way to seal the well-plugs in the base of the body, other than the epoxy that carb rebuilders are currently using?

It seems that with intrduction of 10-15% ethanol - the epoxy degrades after about 9 months or so and causes issues.

This is the 2nd time in the last 2.5 years I have had issues. I am almost crazy enough to have them tig welded permantly closed.

Bill-------


I'm VERY surprised that ethanol added to gasoline would cause a problem with the epoxy. Basically, an epoxy is HIGHLY resistant to degradation by organic solvents, including alcohol. I think I'd try a different epoxy. You might want to find an aerospace supplier and purchase a special epoxy designed for aerospace applications. It might be expensive, but you don't need much.

[Clem Z.]

Re: Quadrajet Question ----

Bill-------


I'm VERY surprised that ethanol added to gasoline would cause a problem with the epoxy. Basically, an epoxy is HIGHLY resistant to degradation by organic solvents, including alcohol. I think I'd try a different epoxy. You might want to find an aerospace supplier and purchase a special epoxy designed for aerospace applications. It might be expensive, but you don't need much.

ethanol gas has been a problem for boat owners who have fiber glass tanks as it dissolves the resin in the fiberglass

[Joe L.]

Re: Quadrajet Question ----

ethanol gas has been a problem for boat owners who have fiber glass tanks as it dissolves the resin in the fiberglass

clem------


That does not surprise me. Fiberglass resin, especially older formulations, is less resistant to organic solvents, including ethanol, than epoxy. That's one of the reasons why I am surprised that folks with Corvettes with 36-1/2 gallon tanks have not experienced severe leakage/tank deterioration problems before now----actually, LONG before now.

I think the fiberglass boat tanks would eventually have problems even if there were no ethanol in the gas. However, the ethanol may accelerate it, especially for older tanks that have already been "ravaged" by the non-ethanol gasoline.

[Bill C.]

Re: Quadrajet Question ----

The body had issues with the well plugs leaking back when I purchased the car (8 years ago). I had a guy in NJ do the rebuild and it was fine for 5 years.

Then came ethanol

I put the carb back on after the resto - was fine for about 6-7 months and then leaks..
Had it rebuilt by the same guy in NJ - no issue until about a year later (now).

He assured me that he uses a high strength and solvent resistent epoxy.
====



Thanks for all the good ideas - I will research an epoxy and do the work myself this time.

[Edward J.]

Re: Quadrajet Question ----

Bill, keep in mind there is also alot of heat under the the body, get something also that may withstand heat generated from the intake manifold.(expansion and contraction may crack epoxy).

[Stuart F.]

Re: Quadrajet Question ----

Back in the early 70's, there was a kit available that used a block of material in the well that I suppose either held the plugs in place and perhaps insulated them from heat as well. Does anyone recall that? I used one in my special built QJ on my 72 just as a precaution to prevent that from occurring. Earlier years were notarious for leaks it was common practice to insert one of these blocks to head off the problem, i.e. proactive kinda.

Stu Fox

[Stephen B.]

Re: Quadrajet Question ----

Consider JB Weld. I have not tried it.

[Bill C.]

Re: Quadrajet Question ----

Thanks for the replies...


Stu -
I hope someone chimes in with regard to the kit.
I would love to give it a try.
I personally think that the fuel blend is more responsible than the heat.

Once the wells are epoxied, I don't know of any way to go back to the cap inserts...

[Clem Z.]

Re: Quadrajet Question ----

set the main body on a clean sheet of white paper resting on the plugs. fill the float bowl with lacquer thinner and let it set. after while check the paper for wet spots. redo the same after setting the body on a hot plate to warm it up. that is the way i check my rebuilds

[Joe L.]

Re: Quadrajet Question ----

Back in the early 70's, there was a kit available that used a block of material in the well that I suppose either held the plugs in place and perhaps insulated them from heat as well. Does anyone recall that? I used one in my special built QJ on my 72 just as a precaution to prevent that from occurring. Earlier years were notarious for leaks it was common practice to insert one of these blocks to head off the problem, i.e. proactive kinda.

Stu Fox

Stu------


Yes, it was a piece of some sort of very dense, fuel resistant foam rubber, cut to fit the area under the plugs. It was supplied with carb rebuild kits and might still be so-supplied. I don't know that it was ever available as a separate kit, but it may have been so-available.

[Clem Z.]

Re: Quadrajet Question ----

the early Q jets used 2 cup type expansion plugs which leaked so there was a kit that used plugs with with "O" rings to seal after you removed the original plugs but once the spun in plugs came into use the leaks were pretty much gone. i have to remove those spun in plugs to modify the carbs for racing and they are in there to stay because you have to drill them out

[Edward J.]

Re: Quadrajet Question ----

Joe, if that is what Stu is talking about, that piece did come in the rebuild kits, I may even have a few of these at my shop,from prev. carb rebuilts.

Bill, if you want I will look for ya and put one in the mail.

[Bill C.]

Re: Quadrajet Question ----

The carb rebuilder drilled out and epoxied four places.

1. Outside, front by fuel inlet
2. the two small wells in front by the PCV inlet
3. A larger well, directly under where the secondary metering rods go.


The last time it leaked from expoxy lifting, was under the center well.
The front smaller ones seemed to be okay.

I plan to take the carb off Monday and use the lacquer thinner/paper test to look for leaks.

I REALLY appreciate everyones suggestions - very helpful.


Once I have this bugger fixed, I may just buy a new Holley spreadbore for driving. I would hope that since it is new, it will handle ethanol blends better than the Qjet.

If I should go this route - what is the best way to store the carb so it does not get varnished inside?
Can I fill it with say "sea foam" and leave it sit wet.
SUGGESTIONS are greatly appreciated.

Thanks in advance!