[gtorich]

just noticed this the other day, after shutting off the car i had a good drip for a minute or so............so today i took off the rod between the front & back carb, drove about 10 minutes, checked again, it was dripping while running & after shutting it down.

I have a non vented gas cap, 66 gto...............i took that off while car was ideling, drip stopped..................let it run awhile, then shut down no drip.

Of course i put the cap back on and drove around for awhile..................as usual with this car it wont do the same thing twice...................no drip.

Will drive around more tonight and see if anything happens...................center carb and rear dont drip.................i have the mike wasson ball seats in place of needle and seats.

Any guesses on this......................still running without the outer carbs hooked up for testing.

Rich

[gtorich]

Ok, took car out for another ride, got it warmed up good................stopped to check while running, dripping in the front carb, the front & rear are not hooked up, dont think i went over 35 mph so not sure why the front one would be getting gas.......................after this check i took off the gas cap and drove home, no drip while running, and no drip sitting for a few minutes.................not sure what to check next..............i have the vent tube in the trunk, looks right as far as i know................will dig into this further

Rich

[gtorich]

LOL...................ok, drove around with the cap off for awhile...................didnt matter, still dripping, talked to dick boneski, hes thinking the front needs to come apart, so guess im out of commision for some time.

Rich

[carbking]

The fuel block is connected to the front carburetor.

IF there is excessive pressure in the line, the front carb will leak, relieving the excess pressure.

When Rochester built the tripower carbs, they used a significantly smaller orifice in the two end carbs than the center carb. These are available in the better carburetor kits. You did not specify orifice size in your valves.

The fuel cap on/off MAY have significance (increased line pressure) or it may be coincidental. When the car is hot, and the weather is hot, do you get a "whooosh" when removing the cap?

Jon

[gtorich]

Originally Posted by carbking

The fuel block is connected to the front carburetor.

IF there is excessive pressure in the line, the front carb will leak, relieving the excess pressure.

When Rochester built the tripower carbs, they used a significantly smaller orifice in the two end carbs than the center carb. These are available in the better carburetor kits. You did not specify orifice size in your valves.

The fuel cap on/off MAY have significance (increased line pressure) or it may be coincidental. When the car is hot, and the weather is hot, do you get a "whooosh" when removing the cap?

Jon

LOL, hey Jon, but the time i bend over with my old ass legs, and my bones creaking i dont hear any "whoosh" taking off the cap.........i was thinking maybe too much fuel pressure since i replaced the fuel pump, just seems odd the other two are not dripping anything.............guess i have to check on this also.............as for now im just gonna run on the center carb untill dick boneski gets back from norwalk..............he only lives a few miles from me..............just odd noticeing this issue, the only thing i did different from years ago after getting the motor re-ringed was taking out the fuel filter before the fuel pump............so i had a filter before pump and then the blue tri power filter before crab, which everyone said you dont need that filter before the pump..............so who knows.............never had a issue with these carbs in the last 10 or so years, just seems odd now for this to happen...............Dick said this carb will have to come apart.................will be interesting to see what the problem is/was.

Rich

[chrisp]

Hook the end carbs linkage up & go for hard ride open them up , may just be a piece of something in the 1 & will come out after a few openings of the end carb

[Dick Boneske]

Thank you for all the suggestions. I eliminated the problem by setting the float levels much lower. The problem is solved.

I hadn't noticed, but for '57 and '58, Pontiac recommended a different way of measuring float level. On every other Rochester 2 barrel I've worked on, the float level was set by measuring from the airhorn gasket to the parting line on the float. the '57'58 procedure measures from the airhorn gasket to the top of the float. The measurement is 1 5/16", which is about 1/4" lower than the other Tri-Power years.

[gtorich]

Dick, glad you figured that one out.....................i did a fuel pressure test today................got the needle pegged at 7 lbs..............will look for a different tester, the one i have is for vacuum and gas..................dont know how accurate that is.........................i bought this fuel pump from ames..............M4507 i believe is the number.................sad that you have to test everything you buy and hope its correct.

Rich

[Kenth]

Originally Posted by Dick Boneske

Thank you for all the suggestions. I eliminated the problem by setting the float levels much lower. The problem is solved.

I hadn't noticed, but for '57 and '58, Pontiac recommended a different way of measuring float level. On every other Rochester 2 barrel I've worked on, the float level was set by measuring from the airhorn gasket to the parting line on the float. the '57'58 procedure measures from the airhorn gasket to the top of the float. The measurement is 1 5/16", which is about 1/4" lower than the other Tri-Power years.

Wrong thread?

[Dick Boneske]

No. The answer was correct for this thread. Float levels on the small end carbs for '57 and '58 are much lower than the later large end carbs. And, the method of measuring float level is different.

[Kenth]

Ok, just thought your reply here would fit in your own thread:

https://forums.maxperformanceinc.com...d.php?t=867744

Glad you solved the issue!

[gtorich]

Originally Posted by gtorich

Dick, glad you figured that one out.....................i did a fuel pressure test today................got the needle pegged at 7 lbs..............will look for a different tester, the one i have is for vacuum and gas..................dont know how accurate that is.........................i bought this fuel pump from ames..............M4507 i believe is the number.................sad that you have to test everything you buy and hope its correct.

Rich

Just to update............put the old pump back on ac delco 40373............so far no issues at all, no drip while running or when shut off............not sure what is pump is rated for but no problems so far................when looking at the ames catalog, doesnt show a pump for less that 6.5............so not sure how that is supposed to work on a tripower car.

Rich