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Trouble with dialing in tripower carbs

Kid_Again

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OK, so I just rebuilt my carbs and, as far as I can tell, they're back together the way that they should be. I trued every mating surface that I could reach, threw a rebuild kit into each and also replaced all six butterflies.

I can start the car but it feels like it has a vacuum leak the size of Montana. First, I have to idle it way up to keep it running. Second, the idle adjustment screws have absolutely no effect when turned...I can turn them all the way down with no difference. It smells rich but not too bad. Backfiring like crazy and turning the distributor has little effect...but i can advance it to the point where it dies.


Hmmmm

All the little vacuum hoses are where they're supposed to be. I'm taking PVC vacuum from the manifold, just below the center carb, on the passenger side.

Geez, with it running this bad, and if it were a vacuum leak, you'd think I'd hear it.

From what I can see, everything that should be is where it's supposed to be.

Maybe the secondary valve diaphragms are leaking?

Still, that's gotta be a BIG leak if it is one.

Any ideas?

Thanks
 

gmjunkie

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Man I feel for you,I had big problems with the Goat!!!!:W:WIt took me 6 months to get it close to right,and I'm still not Happy!!:boogieI had the carbs on and off at lease 50 times!!Have you had the heads milled any???Thats where I found most of my problems!!
 
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I can start the car but it feels like it has a vacuum leak the size of Montana. First, I have to idle it way up to keep it running. Second, the idle adjustment screws have absolutely no effect when turned...I can turn them all the way down with no difference. It smells rich but not too bad. Backfiring like crazy and turning the distributor has little effect...but i can advance it to the point where it dies.

Ineffective idle mixture screws typically result from having the throttle plates too far open at idle, so it's idling from the transfer slots instead of from the idle orifices.

Backfiring through the carb, or after-firing through the exhaust?

:beer
 

Kid_Again

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Don't know what happened to my initial response to your posts:confused


ANYWAY...it backfires through the exhaust


i certainly found one problem since I took off all the vacuum hoses, plugged every vacuum port so that i can start with a clean baseline....the problem i found was the "t" that connects the secondary vacuum diaphrams to the primary carb was cracked (why i didn't notice that before is still a mystery and HOW i broke that is even odder)....i have yet to restart it and replaced the "t" with another plastic version...i just bought a brass "t" to make sure I don't have that problem again

every other vacuum hose and fitting has been checked again

here's another question but neither VNV or i think it would result in a problem

...the engine is a stock zz440...when i removed the OEM intake, i notice a GOB of gack at the front and rear of the lifter valley to ensure a seal...i'd guess there was a 1/4" gap...so when i put the tripower manifold back on, i put what i thought was enough black RTV at each end...but obviously not....and i didn't discover that until i had shut it down...so i re-sealed the front and rear and there are no gaps....could that have contributed to the rough running?....i still think not

thanks for the help!:m
 
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...the engine is a stock zz440...when i removed the OEM intake, i notice a GOB of gack at the front and rear of the lifter valley to ensure a seal...i'd guess there was a 1/4" gap...so when i put the tripower manifold back on, i put what i thought was enough black RTV at each end...but obviously not....and i didn't discover that until i had shut it down...so i re-sealed the front and rear and there are no gaps....could that have contributed to the rough running?....i still think not

thanks for the help!:m

Nope, wouldn't affect how it runs - only how it leaks :).
 

Kid_Again

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OK John,

this is the only thing that i can think of (since i've tried everything else)...

....would the engine display these symptoms if i put the distributor in 180* out of synch?
 

bossvette

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I was chasing a vacuum leak on my Old Yellar truck, it turned out to be from the heads having been cut enough so the intake would not seal properly, different set of heads runs fine now. It was drawing from the underside and passed the starting fluid test.
 

gmjunkie

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I was chasing a vacuum leak on my Old Yellar truck, it turned out to be from the heads having been cut enough so the intake would not seal properly, different set of heads runs fine now. It was drawing from the underside and passed the starting fluid test.
Thats what the problem was on the Goat!! I had the intake shaved a Little,and it's seems alright Now!!:upthumbs
 

Viet Nam Vett

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I was chasing a vacuum leak on my Old Yellar truck, it turned out to be from the heads having been cut enough so the intake would not seal properly, different set of heads runs fine now. It was drawing from the underside and passed the starting fluid test.

The Motor in his wreck is a ZZ454 with Alum heads,brand new motor. The same heads my 502 uses. They are oval intakes. I think he leak tested them while running.
 

Kid_Again

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yeah, sorry...i neglected to respond to the question about the engine


......it's stock, never had the heads off and it ran perfectly prior to the tripower swap....and i had this tripower setup on the old 427 and it ran fine, except for the gas leak upon hot soaking and that problem is totally cured now


so, it's back to basics with the understanding that i've caused a problem but it may not be the carbs/manifold per se....

....i re-checked the clocking of the distributor last night and it is correct, so i didn't do something stupid there

...it's running so badly that, while i'm still suspecting the carbs, its beginnig to sound like an ignition problem to me so i'll ohm out all the wires, check for shorts and generally putz around all the electrical connectors...when i turned over the engine to find #1 TDC last night with the remote switch connected to the starter (REALLY glad i switched to a high torque ministarter - thanks to VNV!), i noticed the coil arcing to both the postive and negative terminals...it got too late but i wonder if i have a cracked coil tower and didn't notice it?

...the ignition is an MSD6A box driving an MSD distributor...i didn't do anything dumb like drop the distributor

...any tests that you can recommend for the 6A box?....if all else fails, I have a brand new 6A that i can swap out



"Other than that, how was the play, Mrs. Lincoln?":eyerole
 

bossvette

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MSD's require plenty of juice you want to see close to 13.5 volts; how are the battery and alternator, it helps to have each head grounded also. I had put a new battery in the YT once that only put out 12 volts and the MSD 6A would not fire took the battery back carrying my voltmeter with me and found one that read close to 14V and that fixed it, it took a call to MSD to sort that one out but the tech told me to be sure to have plenty of juice it was a common problem.
 

Kid_Again

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Hey Craig:

Thanks for the reply.

The MSD is grounded directly to the battery. The hot wire/ground are at least 6ga. New Optima Red Top (VNV spending my money again) and a new 140amp Powermaster alternator. It's great to idle the car and see your battery charge - even with the dual radiator fans on low. Dagnabbit!!!!

With my electrical systems, I CAN NOT take the chance that I get a frown from Mark when I open the hood.

Mark...I'll fabricate your spacer on my Nazi lathe this weekend
 

bossvette

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the idea behind grounding the heads is that the electrons have a good path back to the battery from the spark plug electrode. It was in the instructions from MSD way back when.
well you could always put that stock system on the shelf and let its value rise for the NCRS guys and put a BG six shooter on it I'll bet that would help and 98% of the people looking at it wouldn't know the difference ;LOL
 

Kid_Again

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the idea behind grounding the heads is that the electrons have a good path back to the battery from the spark plug electrode. It was in the instructions from MSD way back when.
well you could always put that stock system on the shelf and let its value rise for the NCRS guys and put a BG six shooter on it I'll bet that would help and 98% of the people looking at it wouldn't know the difference ;LOL



....don't tempt me, that's EXACTLY what i told VNV!!!
 

Viet Nam Vett

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Mark...I'll fabricate your spacer on my Nazi lathe this weekend

The lathe is down OC.... your up in Hopewell with the round stock...???How you gonna do dat..?:D
 

Kid_Again

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The lathe is down OC.... your up in Hopewell with the round stock...???How you gonna do dat..?:D

...i am in hopewell
...the round stock is in hopewell
...the nazi lathe is now in hopewell (Deutschland, Deutschland uber alles...)


....at 7AM, i'll fire up the big block and try the wd40 test on the carbs
 

Kid_Again

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OK, just fired it up and one of two problems solved

the first problem was a short in the ignition system - the white wire to the MSD box that i had cut and sealed lost its taped end and was shorting....now that i took care of that, the engine will get down to a decent rpm BUT

...the center carb is the current problem...i now see that the driver's side primary venturi is spilling gas, even at 1000rpm where the passenger's side is not drawing any fuel from the primary...it's still backfiring but not as much....

...what would be the cause of that?

my first inclination is that the butterfly on one side is opening earlier but it doesn't LOOK like it is

ANY IDEAS?

thanks
 

bossvette

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OK, just fired it up and one of two problems solved

the first problem was a short in the ignition system - the white wire to the MSD box that i had cut and sealed lost its taped end and was shorting....now that i took care of that, the engine will get down to a decent rpm BUT

...the center carb is the current problem...i now see that the driver's side primary venturi is spilling gas, even at 1000rpm where the passenger's side is not drawing any fuel from the primary...it's still backfiring but not as much....

...what would be the cause of that?

my first inclination is that the butterfly on one side is opening earlier but it doesn't LOOK like it is

ANY IDEAS?

thanks

trying to get old carbs running is like :BDH sometimes the castings leak
sometimes the passages get clogged; the butterfly's are on the same shaft they should open together unless one is bent.

....don't tempt me, that's EXACTLY what i told VNV!!!

If you want a dependable driver; I'll bet his tech support is top notch so I'll tempt you some more. ;LOL
 

Tom Bryant

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Do you know what your fuel pressure is?
 

Kid_Again

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good question tom, it's ~5 psi at idle, it's a mechanical street pump

...ok, fired it up again and did the "VNV" test...sprayed wd40 all over the carbs and there was no difference in idle speed nor did it smoke


hmmmmmmm

took the center carb off and here's what i noticed, at least preliminarily....

the float level is fine, there was no schmutz in the float valve which could have held the the valve open, the o-ring is fine with no tears......all the passages in the metering block were clear, same thing in the carb body...the 6.5 power valve works fine and is not cracked, it was tight and had the correct gasket.....i THINK the metering block gasket is correct (appears to leave the correct holes unplugged) but will re-check that

...the jets were tight and are the same that worked fine on the 427......the throttle butterflies may be a BIT off but i don't think its serious, see what you think -> at full stop (idle screw backed off the stop), both transfer slots are blocked and when i open the throttle, the driver's side opens a TCH before the passenger side

...the driver's side idle richness screw was a problem...when i went to turn it, the cork seal turned in the hole which means i couldn't adjust the richness on the driver's side but wonder if that caused enough of a leak to cause all of my problems?

....the throttle shafts seem to be tight enough in the base plate (bushed previously but nothing done to them recently)


maybe its because the car is nassau blue???

...whatever's the problem, it's something that i did to the carbs, i'm sure but i sure as hell can't figure out what that is
 

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