Hello everyone, new to this forum, First off I bought a 455 crate motor, typical stuff edelbrock performer, edelbrock carb etc don't have the cam grind specs -you know how the crate builders like to keep it secret, just your typical bump. This motor ran fine with what came from the builder. I however had to have the tripower for my 66 - this is where the dilema started, the intake I bought was shipped with all three carbs mangled, so I purchased 3 new ones from the only people that that seem to sell the correct style carbs eveyone knows who I am talking about, I'm not going to mention their names becauase I have gotten a ton of parts from them with no issues.These carbs are supposed to rebuilt to factory specs and flow checked. The problem I'm having is the center carb is dumping way to much fuel running rich, fouling plugs backfiring through carb, I have checked and rechecked timing, vacuum leaks with nothing found. I am running the the 4 piece felpro intake gaskets with the Mondello valley pan, MSD billet distributor Auto light 847 plugs gapped at 40 MSD stock type coil. Back to vacuum leaks correct me if I am wrong but if you have a vacuum leak the motor tends to run lean. This thing idles terrible, if I can get it to idle, very hard starting Timing is set at 22 with 32 full advance. I am looking for any suggestions before I start tearing into the carbs. A mechanic friend of mine seems to think the jets are too big - there again the carbs were built to factory specs if anything I would think I would need larger jets 455vs 400, oh I will mention I have a glass fuel bowl that is not correct instead of the 3/8" inlet and outlet lines this one has the 1/4" but has the correct 3/8" fuel lines, I don't know if this would have an effect on it or not just trying to answer as many questions that may arise, the plugs are coming out black sooted up not wet until they stop firing then they are wet. It has the typical burning of the eyes multiplied many times over - It's like is dumping raw fuel, the end carbs I can cover one or both with my hands while it is running with no change so It's back to the center carb. Any help would be greatly appreciated
Thanks Take Care Dave

 

Either it's jetted too big, the power piston is stuck open, or the float level is set way high causing fuel pullover.

You've checked idle mixture? and you know for sure the end carb throttle plates aren't cracked open at idle? Take the linkage off the end carbs and physically close the throttle plates and see what it does.

Everything else checks out, you'll have to open the center carb and see what's going on inside. That or send it back and let the rebuilder do it. "Rebuilt to factory specs" doesn't always mean it is.

If you open it yourself, snap the power piston up and down a few times to make sure it's not stuck open. Possible low vacuum signal may be letting it stay up all the time, but if it ran OK with the 4-barrel vacuum should be OK. What is idle vacuum reading?

 

it sounds like there is something between the needle and seat of the center carb; causing flooding. you're probably going to need to open that carb. up.
but first, try tapping on that carb. with the plastic end of a screwdriver, while it is running. you may be able to dislodge the foreign object that way. tap moderately right behind the filter housing, on the top of the carb.

as far as the jetting goes, after you get it running right-read the plugs. but i wouldn't be surprised if you need to increase the jetting by 1 size(.001").


bill

 

OK I was back on the car this morning, vacuum if you can get it to idle is 8" had 10" prior to tripower with 4v, pulled center carb everything looked good float level set correct no trash, bolted it back together ran the same, pulled plugs all sooted up, just installed yesterday, the exception was the #5 plug which looked new like it was not firing, checked distributor cab no arching etc, rechecked firing order, re checked timing all good. Just fishing now - how could you tell if the intake is not sealing to the heads, or cracked in one of the runners, By the way I had the end carbs linkage disconnected- butterflies closed no gas leaking from venturis- this car has gotten the nickname Re-Do instead of 442, nothing works right the first time. Thanks

 

I forgot to mention the idle mixture screws have been 1 to 4 turns out and everything in between
Thanks Dave

 

Exchange it with one in another cylinder.

Norm

 

Thanks for everyone's help got it right after tearing the carb apart twice I dunno what exactly I did, It usually bothers the H--- out of me when something just mysteriously fixes itself but in this case I'm one happy camper will make cruise the coast in october, again thanks for the info
Dave

 

Those carbs are prone to having a float rub on the wall of the fuel bowl and hang up. Often just removing and replacing the air horn takes care of it. The problem doesn't occur during usage, just when you have the intake/carb setup off the engine and turn it on end or something.

 

Thats good to know- I 'll probably be back in to the carbs, I drove it yesterday to the store for gas - prior to I tried to put gas via a jug, Man it's a pain to put gas in a 66 from one of the new type jugs, I ended up setting the 5 gal jug in the trunk and syphoning it to the tank ,anyway I was running lean, yesterday played with the air mixtur screws today got in running a little rich so hopefully I'll be Ok I'll put the vacuum guage on it to try and fine tune it
Thanks for the input Sunday afternoon I was about ready to put the Edelbrock and 4V back on, but it is a 66 so I know I've got a lot more tinkering and learning
Take Care Dave