moonframer

I have an all stock 67 corvette 427/390. I just installed new AC plugs, points, cond., cap, rotar, etc.The factory Holley was just rebuilt by a professional carb shop. The car has a miss that I can't seem to eliminate and the plugs are absolutely black with carbon and wet.

The strange thing is when I pull the vacuum hose off the dist. to set the timing, the engine almost seems smoother. After I pull the little plug out of the vacuum hose and plug it back on the advance, it gets rough. My engine vacuum is about 18. Any ideas??

DUB

I do not know if this is going to help....but I use a vacuum gauge to set the timing and drive it.

I rarely use a timing light and use the notch on the balancer...beacsue I have encountered over the years so many harmonic balancers that have had the outer timing notch ring spin on teh center hub...and if trusting and using a timing light...is pointless due tot eh mark is off.

I confirm that the mark on the balancer is correct...so when I get it running great...I use my timing light and see what it is set at just for information purposes.

I have had the timing mark on the balancer be off as much as 1 1/2 inches.

I know you just had the carb rebuilt...and I am not saying that they did not do it correctly...but is there a chance that the car is dripping fuel while idling???

DUB

Nowhere Man

You say wet. But what is it. Is it oil,gas or a mixture

Scott Marzahl

I'd start with checking the needle and seat for junk blocking it from closing and check the float adjustment, it might be a bit too high, both can contribute to wet sooty plugs.

Gary's '66

We need more info. Also, what plugs did you install and did you check the gap?

6T7L71CPE

You are leaning out the mixture of an over rich carb. Take the carb back to the rebuilder.

TCracingCA

I would say carb all the way!

Not timing and not plug type or gap!

don't know which carb you are running?

Wet with gas and carbon sounds like a flooding condition and to rich of a mixture- rough running, missing either trying to ignite the unburned raw gas, and then it will soot up the plugs! But is your engine getting to operating temperatures? Did you drive it home a distance with this condition and then pull the plugs? Black soot is rich condition! Etc. ??????

Frankie the Fink

A "professional" rebuild can mean different things. I had a fit with my rebuilt 4 barrels on my '61 fouling plugs - in as little as 50 miles. The rebuild apparently had included replacing the needle valves and seats with the WRONG parts. Took a few weeks to figure it out. Now I rebuild 'em myself.

I think post #6 nailed it...

moonframer

It is hard to tell but pretty sure it's fuel. It's all the way up the threads.
thanks..

moonframer

I will get the carb back to the rebuild shop and have him test it on his shop engine. Thanks

moonframer

I used AC 44N. They were N.O.S. on ebay. Set at .35" Thanks

moonframer

I sure will. Thanks

moonframer

The car ran fine. I pulled the tank because of rusty gas. The car was sitting for many years. I believe I got junk in the carb. While the carb was at the shop I installed new plugs, points, cap etc. Sounds lime a screwed up carb.. Thanks

TCracingCA

Intake gasket! Installation of these is pretty basic! Thus fix that and then see if you still have oil climbing up the threads of the manifold bolts (I put sealant on those anyways!). The reason why I was wondering about oil pressure is just in case there is a drain back problem from the lifter valley. Also an under the manifold splash pan is good, because oil is being slung all over in there!

My opinion on PVC valves is to remove them, but if you want the stock look, then take a big drill and deal with it! I like to on my 327 pull the gas out of the block from the tube area next to the distributor, but not with the stock tube. I found one with a 90 degree angle that is alot cleaner looking and plumb that to the exhaust header to scavenge out pressure. Then I run full breathers on the valve covers or can switch to the Moroso Breather tube from valve cover kit to a catch can.

MikeM

My guess is the carb rebuilder will find more junk in the freshly cleaned carburetor.

If the plugs are really soaked, they may be junk.

65tripleblack

Pictures of the plugs would be helpful.