[smakcruiser]

I just pulled my carburetor off, the intake manifold is entirely black inside. It looks like someone spilled a can of black paint inside of it. I am guessing this is not normal ?

[mkoser]

Originally Posted by b-man

Matt,

I got the impression from your post that the engine sat for 30 years and you fired it up with no rebuild.

Nevertheless, condensation is still an issue even on a new engine. I have a friend who used to start up his race car that sat in a cold garage most of the time, one time he yanked the valve covers and found a milky white substance coating the inside of the covers. Simply condensation, after a good warmup it disappears.

Bart

After I started my 64 this spring, I pulled the oil breather off for some reason. I was horrified to find while milky oil clinging to the inside, in a near panic I changed the oil. It never did it again. I had never seen this car do it before, but I imagine the conditions must have been just right this winter to fill the block with water (condensation).

MK

[smakcruiser]

My pump is putting out just a tad over 8 psi. Do you think this could be contributing to my rich condition? I've read elsewhere that holley 4150's do not like more than 6.5

[65FATCAT]

That could do it, i just went through that with a buddies bbc chevelle, we put a cheapo summit regulator on it, it fixed his rich problem, he was running an edelbrock though.

Either way it can't hurt to have a regulator, just a thought.

[mike nixon]

The high fuel pressure will cause a rich condition.

[smakcruiser]

Put a fuel pressure regulator on this morning. No change, I give up. I am going to have someone smarter than me look at it and see what they can do.

[Al T.]

Does the holley have the heat shield installed between the carb and the gasket? My 66 Vette was running rich and it turned out that it was caused by the shield not being installed. The inside of my intake looked exactly as you described.

Al T.

[smakcruiser]

I am not sure what that is. I do not remember removing on when I tore the engine down. http://www.holley.com/108-70.asp This thing ???

[Al T.]

This was the one I bought for the Vette. Maybe someone else will chime in as to whether this may help. I'm thinking the fact you have an aluminum intake, you may not need it??? When I had my carb rebuilt, the carb guy stated I had to have one as it impacts how the car runs.......at least with a cast iron manifold. I think you need it to block the exhaust crossover on the carb mounting flange of the intake. It also helps prevent fuel percolation when hot.

https://www.paragoncorvette.com/p-35...fle-plate.aspx

[65FATCAT]

Too much carb is what i think, that would cause all the symptoms you have as long as spark is verified at all the plugs, you're just getting too much fuel no matter what you try, find a smaller carb over at a buddies house or somewhere, i'll bet there will be a difference.

If the the inside of the manifold is black, that is raw, unburned fuel, nothing else, the remains of which can only go out the tailpipe in the form of smoke.

[smakcruiser]

How big of a jump should I make? I have 750 with a little work I could try tomorrow or Friday.

[65FATCAT]

Well if you want to get scientific you could check the air/fuel ratio, although i don't know what the numbers should be, i'm positive someone here might know.

That's the only way i know to figure out what's exactly right for your application, to figure out what is right by the "seat of the pants" method, you put different carbs on it until it just works, or jets..etc. From the symptoms you describe, you're running super rich and you haven't been able to reign it in, try any smaller carb and go from there, if it has a stock cam then i would think 650 or so would be more than enough but picking carbs is voodoo to me, hopefully you'll here from smarter people than me soon.

maybe the moderator can move this to the STREET forum so it'll get more coverage and get this old car figured out.

[poison heart]

Idle should be around 14-15 and WOT should be 12s

[Deadhead]

Just an idea, but for less than $200 you could get a Carter & a stock manifold, put that set-up on there & see what happens. You would KNOW that would not be the Prob. then. You could easily spend $200 trying to figure it all out anyway. Just a thought.

[smakcruiser]

I was able to get my 750 CFM on there this morning and see how it ran. Plugs don't look nearly as fouled, the smoke has changed to blue now which means oil. I bet my rings are shot.

[65FATCAT]

Time for a comp/leakdown.

[smakcruiser]

I did a compression test a while ago. I got around 155 in all cylinders except one. One cylinder was around 180. I am going to do leakdown next.

Matt

[65FATCAT]

I did a test on my 65' 389, rebuilt about 10 years ago, got 165 on all cylinders, don't know what the numbers should be, i was just glad they were consistent, it's got the stock #76 heads on it, i would think your 421 with 76 or 77's should be close if it's in good order.

That 180 reading is weird, as far as smoke, oil could be getting by the old valve seals, they are a problem with these heads when they get old, luckily that's a cheap fix, just a ton of labor on your part.