Potential Problem?

As i was poking around the my car and looking in my engine bay i noticed something odd.



On the front of my carb, between the spacer and the intake manifold there is a gap. I can poke the twisty tie in the pic all the way in.

I will say the car runs and idles just fine but to it seems to me there shouldn't be an air gap there. When the PO installed the new carb and intake manifold could they of had an issue and just adjusted the carb and timing to make it run right? What issues can this gap cause?

It will make the car run lean at best. It can allow dirt in and damage the engine at worst. It is something you need to repair.

Am i losing anything performance wise with the engine? I am starting to research all this engine stuff. It has been years since i have even thought about all this stuff. I plan to do a top end rebuild and am researching for what i am looking for.

Yes probably. It's hard to believe it runs good with a vacuum leak. It's an easy fix, just lift the carb and spacer off and replace the gaskets. I am assuming the spacer is large enough to cover the intake opening.

I've seen one other car with a bad leak in the gasket area and it ran fine too. Airflow will take the path of least resistance. At idle there probably isn't too much air going through the leak but at higher rpm the leak would be more prevalent but may be masked and not noticed. It would be lean out the mix some for sure.

Easy fix with new gaskets & the difference may possibly be felt in the seat of the pants.

Post a pic of the problem area once you take the carb off.

It would seem that the leak must not be causing too much of a lean issue although no doubt but that it is. In the long run a lean mixture can burn a hole in your pistons. Not a hard fix and then you will need to re-adjust the mixture.

You can check to see if it's leaking by spraying carb cleaner directly into that area while the car is running. If the idle goes up momentarily, then there is a leak there. If nothing changes, then no leak.

But either way, changing that base gasket is easy enough.

+1 on guys72Mach1 idea. Gotta believe it's affecting vacuum, which affect timing, which affects performance and economy. Little squirt will tell.

Ok, had a little time to mess with it. It was an issue on performance. I just didn't know it.

I pulled the carb all apart and found the gasket to be torn. Will be ordering another one with a phenolic spacer to get rid of the aluminum one first thing tomorrow.

After i found that it was torn i did a little magyvering and put it back together to see how it would run. Wala, it showed itself. Idle rpm's were way low and didn't idle very good. The engine was up to temp as i had just been out cruizing in it before this so i knew it wasn't cold. It responded well to throttle response but as soon as you let off the pedal it would about die or would die. So i stood there and pondered for a minute. Listening to it idle, it sounded like it was about 2-300 rpm's. I don't have a tach but will be getting one. So i adjusted the idle screw till it sounded about the same as it did before i messed with it.

Hmmm, now she's purring. Stomp on pedal and release. Fast response and no sputter. Goes back to a good idle. Do it a couple more times and same thing. So i called my dad and told him to be on standby i was gonna take it out for a spin to see how she is doin.

I went out to the back road and let her ripp. Wow, i was put back in my seat. It was alot more noticeable this time. Came to a stop and then let her rip. Tires squealed. I had not been able to do that before and always thought i should have been able to. I cruised around for awhile getting on it and slowing down. It never gave me a hiccup.

I think i still need to mess with the mixture settings and dial her in better.

I did notice though that i have some dry black soot in my tail pipes now. Not a lot but there is some. Not sure if that is normal or not but my exhaust is brand new and i didn't have the soot before i did this change.

Is the black soot telling me something?

black soot usually means a rich fuel mixture.

idle mixture adjustment does nothing else. At any other rpm mixture is adjusted by jetting changes, float level adjustment, enrichment circuits, aka squirters, power valves and other more serious mods. Black soot in light quantities is not abnormal as a carb is h generally tuned to run richer than stoiometric ratio of 14.7 to 1, with agood tune looking for 12.5 to 1