One problem down

[spstan]

Contacted Mikes carburetor (seems like a decent guy) and he told me that after a carb rebuild (which I did) a very common issue is grit from the fuel system flushes through the carb and sticks in the needle and seat. I didn't believe it cause the needle and seat were brand new and they held air when I blew through a tube connected to the fuel inlet. But I knew floats were ok and fuel pressure was around 4 psi so I replaced needle and seat. Presto - fuel stopped leaking from EVAP cannister and bowl vents. Now all I have to do to the carb is helicoil the front bowl bolt holes that I striped.

The second problem still exists (i.e. exhaust smoke coming from carb throat when first starting). Because this problem disappears after initial start up and the car runs smooth after initial start up I don't think its a timing problem. I'm leaning more toward it being a stuck valve that unsticks after startup. Thoughts? Paul

 

[68PK21 440.6bbl]

Compression test when stone cold.


.

 

[CBODY67]

That should not be "smoke", but air/fuel vapor getting pushed out. IF you perceive you might have a sticking valve, a possible way to help eliminate that might be to do one oil change of Mobil 1 motor oil. With its alleged ester content, "esters" in motor oil dissolve sludge and such, according to what I have read in www.bobistheoilguy.com forum. Might be the easiest and least-invasive thing to do.

CBODY67

 

[spstan]

C; off hand, do you know if Marvel Mystery oil contains esters? Paul

 

[Big_John]

Aunt Ester?

We'll see who gets this joke....

 

[CBODY67]

Probably not., but you might try the outboard motor oil gas mix. There's a recent thread in here on that.

 

[Davea Lux]

You would also want to check the timing chain for excessive slack. A defective timing chain can cause discharge thru the carb throat. You can check the timing chain for excessive slop by manually lining the timing mark up to TDC. Remove the distributor cap, have a helper slowly rock the crankshaft back and forth usi9ng a breaker bar and socked on the big nut that holds the harmonic balancer on. Note how many degrees of crank rotation it takes to get the distributor shaft to move. 15 degrees or more of free play in the timing chain indicates that it is at the point of failure and needs to be replaced.

Dave

 

[spstan]

You would also want to check the timing chain for excessive slack. A defective timing chain can cause discharge thru the carb throat. You can check the timing chain for excessive slop by manually lining the timing mark up to TDC. Remove the distributor cap, have a helper slowly rock the crankshaft back and forth usi9ng a breaker bar and socked on the big nut that holds the harmonic balancer on. Note how many degrees of crank rotation it takes to get the distributor shaft to move. 15 degrees or more of free play in the timing chain indicates that it is at the point of failure and needs to be replaced.

Dave

Dave; iI've heard of that method. But I also read where you can remove the fuel pump (or oil pump - I can't remember which) and feel inside with your finger for a loose timing chain. Have you ever heard of this? wonder if its easier. Paul