Short Bus

Valve adjustment has almost nothing to do with fuel/air mixture.  That is not the cause of your plugs fouling.  Your mechanic may be right about the valves being too tight but he's wrong about why the plug fouling and mixture.

He is checking the valves today with a feeler gauge! I will keep all of you posted!

Okay with the valve rechecked and adjusted and the timing done, the car runs better. No backfire, just slight back and forth hesitation when running the car at the moment of releasing the clutch and engaging 1st gear. To avoid this either you step softly in the gas pedal or Hard. My uncle who has dealt with carbs before says it could be the float level in the carbs. Problem number to is the idle. If i leave the car parked in idle for more than 10 minutes rpm starts to drop from 1050 to 700 and goes up again. The engine does not shut down.

John,

 

Same problem! Here is picture of the spark plugs and the distributor! I have no backfire in the front intake. I have the front carb set at 3.5 turns and the rear 3.25 turns. Still hesitation when releasing clutch and engaging first gear. Either i step smoothly on the pedal or step hard, otherwise hesitation begins.

 

Another problem i still have is the idle. If i leave the car in the parkway at idle for more than 10 minutes, it drops to 700 and rises back to 1000.

 

What a hassle!!! Hope someone here can point me out in the right direction.

 

 

 

Valve adjustment has almost nothing to do with fuel/air mixture.  That is not the cause of your plugs fouling.  Your mechanic may be right about the valves being too tight but he's wrong about why the plug fouling and mixture.

 

If you drove it much with the valve lash too tight you might have damaged some valves.  "Burned", or warped.  Without feeler gauges though, it's hard to see how your "old-school" guy could tell that the lash was too tight.  I don't know if I'd use that guy.  Why not take it back to the shop that installed the cam?

 

You didn't address John Coffey's post at all.  Could the choke be stuck?  Seems like a carburetor problem.  Three black plugs is too rich, not bad valve lash.  I wouldn't let the old-school touch the car.

 

Well Zed Head,

 

I guess you were right. My mechanic has the same opinión as yours, he found the valve too tights and even though he manage to set them at 0.9 and .10, the car is still presenting the back and forth hesitation under 3000 rpm. If you pull the spark plug boot on cylinder 3 the idle does not drop down in comparison to the other cylinders. He believe some valves could be burned. He recommended to purchase the following:

 

12 valves

 

valve guides

 

valve seats

 

and a gasket that goes underneath.

 

I have both of  the idle mixture knobs set to 3.5 turns.I took a picture of the 6 spark plugs (BP6ES) Factory gap at .028 once i came back home starting from cylinder 6, left to right.

 

Please give me your input, if i should settle his opinión and where should i purchase good quality valves, valve guides, and valve seats.

Edited April 11, 201510 yr by jalexquijano

I wouldn't worry about the valves, valve guides, etc.  Your plugs indicate the engine is running lean.  Now that the valves are adjusted check your timing and make sure it matches the factory spec.  If you don't know what that is, set it to 10 degrees BTDC and 850 pm.

 

Check the float level on the carbs, set the idle mixture, and balance (sync) the carbs using a Synchrometer.

Just did a compression test on the cylinders and a fuel pressure test.

 

THe compression test drew the following results:

 

Cylinder 1 : 180 PSI

 

Cylinder 2: 180 PSI

 

Cylinder 3: 185 PSI

 

Cylinder 4; 180 PSI

 

Cylinder 5: 180 PSI

 

Cylinder 6: 175 PSI

 

The fuel pressure was 3 PSI. I am running A Carter P60504 Electric Fuel Pump. Is this pressure enough for both carbs?

 

http://www.summitracing.com/int/parts/crt-p60504/overview/

 

I have both carbs set to 3.5 turns and i am still having a back and forth motion after stepping on the gas and releasing the pedal before reaching 3000 RPM.

Fuel pressure on the low side per FSM but ballpark. Should be OK for ordinary driving. If you have a fuel return line you can block it off; that will raise fuel pressure a little. You could see if it makes any difference, I doubt it though.

As John mentioned earlier, you really need a syncmeter to balance the carbs. I relied on my MK III calibrated eyeballs to ensure my Weber idle speeds were set identically. When I finally got a syncmeter, I was surprised to find one carb needed an additional one full turn to balance.

 

We tend to assume zero manufacturing tolerances when we don't have the tools - this almost always ends up biting you in the butt.

As John mentioned earlier, you really need a syncmeter to balance the carbs. I relied on my MK III calibrated eyeballs to ensure my Weber idle speeds were set identically. When I finally got a syncmeter, I was surprised to find one carb needed an additional one full turn to balance.

 

We tend to assume zero manufacturing tolerances when we don't have the tools - this almost always ends up biting you in the butt.

I want to get rid of the back and forth hesitation under 3000 RPM.  It even happens after i pass a Street bump, where i need to slow down and shift to first again.

I think we need a better explanation of what you mean by "back and forth hesitation".

 

Are you talking about the engine rocking with each revolution or are you talking about the rpm surging and retreating under a steady throttle?