Wierd Holley issue

[Wayne Maybury]

Rick, I tried more advance and nothing really changed, less advance made the car run like crap. The choke is definitely fully open after the engine has run for about 5 minutes.

CHANMADD, the firing order is correct 15426378. The engine runs fine and the car will just burn the tires if asked to do so.

Jac Mac, I will check the head gaskets but the fellow that put the engine together is a pro so I would be very surprised if he made that kind of error. I believe that I have the correct NGK plugs but I will check the number and indicate it here later.

lovehamr, I am not sure about the low speed advance. I have a stock Ford distributor with the vaccum advance disconnected and a Petronix module instead of points.

MOTORHEAD, the engine was rebuilt a couple of years ago but the heads were just changed this spring. The engine was using oil through a couple of the old valve guides so instead of having the cast heads rebuilt, I went for a set of Edlebrock Street aluminum heads. The engine no longer uses any oil. Total mileage on the engine is 5,000 miles since being rebuilt and 1,000 miles since the heads were changed. You ask if this is a new problem and I have to admit that I am not really sure. It runs well but I happened to pull a plug just to take a look and it was white so I started messing with it. It was at that time that I noticed how much gas it was using which was a complete contradiction of the plug color. Really bad gas mileage and white plugs don't make sense.

Once thing I forgot to mention earlier is that the idle speed changes by 50 or 100 rpm on occasion. This usually happens when the hot engine is restarted after sitting for a half hour, it will idle at 500 or 550 in drive instead of 600 rpm. The car has a C4 so a slight change in the idle speed is more noticable than with a manual transmission. I have also changed the power valve just in case that was the problem. Thanks guys.

[Wayne Maybury]

Jac Mac, The plugs are NGK FR5. There are tabs visible on the lower front part of the head gaskets. Just to double check the firing order, I followed the plug wires and there is no mixup.

[Jac Mac]

Originally Posted by Wayne Maybury

Jac Mac, The plugs are NGK FR5. There are tabs visible on the lower front part of the head gaskets. Just to double check the firing order, I followed the plug wires and there is no mixup.

When I suggest stuff like the head gasket back to front I always feel I should apologise in advance for asking!
Your ~50 RPM idle speed may be something as simple as the secondaries not closeing properly, FR-5 plugs may be one grade too hot ( remember NGK & some other brands get colder as the number goes up as opposed to champions etc get colder with lower numbers- I use BKR6E-11 in alloy head windsor stuff with around 10/1 comp.
I dont know how your canadian fuel stacks up against our kiwi stuff, but we find it impossible to tune by plug colour with pump gas & white colour is the norm for a good mixture, but the two dark cyls in your case are a concern. No little black 'balls' clinging to the insulator on the plugs are there?
Have you double checked the timing pointer is showing 'true' TDC?
Also have you checked the rotor phasing in relation to the cap since the pertronix unit was installed ( an incorrect vac adv arm length can also cause this ). A clue to this is the tip of the rotor electrode looking like all the erosion is at one corner.

[Gaz64]

Originally Posted by Jac Mac

When I suggest stuff like the head gasket back to front I always feel I should apologise in advance for asking!
Your ~50 RPM idle speed may be something as simple as the secondaries not closeing properly, FR-5 plugs may be one grade too hot ( remember NGK & some other brands get colder as the number goes up as opposed to champions etc get colder with lower numbers- I use BKR6E-11 in alloy head windsor stuff with around 10/1 comp.
I dont know how your canadian fuel stacks up against our kiwi stuff, but we find it impossible to tune by plug colour with pump gas & white colour is the norm for a good mixture, but the two dark cyls in your case are a concern. No little black 'balls' clinging to the insulator on the plugs are there?
Have you double checked the timing pointer is showing 'true' TDC?
Also have you checked the rotor phasing in relation to the cap since the pertronix unit was installed ( an incorrect vac adv arm length can also cause this ). A clue to this is the tip of the rotor electrode looking like all the erosion is at one corner.

All very good points.

Other things to look at are the colour of the outer shell (exposed to combustion), since the porcelain picks up little colour from unleaded fuel.

With cylinders 5 and 6 side by side, I'd be concerned with their darker colours. I'd say do a leakdown test.

[Tom Kirkham]

Originally Posted by Wayne Maybury

...less advance made the car run like crap... I am not sure about the low speed advance. I have a stock Ford distributor with the vaccum advance disconnected... Really bad gas mileage and white plugs don't make sense.

Hook up the vacuum advance. The Ford distributors have a very lazy and long advance curve. Your engine is running with the spark timing way retarded at cruise RPMs. This is killing your gas mileage. Also as a side note, the main jets have a very small effect at cruise speeds. Get an O2 meter and tuning your carb will be much easier.