Just Foul !!!

[Nuts]

After all the highly tuned race cars from last weekend, I decided to pull the plugs on my car it's been about 1 years. Most all looked great, in fact better than I thought they might, because I've always run a little rich.

But, number 5 plug looked just plain foul, and had oil on it !!! There is also guite a lot of build up around the electrode and down inside the plug. Here are some pictures.

Your advice like always is appreciated...

 

[Ronnie Russell]

Bill, The easy suggestion would be a bad valve seal . But what else could it be?. Maybe oil getting by the rings? The plug is firing good. I would buy a set of plugs, put em in the top of the tool box, change that plug once a month and monitor. I think you use your car for mainly highway cruising and not racing. I would not go to the trouble of pulling the head at this point. Now, at some point in the future, the carbon buildup on the valves will result in a burned valve. Valves are cheap. Are we talking 1 year, 5yrs.??? Who knows. If it were mine, I would replace the plug every now and then and keep on motoring. Maybe not what you wanted to hear, but , just my opinion.

 

[tripower]

Bill, The easy suggestion would be a bad valve seal . But what else could it be?. Maybe oil getting by the rings? The plug is firing good. I would buy a set of plugs, put em in the top of the tool box, change that plug once a month and monitor. I think you use your car for mainly highway cruising and not racing. I would not go to the trouble of pulling the head at this point. Now, at some point in the future, the carbon buildup on the valves will result in a burned valve. Valves are cheap. Are we talking 1 year, 5yrs.??? Who knows. If it were mine, I would replace the plug every now and then and keep on motoring. Maybe not what you wanted to hear, but , just my opinion.

Ronnie, You forgot to mention a good foot tune every so often as well.....

 

[CDNpontiac409guy]

Something else that I've had personal experience with.... intake gasket
The part of the gasket at the lower edge of the port, can become compromised. On these engines in particular, even slight over-tightening of those top / between-the-port bolts, can sort of "un-load" the clamping force at the bottom.
Is the engine consuming a noticable amount of oil ?
A preliminary check could be to hook up a vacuum guage to the intake, and see of you have a noticable "low" pulse.
If found, remedy is usually a simple gasket replacement, and being careful to tighten the top 4 bolts last, and to a little less torque.
:

 

[Phil Reed]

Bill...............I have to disagree with both Ronnie and Aubrey. I feel this is a much more serious issue than they let on.











Immediately have your bubbletop loaded on a car hauler and have it brought to Kansas City. I'd come and get it for you but can't travel right now. Oh.....be sure the title is in the glovebox!!!!!!!!!!

 

[Nuts]

Do you want me to sign the title or just leave it in the glovebox ??? How long before you'd be able to fix her and have her back to me ?

OBW - Can you PM me with your Phone Number ? I can't seem to find the card I got from you way back when.

You must be feeling somewhat better - You got your sense of humor back ??

Thanks
Bill

 

[rstreet]

Bill:
Just put some 42 or 52 heat series plugs in that hole and drive her!!!!!
robert

 

[wldavis]

Aubrey,

Can you explain a little further the pulse you are referring to. How much of a pulse should we look for? Is it ok to hook up the vacuum gauge to the lower front port of an AFB carb (The vacuum advance line.)?

Thanks, Dan

 

[raymar58409]

You would want to hook to manifold vacuum port direct. Say your engine has 15" vacuum the needle would fluctuate for an instance when the affected cylinder was on the intake stroke. Say it might drop to, as an example 13", depending on the amount of leakage, This because that cylinder will not be drawing all the air from the manifold but rather from the lifter valley. The fluctuation would be only a split second so very hard to notice unless leak is large. Sound about right Aubrey??

Ray
Winder GA, I go there a lot.

 

[CDNpontiac409guy]

Dan, I think Ray about summed it up. You'd have to watch the vacuum gauge carefully. Also, I think it's easier to spot with an engine that has a relatively smooth idle.

 

[buildit]

Ronnie and Aubrey have it covered pretty well. When we surfaced heads at the race engine shop, when we leveled the heads, we left the exh port side 1/4 bubble (on the machinist's level) high. Though only a small amount, when assembled, it tilts the head down ever so slightly on the outer side, thereby making the bottom of the intake port seal a little bit tighter than the top. I always request my heads to be surfaced in this way. Aubrey is right, this problem of oil getting by the bottom of the intake port gasket is fairly common, and on other engines too.
I think the cam would have to be very tame to see the variation.

One other possibility, if the heads have press in guides, the intake guide could be slightly loose in the head, allowing oil to sneak by. Or, I have seen the top of the guide broken off flush with the head. Don't know how the guy managed to do that.