[jholmes217]

I recently switched from a old Weiand 8011 to an Eddy Performer RPM. I've done three or four spark plug checks since the switch. 7 plugs are the nice light chocolate milk color, and #8 plug is almost white still. Is this normal for a Performer RPM, or do I maybe have another issue somewhere?
Engine is a 1969 302 block with 1970 port and polished with 1.94 intake and 1.6 exhaust valves. Compression is 9.3 to 1, and the cam is a Comp Cams 274 hydraulic flat tappet. Carb is a 600 vacuum secondary Holley.

 

[DanH]

swap plugs around or new plug and check the wire is the first test

klutz , you got the answer ? could it a vacuum leak klutz ? or , or

 

[jholmes217]

I swap plugs to a different cylinder after each check, and the #8 always comes out more white. Same thing if I put new plugs in. I haven't found any vacuum leaks.

 

[DanH]

this a 15426378 order ? if so make sure 7 & 8 wires are not close to each other

 

[FEandGoingBroke]

Swap that #8 Wire with the #4 wire and re-run. If you still have a white plug later check or intake gasket interference or a leak in the gasket over #8.

 

[289hipo]

i had the same prob with my windsor.the white header paint burned off no 4 and 2 header pipes.i changed carbs and that fixed it.very weird.i also checked for vaccume leasks with a propane torch.without lighing torch open valve and go around intake carb and carb spacer

 

[jholmes217]

Swap that #8 Wire with the #4 wire and re-run. If you still have a white plug later check or intake gasket interference or a leak in the gasket over #8.

Changed all of the plug wires a couple weeks ago Gary, and still doing it. I will try looking for vacuum leaks again. If I don't find any, I'll try changing the Holley for a Summit 600 CFM carb.

 

[KULTULZ]

Vacuum leak is the most likely cause. Ten dollar vacuum gauge will find it (along with propane method also described).

If the ignition was bad (plug/wire) the plug would read fuel fouled.

It may also be a distribution problem either in the carb or intake plenum. As a last resort, you would fatten the primary jet (1) that feeds the plenum side that supplies #8.

THEXTON THX382 Vacuum Leak Detector Wand-

 

[DanH]

Vacuum leak is the most likely cause. Ten dollar vacuum gauge will find it (along with propane method also described).

If the ignition was bad (plug/wire) the plug would read fuel fouled.

It may also be a distribution problem either in the carb or intake plenum. As a last resort, you would fatten the primary jet (1) that feeds the plenum side that supplies #8.

THEXTON THX382 Vacuum Leak Detector Wand-

klutz heres a hint , know why the chair your butt and hand is sitting on isnt burnt black ?
there never was a fire , so its still the same color

 

[jholmes217]

I also have a slight "sputter" at cruise speed that may be related. I did three things roughly at the same time a couple weeks ago. I adjusted the valves (roller rockers), I changed plug wires, and I swapped carbs. I'm thinking the "sputter" and the whitish plug on #8 may be related and caused by the #8 valves not adjusted properly. I was adjusting valves while also trying to watch my kids, so I was interrupted several times and may have done that cylinder wrong. You know how it goes if you have or had little kids. Daddy, I'm thirsty, Daddy I'm hungry, Daddy, I have an owwee. Then you try to pick back up and think "were was I?" I wouldn't trade my kids for the world, but they can be frustrating when you are trying to concentrate or they take a hammer and pound the bumper on your Cobra Jet Mach 1. Lol

 

[FEandGoingBroke]

Might be you're onto something! Get it took care if dag nabbit!

 

[Blulakr]

Do you have a vacuum tee at the back of the manifold?

Keep in mind vacuum leaks aren't always external or near the intake\carb. Any one of the vacuum lines off of a tee or the components they connect to can create vacuum leaks. Leaking brake booster diaphragm, heater controls, trans modulator......

 

[FEandGoingBroke]

Great point Lakr!!!! A vacuum leak in a Vacuum T over runner #8 would provide a plenty lean signal to that cylinder!

 

[KULTULZ]

I also have a slight "sputter" at cruise speed that may be related.

Another indication of a vacuum leak, lean surge.

 

[DanH]

Another indication of a vacuum leak, lean surge.

a sputter and a surge is the same ?

 

[FEandGoingBroke]

Sputter gives a feeling of hesitation and fouling Kul, a Surge is a coming and going of power without the sounds associated with a sputter which is another word for a misfire in some realms.

So technically they can't be used in the same sentence without prepositional phrases that match and distinguish, that would otherwise confound the reader/s.

 

[KULTULZ]

Cut me some slack here sparky... :frown:

 

[jholmes217]

I went and took a quick look last night, but didn't have time to start it and actually check for a vacuum leak. I do have a vacuum T on #8 runner on that intake. I tried to turn it by hand, and it is still tight and still has plugs on the unused ports. I used thread sealer when I installed it. Maybe this weekend I'll take it off and re-install with Teflon tape and see if it fixes it. If not, I'll recheck the valves.

 

[FEandGoingBroke]

There is no way on God's green earth that there could be air leaking past pipe threads in that fitting causing a lean out on #8, it's got to be something else if your plugs are in place.
Having a leak there can cause a lean condition but NOT through the threads unless the fitting is obviously broken.

 

[KULTULZ]

There is no way on God's green earth that there could be air leaking past pipe threads in that fitting causing a lean out on #8, it's got to be something else if your plugs are in place.

Having a leak there can cause a lean condition but NOT through the threads unless the fitting is obviously broken.

hmmpf...

I guess there is no need in automotive to use dope on NPT but it is a necessity in the plumbing world.

I need to keep track of all these little factoids you throw out sparkles. Maybe you should publish a tech text including/describing all of your theories?

BTW (French For I Forgot To Mention)-

There is no such terms as never/no way in automotive service technology.