Header and Heater Boxes?

[IndianaVWKid]

I have a header on my 1600SP, and I was wondering, what does this do, if I have heater boxes in the back of my bus, and A Header..I know it'll make the gas-air mixture different in the combustion chambers..but what's odd, is that the back Spark plugs, were brown, and dry! So obviously hotter....But the front were slightly oily, and dark! I figured it would be the other way around...hmm....anyways, what should I do? Ditch the Header? Ditch the Heater Boxes? Or leave it be?
PLease Help And Thanks Again Y'all!
James
www.geocities.com/indianavwkid

[chillz1]

When you say " is that the back Spark plugs, were brown, and dry! ", do you mean the true back as in the bumper, or the "back of the engine" that many VW owners refer to incorrectly as it is towards the front of the car? If what you are meaning as the back is truly the back, then the free flowing nature of the header makes for a more efficient burn, hence properly colored plugs on an otherwise healthy engine. The two front plugs' color may be a result of restrictive heat exchangers that are gunked up with 30-some years worth of carbon. Even in completely healthy engines with clear heat exchangers, the restrictive nature of the heat exchanger makes the front-most cylinders run slightly hotter and in your case, maybe just hot enough to induce a little blow-by past the rings, creating the odd plug coloring you're observing. Just a few questions if I may. How old is your engine? Recently rebuilt, or high mileage original? What kind of muffler are you running on the header? Do you have much in the way of oil consumption?

[IndianaVWKid]

Well, I believe oil consumption is pretty minimal, I leak quite a few drops here and there. But the engines only got 7,000 miles on it, and it had new rings, pistons, cylinders, and Heads put on(SP heads) sorry, I knew I should have specified Front and back, I mean that the Front Plugs(towards me) were dark, and sooty. Let's recap!
2 Plugs in Back(Rear of the car) are dark Black, and Sooty.
2 plugs in front(Towards front of Bus, Flywheel side) are light brown, and def. burnt a little(aka...It's hotter back there)
So, I mean, this boggles my mind, I figured it would be the other way around! But I've messed with my engine so much, it coulda been from a couple months back. But I switched spark plugs, and drove 100 miles yesterday...and put the main jet back to stock, so I should check it out now.

But any help on the fact that i still have my heaterboxes, and a Single QP, Header...and the effects of this setup on my engine...would be great!

and Oh, It doesn't run hot at all! No more than 190 on the highway, if the temp is 65-70.

James

[chillz1]

the fact that you have two sets of two spark plugs that seem to show different "readings" tends to indicate an imbalance of some sort. It could either be ignition, compression oriented, exhaust flow oriented, or fuel. Firstly, check the two terminals on the underneath of the dist. cap (the ones for the sooty plugs) to see any irregularity as compared to the other two. Check the resistance on your plug wires that are in question. If they are OEM style wires with the resistor type ends, they should have about 1K ohms resistance. How's the compression on the engine? If the two rear cylinders are lower than the front, it could account for your problem, but only if there is a negligable difference, ie: at least 20psi difference (i'm doubtful it's that). Check your valve lash. As for fuel flow, I'm guessing you still have a center mounted single carb? This coupled with a single port setup kind of negates the possibility of any variation in fuel flow between cylinders. I would tend to think the fact that you're running a little rich (you mentioned a larger main jet), along with the free flowing nature of the exhaust header is causing your rear cylinders (rear is rear) to run cooler. The header does a far better job of evacuating the hot exhaust gasses away from the cylinders it runs off of and the heat exchangers on the front cylinders, does a good job at retaining exhaust heat, thereby your "hot looking" plugs. Try the jet change and the above and let me know what happens.