The plug color difference is caused by poor oil control on the plugs that are not "white".. the brown color is not fuel, it's oil. 5,7 and 8 are the worst. Other than that, the plugs look fine, considering your using unleaded fuel, which will not color the plugs. JW
Appreciate the input, Well it's not coming from the valve covers, I guess it could be valve guides or seal related. I think I went a little overboard with the anti seize on the last set of AC Delco plugs. I think along with the oil and goop it's not giving the real picture of the plugs and how much oil. I cleaned the best I could today with a rag and finger before I put a new set of plugs in. I'll check on them in a few driving cycles. Tony
FWIW, when I ran the Edelbrock Performer intake, I always found the #5, 6, 7, and 8 plugs would be darker than the front plugs. When I switched to the SP1 intake, they all looked very much the same, light brown to tan. This is after a year in the engine, I generally change my plugs once a year.
For the past week I've been trying to figure out the oil control problem at the rear of the motor. I learned that I have been sucking a lot of oil up the PCV system and into the intake. I ran a temporary oil catch on the inner fender and it is collecting oil. Driven the car for the last three days and it has collected about a Tbsp. in about 150 miles. Completed a leak down test this afternoon on a fully warmed up engine at TDC on the compression stroke. and all cylinders showed a 6-9% leakage rate. I did run two tests per cylinder zeroed out each time. I thought that this was fantastic news but, the leaking air on all cylinders was coming out of the valve cover breather hole and I thought I read somewhere that this means my rings and or cylinders are shot? Is this really true? also if you covered the breather hole (I did not do this but I did thank my brother) you would here the air coming out from between the block and the intake manifold right in the front passenger corner. Do not think I had a vacuum leak there before but I definitely have a small one now because by covering the hole I think it pushed the RTV out of the seam there. Any other suggestions on oil control that I should or could check? Tony
You're always going to get some leakdown with gapped rings, how much depends on ring seal to the walls and amount of gap established. If you're vigilent regarding file fitting you could minimize the leakdown when the motor is at operating temp. the only time I got 0% leakdown was with zero gap rings. I don't think your leakdown is too excessive. gary
x2 on what Gary said. Even when you get less than 1% with gapless rings you can still hear the air coming through the valley/valve covers. And it always sounds like more than you would think. You need to worry if the air is coming out the carb or exhaust during a leakdown check. When you drive plugs on the street you can forget about plug color short of completely black or brown which is not right. After a long easy cruise I generally like to see them lean for best mileage but once the color builds on them it is hard for them to go white again. Driving down the street for two miles and then checking your plugs doesn't tell you anything. If you have a good ignition putting fresh plugs in does nothing except lightening your wallet. Unless you are using 1 quart every 500 miles or less then you don't have an oil control problem depending on gearing and your main cruising speed. If you have leaks you can see then they need fixed. If you are racing you may use more than that. Anything above 500 miles per quart is just icing on the cake as far as I'm concerned and back in the day Buick said oil mileage may vary by use and luck of the draw. As far as plugs go I used UR5's on a 10.5:1 engine with no problems. I didn't notice what compression you actually have. How many miles have you actually put on the engine so far? IMO this is much ado about nothing especially if your oil mileage is reasonable.
Thanks for the replies guys, I am relieved to hear about the oil from the PCV system. I was pretty sure there was going to be some leakage and I thought less than 10% was in the pretty good running motor group, just wanted to here some thoughts on the air coming out the breather hole or intake area. Obviously I must have misunderstood what I was reading about the worn rings and or cylinders. I think my ignition system works fine but it might not be considered top of the line stuff. Larry suggested a while back to try the UR-5 plugs and I did but I wanted to try the stock plug to see if there was a difference between the heat and gap ranges. I had the UR-5 gapped at .040 last time before I put the R44TS in. I would say that there is about 6500 miles on the new rebuilt motor. Tony
Heat range and timing indicators are seen fairly quickly, as long as you take it out and give it hell.
