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chpr1972
06-14-2017, 11:38 AM
I am chasing an oil leak? 3/5 quarts per 1000 milers. Motor is a 489 BBC. The compression ratio is 10:1 roller cam with .510/.520 lift, 230/236 duration. Fixed the front seal leak and have a very small "just wet" rear main seal/oil pan gasket. A couple of the plugs are oil fouled. #1 is real bad. It didn't show up till I put a colder plug in it. The heads are old iron head ported to the max when I bought them. And they were completely rebuilt with the motor about 5500 miles ago. I think that the heads and motor were surfaced at that time. I'm sure that the heads have been surfaced before. Compression is about 170 and leak down under 7 %
I pulled the valve springs off and they were both appeared good. I replaced them just in case. valves were tight and seals actually held valves up with no air pressure. I have pulled the intake several times replacing bad lifters{long story told else where here on the forum]

My question is this: I am going to pull the intake again and use plenty of sealant around the ports. Should I double gasket it or would that cause more problems. I really don't see a difference in gap but it does not take much to cause a problem.

TheJDMan
06-14-2017, 05:52 PM
You don't want to double gasket the intake if you can avoid it. Most gasket manufacturers offer intake gaskets in different thicknesses if needed. I'm curious what valve seals you currently have installed.

dhutton
06-15-2017, 04:21 AM
What sort of crankcase ventilation do you have?

Don

chpr1972
06-16-2017, 06:58 AM
pcv valve for a 454 LS6. There is no oil in the hose. The problem is that if it was the pcv system all the plugs or a 1 7 4 6 would all be wet. The intake is a Weiand tunnelram with 2 holly throttle bodies and TPI injection system. when the motor was built it was with a Torquer II intake and 750 holly.
The seals are a perfect circle type seal that the machine shop put on. I actually though about putting a set of factory style seals on the #1 cylinder to see what happened.

speED
06-16-2017, 08:53 AM
You could simply disconnect pcv and run breathers if you think pcv system is the cause but, all plugs should be oiled fouled if this is the problem. Check the intake gasket with a caliper to determine that it is crushing the same amount top and bottom/ back and front. Do the rocker arm studs on those cylinders that show signs of oil thread into the intake runner? If so you need to make sure you have sealant on the threads otherwise you will suck oil.

ED