360 Oil Consumption & Blow bye

shfletch

I am new to this forum and glad I finally found some expertise with the AMC engines. I just recently built a fairly healthy 360 for my 77cj and it is using around 1 qt of oil every 200 miles. I found the pcv was sucking major oil and have now put 2 inline catch cans infront of the pcv to keep oil from going into the intake. Since the high lift cam has little vacume I split the pcv line after the catch can and am running 2 pcv valves to help scavange as much out of the crank case as possible, wich seems to be working. I am worried about crank case pressure and blow bye as the rpm's come up and the vacume goes down and was wondering if anyone is using bulltear's vented valve covers's with any luck? I know the cylinders got washed and the rings are not seating, so I pulled the plugs and flushed all cylinders with laquer thinner and switched to a non-detergent 30 weight oil to help seat rings. Has anyone else had this type of problem? Thanks

tufcj

What manifold are you using? With most aftermarket aluminum manifolds you need to transfer the tin baffle from the bottom of the stock manifold, or use the factory style "valley pan" gasket (or both). If you are using the aftermarket gaskets without the valley pan, and don't have the baffle in place, you WILL suck oil thru the PCV system. Bob tufcj

shfletch

I am using the torker with the manifold tin pan and baffled with a scotch bright pad material, we did not use the big tin valley pan due to the oil line fix. I see now that fuzz401 got his to work under the pan gasket. I have done many bbc and sbc but this is my first amc and have heard horror stories about getting the large pan gasket to seal the intake. Does the large pan intake gasket prevent the oil flow through the pcv valve that well? Also, my rear main seal is leaking which also leads me to believe that my crank case pressure is high. Any input on the legend vented valve covers to help relieve pressure. I am using a k&n breather on my oil fill tube.

Holeshot

Time to get it "leaked", a leakdown test. No sense in grasping for straws and guessing what the problem is, verify that you "have an engine", and if so, you can rule out the shortblock & valve job. Sorry to say that you may have some late nights & busted knuckles in the near future. On another note, a pcv system is not needed if you have plenty of crankcase ventilation (to atmosphere on a "race" engine). So if that is indeed the problem, plug the pcv. If you are then blowing oil elsewhere, continue with the leakdown. Fears of a trapped oil scraper & wasted block here!!! I think I'd be pulling the intake to remove the ScotchBrite pad ASAP, if it isn't too late!!! It may have already disintegrated and fed the cylinders abrasives, leading you to another bore job. You should probably tell us all the details of your engine systems, just for the halibut. If it does turn out that your rings are leaking, try what Chevy did to their very early production 265s (I think) when they didn't seal & Chevy was faced with millions in warranty work. Feed the running engine some Bon-Ami to bust the glaze!!!

jeepsr4ever

From my experience without a valley pan or heat sheild your pcv will suck up oil and burn it. I would look to running the pvc into a catch can only and see if the can shows oil in the bottom. Start there then do a leakdown

shfletch

I am currently running the pcv line out of the manifold and into a catch can and then through another one to see if the first one is getting it all. So far after 150 miles the first one has about 5 tablespoons of oil in the bottom of it and the second one is dry. I still want to run the pcv since the engine will also be run on the street and am ok with using a catch can as long as no more oil is going through the intake. Right now I just have a pair of cheap junk chrome valve covers and am seriously thinking about the vented ones from Bulltear. I do not see any info or pictures of the vents they are making for them. I would like to know the dimentions and location of the vents along with how tall the covers are. My main problem right now is ring sealing, on the driver's side I think I have a couple of bad holes still, since some smoke puffs after acceleration and the vacume comes way back up on deceleration. I know many people that have done the bon ami flush and forgot completely about it, I will probably do it this weekend along with a leak down on all 8. Compression on all 8 is fine (190 - 195). The vehicle is a 1977 cj7 that I built from the frame up primarily for dune running and also street legal to drive my mother to church on sundays (at least that's the story for my wife). With the dunes as the main off roading, I wanted the engine to have good power in the upper rpm range and am not to concerned with low end torque. Thanks for your ideas and hopefully will not have to yank it back out to re-hone and ring, but I have had worse problems than that before.