oil burning between shifts

baja2275 · Post by **baja2275** » Tue Dec 13, 2005 9:45 am

I have recently built a 1776 with a 110 cam, prog carb. and stock rebuilt dual port heads with HD springs.
The motor is in a baja of mine and I have probably put 750 to 1000 miles on the motor. I have recently driven it harder than normal because I figure that it has had time to break in, well I have noticed that if I rev to 4000 or more RPMs and then shift, I can see a puff of blue smoke come out of my stinger through my rearview mirror. Not excessive or anything, and can't even notice the oil level going down any.

What would cause this???? Will it eventually go away when the motor gets worn in more????

I checked my ring gaps and everything when assembling and I got everything in spec.

CHAZAVW · Post by **CHAZAVW** » Tue Dec 13, 2005 10:22 am

it is caused by oil getting past the rings. it could be too much pressure in the engine case caused by the new cam..... i would put a breather on the engine if you dont have one!!!

when i first put my 110 cam in the engine it leaked like crazy without a proper breather.....

i now have an engle 120 and no leaks - vent both valve covers and the oil filler tube!!!

i am currently buying stainless lines and AN fittings for mine. i am tired of tubing hitting the header pipes and vanishing!!! 90 degree fittings for the valve covers to keep the stainless line away from my header pipes!!!

rcb78 · Post by **rcb78** » Tue Dec 13, 2005 5:32 pm

The cam you run doesn't have anything to do with case pressure unless you consider the rpms you run because of the cam, and that's stretching it. Are you sure it's blue? Smoke out the exhaust at a high rpm is normal if your running too rich. If you're sure it's oil and it happens as the engine decels with your foot off the throttle, then the oil is probably getting past your valve guides. On decel with a closed throttle there's some pretty good vaccum under the throttle plates that will suck oil in past leaky guides. How's your geometry? --Ryan

baja2275 · Post by **baja2275** » Wed Dec 14, 2005 11:29 am

my rocker geometry is perfect. The only thing I can think of is oil getting past the valve guides. I have a brand new head on 3/4 side and a head that was rebuilt on the 1/2 side. Had to put it on there because one of the spark plug holes got stripped out on the new head so I replaced it with a used head that has new valves and guides in it.

Then I wonder, since the only breather setup I have is a piece of 1/2" rubber hose running from my oil filler to the air cleaner, maybe the pressure in the case is building up and blowing oil up into the air filter. I'll try a breather box and see if it helps.

Guest · Post by **Guest** » Thu Dec 15, 2005 2:46 pm

blue smoke on deceleration is usually guides, closing the butterflies causes a spike in manifold vacuum and it sucks the oil up through the guides.

64 variant · Post by **64 variant** » Thu Dec 15, 2005 2:48 pm

me^^^^^^^^^^^^ oops

500LbGorilla · Post by **500LbGorilla** » Thu Dec 15, 2005 3:00 pm

Guides. No question in my mind.

Rocker geometry can cause rapid wear. But.. yours is perfect, so it must be a bad rebuild job on the heads.