hello all

recent rebuild on my dohc ZC, and I am having a strange oil burning problem. No oil smoke is visible during normal driving, including full-throttle high-rev boots up inclines, but if I roll (in gear) for any length of time with the throttle closed, especially down a hill, when I get back on the gas a cloud appears in the rearview mirror. The size of the oil cloud is dependent on how long I have rolled with the throttle closed, so if I am coming down from a mountain after a day on the hill by the time I get to the bottom there is a lot of smoke. Is this rings, or is oil somehow getting sucked past the valve seals, or what the heck?

any thoughts appreciated.

greg v.

 

That's pretty classic for intake valve stem seals. Coasting with the throttle closed, they get a pretty strong vacuum pulling oil down thru the seals.

 

yeah, I did mention to the engine shop guys that they should do some research and get the right seals in; I hope they did. Is there any way to prove positive that it is the valve seals and not the rings?

thanks

greg v

 

yah. when it starts after sitting, does it smoke?

and, do a leak-down test

 

nope, no smoke at all on start-up after sitting; same with sitting idling in traffic, no smoke when you finally get under way. Seems the only time it burns is when getting on the gas after rolling in gear with throttle closed. And then it becomes very apparent.

thanks

greg v.