Help-Burning oil.
Discussion
I'd be interested in people's opinions and ideas on the following matter.
During the winter my pre serp RV8 5.0litre Griff engine was rebuilt as it was using and burning an excessive amount of oil. During the rebuild it was found to have oval bores so required a small rebore and new long skirt pistons. The rebores ranging from just honing, to about 5thou. Each piston/bore was matched to each other. The engine also had a new cam and followers, timing chain and gears and a new oil pump. The heads were found to be fine and just required the valves re seating.
Since the build, the engine still uses alot of oil (1litre to 300 miles-ish) and kicks out a small cloud of smoke when under initial acceleration. On a journey, I can smell the burnt oil and it leaves an oily deposit on the rear end of the car.
The engine is due to come out again in a couple of months (don't want it off the road for the summer) to investgate and the people involved in the rebuild have a few theories as to why it's still using/burning oil. The engine was rebuild to the highest standards and the performance gained since the rebuild is excellent.
Any ideas people ?? It would be nice to find a nice simple answer to this problem although I doubt it will be the case.
Thanks in advance.
During the winter my pre serp RV8 5.0litre Griff engine was rebuilt as it was using and burning an excessive amount of oil. During the rebuild it was found to have oval bores so required a small rebore and new long skirt pistons. The rebores ranging from just honing, to about 5thou. Each piston/bore was matched to each other. The engine also had a new cam and followers, timing chain and gears and a new oil pump. The heads were found to be fine and just required the valves re seating.
Since the build, the engine still uses alot of oil (1litre to 300 miles-ish) and kicks out a small cloud of smoke when under initial acceleration. On a journey, I can smell the burnt oil and it leaves an oily deposit on the rear end of the car.
The engine is due to come out again in a couple of months (don't want it off the road for the summer) to investgate and the people involved in the rebuild have a few theories as to why it's still using/burning oil. The engine was rebuild to the highest standards and the performance gained since the rebuild is excellent.
Any ideas people ?? It would be nice to find a nice simple answer to this problem although I doubt it will be the case.
Thanks in advance.
Could be worn valve guide seals, but if it has had a rebore it will take a while for the new rings to bed in and in the mean time it will blow more than normal - this can mean more oil gets carried out the breather and back into the inlet manifold. Might be interesting to redirect the breather into a catch tank and see how much oil you collect?
My experience of bad valve seals are nasty puff of smoke 1st startup in the morning. All that expensive synthetic stuff gets time to run ito the chamber overnight.
If its smoking under acceleration that sounds like its getting burnt. Ie, oil it making its way into the combustion area and not seaping in overnight. I'm no expert but looks like the job wasn't so good or original problem was not fixed. 300 miles per litre too ! 500's have wet liners I think, so expect a bit of use but i never had that consumption on my chim 500.
i'm no expert tho ! So dont panic yet !
>> Edited by RobM on Saturday 3rd July 02:18
If its smoking under acceleration that sounds like its getting burnt. Ie, oil it making its way into the combustion area and not seaping in overnight. I'm no expert but looks like the job wasn't so good or original problem was not fixed. 300 miles per litre too ! 500's have wet liners I think, so expect a bit of use but i never had that consumption on my chim 500.
i'm no expert tho ! So dont panic yet !
>> Edited by RobM on Saturday 3rd July 02:18
Thanks for the advice/ideas chaps.
Valve seals were replaced. Valve guides were inspected and found to be within acceptable wear limits.
Interesting idea about a breather catch tank, I was thinking about doing this the other day. I've wondered whether the breather system maybe at fault but there really isn't much to it on a RV8.
I'm hoping it'll just be a faulty new piston ring or something else of a simple nature although one idea is that I've got a porous liner or two.
Valve seals were replaced. Valve guides were inspected and found to be within acceptable wear limits.
Interesting idea about a breather catch tank, I was thinking about doing this the other day. I've wondered whether the breather system maybe at fault but there really isn't much to it on a RV8.
I'm hoping it'll just be a faulty new piston ring or something else of a simple nature although one idea is that I've got a porous liner or two.
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