Please could some one tell me if a 1996 jag x300 XJR S uper charged motor should have
valve stem seals on the exhaust valves. I have just rebuilt the motor with new rings etc, head been done
but when running the motor smokes like crazy. So much so that oil comes out of the number 5 , and 6 exhaust ports.
Has anyone ever had the head crack in the exhaust port area because I am thinking something like that could cause oil to be
sucked into the exhaust port. Does anyone think this is possible? Exhaust ports 1 to 4 don't show ant sign of essive oil.The
car uses 500mls of oil in 10 mins.
Would appreciate any ideas before stripping the motor again.
Peter

 

Peter,

I've moved your question from General Tech Help to X300 forum. Members here with the same model will be able to help.

Graham

 

24V 24 seals.

 

I would remove the exhaust cam and remove the buckets and springs to see if the valve seal are installed correctly. If not fully installed on the guide and allowed to go up and down with the valve it would pump oil into the guide and out into the exhaust. Let me back up a bit, Is the compression off a bit on cylinders #6 and #5? Could have broke or incorrectly aligned oil control rings. I would do a leakage test on all the cylinders to split the possibilities in half.. It would be interesting to remove the exhaust manifolds and with a mirror observe the exhaust valves while open to see if there is any drippage.


Larry Louton

 

Thanks Larry, The compression across all 6 cylinders does not vary by more than 3 psi. I have removed exhaust manifolds
cleaned the ports ,put some oil on the the valves and have noticed no leaks . I think your point about the valve stem seals
needs further investigation.
Thanks very much for the input.
Peter

 

I admit that this sounds like a crazy way of diagnosis. Assemble the top of the engine, Cam cover, coils and such. Leave the exhaust manifolds off and run it. This will be real loud. You would be able to see after a bit of time if oil is dripping through the exhaust valve guide or not. if the valves guides on the first four cylinders stay dry, But the valves and guides get wet on the back two, There is your answer. Remove exhaust cam and inspect/ replace oil seals for exhaust valves.
They make special tools to do this without removing the head.

Larry Louton

 

Thanks Larry will try .