LR4 Low Compression

[BikePilot]

Since smoke comes out the exhaust it's not carbon holding a valve open--thatd be on the intake side.

 

[BeemerNut]

Since smoke comes out the exhaust it's not carbon holding a valve open--thatd be on the intake side.

Sorry boss, does not compute had to reply;

Smoke out the tailpipe sure sounds like an exhaust valve not seating unless you have a special engine which I never heard of which has the "intake side" directly connected to the tail pipe.

Picked up a 73 850 Norton dirt cheap only having 20 psi one cylinder, a chunk of rock hard carbon pounded and stuck under the exhaust valve seat. Cost me a head gasket plus 1/2 hr giving the seat a light full circle contact touch with a seat grinding stone as well the valve face on the valve grinding machine another light touch just for full bright contact.

Same lines a LR owner told me a repair shop telling him why his D1 was running on 7 cylinders because "it has a burnt intake valve". Only if the intake system were swapped out with the exhaust, cam reverse valve timing ground.
Endoscope revealed a long radial exhaust gas torching slit across the valve head. This due to the crappy valve guide seizing up the stem from carbon buildup. Way more common with US Cat equipped LR's vs non Cat around the world. Super lean Kalifornia issued vehicle also. .....~~=o&o>......