3 replies to this topic

[bigmatt4]

hi have just rebuilt my mini engine bored to 1360 re13 cam 1.5 rockers double valve springs and it has smoked from day one i havnt fitted valve stem seals to exhaust valves.

when engine is started from cold it dosnt smoke at all after about 3 minits it starts to smoke at idle turn it off let it sit for 5 minits and restart engine same thing no smoke for 3 minits or so hot or cold engine. 

engine has had full rebuild new valves guides seats pistons rings bearings rebore  rockers and shaft so im wondering do these have problems with the head flooding with oil?

also it looks like the back of the valve spring cap is hitting the top of the valve stem seal by measurements at full valve lift and crushing by 1/2 mm has anyone else had these issues and how did they fix it ? im positive that the rings have bedded in properly and the spark plugs show no signs of oil contamination .

also noticed that black oil is seeping from the bottom of the exhaust ports through the gasket indicating the oil is going down the exhaust guides any sugestions on this would be apreciated i dont really want to remove the cyl head as it has a custom headgasket in it . 

[deanymini]

Have you done a compression test?

[Earwax]

What is the oil pressure.  too high or too much oil getting into rockers could cause leaks down the back of seals. I just had a conversation about this today - my engine builder puts a restrictor into the oil gallery to slightly reduce the volume.  If the hot oil sits on the seals it may cause hardening..  Adjust the pressure relief valve may assist.

[minimadles]

You need to have the valve spring fitted heights checked and the valve lift measured as you may need to alter the valve train geometry to much side load on the valve tip can cause rapid problems with your valve guides. generally the oil that is fed up to the rocker shaft can drain back down to the gearbox through the pushrod holes quite readily