Oil in the inlet manifold

[jpyke]

Hi folks, finally got around to taking the inlet manifold off today. When I lifted the carb pedestal I noticed there was a small pool of oil in the bottom of the manifold and when I removed the manifold itself the runners were quite black and oily as were the inlet ports in the heads. This would explain my mucky oily plugs and the white smoke I'm getting; trouble is I can't work out why it should be drawing in so much oil. I lifted the rocker cover that the breather is connected to and there was certainly no pool of oil underneath - just what you'd expect around the base of the cam lobes etc.

Anyone got any ideas as to why it might be pulling in so much?

[european voyager]

imported post

Are any of the breather hoses blocked ?

[flying farmer]

imported post

Usually excess oil coming through the breather is a sign of worn rings. The extra flow of gas down the breather carries more oil with it and this what you are probably finding. I find an easy way of checking the rings without a compression tester is to find a piece of rubber hose you can hold against the spark plug hole, then blow into each cylinder in turn on a compression stroke while listening at the oil filler. It is quite easy to hear the air bubbling past the rings, and you can compare cylinders too. It also checks how well your valves are seating. I have used this method for years.

Neil

[jpyke]

imported post

Hi Neil, thanks for the advice. I did check the compression a few weeks ago and I found it ranged from 8.3 to 9.5 which I thought seemed reasonably healthy?

[flying farmer]

imported post

I don't actually know what proper figures are for the stag engine, I assume your figures are bar so about 125 to 142 psi. Perhaps someone could enlighten us?

Neil

[mattsay]

imported post

Hi jpyke,

Did you find out what your problem was? Did it cause poor running?

I have the same problem, and good compressions too.

Cheers,

Matt.

[stustag]

imported post

jpyke wrote:

Hi folks, finally got around to taking the inlet manifold off today. When I lifted the carb pedestal I noticed there was a small pool of oil in the bottom of the manifold and when I removed the manifold itself the runners were quite black and oily as were the inlet ports in the heads. This would explain my mucky oily plugs and the white smoke I'm getting; trouble is I can't work out why it should be drawing in so much oil. I lifted the rocker cover that the breather is connected to and there was certainly no pool of oil underneath - just what you'd expect around the base of the cam lobes etc.

Anyone got any ideas as to why it might be pulling in so much?

I had this problem on my Stag and it was accumilated oil from the damper O rings leaking.

A small amount of oil can look like loads when on a flat surface.

Stuart

[jpyke]

imported post

Hi Matt,

I *think* it was probably the gauze filter in the RH cam cover that was quite clogged up. When I refurbished the cam cover I got the filter elements out and gave them a bloody good clean. May be worth a try. I thought originally that it was the cause of bad starting when hot but soon realised that it was actually fuel vaporisation and flooding when left standing from hot. In conclusion I think it unlikely to be the cause of poor running unless there is a great deal of oil in there.

James.