6 replies to this topic

[minivanman8]

I've had to take my newly built engine out to re-shim the primary gear (I believe it is the cause of an oil leak through the clutch housing) and have I the mean time discovered an oily looking substance in the inlet ports.

Engine is a freshly machined (only done 60 miles with it) 1293 with 18cc pistons (for the supercharger) sw5 cam, re faced head, new valve guides, freshly cut valve seats, rebuilt gearbox.

The liquid was golden brown and a light coating over all surfaces in the inlet ports.

I guess this is oil getting in somehow? Any help/suggestions are much appreciated.

[sledgehammer]

Are you getting blue smoke out the exhaust - using oil ?

 

have the ports been cut - opened up ? - have they cut into the push rod holes ? (only takes a tiny hole)

 

are the plugs oiling up ? how much back pressure in rocker cover area ?

 

if it is a bit rich - then the excess fuel could be starting to carburise on the port walls ?

 

what vent setup are you running ?

 

some pics would be useful 

Edited by sledgehammer, 05 September 2013 - 10:23 PM.

[jaydee]

Its fuel.

Very common if you have HS4s or HS2s. Its the steps in the manifolds and the carbs itslef that can cause this.

[minivanman8]

I am running a hif44 carb, no blue smoke from the exhaust that I noticed. I didn't do enough driving to see if it was burning any oil... The level certainly didn't drop drastically.

The ports haven't been cut during this rebuild but they have had some very slight work in a previous life.

The plugs are ever so slightly nearer to a black colour than brick, but not real dark.

It has a crank case breather and that's all (assuming that's what you are referring to regarding vents.

[jaydee]

Its running rich, you want the plugs of a grey colour with modern unleaded fuel.

[minivanman8]

Would that account for the liquid? Stuart at Vmax is going to do a pre running in tune, so I'm not worried about the mixture for now. I'm more worried about whether or not something has failed or is mechanically wrong

[jaydee]

First thing to do, remove dashpot and piston and see if theres fuel around in the venturi. If so, the jet is leaking.

The HIF has very accurate castings nothing to compare to the old HS2 and HS4. There shouldnt be stale fuel in the choke.

Also gaskets not lined up to the manifold, manifold misaligned to inlet ports can cause this.