I seem to be useing a lot of oil in my 1750 x flow.
The guy who sold it me said its been rebored with new pistons etc.
I have checked the compression on all 4 cylinders and they are o/k.
The only thing I can put it down to is the oil being sucked up the breather pipe into the engine via the manifold and being burnt (As blue smoke appears on full throttle and covers anyone who is behind me with oil)
Can I, or should I disconnect the pipe from the manifold and feed it into an oil catch tank sealing off the inlet of the manifold.

Your views are appreciated.

It should be easy to try out the theory by doing it temporarily to see if the blue smoke stops. You won't do any harm trying it.

Cheers

Mark

Can it be fed back into the rocker cover, recycle it back to where it came from?

Could the valve guides be worn out? I can't remember how to diagnose that problem... anyone?

David

If the valve guides were worn out out I think that it would smoke on the over run.


Big cheers
Michael

Not necessarily - if the pistons suck hard on the intake stroke then they can pull oil past the valve and into the cylinder.

Allegedly.

David

Mark, Pete, David and Michael.

Thank you for your replies, I think I will try it with the catch pot 1st, then if its o/k I will connect into the rocker box cover.

I will do a post to tell you the outcome.

Thanks again

Keith.

(lukefab)

[Edited on 6/5/05 by lukefab]

Sounds like the crankcase is pressurising first thing to look at is of course the crankcase breather but if it is as bad as you say I suspect the piston rings haven't bedded in inspite of your compression test results.

Keith

IMHO Feeding it back into the rocker box cover is not a great idea as there is then nowhere for the crankcase pressure to go and will cause oil leaks form the crank seals etc.

If a separate catch tank works then that is the way to go.

see dave andrews http://hometown.aol.com/sarandrews/wateroil.htm
for a good explanation of engine breathing

Cheers

Mark

The rocker cap should have a gauze filter in it to let it breathe so the pressure shouldn't be a problem. If it hasn't got one it is probably what is causing it. Look on here to see what I mean.
http://www.zen11896.zen.co.uk/vixen/parts/kent.html
about 25 items down.

Sorry to sound like a scratched record. but I did a quick google on high oil consumption & blue smoke. Almost every page I looked at came up with 2 usual suspects: worn bores/rings, and worn valve guides/oil seals.
If he's got decent compression then rings can't be SO bad that he's using a heap of oil & producing loads of smoke - I'd go for the valve guides and oil seals.
(but I have been known to be wrong occasionally )

rgds,
David

Another thing to consider ,what oil are you using. Think you will find that Xflow engines should run on 20/50 . Modern oils are to thin and will burn off quickly in X flows. If tou are using anything else it may pay to change it for a decent 20/50 H.T.H

IIRC if its valve guide oil seals, the smoking is worse at start up from cold, as oil has made its way down the valves and into the bores,while the engine has been stood usually stops as the engine warms. could be wrong, its a long time since i ran a boat anchor
Best cure is to rip it out and fit a nice oil tight bike engine mmmmh

One way of checking for valve guide wear without stripping head down is to leave engine idling for maybe 15mins then blip throttle a couple of times. If you get a cloud of oil smoke then it's likely to be worn valves/guides /seals. engine oil stop leak may help with tired seals

If it smokes when cold, but not hot, its the stem seals

Well, what can I say,

A very big thankyou to you all !!!!!!

The way it seems now is to try each of your replies one by one.
I will start tomorrow with the catch pot
and check out the others.

But a bike engine sounds very tempting !!!

Thanks again !!!

Keith

(lukefab)

[Edited on 6/5/05 by lukefab]

Don't do it!!!
Have you thought of the obvious?
Too much oil in the sump to start with?
Crank splashes in oil and throws it up behind pistons, with new rings, not quite bedded in, you get smoke from exhaust, especially on hard acceleration. Came in handy once just after SVA, 2 dirt bikers getting too close so I floored it. Lost them in a cloud of smoke James Bond stylee!

Marcus