Right....I got my brother to follow me home tonight and told him to keep an eye on what exits my exhaust and when.Got to a slip road joining the bypass and i hoofed it in 2nd and 3rd.Looking in my rearview mirror there was no visible signs of smoke...just this very light coloured haze.Got on the mobile to him, to ask what he could see,and what he said was that there was no signs of smoke but he could smell oil!He also mentioned this light haze behind the car.Now i know my car uses unhealthy amounts of oil but it does`nt smoke to badly.I`ve noticed spots of oil on the tailgate and stuff so my thinking now is that its chucking out unburnt oil from the exhaust.How?Well it would have to come down the exhaust guides but would the flow of the gases be strong enough to suck oil down the guides?Just a thought.
Any comments appreiciated
one of my engines used to smell a bit, never did find the actual fault. I put it down to general wear and tear, being rings valve guides stem seals, i just dont know.
A compression test can say a lot about how the engine is running, or by taking the oilcap off when running and covering the hole with your hand to check for back pressure, this can indicate worn valve gear.
Oil can run down the valve guides, i found a few stem seals that had perished to the extent that the area that creates the seal with the valve just wasnt there anymore.
Its quite a fresh engine(10,000mls)which i rebuilt myself.The only part i did`nt do was the head.I left that with an engine shop near me and told him to go over it.Was`nt long before i realised that the stem seals were shagged as it was smoking a little on the overrun.What gets me is the fact that my brother could`nt see any smoke but he could smell oil??That was under hard acceleration taking it to 7,500 in 2nd and 3rd.
I@have the same thing on my Nova, black spots etc.
I find my consumption is greatly reduced when I drive under 3000rpm. As soon as I start belting it oil goes like mad! I also find that if revving high when I clutch to change gear if I wait till the revs die a couple of tho it doesn't smoke.
You should have seen it at Pod, it was competing with Gary's car in the "Most Harmful To The Atmosphere" category!
I`ve found that if i drive on the motorway at a steady ton ish for a long period then my consumption is bad....but it doesnt smoke then..just covers the back with oilspots.I know it sucks oil down the inlets cos it kicks out smoke when i lift off completely and boot it again.Just wondering if it could actually suck oil down the exhaust guides so that it spews neat oil out of the exhaust?
Think i can see the head coming off soon
I'd be suprised if any oil getting throught the head would survive and still be recognisable as such by the time it exits, tbh, but who knows, engines always manage to surprise no matter how much you think you've seen.
why not move the manifold aside and inspect the exhaust ports -the heads I've seen with leaking seals on the exhaust are always very easy to spot simply by the mess present - you got the big manifold right ? - takes a couple minutes to drop it forward a little and have a look see.
Gary....i`ve just noticed that the joint on the compensator flange is very oily,its almost dripping
I rekon this is where my oil is going...down the exhast guide and exiting the exhaust as a mist of unburnt oil.Think the heads gona come off soon
Changing the subject a bit....are the bronze guides better overall than the iron ones or what.I might aswell do those while the head is off
I got the real thing here for porting...the old moriflex job,so yes,i might have a go .You got any pics of the finished job showing what ya do with the guides etc.Do ya fit them, then grind them down flush?Or do ya just taper them.
ok this may sound silly but check you don't have an oil leak, especially one that only occurs n high revs (i.e. blowing it out the rocker breather).
The oil spots could well be where your gunning it and the air pulls the dripping oil under the car splattering it on the back in the swirled air. The haze could be where the oil hits the hot exhaust and burns.
I take it your not over fueling (does your car stink of petrol?). Know cars to be running so rich that a vapour haze is created - anyone remembers 0dders car at the SE rr on his 1st run before he turned down his FPR?. Carn't reason if this could also happen only when gunning it, thoughts anyone?
I agree with Gary that I carbn't really see oil getting n the exhaust and serviving, anyway wouldn't you get clouds of grey smoke in the classic "I'm burning oil" sign?
dont you have a 20 foot pipe from the breather running down the back of the engine bay? you should see how much shite come out that at high revs mate. thats where the black spots are from i would guess. and yeah i am running 60psi and can get that haze.
another goodun is the leaky sump gasket dripping on the manifold - i had that at first
when I say Dremmel Al, I mean one of those 1/3hp things with the flexi shaft and remote motor - good bit of kit - I'm doing a head for astragsi1816v at the mo which paid for it.
re the grinding down of the guides - depends - the shorter colisbro ones I have on the original head didn't really protrude into the port that much, only the exh ones could do with a little flushing - but the ones I got from SBD that're in the head I have on now were a lot longer and needed grinding right down on both inl and exh - could take awhile - you really need a big carbide burr to do it - if you got one of these you're laughing - finished jobs a good 'un though - looks top, and really allows you to flow the whole of the head properely - don't bother with tapering them if you get the long ones - just grind em right off flush - much better for flow.
haven't got any pics I'm afraid other than the old ones of my first head on the site.
fitting is ok I guess If you don't mind using the persuader technique - cos 13mm guides are easier than GM ones though due to their size - if you DIY em, get a bit of hollow bar chopped off to length to set the clearance on the cam side, otherwise it's not easy to set it when you're bashing them in.
I`ve been playin around with my old pourus head and done a couple of inlets.Got myself some of those carbide burrs...the ones with the wide flutes....and they rip out the alloy at quite an alarming rate!
I`ll take some photos Gary,see what ya think.
Back to the old oil consumption thing...My breather pipe goes into a catch tank and my oil leaks have been sorted for a while now.Fuel pressure is set to the standard 50 psi and according to the R/R the fueling is spot on.
Think i`m just making up excuses so that i can rip the engine apart.Reliability is getting boring now