cylinder head question??
Turbo Mini Forums

ok hear goes,

after geting my turbo engine up and running on saterday i found that it was burning oil, as it was not a shit load i determined that i may not be the tubo that was at fault. so i removed the head and found that all the ports has quite a lot of oil in them. from this i thought that it could only be the valve stem oil seals that where faulty. see attached pic below



from the pic i hope you can see that the oil seals are only present on the inlet valves... i have never striped a head befor but im pretty dam sure that all the valves should have seals. am i right in saying this??

also on the fifth valve the disc that the valve springs sit on is missing. does anyone have one of these kicking around??

bloody shody build realy good job i checked this out.

If it breaks... build a much faster one

No, the exhaust valves don't need seals because you're not sucking in when they're open, you're blowing out.

However, your guides and/or your valves could be worn. They should be 8mm in diameter, but I'm not sure how much is too much on the wear. Sorry, I'm a neophyte, still...

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1967 Cooper 's' Turbo build @ www.drjing.com

The other reason that you do not use seals on the exhaust valves is that they run very hot in a turbo applicatiopn, hence the rubber/neoprene/whatever the hell they are seals quickly go crispy from the heat and don't seal anything any more. Also as the doc says, you are pushing out with exhaust gasses not sucking in. And my opinion, I would rather let a little oil down the exhaust guides just for additional lubrication.

if they are the iron guides then i would say they are shagged.

easiest way to tell ( bit late now ) is to park on level ground then run the car so they is plenty of oil sloshing about.

then jack up th rear of the car and see if the smokes get worse then jack up car at the front and see if it gets better if it doeas all this the then the guides are shagged.

insert the inlet into the guide and have a wiggle, you should get a slight side ways and up and down movement but only a little.

any more the a slight wiggle then they are shagged.

try fitting bronze guides then ream out with a 9/32 reamer they should but a nice smooth snugg fit with a slight endfloat to tight will bend the pushrod or bend a valve to lose then you will burn oil.

always looking for them bigger bunches of bannanas

thanks for the ideas. will change the guides anyway now.

If it breaks... build a much faster one

In my book, the iron guides wear quite well. What happens when you use fancy race valves, is that the valves wear, but guides are OK.