Camshaft Replacement M20

[zidney1]

Hi All,

Planning to get the camshaft replaced on my '86 325 but can anyone please advise on things to look out for and other bits that should get replaced at the same time?

Also, will the head have to be re-skimmed once taken off?

Lastly, I'd like the cam to be as smooth as possible rather than powerful at high revs so what would be the best one to go for? (BMW are quoting £300+!)

Many Thanks

Zahid

[murran]

is your cam worn out? good second hand ones should be easy to come by.
or are you wanting a fast road performance replacement?

possibly best to have it skimmed. but take it to a good engineering shop have them check it out to see if it needs it. be a good idea to have it pressure check while its off too. take the valves out and lap them in, new stem seals etc.

[zidney1]

I was hoping it was the tappets but based on the sound being dense and generally sounding like a bag of tools, I've been advised otherwise.

Not after a performance one mate just the smoothest one possible at low revs that people could recommend.

Good shout on the pressure check. Thanks mate

[murran]

bob the cam cover off and check the clearances doesnt take long turn it to tdc on no1 check the clearances the turn the engine over to the next cylinder in the firing order.
i had this on my touring.....
problem......


good s/h cam and rocker was sourced and fitted. managed to do it with the head still on too!

[zidney1]

Thanks Murran - and thanks for going to the trouble of posting a picture.

Pretty impresive to do teh job with the head still on!

[Nay]

Rebuilding an M20 head can be worth the money and effort as 20 years of abuse can really get to it.

As for cams, stick original, or a low degree cam from shrick (from what I've heard). If i'm right in saying, low degrees cams dont have "much" of an effect on an M20, but do make the top end a bit more pokey. Not too sure on smoothness, but as I say, I've heard performance cams dont have a massive effect on the car till you look into the high degree stuff.

Completely dismantle the head. Acid dip and clean it. Pressure test and skim. If you can afford it, new valves (the spings and hats etc should all be re-usable). Re-seat the valves with some grinding paste and a close eye for making it sit tight. Clean the rest of the parts (from old grease) and reassemble using a bit of new engine building grease along the way. Basically for the price of some valves and the odd little bits you can rebuild your head for quite cheap in comparison to the list I emailed you (which glad it helped you! Thanks for letting me know!).

Whilst your there, consider looking up cylinder head polishing. Mildly (so you dont mess it up!) polish the exhaust ports (you still should have it a bit rough for the inlets) and that will give it that extra little touch for up to a few hours work!

Good luck mate.