E30 Zone

Hi all im thinking about changing the timing chain on my is over the summer for peice of mind as i dont have much history for the car and its got 150k on the clock. I was thinking about changing the tappets when i do this as well as it has a slight tap when cold (i've changed the timing tensioner and it still taps). I've read that you need a special bmw tool to take the camshaft of is this true? if i do the tappets how hard is it to go the full hog and whip the head have it skimmed and change the gasket while im at it or would you say, if it aint broke dont fix it?

Chris

it depends on your definition of hard!

if you know what you're doing, and dont mind your patience being tested, then its not really too difficult i suppose. but if you're neither of the above then its gonna be as hard as blind man trying a jigsaw puzzle!!

you need to look into what you're gonna take on before you start ripping things apart, bearing in mind that you wont be able to drive the car for a few days at least....

chris, there's no definitive answer to the cam question. the cams are hollow allegedly, which is supposed to be problematic as they are brittle and allegedly liable to snap. thus there is a bmw tool for the job. If you search on google for m50 camshaft removal etc you'll get a feel for what it does, it basically holds all the valves off the cams so you can remove the cams without risk of snapping them under the pressure of the valves. If you remove the head, you needn't worry as you can hold the valves off with bits of rope or whatever which is equally effective, plus there is another method which works particularly well with the m42 (as its only a 4 pot) which is to find the sweet spot where all valves aren't putting much pressure on the head, this method is detailed on pelicanparts.com. for what its worth i've never heard of anyone snapping an m42 cam and have seen plenty of them out. but i won't take responsibility if you snap one! i think if you didn't know about the tool and potential probs, you'd happily remove the cams with no worries, i think the problem is more likely to manifest itself on the longer 6 pot cams. i guess be careful and remove the bolts slowly and in sequence.
and hyd tappets aren't too difficult afaik, never changed them myself though. if you're thinking of having the head off, might be quite good to get in and replace profile gasket, clean everything up, and do the cams the safest way.
hth
tim

Cheers for the replys, i've taken the head of my mk1 golf before so im not to worried about how hard its going to be, mind you this wont be until the summer. Dont you replace the profile gasket if you do the timing chain anyway.

YEs the cams are hollow!

But you dont really need to use the BMW tool to take them out the head, if you take your time and work all the nuts loose little by little so they all come off evenly the cams will not break.

Andrew

head on a mk1 golf is much easier than the m42 btw. the timing chain assembly is more involved than the veedub belt too. at least you don't have those sodding manifold or downpipe bolts on the bmw m42, there's a bit more access too.
how bad are the tappets?

I wasnt saying that the bmw was easy, more the point that im happy to do the work myself, i read the how to on the bp site and there nothing to technical to do. Its not tapping that much, possibly on one valve only, it goes once the engine is warm. i'll try giving it an engine flush next time i do an oil change and see if it cleans the tappet out a bit. I was just trying to find out how much work is envolved and if its worth going any further than the timing chain. What oil would you use, the person who owned it before me used 5w40 supersynthetic.

i use 5w40. thin oils are supposed to be good for the m42. cool, am sure you'll find the engine work no probs, just thought its worth pointing out that its a bit more of a pita than the golf. its really not too bad though. you sure its a tappet and not an injector or something?

injectors can tap? didnt know that. how can i check, would the injector cause other problems.

yeah mine used to tick like god knows what (and only when cold!)! i thought it was a tappet too until i opened the bonnet and had a listen! you'll be able to locate the sound ish when the bonnet's open - put your ear near the injectors and if its the injectors you'll tell. to fix it the correct way is to have them ultrasonically cleaned at a fuel injection place, i've shut mine up by taking them out and spraying carb cleaner into them to clean them out. seeing as i'll be changing for larger injectors at some pt (and that they're quiet now!), didnt see the point in doing anything else.
i guess injector ticking could be an indication that the injector is not spraying a nice cone shape, its certainly not a good thing, but mine ran fine like that. imo having the injectors ultrasonically cleaned is a good idea anyway really if they're ticking, at least then you know they're spot on.
hth
tim