Hey everyone, i've been driving my E30 a lot more than usual and i've noticed a ticking noise that seems to be coming from under the valve cover. It sounds like it has gotten louder. Anything to be concerned about?
probably valve adjustment, if it hasn't been done for a while http://www.pelicanparts.com/bmw/techarticles/E30-Valve_Adjust/E30-Valve_Adjust.htm
It is my belief that the more a valve adjustment becomes a necessity, the louder it gets, but I don't know if there's validity to that claim. It would make sense if that was the case. Mine was ticking a little bit louder before I had my valves adjusted, but the noise difference is minimal.
Not adjusting the valves may yield in a loss of power and poor fuel economy. It can also damage your valves as well, consequently causing potentially serious engine damage.
Before my valve adjustment, the ticking had gotten noticeably more audible, to the point that it was all I heard. After the adjustment, not only was the noise gone, but the car felt faster and more responsive, plus the fuel economy was much better. I would suppose the opposite would have been true too, had they not been adjusted.
Damage - hmmm... well.. the rocker arms wear, although I can't comment whether the contact point with the valve or the camshaft wears more. I'm gonna guess the part in contact w/ the camshaft wears more. As they wear, the gap between the valve and the rocker is going to increase (I would presume 1000's of an inch, here). Over a really long time, as in the-life-of-the-engine long, I suppose there could be enough wear that the valves wouldn't open quite as much, which would mean a nominally small less amount of air or air/fuel combustion mixture would be getting to the cylinder. I suppose that could affect power. I would think a more direct effect would be on valve timing. If the gap is a little bigger than it's supposed to be, it's going to take fractionally longer for the gap between the rocker and the valve to close, and then for the rocker to be pushing on the valve. Considering that all the timing of that for optimum running is very precise (or should be), the collective effect of the valve timing being off, I would think is going to effect how the engine runs, manifesting itself in some fashion - decreased fuel economy, overall efficiency, perhaps running smoothness. A real engine expert presumably will have a more exact analysis of the effects of valves being out of adjustment. I would think if they got waaay out adjustment, then there could be the risk of pistons hitting the valves, but I think that would be have to be a huge amount of wear. I think you can have the timing belt off 1 tooth in either direction (maybe more, not sure) without suffering damage, although the car would run poorly. I don't know, but I'd have to guess an equivalent amount of wear to equal a timing belt being off a tooth or two, would be a really large amount of wear. Which is not to suggest that it's a good idea to see how long you can go without adjusting valves; valves are just one of the regular maintenance items on these cars.
I would think that as the components wear the valve will not open as far and therefore combustion air will be less which the computer will compensate for with less fuel to keep the mixture right which will result in slightly less maximum power. Also with the larger "gap" between the moving parts, wear will be increased, the ticking is most likely the wear occurring which the viscosity of the oil can not compensate for. I do not see any way for the decreased valve opening to cause piston-valve contact or the "larger" rocker-valve gap to cause non-repairable damage to anything other than the rockers or cam but I am sure someone will correct me if I am in error. Cheers, Bob
Realistically, I'd figure you're correct, and that it's unlikely any damage would be incurred from having the valves way out of adjustment. My point was that out-of-adjustment rocker/valve clearance affects not only valve opening, but timing as well (fractionally, I would guess), and the timing part would be the potential area for a damage issue. It seems though, if things were that far gone, the car would be running so poorly so long before then that it's unlikely anyone would continue driving it (assuming it would stay running) to the point where damage could occur. IF damage actually can occur; it's also possible that the max wear point of the rockers (up to the point where they no longer would be able to transfer motion from the camshaft to the valve, at least as designed) is below a point where there could be valve/piston contact. Hey! I've got an idea! Any volunteers want to run their M20 250,000 miles without adjusting their valves so we can see what happens? Anyone? No?? (gosh, I'm so surprised!)
I read the pelican article online and they said that the valve clearence should be 0.010in with the engine cold, but my Hanyes Manual suggests 0.012in cold. Which do i follow? thanks
... which is: ENGINE COLD: 4-cylinder: 0.008 in. 6-cylinder: 0.010 in. ENGINE WARM: 4-cylinder: 0.010 in. 6-cylinder: 0.012 in.
alright so yesterday i went out and bought a new gasket fromt the dealer. It was like 20 bucks. i get my valve cover off, remove the spark plugs and have my neighbor who is a mechanic come over and take a look. He measured that the gap between the valves and it was 008 inch when the engine was warm, then we let the engine cool and measured it to be .010 inch. Now I never got to top dead center before he measured them, so does this make a difference? He ended up claiming that the valves weren't out of adjustment so feeling retarded I just put the new gasket on and put everything back to the way it was. The ticking noise is still there which my neighbor said was my fuel pump or something and that it was. I don't remember the last time the valves were adjusted but is it possible that they really havent come out of adjustment yet and that i have nothing to worry about?
I think those measurements were fudged. I find it strange that the clearances were larger when cold than when warm.
How much would a shop normally charge to have this job done. I really dont feel like doing it myself to be honest. I'm not so sure that I have enough experience plus it seems like its risky business taking off your valve cover.
I'm no expert but if your valves are fine another problem that causes ticking is if you have low oil/need an oil change as I've had friends who have had ticking and doing this fixed the problem. You should probably check on that. Now as for how much a valve adjustment costs, I have a receipt from Dinan wtih one of those on it among other things. Now if I could just find it and post the price....
Just a note, there will be some ticking from your injectors, but this will be relatively quiet when compared with intake or exhaust valves being out of adjustment. I will also tell your mechanic neighbor that with the e30's, pre-87 had two fuel pumps, neither of them in the engine compartment, and post 87, there was only one, not in the engine compartment. Just a FWIW.... Get the pelican tech article and follow it step by step (or bentley), and you should be able to get your clearances in check. Every 10k -15k miles... MK
ya, the valve adjustment hasn't been done since 150,000 and im now on almost 174,000...i'm not so sure its a huge concern as of right now, atleast im hoping as the car is relatively quite (but ticking noise is audible) and has substantial power..i'm hoping i can find an independent BMW mechanic to do the job but there doesnt seem to be any in my area. I dont think i could trust someone like monro muffler or meineke or any other large chain mechanic shops to do the job but correct my if i'm wrong. the dealer would probably charge an arm and a leg and for me to do it myself just seems to risky and im not particularly comfortable with it0as i already tried, couldnt find TDC and reinstalled a valve cover gasket that may now be leaking oil....
That can be part of your problem. A trusted BMW fanatic friend of mine gave me a rule of thumb about TDC. If you have the belt adjusted forward, it can change your max RPM's about 500. If you have it backward (behind), you can seriously damage your exhaust valves. I would recommend a shop look at it, and you are right about the chain shops, most of them can be trouble, as they know engines for the most part, but domestic engines. You will be better off with an import shop (you know the preference).
