E30 318is -90 - Rattling engine sound

[E30FETT]

Hello,

My M42 engine rattles, I have no idea how many miles it's been running. It rattles just a bit as long as I'm not revving it to 2 700 RPM. When I rev it to 2 700 RPM it rattles kinda much.

I replaced the chain tensioner and the engine rattled as usual, but the worst rattle sound now occurred at 3 000 RPM instead of 2 700 RPM. In half a year I've been driving with the engine like this without any problems. The teeth on my cam sprockets are in bad condition, right? I have the valve cover off at the moment so I can take more pictures if needed.

http://imageupper.com/g/?S020001007U1373204193534896

[vpilarrt]

Rattle is probably due to worn/bad timing chaing rails.

[E30FETT]

Rattle is probably due to worn/bad timing chaing rails.

Yeah but the cam sprockets are also in bad condition. Or are they very bad?

I've been driving with this rattle in half a year now and this is how the engine sounds today (pretty much the same as it did for 6 months ago): http://tinypic.com/player.php?v=ou2udc&s=5

[vpilarrt]

Yes, sprockets are bad also. I would replace the whole system - chain, all 3 drive sprockets, both side rails. You may be able to get away with not replacing the top and bottom guides and the idler sprocket but while you're in there...

[bmwman91]

At the least you need to pop off the top timing case cover and look around. It sounds like the timing assembly is pretty old and worn, and it WILL fail eventually.

[Dj Buttchug]

basically if your cam sprockets are shot its safe to say the whole timing case is in need of an overhaul.

[E30FETT]

I know the best thing to do would be to replace the whole timing chain lot, but if I can't do it at the moment, how long do you think the engine will last?

I mean what's the next step that will happen? I doubt the chain will break but maybe it will jump a few teeth on the cam sprocket and then my valves are gone? Or will the rattling sound get worse before anything bad will happen?

[isamemon]

there is no way of saying how long it will last as is

how much warning....50 feet

really hard to say as I have seen worn chain guides just snap into pieces without any increase in noise until the last few seconds and toast an engine in a friends 318is

kept telling him to fix it before it broke...he kept putting off...ended up selling a perfectly good ( otherwise) car for parts

[E30FETT]

there is no way of saying how long it will last as is

how much warning....50 feet

really hard to say as I have seen worn chain guides just snap into pieces without any increase in noise until the last few seconds and toast an engine in a friends 318is

kept telling him to fix it before it broke...he kept putting off...ended up selling a perfectly good ( otherwise) car for parts

Then the question is if it's worth spending the 500€ on fixing the car. I bet only the parts will cost over 500€. It's half of whats the whole car is worth.

[bmwman91]

Yup, all of the parts involved, if you replace EVERYTHING, will be $500-600. You might be able to get away for less if you use RTV adhesive instead of paper gaskets and don't replace the little idler sprocket.

The timing chain system on these cars is notoriously bad as of now, simply because of the age and miles on most of them. If you do decide to rip the thing open, I HIGHLY recommend looking into swapping an M44 timing case on there. It has a number of improvements over the M42 one and is far less prone to failure. You will end up needing an adapter for the crank position sensor and you'd need to make sure you have M44 oil pump gears since they are different than the M42. That would be a separate thread for you though lol.

[wazzu70]

I believe the later M42 engines had the upgraded timing case as well (with the guide instead of the idler sprocket).

[E30FETT]

This sounds like way too much work and money for such an old engine.

Do you have any other suggestions? Sell the car and buy another E30 with a better engine?

[bmwman91]

Well, it sure is a lot of work. That much I will give you.

As for the cost...well, I am of the opinion that any old German car is a lousy choice for someone that wants a low-cost, hassle free vehicle. The M20 probably costs as much to maintain averaged over time since it needs timing jobs 2x more often than the M42, and valve adjustments. Most M42's have had ZERO maintenance done on their timing assemblies, so whoever picks one up these days has 20 years of neglect to make up for. The up-side is that you will get another 20 years out of it. Probably. The stupid idler sprocket has a tendency to snap off of the timing case, hence the suggestion to upgrade to an M44 case.

[E30FETT]

Well, it sure is a lot of work. That much I will give you.

As for the cost...well, I am of the opinion that any old German car is a lousy choice for someone that wants a low-cost, hassle free vehicle. The M20 probably costs as much to maintain averaged over time since it needs timing jobs 2x more often than the M42, and valve adjustments. Most M42's have had ZERO maintenance done on their timing assemblies, so whoever picks one up these days has 20 years of neglect to make up for. The up-side is that you will get another 20 years out of it. Probably. The stupid idler sprocket has a tendency to snap off of the timing case, hence the suggestion to upgrade to an M44 case.

Okay, the M20 is an OHC and has timing belt?

Sure you need more maintenance but all you have to do is change timing belt and adjust valves which costs nearly nothing?

What about the M44?

Im planning on selling the car since I know I can get it sold for a good price since its an is.

[wazzu70]

Yes, M20 is timing belt. It is also cheap and easy to maintain. I can change a timing belt very quickly.

I wish the M42 had a timing belt instead of a chain!