Non Starter for 10 - Stretched Chain?

[Markymojo]

Afternoon all.

I’ve just said my hellos in the Newbie section where I mentioned this problem, which is more appropriate in this discussion group. I’ve just bought my first and, sadly, broken Z4. It’s a 2.0i 2005 with 76k on the clock.

My friend is a great mechanic but with no experience of Z4s as such so I wonder if I could pass the problem by you to garner more insider knowledge?

The previous owner drove her quite happy car to the local garage because the roof stopped working - never fixed to the soon apparent bigger problem! While it was there they cleared a couple of fault codes and the car wouldn’t then start.

They replaced the cam position sensors but to no avail. They then concluded it was a stretched chain and the timing was out. They packed it all up, gave it back to her and that was the end of that!

I know the chains are prone to stretch and it’s about the right sort of mileage to do so, but I’d be grateful for any thoughts on this and any wider implications or problems that might relate to it?

MM

 

[Truman]

Daft question but have you read any OBD codes to see what the car thinks is wrong? Seems strange that this happened straight after someone had been clearing codes..surely if the chain was stretched enough to cause a non start it would have been giving some sort of problems before that ..? Just my two penn'th..

 

[Z4M-2006]

Thatt could be the earlier "M" series engine i think on a 2005,it was on the crossover.... They dont suffer chain stretch,or i have never heard of it.

If its the "N" series then yes,there is every chance on the 2.0,they also break the guides. Expensive job on a cheap car

 

[Markymojo]

It’s not as daft a question as the answer Truman! As soon as I bought it it was on a low loader up to my friends yard near Windsor. I’m in Exeter so I’ve not seen the car since I bought it last week. I bought it on the basis of the repair quote from the previous owners garage but no I haven’t seen the codes that led them to their conclusion.

My friend hasn’t had chance to run diagnostics yet other than he started it up when it arrived and it misfired and made a noise that suggested to him that the chain was a sprocket or two out. As it originally went in to the garage ok I can only think that after their initial, when the owner told them to put it all back together rather than repair it, they just bodged it?

Z4M I think it is an N46 engine, sadly.

Is it best policy to go with original bmw timing chain/sprocket kits or is there a strong, quality alternative?

Thanks guys.

 

[Z4M-2006]

Bmw OEM stuff is about the best you can get .

It’s still not brilliant but what can you do .

I’m sure for the N46 there is a tool that screws into where the chain tensioner sits that will access chain stretch, that said it sounds like this one has jumped or snapped to get it to a non run situation .

It will be an expensive job, especially if there is valve damage..