broken timing belt could be ok?

Fri Oct 31, 2008 12:21 pm

After a broken timing belt, do I change the belt or change the engine?

A year ago I bought this '92 316i Touring in desperate need and complete ignorance. No history, but the car seems to have stood around doing nothing for some time.

Last week the timing belt broke. I searched the forum, and... everybody knew this was going to happen except me! Oh well. You live and learn.

The think is, before I decided it was a broken timing belt, before I knew what an 'interference engine' is, I turned the engine over several times with the starter. Nothing was stuck, there were no bangs. So here's my question: is it possible I have been very lucky and not trashed the top of the engine? If there's a good chance, then I could change the belt. But you know how it is, I don't want to spend money and do that if the odds are really against me.

Cheers for any advice. I guess I got to make a decision this weekend.

Fri Oct 31, 2008 8:12 pm

whip the rocker cover off first...... if you can see gaps inbetween the tappets and the cam lobes then you have valves stuck down cus theyre bent.

Fri Oct 31, 2008 11:38 pm

Thanks, I'll do that. I'm looking at the picture of the cam in the wiki http://www.e30zone.net/e30zonewiki/inde ... elt_Change
I'm thinking if the valves could clear the piston heads safely, what position would the cam be in? Is it possible to tell?

It's a great forum btw, amazing how much information is here.

Sat Nov 01, 2008 12:38 am

on an interferance engine, no matter how fast the engine was turning or where ever the cam stopped when the belt went tits up. whatever position the cam is you cant turn the bottomend round without hitting a valve somewhere. thats the definition of an interferance engine!
its pot luck as to what valves are bent depending where/how fast the cam stopped and how quickly the cam and bottom end stopped turning when the belt went.
i sorted out a 2001 30valve v6 audi a4 at work a couple of weeks ago, the belt or rather the water pump had failed chucking the belt off. he was on the motorway at the time........... just 4 exhaust valves were untouched. his bill was over £1000.

get a s/h head and a gasket set, fit that its cheapest/easiest way. someone on here will sell you a head for the price of a 24 pack of carlsberg!

Sat Nov 01, 2008 12:45 am

Plus a new timing belt and you mite as well do the water pump while you are there

Sat Nov 01, 2008 1:16 am

I had one go on a 2L Cortina years ago, put a new belt on at the roadside and kept the car for another 12,000 miles with no problems. Sometimes you can be lucky.

Sat Nov 01, 2008 1:28 am

Bewdley320T wrote:I had one go on a 2L Cortina years ago, put a new belt on at the roadside and kept the car for another 12,000 miles with no problems. Sometimes you can be lucky.

i had a 1800 pinto sierra that chucked a belt when i was sitting on the motorway at 90 and it was exactly the same i put a belt on it and its still running around

sadly with my experiance with bmw engines if they break a belt its a replacement head

Sat Nov 01, 2008 8:25 am

Out of interest would the pistons be damaged at all? My girlfriends tourer got towed home yesterday by the RAC with the diagnosis of failed cam belt

I've got a spare engine (as you do) and was wondering if it would be easier to swop the heads or change the whole engine??

Sorry for jumping in on your thread 2BadJim..

Charlie

Sat Nov 01, 2008 8:36 am

Bewdley320T wrote:I had one go on a 2L Cortina years ago, put a new belt on at the roadside and kept the car for another 12,000 miles with no problems. Sometimes you can be lucky.

jbh wrote:i had a 1800 pinto sierra that chucked a belt when i was sitting on the motorway at 90 and it was exactly the same i put a belt on it and its still running around

You were both very lucky, then.
30+ years in the motor trade including the period when the Pinto was at its most popular and I've never known a Pinto to break a timing belt at any speed and not bend at least 3 valves.

Sat Nov 01, 2008 9:52 am

Ok, thanks very much to all, I guess a new head or engine is the way to go. Over to parts wanted!

Sat Nov 01, 2008 10:00 am

does anyone know any home tricks for skimming the head when you get it off i usually just clean of with some fine sandpaper and a gasket remover???

Sat Nov 01, 2008 10:03 am

You can check a head with a straight edge or two, but, unless you have a surface grinder tucked away somewhere, it has to be professionally done. Not expensive.

Sat Nov 01, 2008 10:13 am

OK I posted on parts wanted, but just to get max. coverage - I'm looking for a new cylinder head for a m40 316i, or I'd consider a complete engine, 316i or even I guess a 318 would fit?

Any advice on the conversion? I guess the diff is different, but is the exhaust the same? And what about the speedo? I looked at the engine swaps forum but maybe I'm blind. I didn't find anything about converting 1.6 to 1.8, it's all about how to put a rolls royce merlin into a go kart!

Sat Nov 01, 2008 10:15 am

i hear on another post that an m50 is a good change and cheap to get done?

Wed Nov 12, 2008 12:14 am

i have a 318i timing belt chewed about 8 teeth couple months ago, ew beltand timed up and its fine lol guess i was just lucky.

Wed Nov 12, 2008 12:35 am

2BadJim wrote:OK I posted on parts wanted, but just to get max. coverage - I'm looking for a new cylinder head for a m40 316i, or I'd consider a complete engine, 316i or even I guess a 318 would fit?

Any advice on the conversion? I guess the diff is different, but is the exhaust the same? And what about the speedo? I looked at the engine swaps forum but maybe I'm blind. I didn't find anything about converting 1.6 to 1.8, it's all about how to put a rolls royce merlin into a go kart!

Apart from the obvious 200cc bit, 1.6 and 1.8 engines are virtually identical. Heads are completely the same.