Help: Chain slipped

[BlownGasket]

its a 91 318i
some history, This car was taken apart and put back together without the use of a book or knowledge. The guides for the timing chain had broke and were being replaced. The chain tentioner was set wrong or never primed I read that the car should be held at 3,500rpm for it to prime on the initial startup i know this wasnt done. The Chain sliped right after startup throwing the cams off and braking the top guide. I'v got the front of the engine open again and am trying to find TDC on the compression stroke so that I can set the cams. I have an engine stop tool but how do I figure out if its compression stroke or exhaust stroke if the cams are already off ?? Theres a crank trigger on the crank pulley in the front and another pickup sensor on the cam at the sprocket. neither of these line up at the sametime. I cant figure out which cam is off or if borth are. The front lobes are supposed to point at each other when at TDC but these ones don't. Everything the book tells me to refrence to is off. So whats the trick in finding TDC on compression stroke ?? from there I'll undo the sprockets.chain and reset the cams... And what are my chances of the valves being bent

some one told me this engine wasnt widely used in its production year educate me a little if you dont mind.. Thanks alot for your help and replys ahead of time !

[bullmand]

Try this link. It's got a great description with pictures of a chain replacement. It may help.

http://www.esatclear.ie/~bpurcell/318istimingchain.html

[nickmpower]

there is a little mark on the crank gear where TDC is. its an arrow and there is a mark you are supposed to point it too. You can also just stick a rod in the spark plug hole and turn it till its at the top. the cams should be pointing inwards towards each other but they will both be up slightly. then look at the back and square them up. I cant help with the cam gear placement. Same think happend to me and im looking for an engine becuas a valve broke off

[bmwman91]

Yeah, the spark plug hole trick worked for me. I used a piece of welding rod and a sharpie to find cylinder #1's piston's highest point, turning the engine with a breaker bar on the damper bolt.

Aligning the cams is easy enough. The backs of the cams (firewall side) are square. You want these perfectly parallel. It is easy enough to tell when they are phased right as the cylinder 1 lobes are points more or less at eachother as shown on the link above. I used a piece of flat steel bar to get them parallel, and a crescent wrench on the square back to make adjustments.

[BlownGasket]

how far or not far off were your cams to break a valve ? This engine is off by about a heavy 45* at the cams :eek:

I just want to put it back together timed and if the valves are done what do they cost ? im a little nervouse about a valve falling apart now..

[nickmpower]

i have several sets of used good valves. I could probably part with a set. New i think an intake valve is like $20 and a exhuast is like $30

just take the plugs out and see if you can feel anything when you turn it over, mine was not off by very much

[BlownGasket]

Ok. Today im going to see if I can feal the valves when i rotate the engine.
I'm in Canada and found a website that sells parts I can buy the top quide which broke for 30$ canadian and a new tentioner for 70$ and a chain for 100$ am I going to find a better price if i look harder ?
http://parts.autopartsonlinecanada.com/parts/apocanada/years.jsp?make=BM