Greetings. I tried finding this information using the search feature, but found nothing, so I apologize if this has been talked about already.

Obviously, the thread titles says it all. I've broken the timing belt on my 1983 245 DL.

I have a Bentley manual and am having no trouble doing the job, finding the timing marks, etc. However, I am concerned I do have the crank in the correct position.

This may be a dumb question, but how do I know I don't have TDC on cylinder one on the exhaust stroke instead of the compression stroke?

My brain tells me once the crank, cam and intermediate sprockets are no longer connected, you're starting from scratch and TDC is TDC, but I simply don't know for sure and I don't want to have to take everything apart again to redo it if I get it wrong.

Thank you in advance
H2OSBLGT

 

You do start from "scratch"--you line all three marks the way they are supposed to be lined up, the crank, the cam, and the intermediate shaft and slide the belt on careful not to disturb the alignment. At that point everything is the it should be; then rotate by hand the engine a couple of times and check the marks again. If they are still lined up, you are good. I use a mirror to see down there and make sure the marks are where they should be-- the int. shaft one is hard to see looking at it from above. I am doing a b230ft belt today myself, it's all apart, I am gonna get it buttoned up after a valve job, (the head is all on already, just the belt's left)...

 

Yeah, once you have the belt off, there is no exhaust or compression stroke cause that is determined entirely by the cam position. Since it is aligned to the cam mark, that ensures it is a compression stroke. Therefore, the crank just needs to be in TDC position for #1 cylinder.

 

Thank you guys! I feel silly for worrying so much about this. My car has been sitting in my driveway for two days with the belt already ON, aligned with the marks while I researched and worried about this.

Should have it running shortly