Tdc

I didn't know if this was the right sub forum to post this but it does have to do with a BMW 325i. When i was taking the engine head off to replace the gasket. The chilton's book said to align the piston to TDC before removal. I did so, but was wondering why you have to? Is it some kinda compression stroke ratio or what? Thanks.

Do a Google ''Youtube head gasket repair''I like using a compression guage on cylinder 1 @ Tdc!

Not a compression issue, more of an interference isssue. If that engine is an interference engine (I don't know that it is), if you don't have the #1 piston at TDC and the cam at no. 1 TDC position you'll hit valves and bend them.

I see. Thanks for your info guys.