Project 16: Tensioner Update / Installation

[Wayne at Pelican Parts]

Got any questions on Project 16 for your E36 or E30? Ask them here!

-Wayne

[vader_z]

Just a quick question. Is it safe to use PN 11-31-1-405-081 chain tensioner on my 1995 325i with a M50 built 12/94? Or should I stick with a replacement spring and plunger from BMW?

-Thanks!
Colin

[aperry]

I'd like to second the motion for clarification.

My own 1995 325i is soon to be treated to a new timing set (sprockets, chains, guides, tensioners, and anything else that looks like a wear item) and I'd like to know, for sure, which tensioner to get.

It looks like it depends on which guide rail style is installed, as to which tensioner style is needed. The earlier tensioner/rail style appears to have a slot in the piston where it contacts the rail, whereas the later combination appears to have a flat piston.

It looks like the switch to the newer, flat style of tensioner/guide rail happened around 09/1994 for the M50.

But it doesn't look like the M3's S50 motor (which it would seem obvious to borrow from) ever received the updated rails, with the change in style not happening until 1996 with the release of the S52.

So: It seems that, for my post-09/1994 M50 (or an M52), I'd need a tensioner for the S52, as installed on the post-1996 E36 M3, which would be part 11-31-1-404-438.

Cordially, if I instead had a pre-09/1994 M50, I'd want a tensioner from the S50, which would be part number 11-31-1-405-081.

But I'm just guessing. Could anyone who has already had one of these apart shed some light on the subject?