I'm in the middle of changing the timing belt on my '03 MSport.... I was replacing the cam sprockets after changing the seals with all the timing marks lined up. I was tightening the bolt on the passenger side sprocket and it slipped and 'jumped' forward about an inch or so...when I tried to put it back on the timing mark, it slipped again and jumped the same distance the other way....

Did I just F-up the valves ??? Is there a way of telling??

 

You're OK. The reason that cam rotates back and forth several degrees is that when at the proper timing position one or more of the cam lobes is centered on its valve tappet and that valve is fully open (spring compressed) so any slight movement in either direction and the valve popps back up -turning the cam. Valves that are closing will not hit anything that will damage them. Here's a quote from the factory manual:

The camshaft sprocket (right side) can turn easily due to
the spring force applied, so be careful not to get your fin-
gers caught.

You have to work hard to get it to balance at the timing mark and and hold the sprocket from turning with a tool while tightening the bolt. I used a length of 1" X 1/4" bar stock heated and bent at 90 degrees so that the short bent end fit into the slots in the cam pulley. Before I tried that my cam flipped back and forth many times and my engine runs great.

Ron

 

*PHEW!!* Thanks a HEAP!! When that bugger slipped last night, I went numb! And you're right about watching your fingers...there's a lot of force in that and I'd hate to get jammed in the sprocket when it jumps!

I just got the belt installed and am taking a break for lunch before I rotate to check the timing marks and pull the pin on the auto-tensioner. If that looks good then I'll start the re-assembly.

I've taken a bunch of photos while doing this (timing belt, spark plugs/wires, and valve cover gaskets) for reference when putting things back together...should I put some up on a post here?

 

Glad to help.

Sure, everyone likes photos and it would be helpful to others if you have time and interest.

(FYI there's already a good photo album on spark plug changing on the monterosportonline.com site) http://monterosportonline.com/diy-perf2.html so you may not want/need to spend a lot of time there unless you used a different method.

Good luck with the rest of your project.

Ron