Aligning crank and CAM sprockets without the aid of the belt. Assuming it is not anywhere close to correct.

KRYE

MEMBER
2005 SUBARU IMPREZA
2.5L
4 CYL
AWD
MANUAL
120,000 MILES

I was preparing to change the timing belt so I pulled the timing belt cover off. Was lining up notches by turning crank with the belt on. As I was turning, everything slipped. I thought I had stripped the crank bolt, broke my ratchet or my socket. Upon inspection, all were fine. What I did find was that the belt was missing about 10 -15 teeth. Now previously, when I pulled the timing belt cover off, I had noticed some metal shavings a couple pieces of small, twisted shrapnel, and a bearing cover from the geared roller/cog. Upon further investigation, I noticed the geared roller/cog was missing a few bearings and surmised the pieces of shrapnel was what was left of the bearings. The crank and cams off the mark now and I am concerned that they were not lined up when I opened the timing belt cover to begin with. How should I go about lining everything up without the aid of the old belt? Can I simply rotate the cams so they are lined up with the notches and then do the same with the crank?

1 Reply

CARADIODOC

MECHANIC
33,741 POSTS

The 2.5L is an interference engine so it's going to have bent valves. I would do a cylinder leakage test first. That involves turning the crankshaft until a piston is at top dead center, turning the camshaft(s) until the valves are closed, then compressed air is pumped in and you read the percent of leakage on the tester. Auto parts stores that rent or borrow tools may have the tester.

If valves have to be replaced, the engine machine shop that does the work will have information on setting up the camshaft and timing marks. Typically they will make a copy of that for you.