11 replies to this topic

[Gunpilot]

I searched this forum and archives, and still have questions....

I decided to install new lifters and change to synthetic oil to reduce clatter in my 1992 with 120K miles.

I did not check timing before I sterted, but it was running great.

I set cams per maintenance manual and marked timing belt before removal. Installed new lifters and replaced cams and timing belt aligned with all the marks.

Car started right up with no hesitation. I decided to check timing, and the mark is about an inch left of the plastic indicator.

I messed with CAS and it got worse when I tried to correct it to 10 degrees.

My question is.. Do you think the belt may have slipped on the crank sprocket, or the crank sprocket rotated when I installed the belt back on cams? What should I do? What is the procedure for "starting over"? Should I leave as is, or try to correct it?

Here is what I gather from research to start over.

1. Set cams to Intake "I up on left and Exhaust "E" up on right (as looking at engine).

2. Remove all timing belt covers and timing belt

3. Confirm number 1 cylinder at top of stroke with a dowel in spark plug hole

4. Confirm crank is TDC with mark on crank sprocket to engine block

5. Reinstall belt with all marks pointing up.

6. Check timing

Does that sound correct. Helpful hints are appreciated.

[steveracer]

Your motor has 120k on it?

Likely the outer ring of the balancer(the one with the mark on it) has slipped in relation to the inner ring that is indexed on the crankshaft.

Follow the steps you have listed above, put the timing covers back on and then mechanically check #1 for TDC. If it's off more than 1-2 degrees the balancer has slipped, this is more common than you might think.

You can make a new mark at 0 degrees and set your timing from there for now, but the best fix is a new balancer. They're not horribly expensive and come off the hub with the 4 10mm bolts.

I had set my timing once, the marks were off by 6 degrees, and not touched it for many months. Went back to check it and it was off by more than 20...so, now I keep a spare balancer in the parts box.

[Keith Novak]

Your procedure sounds right but be very careful that you don't turn the crank while getting the belts on the sprockets.

Definately check TDC and that you installed the sprockets on the cams properly. When checking TDC, the pistons don't move much the last couple degrees so rock the crank back and forth about 20* to find the center of two measured distances of piston travel or use a dial indicator. Otherwise you can easily be off several degrees.

With the belt off, I set both cams, place adustable wrenches on each one with the handles pointed to the center and clamp the handles together so that they don't try to slip relative to each other while getting the belt on. Otherwise one always does.

It's easy for the belt to slip around the crank while getting the belt on so I gave up on marking the belt and cams. It's also easy to turn the crank if you're fighting to get the belt on.

Once you get the belt back on and snug the idler, check all your marks again and count the belt teeth between the marks on the top of both sprockets. I think 14 is the right number but someone would need to confirm that. It's also easy to be off 1 tooth.

Sometimes I hit it dead on 1st try. Sometimes it takes me a few times. I made a mark on my CAS for where timing should be for easy reference but if not, it's tipped a few degrees clockwise.

[Gatoratty]

Also make sure you jump the Ten and Gnd pins in the diagnostic port.

[Cy Peake]

And stick with non-synthetic oil unless you want to discover a bunch of new leaks.

[dmathias]

Do you think the belt may have slipped on the crank sprocket, or the crank sprocket rotated when I installed the belt back on cams?

Very easy to do, don't ask how I know.

Very easy to confirm, and repair. Just need to pull the cam cover and upper plastic timing belt cover. Sounds like you already know the solution.

[FTodaro]

Also make sure you jump the Ten and Gnd pins in the diagnostic port.

+1 This is the first step if you did not do this otherwise timing is all over the place.

[Gunpilot]

The cars so smooth, and that makes it hard to tear it apart again. I know I gotta do it to prevent any damage, so here it goes.....

[rob20rx7]

I just had the same exact problem on mine after redoing my head. I had to actually take off the valve and timming covers 3 times. In my head i could sware the mark made on the front pulley had shifted bit i just didnt think that was possible. Now i read that it is possible and that i may consider buying a new balancer. I actually ran the car like that this weekend because i just could not break my head anymore. The car just didnt have the power the others had so im going to go through it one more time.

Let me know what you find out.

Thanks!
RoB

[Gunpilot]

Finally got it! This is what i did (with advice from forum)

1. Exposed cams and timing belt
2. Positioned cams intake and exhaust pointed up
3. Loosened timing belt tensioner
4. Put dowel into #1 cylinder
5. Rocked crank back and forth and watched dowel. Stopped when it was at its up most position
6. Confirmed crank mark on gear was at TDC (it was)
7. Cams were a bit off from up, so I removed belt, repositioned cams, and reinstalled belt (the crecent wrench and clamp trick worked like a champ)
8. Confirmed TDC with gear mark and watching dowel as I rocked crank back and forth
9. Tightened tensioner and reconfirmed TDC and that cams were pointing straight up
<br><br>
10. Installed timing covers (pully mark was now at 0. It was off before)
<br><br>
11. Started car, warmed it up, jumped GND and TEN ports, adjusted idle, shot the timimng light.
12. Timing indicated 12, so I adjusted to factory recommended 10.
13. ALL DONE!

[dmathias]

Taa daa!

[steveracer]

The angle in the last pic looks like it's off 2*.

I'd get out the micrometer to make sure of absolute TDC, and adjust from there, and check it frequently knowing what I know now.

I've seen 1* of timing make 2 extra ponies...