timing belt slipping off cam *help please* - Honda Prelude Forum

natcc99 · 03-07-2006, 11:01 PM

hello

I'm in the process of changing my timing belt and I'm having problems keeping the timing belt on the cam gears.

When I took the everything apart, I noticed that the old timing belt was rubbing against the plastic housing.
Here's are some pictures of the OLD timing belt at 100K miles.
as you can see from the pictures, the edge of the timing belt was worn away.

here's the junk that I found on the timing belt cover

****new timing belt****

To make a long story short, I installed the new timing belt and found out that I somehow misaligned the cam to the crank and had to take everything part...again

I noticed that my NEW belt is ALSO falling to the same edge of the cam gears. Part of my new timing belt is already worn away.

After aligning everything correctly, I put the timing belt back on and activated the auto tensioner buy pulling out the holding bracket.

I then turn the crank several full revolutions manually while keeping an eye on the belt. After about 5 revolutions, I can see the belt coming closer to the edge and actually starting to fall off it. It doesn't matter which direction I turn it...both clockwise and counterclockwise give the same belt slipping scenario

If I turn it counterclockwise, it appears that the belt starts to slip off the intake cam first (cam nearest to the window).
The good news is that the marks always line up after each revolution.

Has anyone experience such a problem? Any suggestions?

*Background info*
When I changed the timing belt, I changed everything.
Belts, auto tensioner, water pump, bearings, spring etc
pretty much the only thing I didn't replace were the balancer gears, the crank gear and cam gears.

THANKS!

petern101 · 03-07-2006, 11:14 PM

lucky you caught yours

my car had 90k on it and shaved off so much the timing belt snapped

natcc99 · 03-07-2006, 11:19 PM

Quote:

Originally Posted by petern101

lucky you caught yours

my car had 90k on it and shaved off so much the timing belt snapped

Yikes! sorry to hear that. Sounds like you had the same problem with the belt slipping off the gear.
Were you able to find out why it was being shaved off?

natcc99 · 03-07-2006, 11:40 PM

*updated pics*

Here are some pictures of the NEW belt.

This is a picture before turning the engine over. Notice how the belt is on the gears, somewhat centered

***

This is a picture of just only THREE rotation of the engine. (counter-clock-wise) Notice how the belt has already shifted over.

***

Here's a picture of the belt with about 10 turns of the engine. Note how the belt is further over and also how it's already worn down. If it wasn't for the cover, I would think it would eventually fall off the gears. Yes, that is my new belt after only driving for a few days.

any help would be great.
Thanks!

petern101 · 03-07-2006, 11:51 PM

hmm i should check mine to see if anything has changed

Gerhard · 03-08-2006, 07:17 AM

Sned a message to Joon525, he'll be able to give yu some insight to the problem. He's the timing belt wizard.

I'd consider using a kevlar timng belt. Then it will not snap even if it rubs...

pIOUs · 03-08-2006, 06:08 PM

Looks like you are going to have to check the runout on the Cams, idler pulley, and crank to get an answer. That suck. I think mine shifted on the pullies prior to snapping, but I assumed that the auto-tensioner had failed. Good luck.

Gerhard · 03-08-2006, 06:12 PM

Quote:

Originally Posted by pIOUs

Looks like you are going to have to check the runout on the Cams, idler pulley, and crank to get an answer. That suck. I think mine shifted on the pullies prior to snapping, but I assumed that the auto-tensioner had failed. Good luck.

That's a good question: How many miles are on the unit?

axio · 03-08-2006, 06:22 PM

I have the same problem as well.

I did the timing belt job on my lude about 3 weeks ago. A week later, I did a valve adjustment (cuz I was trying to determine what this metallic rattling was, and I had thought it was the autotensioner, but it was really just an exhaust valve out of spec), and I noticed that the timing belt I had put on just a week earlier had started to move towards the driver-side edge. Actually, it was hanging off about 1mm or so, and showed a little wear along the edge. The head side of the belt was about 2-3 mm away from the edge.

I did the same thing you did, pushing the belt back towards the middle of the cam gear, and spun a few rotations on it, and each time, it'd start moving out towards that same misaligned spot.

I started to wonder if this was normal, so I looked at the wear on the cam gear themselves. I noticed my new belt was running flush with this dirt/worn line on the cam gear, probably from the wear, or maybe it was darker on the 2-3 mm on the head side of the cam gear cuz no belt was covering it? I can't remember. In either case, I could see a distinction. So I wonder if it's normal.

I actually have my old engine sitting on an engine stand right now, so I went to go look and compare, and my old engine was the same. The timing belt on the driver side was worn flush with the edge of the cam gear, or maybe it was sticking out just a little, I can't remember. On the head side of the timing belt, it was about 2-3 mm away from the edge of the cam gear.

This old engine has never had the stock timing belt replaced, nor any headwork done, nor anything done to any of the timing belt gears, crank, etc, so it was basically like that from the factory. The new engine is the same way, the wear on the cam gears were there from the original install of the timing belt from the factory. Either this is normal, or I coincidentally have two engines that have this problem.

ThatPreludeGuy · 03-08-2006, 07:52 PM

The timing belt moving slightly off center isnt all that abnormal since from what I've seen almost all have had some sort of wear against the cover. Now slipping to the point where it wears down and breaks or does some serious damage is of course abnormal. Now one other point is from what I remember the motor should only be turned in one direction (I cant remember which way the motors supposed to spin to be honest). This shouldnt have anything to do with the problem you're having but rather something I wanted to point out from you post about your troubleshooting. And yes Ray might have a better idea as to why that's occuring since I remember we ran into something similar when we did his but nothing that was so bad that it was a show stopper.

natcc99 · 03-08-2006, 10:13 PM

Hey everyone thanks for all the help

I ended up taking everything out and starting over since i had no idea what the problem was. So far so good because it appears that the belt is staying on the gears this time.
I'm going to drive it for a few days and then open it up this weekend to check its condition.

To answer your question:
Our engines rotate counter-clockwise.
Also, it's normal that the timing belt rides along the edge of the cam gears; however, I don't think it's suppose to "fall off" it.