Timing Belt Question (pics) - Honda Prelude Forum

munscher · 04-17-2005, 02:52 PM

Background: My engine has been rather noisy (post with sound clip )and I finally got around to re-adjusting the valves. I did a valve job about 6 months ago, but wanted to check my work. The exhaust valves all seemed to be right on, but the intake valves were a little loose so I tightened them up a little.

The timing belt (at least to me) seems to be off in some way shape or form. When turning the crank to position the cams it goes... hard, easy, hard, easy, hard, easy, etc... the hard meaning hard to turn and the easy meaning easy to turn. The 'hard to turn' coincides with tension in the timing belt between the two cam gears (pics below) and the 'easy to turn' coincides with slack between the two cam gears. Is this normal? Or is maybe the tensioner off or something? I'm not sure.

First 3 pics show the timing belt positioned when there is slack between the cam gears. You can see there's just under an inch of play in the belt (The rules shows tenths of an inch).

These next 3 pics show the play from farther back.

The next 2 pics show the timing belt positioned when there is no slack. You can see there is about a quarter inch of play.

These last pics show the cam gears at TDC and the cams.

So does this seem normal, or is something definately wrong? Also, when I put everything back together and cranked the engine.... after it warmed up it was noticeably quieter than it was before i adjusted the valves. However, I could still hear a nosie that seemed to be coming from the timing belt area. Maybe its hitting the cover? or something with the tensioner?

Thanks for any help!

yield · 04-17-2005, 03:04 PM

I think that is normal but your belt is looking pretty beat up. Are you due for a change soon?

Tola · 04-17-2005, 03:48 PM

Your belt does look really stretched out. You should seriously consider replacing it if you haven't already. Your cams APPEAR to line up properly - but is the crank and the two balancers also aligned? If your spark plugs are still in as you're manually turning the crank, then yes, the ease of turning alternates between easy and hard.

munscher · 04-17-2005, 04:26 PM

Thanks for the replies so far....

The timing belt was replaced around 95k i believe (ill check the previous guys records to be sure about that), i am currently at 140k.

The spark plugs were all removed beforehand.

No idea about the crank and the two balancers b/c they're all covered up.

What would physically be making a noise in that area? And also, what causes the tension, slack, tension, slack pattern between the cam gears? Just the stretching of the belt over time?

irishpilot · 04-17-2005, 05:40 PM

I would say that the belt needs to be changed soon. mine looked better than that and it had alot more miles on it, something around 80,000.

I'm not a 100% sure, but I think your supposed to have between 1/2" to 1" of play in the belt, so you may have too much play.

I did my Timing belt and it was alot tighter than that

paulyg · 04-17-2005, 05:47 PM

It's normal for to have that hard...easy...hard..easy thing when you are turning the motor over. The "hard" part is when a cylinder on the compression stroke.

You timing belt looks in bad shape. It does appear to have a lot of slack. But more concerning than that is how the one edge is tattered. That's bad news. It's eaither really stretched out from wear, or is not tensioned properly.

4bidden · 04-17-2005, 09:26 PM

Get that replaced ASAP, NOT good.

aneurysm · 04-17-2005, 10:33 PM

ditto as the rest. that belt looks like its in horrible shape. You should replace it and do the whole timing belt job (balancer belt, water pump, etc - that way you know for sure that your belt is good and that everything is lined up as it should be, including balancer shafts.

brad