Wandering timing belt

wild man · 08-22-2009, 05:29 PM

I have noticed that my timing belt wanders back-and-forth, maybe 1/8" or so, while the car is idling. According to maintenance records, the belts and idler pulleys were changed about 48 Kmiles ago. What would be the most likely cause of this?

Grandad#3 · 08-22-2009, 06:00 PM

Wlldman,

Are you saying the belts were changed 48 thousand miles ago? If so you are way past due for another belt and roller change out. We normally change out belts and rollers every 30K miles and water pump every other belt change with a new pump.

Cheers,
Larry

HondaDustR · 08-22-2009, 06:25 PM

Yes. Change the belts now. I know there are 45K and even 60K interval recomendations floating around out there, but failures have proven to drasticaly increase in chance much after 30K miles, which is the correct time. If the bearings in the rollers feel loose at all or rough, replace them. It would be a good idea to just replace them regardless, so you know exactly how old they will be. If the water pump spins freely with no roughness, grinding, or noise, and the shaft feels nice and tight laterally, and doesn't leak, it's probably ok, but again, it's advisable to replace it anyway. A head rebuild job is alot more expensive and time consuming to have to add to the project if any of those components fail.

wild man · 08-22-2009, 09:32 PM

30K? Wow, I thought the recommended interval was 60K. OK, I just looked through the papers and it looks like I was off by 10K. There is 38K on them, and here is what was replaced:

6PK1000 Belt (alternator & A/C?) 21.95
10X950 Belt (power steering?) 9.95
944.105.323.02 Timing Belt 24.95
944.102.219.02 Balance Shaft Belt 58.85
03182 Distributor Cap 51.83
04155 Rotor 55.78
WR7DP Spark Plugs 14.80
W719122 Oil Filter 9.95
944.105.631.04 Roller 44.55
944.105.241.03 Roller Cam Belt 37.25
944.102.277.06 Roller Aux. 39.45
944.102.025.07 Tensioner Aux. 35.20

This totals over $400. The receipt, from "European Imports, Specializing in German Car Service", located in Jersey Shore, PA, also lists 277.19 in labor for:

R & R Timing & Balance Shaft Belts - Balance Shaft Belt Broken - Rollers & Tensioner Bad - Replace all, Tune-up - R & R Plugs, Cap & Rotor, make all necessary adjustments

There was also 18.00 labor for: R & R Lower Covers and Overall Checkup

On top of this was 18.00 for state inspection and sticker, 16.45 for 7 liters of Valvoline 20W50, and 44.05 in state sales tax. The total was 778.20.

I know I only need to change the toothed belts and the rollers (and the WP, of which I have 2 used, both seeming to have nice-and-tight bearings and seals). But are the 4 rollers that are listed, the only ones I need to worry about? And, are those prices for the belts and rollers realistic, or are there better deals to be had? (I sure hope so!)

HondaDustR · 08-23-2009, 05:29 AM

I think Pelican sells them a bit cheaper than that. The original contitech balance belt has become insanely expensive lately. They must have discontinued it. Pelican now sells the Gates belt, which is just fine.

http://www.pelicanparts.com/catalog/shopcart/944M/POR_944M_ENGman_pg4.htm

1985porsche944 · 08-23-2009, 06:09 AM

Lets just say your getting onto borrowed time and if it's been over 5 yrs since it was changed I wouldn't be driving it too much more. Also, even if the belt looks new it might just break. Timing belts have a tendency to not show too much wear.

HondaDustR · 08-23-2009, 01:13 PM

Yeah, seems like what usually happens is a couple teeth strip off, rather than an all out belt torn in 2. All it takes is the timing to slip further than 1 tooth and it's all over for the valves.

Slam · 08-24-2009, 09:33 AM

A walking belt is a sure sign that bearings in a tensioner or water pump are going bad. Change those belts pronto and the just keep a log of when you do the work so you'll know for next time. I change my timing belt every second summer and do the water pump and balance belt every second timing belt. That's pretty much standard maintenance.