leperboy

I'm stumped. Within about 100 or so miles of the TB being installed, I have gotten two TB warning lights. The first time, I checked tension and it was at the lower edge of the Kempf Tool. The second time was Friday and I decided to just tear down and see what was going on. I have everything apart and:

- Pivot bolt is perfectly straight
- water pump has no play around its axis, spins fine
- cam gears have no play (crank and oil are fine too)
- tensioner is holding and is full of oil
- cam timing is still on
- belt doesn't show signs of excessive wear
- belt was still tracking right where it was installed

When the job was done in April, I rebuilt the tensioner, installed new rollers and the water pump was done. It is a Porsche belt. The two warnings came 50 miles after installation, and then 50 miles after I retightened.

I have pulled the tensioner apart and will rebuild it again. Should I buy a new belt, too? I find it unlikely that the belt is the problem, but don't know where else to look.

Any suggestions?

Thanks,
Matt

FlyingDog

Locknut on the tensioner bolt missing/loose?

Idiot light broken?

Retension, disable idiot light, check tension after 50 miles, check tension after 1500 miles, leave it alone.

the flyin' scotsman

What was the belt tension on the second light?

If your absolutly sure that the tension was correct after the first adjust then the belt is perhaps bad.

Or........the warning light wire etc is not correct.


MHO.............dump the tensioner and get Porkens excellent alternative...........I'm now approaching 3k kms since install and the engine's been up there with no worries.

ROG100

Matt,
I assume you are using the Kemph tool?
If so set the belt on the tight side of the window.
I used to have this problem after a TB job and concluded that the TB will be on the loose side if set in the middle of the tool window.
You seem to have everything correct.
Roger

leperboy

Hi Roger,
Yes, I am using the Kempf tool. I set it at the high side because I had read that is more correct for the 32V. First time I got a warning, when I went back to check it, the tension measured at the low end, so it definitely lost tension.

I reset it at the high end, almost all the way to the high edge, drove about 50 miles and got the warning again.

I have no reason to think the warning is wrong. Although, I did forget to check it this time when tearing down, but I believe the warning. The system is assembled correctly, and all wires are in good shape.

As for disabling the idiot light: uh, I sort of like this car with all its valves straight, so I think I'll keep it enabled.

Matt

the flyin' scotsman

............another thing; do I read your post correctly?

100 miles since April?

ROG100

Matt,
Was it a new pivot bolt? How did you know it was straight if it was the original?
Any change in the tracking on the gears?
Maybe the warning set up on the tensioner arm - recheck it and make sure its not a false reading.

On the kemph tool the reading should be more towards the edge of the window nearest you?
Roger

leperboy

Yes. It also had a complete intake R&R, new exhaust, plugs, wires, rubber, new brakes and rotors, fuel lines, new relays, fuses, etc, etc. It's a project car that I just have gotten into driving condition. And I have a full-time job, a writing career and several web sites to operate. So, my time is limited to work on it.

Really, 100 miles in the last month, but it's getting a new torque tube as the one in there is bad, which is limiting me now. So, I'm still waiting to drive it a lot.

Matt

leperboy

New pivot bolt. I sheared the first new one and this is the second. I rolled it on a flat surface and it's straight as can be. No change in the gears. They are still dead on. I mean, they are within 0.1 degrees of dead on still. Both gears.

As for the Kempf tool: right. Tighter is the edge of the window nearer me. No problems there.

Matt

the flyin' scotsman

With no idea of the second tension level you have to make some assumptions............the tension was indeed slack and required tightenng again suspect the belt...................or there issue with the warning system.

Confirmation of the very low miles since install and time period, 6 mths, may have allowed the new belt to stretch.

GregBBRD

There is no chance a Porsche belt will stretch enough in 100 miles to allow the light to come on. There has to be something very wrong. I assume that you are tensioning the belt at TDC and the rotors pointing towards the driver's side of the car each time?

Have you double checked the direction of the discs in the tensioner? Is the tensioner holding oil correctly? Sometimes the discs will wear from being run low/out of oil from a boot failure. See how tight the discs fit onto the center shaft. If they are very loose, they can move around and the tension will change.

The gears wear very badly. The cam belt can be "sinking" into worn gears. The steel gear on the cranks wears like crazy, but no one ever looks very close at it. Check all the gears for wear. Are there any marks on the teeth of the belt from the gears? Generally, if the cam gears need to be replaced, all the gears need to be replaced.

I assume that you got the correct belt? Porsche still sells both styles. Make sure you didn't get a square toothed belt, by mistake.

leperboy

Hi Greg. Yes, tensioned at TDC every time, every time, with the gear indents lined up with the indents. I check multiple times, turning the crank 720 degrees between checks.

The Belleville discs are in the same orientation I received them in, which is the same as the WSM. I am sure they are correct. Discs are tight as of today. As for tension oil: it was full when I pulled the tensioner off today. I checked it after the first light and it needed about five drops before it came out the lower bleeder.

I've checked them during each TB job and they look great. The anodized layer is not worn through, the steel crank and oil gears are good. The belt is the correct round-tooth belt, Porsche OEM. I inspected both sides of it today and can't see any defects. The printing is still on the back, so it's not rubbing hard on anything. No fraying on edges.

I can't see anything amiss, which is what stumps me. I have done a lot of idling while I worked the car, but there are few miles. I have used about half a tank of gas, so it's just not a lot of use.

I'll photo everything and maybe someone can point out a flaw.

Matt

GregBBRD

Matt:

Are you filling the tensioner yourself?

leperboy

Hi Greg. Yes, I have filled the tensioner myself. I do it slowly to make sure oil gets past the washers and through the valve. When I drained it today, it was full around the washers and behind the valve.

Here are, in order, my DS cam gear, PS cam gear, crank gear, oil pump gear, tensioner arm and tensioner. Looking at the photos, I can see the cam gears are starting to wear, which I hadn't seen before. I'll replace them, but they don't look bad enough to be a problem yet.













Matt

davek9

What temp is the engine at when you are checking the tension, is is cold?
I would think cold would be the best as you would know what the level of expansion is.