GregBBRD

The gears certainly are not worn enough to cause problems, although they will be chewing up the new belt in a fairly low amount of time.

Everything looks in order. Interesting that you took it apart with the rotors pointing towards the left and marked the cam gears in this location. You are on TDC #6, not TDC #1. If you are tensioning the belt in this position, that will cause the belt to be loose. The rotors need to point to the right side to be at TDC #1.

borland

I think Greg hit the head on the hammer. TDC may or may not be the same as TDC #1 cylinder.

After each adjustment of the tensioner screw, you must rotate the crank two full turns back to TDC #1 before checking the tension again with the tensioner tool. That is what is precribed in the WSM.

You have thread sealant correctly on the pivot bolt threads, but none seems to be applied on the tensioner adjustment screw.

Also, doesn't look like you are cleaning parts to remove grease and contaminates at the front of the engine. Those areas should be spotless before assembly.

leperboy

I locked the flywheel at 315 degrees past TDC. The passenger side jumped after I took the belt off. I thought you could do it at both 315 or 675 degrees on the crank. Should I be doing it at 675?

When I tension, I do it only at TDC #1, or 0 degrees out of 720.

Matt

leperboy

I have blue loctite applied to the tensioner bolt. Is there something else to use? As for cleaning: I will clean before I assemble, but I am in the disassemble process right now.

Matt

GregBBRD

As long as you tension at TDC #1, there is not an issue. You are making it a bit tougher on yourself by not having the timing marks near the marks. Take it apart and put it back together at 45 degrees BTDC. I gave up on using old tensioner bolts. They seem to invariably leak. They are relatively cheap and that factory blue stuff doesn't ever leak.

I have no experience with the tool you are using to tension, although I've seen them. I used the factory gauge. The belt gets tensioned to 5.0 to 5.2 with the factory gauge when new. We alaways do them to 5.2. They will get down to somewhere between 3.2 to 3.7 in the first 2000-2500 miles. The light will not come on in that range. The belt has to be below 2.8 for the light to come on....in my experience. if anyone ever called with a belt light on in the first 2000 miles, it would definately get my attention.

Make sure that you check the cam drive sprockets for cracks when you remove the gears.

borland

blue loctite on the tensioner bolt will result in a oil leak. Use a non hardening thread sealant, or as Greg suggests, a new adjuster bolt from Porsche.

Use the same thread sealant on for the pivot bolt that screws into the water pump, as well as the one retaining bolt for the tensioner which the WSM states to use thread sealant/loctite.

Mrmerlin

Matt do you have the old belt? maybe you could compare them. I would be suspicious of the water pump, i know you said its tight but they somtimes the shaft axis will start bending in an upwards direction, see if you can verify the water pumps axis, it should be perpendicular to the block, plus you can check all of the other things that have been mentioned, I use Loctite pipe sealant on the long tensioner bolt before screwing it all the way in, no leaks

leperboy

It seems like we are getting into some minor details that aren't the isue here, but thanks for the suggestions. I will use the pipe sealant I used on the tensioner bolt and pivot bolt for the tension screw. It was not leaking yet, but I trust the experts.

I don't have the old belt. I doubt my untrained eyes would have noticed any difference since it is probably less than a couple millimeters over seven feet.

As for the water pump, I haven't been able to detect any bend in the shaft. The pulley rotates without any wobble and has no play. I will spin it a bunch more times with a more critical eye, though.

Right now, I am going to reassemble with a focus on the alignment of everything and make sure the tensioner is functioning perfectly. I'll check my sensor wiring, too.

Thanks for the suggestions,
Matt

the flyin' scotsman

From your pics the cams are oriented incorrectly. The engine should be set at 45 degrees BTDC cyl. #1.

At TDC cyl #1 the crank is aligned with the pointer for TDC and both distributor rotors point to the right as you stand in front of the car. This is the position for checking the tension with the stock tensioner.

For removing the belt the engine has to be turned 675 degrees from TDC which now aligns at 45 BTDC. The pistons are now all far enough away from the cylinder heads to allow the cams to turn and no worries of valve touching.

Mike Frye

Hey Matt,

This stinks. You don't need this on top of your other projects.

I think a few people have experienced issues with belts stretching. I know I read about a case where Bill Ball had a belt that showed low tension more than once, so he replaced it just to be safe. I don't know what brand it was. I think JHowell37 just had a similar issue that may be a belt stretching issue. He wasn't sure if it was a bad contact or the belt, but the warning light came on for him.

You said you plan to replace the cam gears, I think that's a good idea, but I don't think that would cause your tension issue. It looks like they're shiny but not 'dished' like mine were (along with my oil pump gear).

It almost looks like there's a mark on the center of each cam gear where something may have rubbed? Maybe something like a pebble or something got stuck in your belt, and was in there when you set the tension and subsequently has become dislodged? That would explain the tension issues (sometimes it was in between the belt and a gear, sometimes it wasn't? Maybe if you check the inside of the belt you'll find a mark where something may have been embedded in there. I think I can even see something on your crank gear all the way on the left.


Maybe it's just in my head though.

dr bob

Don't want to beat a dead horse to death here, but...

For disassembly, you can set the CRANK at the 45 degree mark without regard to which way the rotors are pointing. When it comes time to assemble, rotate the CAMS so that their 45 degree marks line up with the indicator on the backing plate, and suddenly you'll be at TDC on #1 without moving the crank.

Back to the problem at hand--

If everything looks good as far as gears and rollers and the pivot bolt, it's time to use a new belt. There are just a couple users here who have reported belt stretch symptoms similar to yours, and each was cured when a new Porsche belt was installed. Considering how much fun it is to do this teardown and inspection, the cost of the new belt is minor. IMHO, anyway.

SteveG

Just for clarification: use gasket sealant on the (facing engine) right end of tension bolt (this end enters the tensioner cylinder). I had not read about using sealant on this bolt, but it makes sense. While removing the belt, as I turned the bolt ccw to loosen tension, oil came out of the tensioner.

leperboy

Nah, it's just another opportunity to do some WYAIT. As long as it's apart and I am waiting for some pieces, I can replace the heat exchange valve and the oil sending unit. And since I'll lose a little oil, I'll drain all the oil and put in new with a quart of Rislone for the sticky lifter, plus do the smog pump delete with the 20" or 21"(?) v-belt, since I have the X now.

And as long as I have the MAF off, I can check the calibration of it and reinspect all my new fuel lines. Plus, I can do some more cleaning all over.

It only took three hours to tear down this time, so I guess I'm getting good at this TB job. Well, quick anyway. I just hate to put it back together without knowing for sure how to fix the problem.

Matt

the flyin' scotsman

Lost me............my car had no 45 BTDC #1 marks on the cam gears until I put them there.

Agree with the belt being potentially bad..........curious as to what number is on it to see if there's batch issue from the manufacturer.

Mike Frye

Does anyone else see the shiny part of the gears that I'm seeing? I've seen this with a rock stuck in a serpentine belt before, I know it's unlikely with the back side of the belt going around the tensioner and WP rollers, but it looks odd to me.