Åke,

I've had the same water pump installed now for about 50k miles and a couple timing belts. Like yours, it looks feels performs as new the last time it was exposed. I have a new Porsche pump in the spares bin, and may put it in at the next belt change (scheduled next winter) just because the engine bay is a good place to store it. Car gets new coolant about every fifth fuel tank fill these days it seems, so no worries about that side of it.

 

I have some Gates racing belts which are going into other engines. The Dayco belt part no.219SP254H is made in Italy according to the box.
The Dayco belt does not fit the early square tooth pulleys, I have checked.
Åke

 

I had the Gates racing belt installed during my GB stroker project

I was surprised to hear that after the first retention after 1500 miles, the next retention after 5000 miles indicated it had further stretched to 3.2.

I thought the benefit of that belt was that it stretched far less than the OEM belt

Guess not.

 

Your source is suspect. (Well established implicit bias.)

 

Don't know what to say other than when Todd tested the racing belt and the stock belt they were not even in the same ballpark. With the stiff valve springs in his car, he was able to turn the crank several degrees before the cams started to rotate. With the racing belt, it was a direct 1:1 movement the way it should be.

And yes after several thousand miles he's checked it.

 

I have the Long Life belts on a number of my cars - both garage queens and daily drivers.
One has been on for 7 years and checks perfect every time.
Did GB check your belt?
You are the first to mention an issue and due the the very make up of the belt I would find that hard to believe after 5000 miles.
If it was GB who checked it I believe him but something is obviously wrong.
I get NO stretch out of the standard Gates belts and I have never heard of others having issues.
Maybe the super power of the stroker is stretching the belt. I will certainly pass your findings back to the Gates engineers.

 

First belt on mine was a Gates and was done after 5 years with a Conti belt and I'm happier with it...car feels a little more "flexible" or something...I can't describe it but for some reason I get the impression the conti belt has a little elasticity and maybe as the engine expands puts a little less strain on things? I'm hoping to use a Conti belt again next year when it's time but I outsource that job because interference engine so it's whatever decision my shop makes...

 

??????????????????
Every belt stretches....why wouldn't they? Still some sort of rubber with fibers inside.

We set our new belts to 5.0 "Porsche Belt Units" with the 9201 tool. I use both Porsche and Gates (standard) belts, depending on what Mary has ordered and has in inventory (Mary usually gives us Porsche belts to install.) Both Gates and Porsche belts will be "down" to 3.8 by the 2500 mile checking interval. This number never varies more than .1 belt units (with new gears), unless it gets checked slightly early at 2,000 miles. (Our "expected" number is 4.0 "belt units" at 2,000 miles.) The belt tension light is super reliable and incredibly consistent. Unless something is wrong with the system, it will light at 3.2-3.0 "Porsche Belt Units". With good belt gears, we NEVER expect the belt light to come on, before the 2,500 mile interval. Occasionally, we will install a new belt on gears that are just beginning to go though the coating....trying to get another 30,000 miles "out" of the gears....and sometimes the belt tension light will come on just before 2,500 miles, with worn gears.

If the belt light comes on before 2,500 miles (with new gears) and the belt tension is 3.2 or less, we will disassemble the front of the engine and try to figure out WTF went wrong. 100% of the time we would do this. I do not expect this to occur!

The wonder of detailed records eliminates any chance of bias:

Randy's engine used a "Gates Racing Belt", of which I had had very limited experience with, before using one on Randy's engine. (My total run time on one of these belts was 30 minutes on another stroker engine.) Randy insisted I use this belt, which was fine with me. The belt was tensioned to 4.8 "Porsche Belt Units", on the engine stand.

The engine was delivered to Randy with 242,739 miles on it. At this point in time the engine had approximately 200 miles of running, testing, and tuning.

The engine (complete vehicle) came back at 244,074 miles (1335 miles since delivery) for an oil change. We checked the belt at this service. It was at 4.4 "Porsche Belts Units". We retensioned it to 4.8 units. The amount of stretch seemed low, although the tensioning "window" was certainly a bit early for us.

The vehicle returned to us at 264,574 for a complete service, 21,835 miles from the delivery mileage, 20,500 miles from the last belt tension. The belt tension was 3.2 "Porsche Belt Units" and was re-adjusted to 4.9 "Porsche Belt Units". Randy did not indicate that the belt light had come on, or not.

I was completely "fine" with this and did not even mention it to Randy....actually didn't even give it a second thought.

Randy was apparently surprised and pointed out, to me, that this was more stretch than he expected.

Between the time Randy's engine was originally built and checked at 264,574 miles, I purchased a replacement belt tension gauge, from Porsche, to replace my older gauge. The older gauge had suddenly begun to have problems being consistent and I was getting readings that varied .3 "Porsche Belt Units", regardless of calibration.

Randy's engine has stock 928 cams, stock 928 valve springs, stock 928 lifters, stock 928 valves.

That's the exact history, do with it as you desire.....I've got no "skin" in this discussion.

 

As far as the OP is concerned:

I'm now encouraging everyone (else) to run Continental belts and one of the several different iterations of an aftermarket belt tensioner (any version will do.) Also install any aftermarket water pump, never a factory pump. If you have a choice, be sure to install a water pump with a metal impeller....Porsche had absolutely no fricking idea why they changed this to plastic, back in 1989! If you are changing the timing gears, make sure that you do not replace the crank gear (after all, it is steel and can't possibly wear. And, never update the aluminum oil pump gear to a steel one.

We literally started redoing another one, today, with less than 10,000 miles on the belt.....the fifth "redo" this month! God, please bless those aftermarket belts, tensioners, and water pumps!

Job security, for years to come!

In all truthfulness......we did replace a factory belt and a factory water pump, last week, on a regular client's car. The belt and water pump had 50,000 miles on them....and the client wanted them changed. The belt light had not come on....no issues, at all. The water pump had absolutely no sign of any coolant coming out the "weep" hole and has a perfect sounding bearing. The client was not convinced that the pump would last another 50,000 miles and wanted it to be changed.

Anyone want a great used late model factory water pump? $250 to the first person.

 

Red Flash
It is running great today. When the pump was changed the coolant level was well below the heads from leaking so if acidic corrosion is what you are thinking then more likely I would have a head gasket failure which I don't. What little coolant that was remaining was the same colour as new. Compression was above 170 in all but one which was 165. not enough difference to tear it down. Even with that number on the clock the rod bearings which I changed out had virtually no wear to speak of. Now we have really hijacked this gents post. Apologies.

 

To paraphrase It's a Wonderful Life, every time a 'belt unit' rings, an aftermarket tensioner is installed.
I reckon the Conti may be the best belt of all because of its elastic nature. At higher RPMs the cams theoretically will retard as the belt becomes longer, extending the power band. (Best to use an aftermarket tensioner which can dynamically adjust to belt length!)

I have an extra set of cam covers I was going to modify so that the cam gears could be timed with a strobe light (with an ignition chip with no advance) along with Conti, standard ,and racing Gates belts. It would be nice to know what to set each bank advanced to match the expected cam retard. Unfortunately, I just got too busy.


To the OP, I've used/abused all three types of belts without issue.

 

I can see how you think that: "It's (almost) a Wonderful Life."

You make money on selling something which I make money removing and fixing properly (on vehicles that come into my shop with premature timing belt problems....which I define as occurring before the 50,000-60,000 mile replacement cycle.)

The only problem with your version of "It's a Wonderful Life" is that the consumer gets to pay for the same repair....twice.

 

Riiiight. Fortunately, most everyone on this forum knows by now that you make stuff up exaggerate both your knowledge, especially theory, and problems with other peoples' products.

At one time, you were of the opinion that the timing belt didn't stretch at high rpms. So much I have taught you, grasshopper.



You threw out some new crazy theory recently. I wish I could find it. You just don't know that you don't know.

 

All the belts contnue to stretch over their lifetime , some more then the Gates racing version , which I believe is impragnated with kevlar .
I use lambda senses in the exhasut ,(race car running on e85) you can tell when the cam timng is out from the various lambda sensor reading , at cold and during warmup when the timig is correct ie lift is correct for all cylinders you will see the lamba slowly creep towards the target lambda when hot .
This is incredibly important when you run and interference engine with high compression , as you want all the clearances to be the same . A rubber belt forces you to revaluate this as the belt will alway strech during their liftime service life . the gates racing belt just stretches less.
By the way is the porschs timing adjuster still available to purchase ?

 

Dude, you need professional therapy - or meds.