Cam timing inconsistant with each revolution
07-25-2010, 01:06 AM
#106
Former Sponsor
As a data point, the 3 I've had apart all had shiny wear on one of the two idler rollers. IIRC, Porsche removed one of these two rollers on later cars?
I replaced the bearings, and swapped them so the untouched roller was on the side that got wear.
The pics below show the wear - the one on the right had belt contact in the pic during disassembly.
The other pic is after I pressed in new bearings and swapped them, but shows the wear pattern better.
edit: Yes, I'm aware that in the second pic, the washer behind the crank gear is round the wrong way - was my first TBWP, and I did correct it before putting the belt etc. on
I replaced the bearings, and swapped them so the untouched roller was on the side that got wear.
The pics below show the wear - the one on the right had belt contact in the pic during disassembly.
The other pic is after I pressed in new bearings and swapped them, but shows the wear pattern better.
edit: Yes, I'm aware that in the second pic, the washer behind the crank gear is round the wrong way - was my first TBWP, and I did correct it before putting the belt etc. on
That right roller is on the tension side of the belt and the belt does "skim" it, normally. Porsche only ran that double roller for a few years and then eliminated the right roller on the later cars.
07-25-2010, 01:25 AM
#107
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07-25-2010, 01:55 AM
#109
Inventor
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07-25-2010, 02:11 AM
#110
Rest in Peace
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I am not sensitive in the least, however you should be sensitive to is the fact that your attitude alone is enough for me, and others is enough to never install or offer one of your products to any of my customers, much less leave any of them on our own cars.
07-25-2010, 02:56 AM
#111
Inventor
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My work speaks for itself. If your 'customers' want to pay for belt retensions, covers off dial indicator setting of the cam timing, etc, so much the better for you, I suppose. 
Although I enjoy treating HolzKöpfe with humor, my main goal is to counter the falsehoods that your partner GB keeps regurgitating. The reason for knocking things that work, and makes owning a 928 easier, makes no sense to me, but folks are just weird sometimes.
I've got no quarrel with him as long as he doesn't pretend to be an expert on my products.
BTW: fighting other peoples' battles... makes them look even weaker than they are... and makes you look like an ***-kisser. IMHO.
Although I enjoy treating HolzKöpfe with humor, my main goal is to counter the falsehoods that your partner GB keeps regurgitating. The reason for knocking things that work, and makes owning a 928 easier, makes no sense to me, but folks are just weird sometimes.
I've got no quarrel with him as long as he doesn't pretend to be an expert on my products.
BTW: fighting other peoples' battles... makes them look even weaker than they are... and makes you look like an ***-kisser. IMHO.
07-25-2010, 03:04 AM
#112
Former Sponsor
No doubt about that, in my shop.
07-25-2010, 03:12 AM
#113
Damn guys, we are kinda on the same team. I think some time away from this thread might do everyone some good.
07-25-2010, 03:53 AM
#114
Former Sponsor
Re-read this thread. Just for giggles, substitute your name in every place that Kenhole addresses me....and see how much you then feel about being on the same team.....
All I've asked for, from the very beginning of any discussion about his tensioner system (go back and look at the other discussions we've had) is data and information about loads (which obviously doesn't exist), etc. All I've ever gotten is wise *** condenscending bull****, instead of answers.
If you are really from Texas, you'd already be on the plane to Portland.
07-25-2010, 04:24 AM
#115
Inventor
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Hey you two... get a room! 
Oh dear, hurty feelers. 
'Kenhole' - catchy!
Ye reap what ye sow. You started this whole mess by saying the PKsn'r was bad from the start. All this data BS is a way for you to say you're 'just being diligent'.
Oooo... internet bluster. 
Fugedabodit.
PS: I know you're dying to turn off the ignore... I can wait.
'Kenhole' - catchy!
All I've asked for, from the very beginning of any discussion about his tensioner system (go back and look at the other discussions we've had) is data and information about loads (which obviously doesn't exist), etc. All I've ever gotten is wise *** condenscending bull****, instead of answers.
Fugedabodit.
PS: I know you're dying to turn off the ignore... I can wait.
07-25-2010, 04:55 AM
#116
Nordschleife Master
. Bonus points to anyone who ever posted on Fidonet before the internet became commercial I get the feeling this thread is heading for the abyss.. so I've saved Simon's posts for re-reading. Happy to repost them in a new thread with his permission should it be needed.
On the plus side, this thread has crystalized for me two facts..
1. I'm going to install my Porkensioner on my '89 S4 next time I have the belt off (probably for a cam down.. er.. retrograde to S3 cams
). 2. I need to get one of Ed Standke's modified water pumps for my peace of mind, to fit at the same time.
Anyway.. carry on...
07-25-2010, 05:00 AM
#117
Rennlist Member
07-25-2010, 07:40 PM
#118
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I did some digging on how other V8s with belts handle things. Both Audi and Lexus use what appears to be spring loaded tension control devices, Audi having a gas strut with a spring helper that needs to be at a set length on install. IIRC one of them also drives the water pump off the belt. Neither seems to drive the oil pump off the belt. The Lexus recommended change interval is 100,000mi. Looks like BMW still use chains, also MB as as far as I can find quickly.
jp 83 Euro S AT 52k
jp 83 Euro S AT 52k
07-26-2010, 05:03 AM
#119
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I did some digging on how other V8s with belts handle things. Both Audi and Lexus use what appears to be spring loaded tension control devices, Audi having a gas strut with a spring helper that needs to be at a set length on install. IIRC one of them also drives the water pump off the belt. Neither seems to drive the oil pump off the belt. The Lexus recommended change interval is 100,000mi. Looks like BMW still use chains, also MB as as far as I can find quickly.
jp 83 Euro S AT 52k
jp 83 Euro S AT 52k
http://www.tundrasolutions.com/forum...iming-belt.pdf
07-26-2010, 10:10 AM
#120
Race Car
Letting a belt flap around greatly reduces belt life. I have seen this many times on other belt systems with old hydraulic tensioners that no longer dampened vibrations as well causing belt flap. I remember a specific case where a belt that was supposed to last 6 years only lasted 2 years.
Dan
'91 928GT S/C
475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ft