Timing Belt / Tensioner Recommendation
01-05-2010, 08:42 PM
#151
Just my opinion, but I'm sold on the Porken Tensioner. Will be going that route on my own when the time comes. And I'm not just saying that because I work with Roger some of the time, it is a well thought out process. Sterling and I went rounds about this and after he watched me do an install and saw how it worked, he quickly put one on his car.
That's all I will add to the discussion.
That's all I will add to the discussion.
01-05-2010, 08:42 PM
#152
Rest in Peace
Rennlist Member
Rennlist Member
Join Date: May 2006
Location: Bird lover in Sharpsburg
Posts: 9,903
Likes: 0
Received 2 Likes
on
2 Posts
It's worth closely inspecting those cams gears. The teeth look cupped and definatley the annodizing is gone. Once they coating is gone, the cams wear done. Best to consider replacing them along with the oil and crank gear.
The 32V'r cam timing tool would make setting the new cams easy at 45' (www.liftbars.com).
The 32V'r cam timing tool would make setting the new cams easy at 45' (www.liftbars.com).
01-05-2010, 08:46 PM
#153
Three Wheelin'
I an looking to redo the timing belt and water pump, the PO said he already did it but has no documents. All the other work he did was half *** at best, so I feel might as well do it while I am doing the top end. My question is is it worth rebuilding the OE tensioner or going with the PK tensioner. I can see good on both sides, I do have a budget and a lot of item I would like to do. Thanks Jack
My own tensioner was not touched since the car was bought in 89, When I got it in 08 the only thing on the timing belt job was just the belt change in 97, no tensioner rebuilt or water pump change, of course when I took it apart the rubber boot was broken and there was no oil in the tensioner, but the Porsche belt was fine and not loose, the owner before me had it for less than a year and had drove the car for 19000 miles. car had 95000 miles when I got it and then drove it home 400 miles away.
01-05-2010, 08:58 PM
#154
Instructor
Thread Starter
01-05-2010, 09:02 PM
#155
Rest in Peace
Rennlist Member
Rennlist Member
Join Date: May 2006
Location: Bird lover in Sharpsburg
Posts: 9,903
Likes: 0
Received 2 Likes
on
2 Posts
Most of the time you have some one say they did the job, but all they did at best was to just replace the belt and not even touch the tensioner. I think its about a couple of hundred dollars cheaper to just rebuilt the original tensioner and it will work just fine. I doubt that the tensioner was rebuilt on the above pictures and it still managed to last 45000 miles with probably no oil in it either.
My own tensioner was not touched since the car was bought in 89, When I got it in 08 the only thing on the timing belt job was just the belt change in 97, no tensioner rebuilt or water pump change, of course when I took it apart the rubber boot was broken and there was no oil in the tensioner, but the Porsche belt was fine and not loose, the owner before me had it for less than a year and had drove the car for 19000 miles. car had 95000 miles when I got it and then drove it home 400 miles away.
My own tensioner was not touched since the car was bought in 89, When I got it in 08 the only thing on the timing belt job was just the belt change in 97, no tensioner rebuilt or water pump change, of course when I took it apart the rubber boot was broken and there was no oil in the tensioner, but the Porsche belt was fine and not loose, the owner before me had it for less than a year and had drove the car for 19000 miles. car had 95000 miles when I got it and then drove it home 400 miles away.
I give my customers a choice of how it is done, they either let me replace everything it needs or they take it someplace else.
You are right, lot of folks just throw a belt on it, the Conti is cheap, they are all the same right (sarcastic) and call it a day.
01-05-2010, 09:02 PM
#156
Instructor
Thread Starter
Any thoughts on the Air Pump? Once again, I've read Pros & Cons on removing it. The Alt, AC and PS Pump are all spinning quietly. The air pump makes noise when i spin the pulley. Sounds like it could be a bearing.
01-05-2010, 09:06 PM
#158
Rennlist Member
If budget allows, replacing rotors and caps would be a good idea. At least polish the contacts on the existing ones. I find that has been a very important performance tip on the 85 and 86 cars I've been working with.
01-05-2010, 09:09 PM
#159
Three Wheelin'
Search on 'air pump removal'. Unless you need to do smog tests locally, it's probably worth taking off the pump, plastic diverter tubes and plugging the vaccum tube. I think the convensional wisdom is to cut/crimp the metal air tubes that go to the cats.
01-05-2010, 09:28 PM
#160
Three Wheelin'
I have not added it up, but it is going to be close to the same amount of money after you replace the idlers, and 95% will need them.
I give my customers a choice of how it is done, they either let me replace everything it needs or they take it someplace else.
You are right, lot of folks just throw a belt on it, the Conti is cheap, they are all the same right (sarcastic) and call it a day.
I give my customers a choice of how it is done, they either let me replace everything it needs or they take it someplace else.
You are right, lot of folks just throw a belt on it, the Conti is cheap, they are all the same right (sarcastic) and call it a day.
Dont really remember how much was it for the new design tensioner, I liked the idea but couldn't afford it that time.
My only concern is since anyone could have a water pump failure, like the pulley seizing, there could be a chance that the light would come on to show that there is a problem before the belt snapping from friction.
01-05-2010, 09:47 PM
#161
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
VBATLA--
You are at that perfect cusp of belt and drive component life: It's obvious from the pictures that EVERYTHING will need to be renewed. Cam gears are cupped. tensioner arm isn't square anymore, either bent or the pivot bolt is bent or the plastic bushings are worn out. The other gears, on the oil pump and the crankshaft, need to be replaced at the same time. geta new-design water pump too, with new bolts and factory gasket.
You'll need to either rebuild the old tensioner, or replace the old tensioner with a Porkensioner. This is where it gets to be fun. The old tensioner needs o-ring, gasket, boot, small clamp. large clamp, and about five ounces of oil. If the coating on the inside is damaged, you get to buy a new or maybe a good used one. It also needs two bushings for the tensioner arm, possibly a pin or bolt, and two rollers. --Or-- get the Porkensioner package. With your need for all-new 'other' parts anyway, this one's a simple choice to Ken's part.
----
For those playing along at home, consider how fortuitous is this owners visit under those covers. The edge wear is likely caused by a bent pin or worn bushings or damaged rollers. The slack belt is a combo of that plus the significant wear on the cam sprockets. If the previous job had been done with the P'kensioner, the slack belt from the worn cam sprockets would still exist, and the owner still would not know about the problem until inspection or belt failure. Starting with all-new drive pieces means that those normal wear items are less likely to cause any problems during the life of the new belt, we can be a lot more comfortable using Ken's tensioner. If you are not going in with all the the new drive pieces though, you may decide that regular belt and tensioner inspection with Ken's piece is a good idea. It might be as simple as measuring the piston extension cold at TDC, and turning on the worry if it gets further out than xx millimeters.
Most all of the readers here use their 928 as a hobby car or a toy. Mine qualifies for hobby/toy status, but it's also my daily driver. No driving commute so there's not much damage done there if the car breaks, but still I'm out my set of regular wheels if anything serious fails. My fallback is using K's 4Runner, but lets just say that the Bob-using-K's-4Runner option is less than popular. Bottom line is that I tend to be religiou about keeping the car in good reliable driving condition. Plus it would hurt me to have to spend a couple $thousand minimum to recover from a broken belt and the consequential damages.
I'm sure that you can all appreciate Greg Brown's position, where he has the potential for several $thousand in liability if he makes a choice that might be blamed later for a problem. At least with a warning light, there's some shared responsibility in the event of a wear-related failure that would otherwise warn the driver. The issue is really a lot more complex than whether Ken's solution is more reliable, functions better, lasts longer. Customer acceptance is a requirement, and too many customers conveniently forget all the pre-installation discussions if something goes bad later, even if the later problem is completely unrelated to the tensioner itself.
I still plan to buy one, figure out a way to get the warning light to work, and install it. I'll be doing the whole TB project later this winter anyway, so getting one soon will give me some time to brainstorm a switch solution. It's very likely to be very simple.
You are at that perfect cusp of belt and drive component life: It's obvious from the pictures that EVERYTHING will need to be renewed. Cam gears are cupped. tensioner arm isn't square anymore, either bent or the pivot bolt is bent or the plastic bushings are worn out. The other gears, on the oil pump and the crankshaft, need to be replaced at the same time. geta new-design water pump too, with new bolts and factory gasket.
You'll need to either rebuild the old tensioner, or replace the old tensioner with a Porkensioner. This is where it gets to be fun. The old tensioner needs o-ring, gasket, boot, small clamp. large clamp, and about five ounces of oil. If the coating on the inside is damaged, you get to buy a new or maybe a good used one. It also needs two bushings for the tensioner arm, possibly a pin or bolt, and two rollers. --Or-- get the Porkensioner package. With your need for all-new 'other' parts anyway, this one's a simple choice to Ken's part.
----
For those playing along at home, consider how fortuitous is this owners visit under those covers. The edge wear is likely caused by a bent pin or worn bushings or damaged rollers. The slack belt is a combo of that plus the significant wear on the cam sprockets. If the previous job had been done with the P'kensioner, the slack belt from the worn cam sprockets would still exist, and the owner still would not know about the problem until inspection or belt failure. Starting with all-new drive pieces means that those normal wear items are less likely to cause any problems during the life of the new belt, we can be a lot more comfortable using Ken's tensioner. If you are not going in with all the the new drive pieces though, you may decide that regular belt and tensioner inspection with Ken's piece is a good idea. It might be as simple as measuring the piston extension cold at TDC, and turning on the worry if it gets further out than xx millimeters.
Most all of the readers here use their 928 as a hobby car or a toy. Mine qualifies for hobby/toy status, but it's also my daily driver. No driving commute so there's not much damage done there if the car breaks, but still I'm out my set of regular wheels if anything serious fails. My fallback is using K's 4Runner, but lets just say that the Bob-using-K's-4Runner option is less than popular. Bottom line is that I tend to be religiou about keeping the car in good reliable driving condition. Plus it would hurt me to have to spend a couple $thousand minimum to recover from a broken belt and the consequential damages.
I'm sure that you can all appreciate Greg Brown's position, where he has the potential for several $thousand in liability if he makes a choice that might be blamed later for a problem. At least with a warning light, there's some shared responsibility in the event of a wear-related failure that would otherwise warn the driver. The issue is really a lot more complex than whether Ken's solution is more reliable, functions better, lasts longer. Customer acceptance is a requirement, and too many customers conveniently forget all the pre-installation discussions if something goes bad later, even if the later problem is completely unrelated to the tensioner itself.
I still plan to buy one, figure out a way to get the warning light to work, and install it. I'll be doing the whole TB project later this winter anyway, so getting one soon will give me some time to brainstorm a switch solution. It's very likely to be very simple.
01-05-2010, 10:31 PM
#162
Rennlist Member
Notes:
I still plan to buy one, figure out a way to get the warning light to work, and install it. I'll be doing the whole TB project later this winter anyway, so getting one soon will give me some time to brainstorm a switch solution. It's very likely to be very simple.[/QUOTE]
I'm sure when I was researching my choices late last winter, there was a thread discussing the options/ideas for rigging a warnng light with Ken's setup...can't for the life of me find it now though...sorry.
Had something to do with a very light wire strung over a cam sprocket at close tolerance which would break and trip the light if the belt contacted it for any reason.
In any event, I went with Ken's setup for the tensioner this past spring, and now with 7,000 miles, no issues.
I'm sure when I was researching my choices late last winter, there was a thread discussing the options/ideas for rigging a warnng light with Ken's setup...can't for the life of me find it now though...sorry.
Had something to do with a very light wire strung over a cam sprocket at close tolerance which would break and trip the light if the belt contacted it for any reason.
In any event, I went with Ken's setup for the tensioner this past spring, and now with 7,000 miles, no issues.
01-05-2010, 11:20 PM
#163
Nordschleife Master
Ya gotta really sand down the sprockets to contribute to that looseness. 0.010 will look like hell but not make the belt that loose. Looks like plain belt stretch. Maybe not tensioned right. Maybe a shot bearing on a pulley or the waterpump.
01-05-2010, 11:47 PM
#165
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
Currently at my prices the difference using a non airpump PKensioner is $200 v $337. Original v New design.
A small price to pay for peace of mind in my book.
A small price to pay for peace of mind in my book.
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."