heinrich

Chaad, YES. The pro's are botching it. Simply-put, a great mechanic is one who is great at his/her work. I have seen MANY MANY MANY botched tbelt jobs. One of them was a job for $8,000 where the cam was replaced with the entire tbelt assembly, including tensioner. unfortunately the parts were the WRONG ones, and clearly obviously so. Yet a few miles later the engine nearly grenaded. it literally ate the tbelt as a result of a frozen new pump as a result of overtensioning as a result of wrong tensioner.

So ... choose your poison. I've seen many people helicoil the most unusual things. I've seen an owner drill out a broken head stud on an early car, straight into the water jacket; and instal an oil pump upside down with hand-tight bolts and a new-drilled hole, till he realised it was upside down. Seen paste used for ALL engine gaskets. Seen home paint jobs that look like my 7yo did it in crayon.

Choose your poison. Self ... or pro ... who can you trust? I trust myself. If i were someone else, I would likely not trust myself. Unless I were Bill Ball or a few select other knowledgeable people. In that case, I'd find the most knowledgeable wrench I could, and pray they really were as good.

UKKid35

Pro techs aren't botching the job but someone is - a number of owners have reported that they've found the tensioner warning grounded, that really is a cruel trick to play on the unsuspecting or uninformed owner.

I was unlucky in a more subtle way. I asked a shop to retension my belt after the light came on. It definitely never came on again, but I suspect the reason that the belt subsequently failed was that it was overtensioned causing the cam sprockets to wear and sheer the belt teeth. If it wasn't overtensioned then I should have been warned about the condition of the sprockets and the likelihood that the belt would fail prematurely.

Either way I have no comeback, the shop went out of business.

How much of a problem is TB related failure? For me it was a big problem...

heinrich

The belt fails in very predictable scenarios. Usually it is simply a slip and though the belt is OK, the valves are bent. Another common failure is as Paul says, the razor sharp cam sprocket teeth that cut teeth off the belt, or otherwise cut the belt. Another common failure is a seized waterpump. Once that thing seizes, the belt will follow very soon. luckily temp goes up dramatically at this point which *could* save the engine since any sane driver would turn it off at this point.

lawndart

Mitchell on Demand shows 7.8 to do the waterpump and 6.5 to do just the timing belt. They also allow .2 to r&r each cam sprocket, .3 to do crank sprocket , .8 to replace the tensioner and .2 to r&r the tensioner pulley. Hope that helps.

PorKen

32 valve engines have too much stuff on them.

I just redid my waterpump in about 2 hours. Granted, I was in a hurry, all the seals and hardware have been changed, and I don't use the TB covers.


Don't laugh at my sharp shiny gears!

heinrich

I like that ps bracket -- is it custom?

Bill Ball

That first pic is AFTER the new belt was on and a good cleaning.

The piece of paper on the floor in the foreground of the second picture is from Tony's write-up on the tensioner. Tony, John Pirtle, Jager and Wally's write-up were all printed out and in a nearby folder the whole time I did the first job. The resources were great. The first one is still and adventure for a pubescent 928 owner.

Bill Ball

How are these number used? So, 7.8 for the pump and 6.5 for the TB. Since the jobs overlap considerably then 10 makes sense for both. The books don't show jobs that way? They show the sprockets ad gear as part of another job, right?

Richard S

Wasn't there a case a while back where the shop (a dealership I believe) charged for the labor by adding together the book time for TB (6.5) and WP (7.8), thus doubling the labor charge? Always best to do it yourself....very satisfying when you first turn the key and it fires right up!

Rich

lawndart

Actually the WP and TB are listed under seperate headings, with the WP including the timing belt as I see it. The add ons are listed under the TB job. They also show the same times for the 924, 944, 968 and Boxster

AO

Kinda like poppin yer cherry. That how it was for me.

docmirror

I must concur on the botch job comments. I've seen what a 928 challenged Porsche-certified mechanic has done first hand to two different jobs. Horrible workmanship. Poor planning, limited understanding of the tensioner system, wrong torques, and just sloppiness.

my TB was done just before I bought the car, and the pully had those big tooth marks on it from the pipe wrench. That kind of stuff really grates on me. Other things I've seen - missing bolts in the WP, wrong belt type on pulleys, didn't R&R cam sprockets on clearly worn out units, empty tensioner, etc. I won't let anyone handle my car anymore. It's scares the %$&*@$ out of me.

Doc

Vilhuer

If people would pay me $2K for the job belt and pump change would be my main job. Since they are not, I have to have decent day job. For $1500 one buys a lot of tools for DIY. Knowing how workshops almost universally manage to do it wrong, DIY is really only good alternative.

worf928

Let's assume that the 7.8 figure includes the belt and the pump.

I can certainly see .8 to R&R the tensioner. But, is that the time to R&R the tensioner and the time it takes to rebuild the tensioner? Or just the time it takes to charge you what? $800 for a new tensioner? 0.2 hours - that's 12 minutes - to R&R the pulley? Let us assume that that's the idler and main pulley assembly. Does that 12 minutes also include the time necessary to press out the old pulleys, press in the new ones and replace the plastic pivot bolt bushings? What about polishing the extra paint from the pivot bolt on the thouroughly over-painted rebuilt water pump so that the roller assembly will actually pivot? Cleaning the gasket surface of the PermaSnot from the last job? I think not.

That's a total of 8.8 hours for a complete t-belt job according to The Book.

I've done half-a-dozon+ t-belt jobs. It's an 11 hour job +/- 30 minutes to do it right, to double check everything, to use a torque wrench on all the important fasteners, to do a static idle test, burp the coolant, and to make sure everything is back to factory. And that assumes that nothing - not even a single fastener - breaks and that you don't have to correct the mistakes of the previous "Pros" while you are in there. Maybe the second time on the same car - when you know everything is right to start with - you could shave it down to 9 or 10 for the full monty job.

[RANT]I think Book Time is the worst thing that ever happened to 928s. Book Time is why I find front main harnesses routed incorrectly - oops forgot to thread it through the belt..., or cut in-half and butt-spliced back together, disconnected hall sensors, shredded belt-tension circuits, front air dams held onto the car with freekin' zip ties, cam timing off by a tooth, tensioners with no oil in them, cracked fan shrouds, .... UGH. [/RANT]

Ok. I feel better now.

worf928

What does The Book list for a Belt re-tension?