muso58

I have done many major rebuilds on lot of different types of engine and have lost count of how many belts I have changed and havent lost one yet. I recently rebelted my newly aquired 944,without any form of tensioner.During my brain picking expeditions on this great forum I discovered on a couple of occasions that people had used this fancy porsche tool and discovered the belts to be making undue whining ie over adjusted, so they had knocked back adjustment,till the whining stopped.In which case tool was pointless. What I did was used the 90 deg twist method to get an initial adjustment( I think it would take a lot more than a small twist to damage fibres in the belt) and as it happened the belt appeared a little tight ie whining I backed off the adjustment a little and it cured the problem, this procedure is similar to using the tool and ignoring the result! if you understand what i mean. I dont think there is any difference between porsche belt adjustment and say honda legend v6, jensen healey lotus twin cam engine, celica twin cams, honda accord twin cams, To name but a few that have been under my spanners. I think it is true to say that experience gives you a certain feel for these sort of things but everything has to be learned!! hope this helps Steve Elliott

Dano_944

Sounds like your touch is good, as well as your mechanical intuition.

However, gambling with belt tension, especially on motors that can strike and break valves with a snapped belt, is risky, in my opinion.

Additionally, slightly over-tensioned belts can lead to premature wearing of the roller and tensioner bearings, and water pump bearings (but, you knew that). With only one bearing set in the water pump, overtensioned belts can lead to a blown/frozen water pump (as happened to me by a mechanic who "didn't think he needed to use that silly gauge"), and a complete replacement of belts, rollers, tensioners, seals, water pump. (And, he wanted to charge me for the job!)

So, how's your skill at blackjack, roullett, and craps? It's your gamble and your money. ;-) Personally, I'll use the tool.

My 2 pesos. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Type_LT

I'm trying to figure out a safe way to do this without the special tool, I don't think it's needed either however I would like to use some reference point to determine belt tension. It may require me renting the tool from toolmaster and measuring belt deflection.

*Michael.*

I thought that the whining noise was normal. So your saying that if it is making the famous "whine" that the belt is over tensioned?

fpena944

What about on the 16 valve cars with the automatic tensioner? Does it then seem like the tool is really that necessary?

Michael Stephenson

On the 16 valve cars the balance belt still needs to be tensioned.

The Auto tensioner does not adjust itself, it has to be loosened and re-tightened while the engine is at TDC. Also I have heard that the automatic tensioner is not always accurate.

About an alternative tool, check out this past thread:
<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=15&t=005248&p=" target="_blank">Cricket Belt Tension Tool ( anyone used it?)</a>

muso58

Didnt mean to get anyones back up, If you read and understood my post what I was saying was that I have worked on many high tech engines (see above) and dont see why this tool is neccessary in this case !!

MadMax

I am not all that certain that it is absolutely necessary but it is NOT one of those things I would personally like to risk. $400 for the tool versus $5000 for a new head??? I'd spend the money on the tool. You can even rent the damned things. I would not trust an "auto" tensioner with a 15-20 year old design. Even with the 16 valvers I would set the tension of both belts using the tool.

As always YMMV. Do whatever you think is best for you but if Porsche says use the tool that is good enough for me. Since I have never designed my own sports car I will default to the engineers that have and use the tool.

Max

art

I agree with muso58 that a belt is a belt (made by gates in most cases). The caveat here is that the 944 is an all aluminum engine as are some of the others that he mentions. This adds an extra thermal expansion issue that makes belt tension more important.

I did mine by feel, and have no idea if it is right, but I have around 3k on it with no problems. It does seem awfully tight when hot, though...

A friend recently told me about a tool that measures the torque required to twist the belt. I guess it is simpler that the porsche tool. He used it on his 928.

Art

art

I agree with muso58 that a belt is a belt (made by gates in most cases). The caveat here is that the 944 is an all aluminum engine as are some of the others that he mentions. This adds an extra thermal expansion issue that makes belt tension more important.

I did mine by feel, and have no idea if it is right, but I have around 3k on it with no problems. It does seem awfully tight when hot, though...

A friend recently told me about a tool that measures the torque required to twist the belt. I guess it is simpler that the porsche tool. He used it on his 928.

Art

jordanolder

I used the kricket tool on my $500 944 and it works fine so far.

I do get the whining noise, but I've also heard that noise on 2 other 944's tensioned by mechanics with factory tools.

The whinning noise always goes away.

Is it bad to have that noise? Anyone who really knows?

Ahmet

I tensioned my 84 944 by hand twice, and put a total of around 30k on it with 'my tension' on the belts. It was on the loose side, lasted fine.

I just did the belts on my turbo, due to another leak the belts only have 10 miles on them, we shall see what it does.

Whine is normal when the belt is (intentionally) a little over tight for breaking in the belt. After 2k miles the noise should subdue, but if not it is due for an adjustment anyway.
Ahmet

jordanolder

ok, I guess I should loosen it.

I notice that the car heats up when it comes to an idle somtimes, but if I rev the engine and get more water going through it then it cools down.

Could this be because of not enough tension on the belt at the point of the water pump pulley?

Operator

i have an S
i just got the belts/pump/rollers/seals done 2k miles ago and my mech did the tension by "feel" and it hasnt exploded yet
i guess ill be going in for that 2k retension soon eh?

Bob S. 1984 Silver

Jordan:

It may be just the nature of the beast. All water cooled VWs do the somewhat the same thing...230 degrees in traffic, down to 200-205 at speed. Your revving of the engine does increase the flow of the coolant which is half the added cooling (in addition to the forward motion at speed). Of course, if the problem is severe enough, this could also indicate a failing water pump (someone here had one with a loose impeller..don't remember who). At what point do your cooling fans cut in? (where on the gauge?) Should be between the second and third mark.

Good luck

Bob S.