944 Timing belt question

[Gawernator]

So, on my (new to me) '83 944 I have looked through the maintenance records and can't find any recent indications of a timing belt replacement, so I'm going to assume it's been long enough and get a new belt and go to town. The only thing is, I know that this job requires a special tensioner that is supplied by Porsche and very costly. When I search for the tensioner for my year one of the first results is this: 83 1983 Porsche 944 Timing Belt Tensioner - Engine Mechanical - Ruville - *********

It looks quite different to me than the Porsche device, can someone please enlighten me to what's going on?

EDIT: http://www.***********************/mmp/porsche~944~timing_belt_tensioner~parts.html

Perhaps the design was changed during a certain year? I must confess I don't know very well how the operation of the timing belt works

[Cocacolakidd]

There are some very good videos on U-Tube that will explain allot about the timing belt and rollers.

Go to : U-tube - Yahoo! Search Results

Then in the middle of that page is a search bar - plug in> Timing Belt Change Porsche 944 - Video #1 <
Video #2
Video #3
Etc, etc...

The videos go from 1 thru 8 - view them all

[Jrboulder]

First off, as mentioned before, thanks for your service

Those links are to the actual tensioner that is bolted to the engine and is an integral part of the timing belt system.

The 83-86 cars had the eccentric tensioner roller that was pretty simple to use although you have to use the P9201 tensioning tool to find the right tension value. The 9201 is probably what you were thinking of. it runs something like $625 new so it's quite an investment as far as rarely used tools go.

the 87-91 cars had a spring loaded tensioner that once you had your belts on you would release the nut holding the spring loaded tensioner arm and it would put a force on the belt and then you tighten the nut and it holds the arm in that place. Some people don't trust it. I do. No, unfortunately you can't put it on an early car.

Personally, I'd recommend for someone who has never done the belts to do them with the "twist method" and take it straight to a Porsche shop and have them tension the belts and make sure you put it together right. It will cost you something like $100 but it's worthwhile at least on the first time.

Other options are the "cricket" tool and the arnworx 902X. Many people here use them and they work good for the timing belt but as far as I know, you can't use them to tension the balance shaft belt.

Jackson

[Jrboulder]

P9021 Tensioning Tool:


Tensioner roller for your car:


Belts:


Porsche 944 Turbo Water Pump Change - part 1.wmv - YouTube

Porsche 944 Turbo Water Pump Change - part 2 - YouTube

Porsche 944 turbo Water Pump and Belt change - part 3 - YouTube

[Gawernator]

Thanks for your helpful responses. Sometime tomorrow I'll have a quote from a local Porsche/German car shop for the timing belt replacement... I hate paying for labor and not doing the work myself but in this situation I don't have the tool needed, not yet anyways, and I am a bit scared of driving the car knowing its interference design and the possible disastrous results that could ensue. After all the maintenance I've already done, the car and engine run quite smoothly, and I'm kind of scared because of that. I feel like there's probably something I have missed that's just waiting to fail, some pump or seal or belt... The next thing to replace are the struts and shock absorbers

[John_AZ]

Just to add, recent post:

http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/667819-best-timing-replacement-instruction.html

GL
John

[Gawernator]

Thank you John.

[v2rocket_aka944]

Consider yourself lucky to have an early car - the eccentric roller is cheaper and much easier to work with and saves considerable time.

The late style spring tensioner is a POS, plain and simple. Adds another hour to the TB job.

[Gawernator]

Sweet, thanks

[Gawernator]

Ok, one more question on the tool I need. Arnnworx seems like a good resource for this job, but I'm not sure if I need one tool or the other, the cheaper Krikit tool doesn't seem to be what I need.

9131-944 Belt Tensioning Tool Porsche 944 belt tension tool [9131-944] - $52.00 : ArnnWorx Specialty Tools
This? Or,
920X-944 Timing Belt Tensioning Tool 920X Timing Belt Tension Tool [920X] - $175.00 : ArnnWorx Specialty Tools
This?
Pros and cons?

[mytrplseven]

Boy, I hate to see people spend so much money on belt tension guages. Well each to their own. The one tool that was worth it's weight in gold, to me, was the flywheel lock. Oh, yeah, I forgot, the transverse engine support (for when I did the oil pan gasket and the clutch change).

[AKCJ]

The 920X is the one I use - I've used it several times and it works very very well. I can highly recommend it for both timing and balance belts.

The 9131 is probably fine but I haven't personally used it. I do trust the seller and would buy it if I didn't already have the other one. Bruce makes and sells good stuff.

[eligunn]

My experience is that you can totally tension the belt just by using your own judgment.
I have personally seen reputable Porsche mechanics reach in there and give the thing a tug or two and then tighten the nut and let her rip.

I have found that there is a visual reference you can use to know whether or not it's in the ballpark.

First of all you want to turn the tensioner counter clockwise to tension the belt. So that it gets closer to the water pump pulley.

At this time the point of the hex part of the tensioner you have your wrench on points right about the center pf the water pump pulley, and you can make minute variations from there. If you are pointed at the center of the pulley you should be close with the tension.

I think the tensioner tool just complicates things and makes you question your judgment. However, the consequences are severe if you screw this up. The last time I had a head rebuilt it was about 300 bucks just for the machine shop bill plus a head gasket on top of that.

[John_AZ]

eliqunn has experience with the '88 924S & 944s.

I reread the explanation a couple of times to understand his method.

Reposting an explanation from Van on Rennlist who has done a few DIY videos helped me.



I do not recommend buying any version of the Krikit belt tension tool. It is sold locally at NAPA, KR1 I think, it also is sold as the Optibelt tool, and a few other names.

You will not get an accurate reading with the tool on the cam belt.
I use it for the balance belt to get close---(the belt will feel real loose with any method).

If you have fears or nightmares about bending valves when the belt slips or about the correct tension, get the Arnworx tool. Many reviews on the accuracy of the expensive set. I have not used the new $50 tool to advise but Bruce Arnn is methodical -- compulsive in the tension process.

GL
John

[BeerBurner]

Originally Posted by AKCJ

The 920X is the one I use - I've used it several times and it works very very well. I can highly recommend it for both timing and balance belts.

I use this one as well. Granted, I haven't used it on an earlier 944 (although I have lent it out to people who have) but it is simple, easy to use and the complete kit (with wrenches, fly wheel lock, etc.) has already paid for itself several times over.

BB.

[eligunn]

John_AZ, I was talking about the kind of tensioner without the spring, as viewed in the diagram above.
However whenever I see one tightened properly it is rotated counter clockwise, with the point that is facing the balance belt roller in the diagram approximately 270 degrees counter clockwise to what is viewed in the picture, which I think might be misleading to someone who is trying to line their tensioner up with that one.

Turning the tensioner counter clockwise puts more surface area of the belt in contact with the water pump pulley. And with the point of that hex aiming toward the center of the pulley you know you are close. What you see in the diagram is the flat side of the hex part that has obviously been rotated clockwise to tension, reducing the area of belt contact on the pulley which is wrong.

[Gawernator]

I don't feel I have the expertise yet to tension without the tool, and I do have fears of bent valves. All this advice is great guys.

[John_AZ]

Originally Posted by eligunn

My experience is that you can totally tension the belt just by using your own judgment.
I have personally seen reputable Porsche mechanics reach in there and give the thing a tug or two and then tighten the nut and let her rip.

I have found that there is a visual reference you can use to know whether or not it's in the ballpark.

First of all you want to turn the tensioner counter clockwise to tension the belt. So that it gets closer to the water pump pulley.

At this time the point of the hex part of the tensioner you have your wrench on points right about the center pf the water pump pulley, and you can make minute variations from there. If you are pointed at the center of the pulley you should be close with the tension.

I think the tensioner tool just complicates things and makes you question your judgment. However, the consequences are severe if you screw this up. The last time I had a head rebuilt it was about 300 bucks just for the machine shop bill plus a head gasket on top of that.

Originally Posted by eligunn

John_AZ, I was talking about the kind of tensioner without the spring, as viewed in the diagram above.
However whenever I see one tightened properly it is rotated counter clockwise, with the point that is facing the balance belt roller in the diagram approximately 270 degrees counter clockwise to what is viewed in the picture, which I think might be misleading to someone who is trying to line their tensioner up with that one.

Turning the tensioner counter clockwise puts more surface area of the belt in contact with the water pump pulley. And with the point of that hex aiming toward the center of the pulley you know you are close. What you see in the diagram is the flat side of the hex part that has obviously been rotated clockwise to tension, reducing the area of belt contact on the pulley which is wrong.

eliqunn,

Your experience may tell you the belt is correctly tensioned by the "hex part of the tensioner".

The point of Vans paragraph and my method is to protect the waterpump from bearing failure or seal failure which will happen if you over tension the belt.

http://forums.pelicanparts.com/6647314-post7.html

Your visual reference point may change if the belt has been on the car for 30K miles and has stretched.
New belts have to be retensioned after 1500-2000 miles and your visual reference point will not be the same.

John