Just did timing belt for first time
 

As title says, just did my first timing and balance belt. My first on any car. A few impressions for anyone who cares.

Four years (about 15k miles) ago, I had a shop to the belts, waterpump, and rollers, so I just did the belts this time. First off, it's really not that hard, just a little nerve racking, since a mistake can be so costly. It took me three days, working a few hours here and there each day. The most time was spent getting the tension set.

For the record the arnnworx 9131-944 is the biggest POS ever. If you ever feel inclined to waste $52, I'll send you my paypal address. I did the belts last week, and redid the tension again today. I could here water pump groan, so the car sat till I could do it again. This time I did the twist and waterpump method, and no more groan. I'm not 100 percent sure of my skills, and am contemplating having the local 944 shop double check the tension.

The 24/27 mm Combination Thin Wrench from arnnworx works great after one modification. See pic below.



http://forums.pelicanparts.com/uploa...1346890369.jpg


The wrench might have worked fine, without cutting it, if I had drained the coolant and removed the upper radiator hose. Since I wasn't doing the waterpump, I had no great desire to remove the hose and the end kept catching on the hose.

Harbor freight to the rescue again. This extendable rachet is great for finding TDC.

3/8" x 1/4" Dual Drive Extendable Ratchet


http://forums.pelicanparts.com/uploa...1346890609.jpg

You can look through the housing for the OT mark, while rotating the engine. All you need is a step stool.

To top it all off, the old belts still looked brand new and you could even still read the conti label on them. Oh well.

Special thanks to clarks and this forum, or I would never have even attempted this myself.

Belts on these cars are supposed to be annoying, that tool knows the correct tension better than you do

The first time took me two very long days. The second I was driving the car to dinner. Good work.

I always use the feel method on TB that don't have an auto tenstioner. Never a problem. Good job glad you shared.

What method do you use on the ones that do have an auto tensioner?

It could have been operator error for sure, but it didn't work for me. I only got less than a 45 degree twist on the timing belt and under a 90 degree twist on the balance belt. I should also mention that after loosing the balance belt a great deal, I got the same reading on it off the 9131-944. YMMV

Curious if you used the Arnnworx "Combo pin wrench" or another tool to remove the balance shaft cogs. What's a good inexpensive tool for that?

First tension per Porsche approved method or any method or tool you have and feel comfortable with.

Porsche updated the procedure for the "machanical spring tensioner" on the late cars:

http://forums.pelicanparts.com/uploa...1346933417.jpg

Then use the Water Pump Pully Test

http://forums.pelicanparts.com/uploa...1346933525.jpg


I retension the cam belt after 500 miles. This gives the belt time to "fit" in the pulley cogs and initial stretch.

I change the $12 cam belt every 2 or 3 years or sooner if any coolant or oil fluid gets on the belt.

John

A good tool to use for the balance shaft cogs is a long handle needle nose pliers.

I used this from Harbor Freight

2 Piece 11" Straight & 90ø Angle Long Reach Pliers

Would the 90* needle nose pliers work for removing the snap ring in the water pump?? Or just get the snap ring pliers??

Get a 90* snap ring pliers, but not at Harbor Freight--will bend.

Never used the Arnnworx tool - glad to have some feedback on it. I use a combination of the $30 el cheapo Krikit belt tension tool and the twist method/waterpump pulley method. Never had an issue; people knock the Krikit, but if you go and practice a lot with it, and do multiple readings, you CAN get a consistent feel for the tension with it.

John_AZ, was the waterpump pulley method yours?

Years of belt tension experience, years of searching and years or reading water pump seal and bearing failure and belt failure.

I bought the '88 924S in 1995 before Pelican and my join date of 2001.
I owned a couple early Porsche and thought I should be able to do a belt change.
I bought the Krikit direct from the factory for $10.
Spent a full weekend on the cam belt tension and waking up with cold sweats the first couple of belt changes. Probably redid it 5 times and still worried. I did not trust the Krikit.

The water pump pulley test is a combination of many members methods and cautions about the water pump bearing and seal failure caused by an over-tensioned cam belt..
The earliest mention of the pully test was in the late 90s, "I put my fingers and thumb on the WP pulley and tried to move"--member ID lost.

I have revised the method with suggestions from HondaDustR and many others.

I take credit for the yellow background ;)

The Krikit is almost impossible to be accurate twice in a row for the cam belt. The indicator lever is not calibrated enough---only to be close "with multiple readings".
I use the Krikit on the BB balance belt.

With a new cam belt---any method should have more tension as the belt will stretch and fit in the cogs. The Porsche OEM tool-P9201 has specs for a new belt (which have changed but close). The Krikit new belt specs vary ??.
Re-tension is now suggested at 500 to 1000 miles.

Finally, keeping a cam belt on for 30-45,000 is a fools choice.

Both my 924Ss came with a rebuilt WP installed prior to purchase-in 1995 & 1998. Still on the same pumps-one on the shelf waiting...

GL
John

How often do you change your timing belt John?

I've been a fan of tightening the timing belt until I can just barely move the drive hub of the water pump by hand. I tighten the balance belt until I can barely get a 180 degree twist out of the belt. The idler roller adjustment is such that when the other belts are done, the idler should have about a credit card clearance between the belt and the roller. Retension new belts after around 1500 miles and that's it. They have a slight, barely noticeable whine (which I'm sure is the balance belt) but all else is good. I pull the front cover once a year to check for any tension or rubber ware indications and have had no abnormal indications.

The '87 gets a new belt about every 2 years lately.

HG head gasket, front oil pump sleeve and crank shaft seal x2, or if a couple a years pass I just change the cam belt when inspecting and retensioning.

The '88 about every 3 years--less miles driven. Living in the desert and driving trips in summer at 110* just a precaution.

$12 cam belt and a couple hours of work-priceless :D

John

I'd rather do that than rebuild a head :'( there's too much conflicting info on the "best" way to tension the belts.

I am coming up on mine. It is something I stay awake at night worrying about! ( well, almost )

I am glad that my current car is a late tensioner type. Makes me feel somewhat better, anyway. About me getting the tension right, that is.

Jeff

So if the rollers look ok then you just do the belt? I'm trying to figure out if everyone is changing the belts and rollers every time.

The rollers should be checked at every belt change---not replaced unless bad.
Spin the rollers and feel for grit, wobble, pull and tug.

The Porsche Dealer suggests every 60,000 miles to change all rollers.

Porsche also has a TSB-technical service bulletin on the cam belt tension roller:

The cam belt tension roller is OK if it feels loose or "noisy"---But monitor closely.

Clarks suggests every 90,000 miles----(every other belt change 45K + 45K =90K miles)

I change the belts more often and sugest you use the 60,000 mileage as a guide.

Per Clarks:
http://forums.pelicanparts.com/uploa...1347021033.jpg

If you do not have service records, change the rollers.
Get the full belt and roller Contitech kit===Pelican Parts.
The updated WaterPumps need the 46mm cam tension roller kit.

GL
John