1983 944 water pump pulley size...?

[onthesolidrock]

So, im about to replace my timing and balance belts on my 944, NON TURBO, but ive hit a bit of a speed bump... pelican offers the kit but apparently there are 2 water pump pulleys sizes.... how can i tell what size my pulley is without taking the covers off and measuring it? did early n/a 944's come with a 36mm or 46mm pulley? really dont want to tear half this apart just to wait a week to get my parts and forget how things were, unless i really have to. any tips or advice is more than welcome, thanks!

[thomasryan]

Take the top cover off and see if your pump has the guide plate.

[John_AZ]

OR Maybe if you are lucky,

The updated turbo water pump USUALLY has a "WHITE' plastic block off plate that can be seen from the front of the engine and this should give you an indication if you have the 46.2mm waterpump idle roller. Not a firm guarantee but usually yes.

Block off plate for the updated pump;
1987 Porsche 924 S Coupe - Water Pump, Thermostat & Hoses - Page 1

This is different from what thomasryan mentioned---the guide plate under the belt covers...
1987 Porsche 924 S Coupe - Camshafts & Timing Chains - Page 2

J_AZ

[Rasta Monsta]

Wait, how are the plates different? Anything other than color?

[John_AZ]

I have the "white" plastic block off plate, I suppose you can paint them another color.
John

[Jim Chambers]

I'm confused. Is the roller size an "early/late" water pump question, or an "original/updated" replacement" part question. I have a '87 924S and need to order a kit as well. I believe I have the later spring belt tensioner system. I will also be replacing my water pump as I believe it is still original after 28 years and 61K miles.

[John_AZ]

What is your engine number?

[Jim Chambers]

Engine M43H 10820

[John_AZ]

You have an "early" engine in an early production 1987 924S.

Almost certain it came with the "OLD style" water pump. (NOT the updated turbo pump with belt guard)

You can get a belt kit for the early OLD style water pump but if you plan to upgrade to the new style turbo water pump, you need to get a kit that has a waterpump roller that is 46.2mm across.

If you update the pump you also have to cut the rear belt covers for the new pump to fit.

PICTURES:
http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/774460-early-late-water-pump-question.html
"
SO, IF you do not see the updated white "NOSE"-block off plate on your pump from the engine bay, you probably have the old style pump from the information you gave --61K miles.

BUT since you have to cut the rear belt guard anyway, just take off the front belt guard and check to be absolutely, positively sure.

Then buy the updated pump, the block off plate, the steel belt guard, a set of new water pump bolts, belt and roller kit, some sealant for the gasket-=-black or green I use aviation sealant. (crap to get off but I prevent a "do over") and stuff for the WYAIT items.

EDIT: The engine may not have the updated "Mechanical Belt Tensioner". You also have to get a kit with the correct cam belt tension roller.

GL
J_AZ

[Jim Chambers]

Thank you John. Is it important to install the updated pump? What problems does it solve? Sounds like extra work and cost. Is a new/rebuilt old style an option? I have never done 944 belts/rollers so am not full of confidence.

[John_AZ]

My highly untechnical reply would be that the improved design incorporating the shiny steel belt guard prevents a cam belt vibration which could cause a premature cam belt failure.

The new updated water pump also has an upgraded bearing and seal.

Possibly more improvements.

If you have no experience in adjusting the cam belt I suggest you spend more money on the new tool from Arnnworx to adjust the belts.

920Xv6 Timing Belt Tensioning Tool - Version 6.1 920X Timing Belt Tension Tool [920Xv6.1] - $160.00 : ArnnWorx Specialty Tools

J_AZ

EDIT again..

As long as you are doing the belts, rollers and water pump, you should also reseal the front of the engine. Replace the seals and other parts WYAIT: Example

http://www.pelicanparts.com/catalog/SuperCat/0991/POR_0991_ENGREB_pg1.htm#item4

More?

J_AZ

[Jim Chambers]

I have been looking at the Arnnworx tools. Need the gauge for sure. He has two kits at $195 and $295. Are the additional tools essential. I'm sure the flywheel lock is required.

[M. Murphy]

Good advice from John. Perhaps from this picture you can see what he is referring regarding the block off plate (looks more like a plumbing fixture) and the belt guard. That belt guard is located at the most critical area because if there is any belt whipping without it the teeth could contact going in opposite directions. Disaster!

[thomasryan]

Jim, it is easier with the proper tools. Bruces tools are fabulous.

It looks daunting the first time. You will need a small torque wrench for the water pump and another that will do 150 ft pounds for the crank bolt. You will need some 574 sealant and a dab of never seize on the cogs and woodruff/feather keys will make the job easier next time.

If you get the onion skin seal kit, pitch those hamburgtećh shaft seals and use victor rein brand. Lube the back side of the seal lips for the initial start up. If the keys get roughed up during the removal process, replace them.

The lower balance shaft housing has a single fastener from the back side. Changing the races might save a headache down the road. Especially, the oil pump drive.

Van and Jürgen have good videos on the procedure and a 924board has some helpful tidbits on getting the balance cogs aligned properly. When you have completed your work, spin the motor by hand a few turns and double check everything.

It cost a little bit extra the first time. It can be done in about 4 hours after you get the procedure down.

Belt construction has improved over the years and changing out a functioning water pump seems rather silly. The high tension required for the timing belt does impose quite a side load on the water pump bearing.

[Jim Chambers]

Thank you M. Murphy and Thomas. I need all the advice I can get.
Hopefully once the belts are off I can get a sense of the pump bearing condition by feel. Also see any weeping if present. Guess I really won't know what to do until I'm underway. Not anxious to do more than absolutely necessary. With near 40K miles and 25 years since last known belt replacement, I know new belts are essential.

[M. Murphy]

Jim, Having gone down this road with my 83 two years ago I will offer a couple of things.
Do you have an air compressor? If not, I would strongly suggest you get one. Same with an inexpensive 1/4 inch small right angle tool grinder from Harbor Freight. To be used in the tool grinder an SGS 1/8x3/32x1/4 inch carbide burr.
Why do I suggest this?
Once you get the front of the crankshaft exposed you will most likely discover that instead of the expected woodruff key you will have what is called a feather key. It will be identified by radiused ends where the woodruff key is squared. A woodruff key with some light persuasive taps and PBS Blaster will rock right out of its slot. A feather key will still be there after the application of a tactical nuke!
With the grinder and the carbide burr you can pretend to be a dentist and grind a good portion of the key away making it easier to remove.
The rest of it, just take your time and remember, Harbor Freight has all kinds of pullers and other tools you'll need. Good luck.

[thomasryan]

My pump was 22 years old and the impeller and the shaft had parted ways. Plan on that expenditure.

Side cutters work well on either style key as long as you have a new one ready to go. That feather key seems like a tolerance fit!

Dive in....Collin Hay would call it 'overkill'.

[M. Murphy]

It is definitely a tolerance fit, brand new side cutters didn't do it for me.

[Jim Chambers]

Assume we are talking about a key which keeps the crank pulley in place. Why do I need to remove it? Seal replacement? Wasn't thinking I needed to do that. Part of the above recommended "re-seal" of the front of the engine?

[M. Murphy]

Yes, that was my assumption that you would change it while you are in there.