WATERPUMP B-ENGINES (12-cog type)

The B-engine inherited the gear driven, block mounted waterpump from the Triumph/Ricardo engine. A lot has been said and written about this "unconventional" pump, and several solutions have been suggested on how to improve/modify it.
- One guy I heard of, wanted to add a V-belt driven shaft on top of the block, to drive some sort of pump placed on top of the lid of the original pump. Sounds complicated to me...
- Some other guys came up with an electric waterpump, apparently a common thing to do on drag-racers. A race inspired idea? Interesting! ... -Tell me something, how long does a drag-race last? Only a few seconds? Thought so. Those electric waterpumps are not designed to replace the mechanical driven main pump in an everyday car, they dont have the required capacity nor any life-length to speak of. If they had, they would be HUGE!

Someone once claimed a noticeably better performance after fitting an el-pump. If my car did that, it would really make me worry... You won't notice a boost of ONE horsepower in your car. It takes several horsepowers to make a difference. If the "better performance-theory" is correct, it means that the gear driven waterpump requires several horsepowers. To give you an image of how large an equivalent electric motor would have to be, I'd like to point out that the starter motor is 1,1 Hp. And now you've substituted the "several horsepower" mechanical pump for a 100w (0,13 Hp) el-pump ? Do you still think it'll do the job? The best known way of improving performance on a Saab engine, is fitting a turbo.

I must admit I dont know the exact power-demand of a Saab waterpump, but I've got a pretty good idea. And its NOT several horsepowers. Much less. A heavy duty electric pump will do the job just fine, for everyday commuting. And in some cases, solve a problem. But I'm not so sure a turbo engine would last very long with it...

The last example of scepticism regarding Saab's gear driven waterpump was printed in an article in the Swedish auto magazine BILSPORT, nr 4. february 2001, featuring a custom built, rally inspired 900 Turbo. The owner was concerned that the cogwheels would snap at high engine revs.

Let's take a closer look at this conspicious pump. A timing chain driven idler shaft drives the water pump, distributor and the oil pump through angular geardrives. I can assure you it requires a lot more energy to pressurize the black sludge, rather than spinning an impeller in water. It really is the oil pump he should worry about, if he must.
The truth is, these water pumps are just as reliable as any other pumps. Thousands of Saab's with these pumps are daily being driven, absolutely troublefree. Its main problem can be narrowed down to one or several of these points:

- Neglective car owners, who fail to see the signs of pump wear-out. (All pumps do that, eventually) Not a lot of twenty-year-old-or-more cars are handed over to the dealer for service/inspection, on a 10 000 Km basis. If the leak isn't caught at an early stage the result may be water in the oil, oil in the water, a seized pump-bearing, damaged cogwheels and/or a broken idler shaft.
- Sloppy mechanics. This job requires special tools, meticulous precision and detailed knowledge of what goes on inside the cast iron lump. Saab-garages mostly demand silly money to change a pump, so the job is often handed over to the first guy who's cheap. All guys are mechanics, right? "-Special tools? Naah, we'll think of something".
- Incorrect procedure in the workshop manuals. Here's a nasty one! According to the workshop manuals, two versions of the pump exist, both with the same parts number. (There must be two component-suppliers) This is true, but the procedure for one of them is not very adviseable to follow! No doubt Saab supplied the data, though. Haynes is off the hook. The method described may have worked very well indeed for Saab's engine-plant, given their assembly line worker's access to purpose-designed facilities. But following those instructions when changing a pump, may lead to its failure and internal damage to the engine. Very soon. A friend of mine's m81 99 GLi lasted two months, after she had the pump changed by an authorized Saab dealer.

CHANGING WATERPUMP, B-ENGINE
Check for signs of pump wear-out, from time to time. Sinking expansion-tank level is one sign. Blueish water on the ground, under the car, is another. But to be absolutely sure, inspect the waterpump leak-hole for moisture. It's on the side of the block, right beneath the pump lid. On twin carburettor engines, inspection involves a torch and a mirror.

My Haynes manual describes how to change it, I'll just add a few points.
- The manual says, -drain the coolant from the engine. Very important! If nothing comes out when you undo the drain plug, poke in the hole with a screwdriver.
- To remove the alternator bracket, the engine must be raised. But it isn't necessary to remove the eng-mount nuts. Just loosen them, and screw them to the top of the threads. Then jack up the engine. The rubber will flex a little, and the awkward alternator bracket bolt comes out.
- The Haynes manual suggest that if the special waterpump-extractor-tool is nowhere to be found, you can use two screwdrivers (or something) to lever the pump out. Dont even THINK about it! I must admit, I know at least two guys who (claimes to) have done this successfully. And another two who were not that lucky... You never know.

- When you use the extractor-tool, make sure the pump can spin freely (within the play of the geardrive) during the whole process. The important thing here, is that the geardrive must not bind, as the pump is pulled upwards. As the pump rises, it must be rotated. Elevate the pump slowly and gently, a little at-a-time. Brutal force here, can result in a broken cogwheel or idlershaft. Which means it's lifting-out-the-engine-for-complete-dismantling-and-overhaul -time.
- When the pump is up and away, clean the area thoroughly. Sandpaper, Olfa-knife, airgun, the works!
When driving the bearing onto the shaft, it helps to have carried out some preparations.
- Leave the shaft in a deep-freezer for a few hours, -to make it smaller. Set the stove-thermometer to 110C, wait until the thermostat switches off and switch off the stove. Then put the bearing in for twenty minutes, -to make it larger.
- Smear a little oil on the bearing and gear before driving them into the engine block

Now let's look at the two different pumps. Both come in a box full of pieces, you're supposed to assemble it yourself. Almost like a Lego or a Meccano kit.
- On one type, the impeller is retained by a nut. It will slide nicely over the pump-shaft. Follow the rest of the procedure in the book, and off you go!

- On the other type, the impeller is a press fit. Its hole is slightly smaller than the pump-shaft, and it is supposed to be pressed on. After taking so much care assembling all the parts, making absolutely sure the bearing is not forced, they want us to press the impeller down the shaft!?!?? NO WAY ! Read the manual, and see what happens if you press too far...

Here's what you do:
- Before any parts are assembled, put the pump-shaft in a lathe. Grind off material until the impeller will slide nicely over the pump-shaft. Now you must buy a nut. (M12x1,5-L)
- When the bearing and the shaft are in the engine block, apply a drop of Locktite metal-adhesive (it's for gluing diesel whirlchambers into cyl-heads, -honest!), before sliding the impeller over the pump-shaft. Then tighten the nut. Follow the rest of the procedure in the book, and off you go!

PS. After this treatment, my pump has worked faultlessly since the autumn of -98.

Leak hole	Alt. bracket bolt	Pump removal tool	The lathe treatment	Pump install tool