Fitting ‘t Kreng’s water pump

The title says it all. But sadly a fair amount of time yesterday and today was taken up watching the race of the year; Les 24 Heures du Mans. But I did manage to fit the reconditioned water pump. Where the old pump had put up something resembling a fight while removing it, the new one went in pretty smoothly. Probably helped by applying plenty of lubrication to all surfaces and the fact I paid some attention to meshing the water pumps gears with the gears from the idler shaft. After which the pump could be turned into position using a ring spanner on the impeller’s mounting bolt and turning it counter clock wise. As easy as that. Oh … and I didn’t change the bearing bush in the block as it was in good condition. And I do hope that within a few years I will be able to built a new engine for this car!

Next job was setting the clearance between the water pump’s impeller and the pump’s cover.. Rather straight forward though it took some time to get the base reading. According to the book you measure the gap between cover and the blocks contact surface (0,40 mm) and add 0,30 - 0,50 mm for the required gasket thickness. In the end I went for a gasket with a thickness of ± 0,80mm from my spares.

With the water pump back in place I could start with the less glamorous parts of the job, cleaning threads and removing old gaskets. Which did take much more time than expected.

So by the time everything was cleaned my mobile phone’s battery was running low, and the Le Mans race was entering its final stages. But it left me with enough time to fit the inlet manifold (paying extra attention to the infamous connecting tube (UKC2538, between the thermostat cover and the water pump cover) and clear away the tools. All in time to watch the final hour of the race on the telly. Refitting the carburettors etcetera hopefully in the coming week or so ... At least full circle with noon yesterday!

Removing ‘t Kreng’s water pump

With the replacement water pump for ‘t Kreng ready, I started on the final job. Fitting it to the engine. But before I could do that I first had to remove the old pump. Starting with the always rather messy job of draining the coolant fluid. But I am getting good at it as I only spilled about half a pint on the drive!

With the coolant drained from the engine I could begin with the removal of all the parts that are covering the water pump’s cover Starting with the coolant hoses, followed by the fuel lines, the throttle and choke .cables, the carburettors and the inlet manifold.

And this left me with the final parts. The water pump cover and the water pump itself. I did have some worries about the water pump’s cover, as they have a tendency to corrode solid into the engine. This being caused by galvanic corrosion between the alloy cover and the cast iron block. I needn’t have worried. The anti-seize paste I used 17 years ago did its job. The cover came out without any problems. The pump itself put up something resembling a fight but lost against my proven extraction tools.

With the pump out it was time to inspect all parts that had come off. To start with the infamous connecting tube (UKC2538) between the thermostat housing and the water pump cover. Those who follow this blog might remember that this tube had been leaking on and of for a few years. And there sure was a reason for that. The two rubber O-rings on the tube had completely dried out and hardened. And as such no longer effective in sealing.

Next item to check was the pump itself. And that too was rather obvious. The water seal underneath the impeller was completely worn. Actually so worn that the spring inside the seal had reached its maximum travel. Leaving the seal free from the underside of the impeller. With the brass bearing cage fitted the bottom of the water seal should be sitting just free of the water thrower disc. In this case there was enough room to move the seal up and down. And air gaps are pretty poor at sealing!

Final item to check was the water pump cover. I have seen a few over the years that were badly damaged by cavitation. Probably caused by incorrect coolant (plain water) in combination with an incorrect set gap between the impeller and the pump cover. But as can be seen in the picture above, this one turned out to be in pretty good condition. Cleaning and reassembly next.

Water pump reconditioning part 2

I left this job with a generous amount of penetrating oil on the water thrower, to do its job in the joint between the water thrower disc and the pump’s axle. And while the penetrating oil was doing its job, I fabricated a simple tool from a flat steel strip (think very thin wrench) to support the water thrower as much as possible while hammering the axle out. But I forgot the folded edge of the disc. Luckily there was enough space for the tool between the oil seal and the bearing. And using the oil seal to spread the load, the water thrower disc came of undamaged. Removing the oxidation on the axle shaft above the water thrower on a lathe certainly helped here!

And with all parts removed from the shaft they could be cleaned in preparation for the final stage; reassembly of the water pump's various parts.

The reassembly of the water pump should have been a piece of cake. And it was, right up to the second to last part; the water seal. But while trying to push it in position by hand I managed to break the carbon ring. This might be explained by the fact that the seal came from my spare parts and probably was well over 30 years old. And as such the rubber had probably become too hard and the carbon seal ring to brittle?

Luckily I did have another water pump reconditioning kit, so that was robbed of its coolant seal. This time I used a small round plastic container to press the seal into the bearing cage without breaking the carbon seal. Sadly the plastic container slipped with less than 1 millimetre to go, and the second coolant seal was fit for the bin.
I am glad these seals are now available separately, so a new one was ordered. But it meant some extra time lost while waiting for the new seal to arrive..

This time the water seal went into the brass bearing cage without any problems. Which left me with the final parts. The impeller and its O-ring.

Next job is getting the spanners out and replacing ‘t Kreng’s water pump. This is scheduled for the coming weekend.

Water pump reconditioning part 1

It’s been a while since the last update on the coolant leak from ‘t Kreng’s water pump. Well the leak is still there, and still big enough to ignore. Though it looks like it has lessened slightly. Maybe that is just wishful thinking! So I thought it might be a good idea to start reconditioning a water pump from my spares stock. Main reason being to keep the car more or less mobile as long as possible, and to shorten the time it is immobile.

A short search through my spares came up with two good candidates for reconditioning. Though from one I first had to remove the brass cage from the engine from which it originated. Glad I knew were I had stored my home made “cage-puller”, as it makes this job so much easier!

And this pump turned out to be the best candidate. So next job was a trip to a friend’s work shop as he has a hydraulic press and a lathe. And these are necessary tools for removing the impeller from the pump’s axle, and cleaning the mating face for the seal.

Currently the machined impeller is in an oil bath to aid removal of any remaining corrosion. And the axle is positioned vertically in a support with some penetrating oil on top of the water thrower disc. Hopefully this will come off undamaged, as these are no longer available.

And to end a day well spent on things TR7 I spent a few more hours on the interior for the ’76 car. More on that later.