Dry Sump -Part 2 - Fitting the 3 Stage Dry Sump Oil Pump

OK with the sump pan fitted it's time to fit the external combined scavenge and high pressure pump. There are two separate scavenge pumps (these have cranked steel pipes sealed with masking tape) and a single high pressure stage whose input is sealed with a red cap. All the inputs are on the bottom of the pump and the two out puts are on the top. To the far right of the pump is the pressure control and adjusting valve
All three pumps are driven from a single shaft using the original oil pump drive in the block. Fitting this pump requires the original oil and water pumps to be discarded although some of the components need to be reclaimed from the old kit.
First I cleaned all around the water pump housing, when the water and oil pumps are removed the main oil galleries are exposed and I didn't want any grot falling in there! Next I removed the hose from the water pump's outlet and undid and removed the green hose union from the water pump's inlet.

This gave me access to the three mounting bolts that hold the pump to the block.




These undid easily using an 8mm socket and the water pump cover and it's sealing gasket could be removed, exposing the vanes of the impellor.
The impeller bolts onto a shaft which runs right through the water an oil pumps and connects with the oil pump drive deep in the block. In order to remove the shaft and split the oil and water pumps I had to undo the bolt in the centre of the impeller.






I think you could lock the gearbox in gear, which in turn would lock the pump shaft in place, but a much easier way is to jam the blades of the impeller with a screw driver and undo the bolt. It's not very tight as like just about everything else on this engine it's only done up to weedy torque settings. However I didn't want the shaft falling out as I removed the water pump so I only loosened the bolt. I wasn't too worried about damage to the impeller as I'll be using a separate water pump, but in the end it wasn't even marked.
Now it was time to remove the water pump, the oil transfer barrel and the oil pump rotor. All three bits come out as a single unit held together via the pump drive shaft. And all I did was pull it gently upwards and the whole unit emerged smoothly from the block.


Below you can see the complete unit as it was removed. In my hand is the water pump housing, and around it's perimeter you can see an O ring that I need later.

The long cylindrical component is the oil transfer barrel which forms the top face of the oil pump and also routes the high pressure output from the OEM pump to the oil filter. In the bottom face of the transfer barrel is a round hole which must be fitted over a pin in the block to ensure that the barrel is in the correct orientation. Below that is the lobed centre section of the OEM oil pump. Just visible in the bottom of the rotor is a groove where a pin sits that both retains the oil pump rotor on the shaft and drives it round. And at the bottom of the shaft is the notch which engages with the drive shaft in the block.



In this picture you can see the other half of the oil pump, and at approximately the 7 o'clock position you can also see the orientation pin for the transfer barrel.
In the centre hole you can just see the flat blade of the oil pump drive flange.




In accordance with the Pace instructions I removed the the oil outer rotor, it has a hole in the centre shaped like a 5 pointed star. It's a tight but sliding fit in the housing and lifted out easily.

Now I needed to split the oil pump rotor, the oil transfer barrel and the drive shaft from the water pump housing. This was why I had loosened the bolt earlier! I wound the nut out of the end of the shaft and then wound it back in again about three turns. A good tap on the bolt with a soft faced hammer forced the shaft out of the back of the water pump housing. I could then remove the bolt and water impeller from the front of the water pump, and the oil transfer barrel, oil pump rotor and retaining pin slid of the shaft after it had been removed from the rear. Above you can clearly see the hole for the orientation pin, and in the background the disassembled shaft and rotor assembly.

Of all these components only the oil transfer barrel is used by the Pace Kit and this needs to be reinserted into the block.

This is a picture of the transfer barrel after I had correctly inserted it. It sits flush with the face of the block, but it will also sit flush if the orientation pin is sitting in one of the large holes in the base of the transfer barrel but this is wrong. Basically if it will rotate at all it's incorrectly fitted.







The only other thing I needed to retrieve from the old water pump was it's sealing O ring. This I transferred to a similar groovein the mating face of the pace pump.




So I was now ready to begin fitting the pace pump. It also has a slot in the end of the drive shaft which must engage with the drive flange deep in the block. Basically I found it easiest to roughly orientate the shaft to the correct position, then slide the Pace drive shaft down the hole in the centre of the oil transfer barrel until it touched the drive dog. I then gently rotated the complete pump until the two shafts engaged and the it dropped into place.

I then had to remove the pump when I realised I'd forgotten to fit the O ring from the water pump into the groove in the mating face of the pace pump. Then I fitted it again m I'm Olympic Standard inept!

I got it lined up first time and the pump fitted perfectly, but as it dropped into place I noticed that in two of the bolt holes the threads do not come all the way to the end of the hole, (you can see this in the picture above) and also that two of the mounting holes in the Pace pump were much bigger than the third even though they all take the same M6 bolt. After a bit of puzzling it became obvious that two of the holes needed the locating dowels transferred from the water pump housing although this wasn't stated in the instructions.


So I removed the pump (again) in order to transfer the dowels over.

It was about now that I had a near disaster! As I removed the pump it dragged the oil transfer tube out of the block with it, and there was a clearly audible "TINKLE" as a metal part fell down somewhere. I gingerly looked in the oil pump housing to see that the locating pin that orientates the transfer barrel had been lifted up by the barrel when it was pulled out by the pump. The oil film holding the pin to the barrel had given up it's grip after the pin was clear of it's mounting hole and the pin had fallen back down inside the oil pump housing. Fortunately it had lodged on a machined shelf at the base of the pump housing, but it could easily have been lost into the main oil ways. I was so relieved that I could retrieve it that I forgot to take a photo. But from then on I took care to lift the pump out carefully and ensure that it didn't drag the transfer barrel with it. I also took care to replace the pin carefully in the correct position.


Then I removed the two dowels from the water pump and fitted them to the block, I then tried fitting the pump again. This time lining up the pump with both the drive flange and the locating dowels while simultaneously trying not to pinch the O ring was quite a challenge. It took several efforts, each time I partially removed the pump, twisted the drive shaft a small amount and retried fitting it. I was only successful after some therapeutic swearing was applied, when it finally connected correctly with the drive flange and dropped neatly into place. It took no force but just simply slid home, so if you are forcing it something is not lined up or worse still the pumps drive shaft has a slight bend which would mean Pace need to replace it

Here's a picture of the pump in place awaiting bolting up. What's not readily apparent is how limited access is to the bolt holes, and I found that I actually had to remove both the cover plate (on top) and the feed tube (on bottom) on the scavenge pump nearest the block in order to get the bolts to fit into the holes.

By the way the red covers are available from Think Automotive and are worth keeping in your spares box incase you ever need to disconnect the system in the paddock


As with the sump Pace hadn't supplied suitable bolts (although they will do now) and the originals cannot be re used. So I had to source 2xM6 30-35mm un plated cap bolts for the two holes fitted with the locating dowels and 1x 25mm M6 un plated cap bolt for the hole that is visible in the picture above right. After much faffing around because access is really quite limited I managed to torque the pump to block mounting bolts up to the 15nm specified in my workshop manual. Incidentally Pace again recommended using un plated bolts because they are stronger.



All that was left was to fit the rubber hoses between the scavenge pipe inlets on the pump and the scavenge pipe outlet on the sump. These hoses are under sustained vacuum when the pump is running and are therefore very thick walled and inflexible. As I already had one of the scavenge tubes off the pump I fitted the hose to it while it was on the bench. As you can see the scavenge tubes are also fitted with sealing O rings that I took care not to lose.




I then oiled it's mating partner on the sump and slid the hose onto that too. Oiling both hoses allowed me then to slip and slide the tube fitting about until I could re bolt the scavenge inlet to the pump. This proved so successful that I unbolted the other scavenge inlet pipe and repeated the process. The Pace notes warned me to be very careful not to strip the threads in either the Aluminium sump or the pump when refitting the bolts, so I only just "nipped" them up far enough to compress the spring washers. Later checking with a torque wrench showed them to be at about 8nm.


So the installation is complete. I went around and checked all the bolts for tightness on both the sump and the pump, I double checked the scavenge pipes and blanking plate on the pump and did up the Jubilee clips on the scavenge hoses. Job done! Now I can start thinking about installing the engine in the chassis.
Here's a couple of pictures of the completed installation








Just one last thing as you may recall I removed the original oil pump's components. Well here they are! I always find it entertaining that my intuition clearly tells me that the middle rotor cannot rotate within the outer shell, and yet plainly it does. I'm also mightily impressed by such accurate machining.

Visual inspection of the pump shows that there is minimal wear on the lobes ... another good sign regarding the health of this engine.

And I now have a very finely machined and strangely tactile paperweight!