Dry Sump- Part 1 - Fitting the Sump

Step one, first remove the bike engine from the the car and place on sturdy clean bench. My ZX12R was nestling in the engine bay of the EVO, and unfortunately I didn't have a hoist to hand. So after a Worlds Strongest Man moment when I hefted the engine out of the car and onto the bench I was ready to start work. Do Not do this! These engines weigh 80+ Kilos and lifting them single handed is not to be recommended .




With the engine on the bench it was time to first remove the existing sump pan, this was retained by 15 M6 bolts with 8mm hex heads. Two of the bolts are slightly shorter than the others and the position of these is marked on the sump by a small arrow. On the right hand side of the sump in my photo is the oil level sight glass. This is simply pushed into a hole in the block where it is sealed with an O ring and retained in place with two bolts that go into the side of the sump pan. So I removed the sight glass bolts and pulled it sideways out of the block, hmmm that was easy. I then removed the remaining sump pan bolts. and the sump pan itself whereupon the ZX12R promptly spat half a litre of engine oil all over my nice clean bench... sheesh well I suppose it will waterproof it.

So this was my first view of the inside of a ZX12R. The first thing I did was to check the sump for any metal flakes or debris in the oil film. Mercifully there were none at all so hopefully this engine is a perfectly good runner. I've labelled up all the bits that I needed to remove or alter.


First I removed the original oil pickup (it simply pulls off), and I then removed the rubber sealing ring from the where the pickup moulding connects with the main oil way in the block, again it just pulls out.








Next it was on to the oil transfer pipes. The oil transfer pipes are very important things to get right. These distribute high pressure oil from the main oil galleries to big end bearings and other important bits that tend to go bang in expensive ways if not lubricated.

However the oil transfer pipes are simply pushed into the oil ways and sealed with and O ring. They are not bolted on in any way, but are retained by bosses moulded into the original sump pan. In the Pace sump the support bosses are replaced by 4 adjustable grub screws which allow for the fact that different engines have differing diameters of oil transfer pipe. The 4 grub screws need to be adjusted to the correct height and "loctited" in place. Pace told me to allow a small clearance between the grub screw and the transfer pipe to ensure that it wouldn't be pinched or stressed but that the pipe couldn't be blown out by the oil pressure. Around 0.5mm should be fine

I decided to measure the gap using some callipers and then transfer this gap to the grub screw exactly. When I fit the sump to the engine with a new gasket the width of the gasket should ensure that a small clearance is maintained.

These pictures aren't very clear I'm afraid but basically I placed a straight edge across the machined mating face of the original sump and measured from the support boss to the straight edged using sliding callipers. Then without moving the callipers I adjusted the grubs screws so that the callipers would just fit between the screw and a straight edge placed across the mating face of the Pace sump.

The grub screws were already "Loctited" in place but the compound was still liquid and hadn't yet "gone off" so I could easily make the adjustments. I performed this process 4 time, once for each support boss but I think the measurements were largely identical.

Lastly I checked the clearance using a dodge my dear old dad taught me. I placed a small blob of Blue Tack on each grub screw and then bolted the Pace sump to the engine with a new gasket. I then removed the sump and the Blue Tack blobs had been squeezed between the grub screws and the oil pipes. The depth of the Blue Tack left in the squeezed section shows the clearance. My test shows that the gasket was a little thicker than I thought so I wound the grubs screws out 1\8th of a turn. Incidentally the grub screws are quite a coarse thread, a finer thread would allow more accurate adjustment.

I then very carefully collected all the 4 blobs of Blue Tack out of the engine and carefully removed all traces of them.

The next thing to change was the pressure relief valve. The Pace system has an adjustable pressure control valve integrated into the pump, therefore the PRV in the engine is unnecessary and needs to be removed. The PRV is a large hexagon that fits a 19mm socket and can just be unwound from it's fitting on the main oil gallery. However it had been thread locked in place with a compound that produced several hard fragments, which I had to take care to remove completely.





The Pace sump comes completes with a blanking plug for blocking off the PRV's hole in the main oil gallery. In accordance with their instructions I fitted it with a thread lock and sealing compound and tightened it to the torque specified in my dealer's manual (15nm)


Next on the agenda was to transfer to locating dowels from the old sump or engine block to corresponding holes in the Pace sump.



The dowels are a push fit into the block and sump and so may pull out when the original sump is removed. I transferred the dowels to the Pace sump as I find it easier to have them in the part I'm fitting, and they help to line it up and retain the gasket during the fitting process.
There are two dowels to transfer, and the locating holes in the Pace sump are located near the main oil inlet and on the opposite side of the sump from the inlet




Next I moved on to the hole left in the side of the block, where the oil level sight glass was removed. The Pace kit includes a short cap bolt, an O ring, 2 washers and a nyloc nut for plugging this hole. The Pace instructions suggest that an alternative would be to tap a thread into the hole and insert a NPTF plug, but life is too short for such unnecessary work! Besides tapping the hole would possibly introduced metal swarf into the sump.





So I elected to go for the simple bolt and O ring approach. A quick inspection of the hole in the block showed that it was machined on the outside to accept the O ring, obvious really as the sight glass assembly is inserted from the outside of the engine.
The Pace instructions suggest using an additional sealant to prevent leaks, so I gave the washer and O ring a generous smearing of Tiger Seal (much more generous than in the photos) and bolted the assembly into the block. You can see from the photo that I omitted the interior washer so that sufficient bolt thread protruded beyond to Nyloc to ensure that the nut didn't vibrate loose and fall off into the sump.


Next it was on to the oil return tube and bracket. My engine has a flexible tube that runs from a connection high up in the block, to the deepest part of the original sump pan.
It's loosely retained in place by a small folded metal bracket and two gold colour bolts on either side of the tube. The bracket does not pinch the tube but simply appears to be a retainer to prevent the tube from getting tangled into the gearbox. The tube has a notch in the bottom end
The tube is obviously too long for the pace sump which is only about 1 inch deep, and the heads of the bracket's retaining bolts fouled on bosses in the sump so something had to be done with it.

The Pace instructions, and my workshop manual didn't mention the tube at all so I rang Pace. Unfortunately they had never heard of the tube either, as it doesn't appear to be present on any of the engines that they had seen, so it may be unique to the A1 engine. Pace while unable to offer any advice said that they would however be very interested in what I decided to do. Great it looks like I'm on my own :-( So it's back to first principles.




The tube can only perform one of three functions, it's either a suction tube for lifting oil to the top end of the engine, an oil drain tube or a breather to equalise pressure in the crankcase.

Option 1 seems unlikely as the tube is flexible and would collapse under any sort of suction, also the notch in the end would appear to be an anti siphon device. Option 3 acting as a breather is plausible, but the tube terminates in the deepest part of the sump and so should be well below the normal surface of the oil reservoir.

My guess is that it's an oil return tube, placed so that oil returning from the top end of the engine is directed straight into the deepest part of the sump, where it can be easily picked up by the oil pump intake. This has the obvious advantage that it helps prevent oil starvation, but also the oil is quickly returned to the sump without running down the inside of the crank case were it would be heated. Thus maybe this arrangement helps keep oil temperatures down too!


So if it's an oil return tube I can simply shorten it and it will continue to return oil to the sump. I shortened it so that it protrudes about 18-20mm beyond the end of the block\sump mating face. The Pace sump is deeper than this so the tube shouldn't have any problems with the exit being pushed up against the bottom of the sump and becoming blocked. I also duplicated the notch that was present in the original tube.
This then left me with the problem that I had to remove the retaining bracket to fit the Pace sump pan. I hoped that the much reduced length of the pipe would prevent itfrom moving but was a bit worried. However a trial fitting of the sump revealed two fortuitous side effects of shortening the pipe.

The protruding section of pipe neatly fitted into an area of the PACE sump between the external wall of the sump and one of the scavenge pump pick up tubes which will promote scavenging.
The pick up tube would therefore retain the pipe in position, but also the pipe would be discharging it's oil flow close to the scavenge pump's inlet, thus neatly mirroring the original function of the pipe. Problem solved (I hope!)






The last job and possibly the most important is to fit the transfer fitting that connects the oil inlet in the Pace sump to the main oil inlet in the block. The fitting is a short length of aluminium tube with two O rings.
The fitting is simply pushed into either the port in the centre of the Pace sump, or into the main oil inlet in the block.






After a bit of experimentation and a trial fitting I decided to fit it to the block and offer the sump up to it as part of the final fitting process. So I oiled the receiving port in the block and pushed the fitting in, it need to be positioned in the hole and pushed in as far as the O ring. I then gave it a firm biff with the heel of my hand and the O ring compressed and it slid fully home. You can see that only the outer O ring is visible.
So with the grub screws adjusted, the sight glass hole filled, the dowels transferred, the oil drain pipe sorted, the PRV replaced with a plug and the high pressure oil port connection in place it was time to complete the installation of the sump pan.
This was very tricky, I had to line up the dowels, guide the oil transfer pipe in the area by the scavenge pump input and guide the port in the pace sump onto the high pressure transfer fitting. Eventually I got to a position where it was all lined up but the sump wouldn't slide home, this was because the outer O ring on the oil transfer fitting was in the port on the sump but had not yet been "Popped" home. So I wound a couple of mounting bolts into each side of the sump pan and placed it under some gentle compression. Then after checking that the dowels were engaged and everything was correctly positioned and nicely lined up I gave the centre of the sump pan a smart biff with the heel of my hand.

A click, a nice movement and the fact that the sump now sat naturally at the correct mating position indicated that the fitting had been driven home and the sump can be bolted up.


It was now that I discovered that you can't reuse the original sump mounting bolts to fit the Pace Sump. Pace hadn't supplied any mounting bolts (although I think they will do from now on) so I had to source 15 x M6 40mm un plated cap bolts. When I fitted these I discovered the the holes where the locating dowels are fitted are actually deeper and require 50mm bolts. So actually I needed 13 M6 x40mm and 2 M6 50mm cap bolts. I didn't have any un plated M6x50mm caps so I've fitted plated ones, but un plated are better because they are stronger. The two longer bolts are the only ones inserted in the position above. BTW I loctited the bolts in place to prevent them from vibrating loose. I tightened the bolts up evenly to the torque specified in my workshop manual (15nm)

Who Hoo that's the sump fitted. I always like it when I can close up an engine after having worked on the internals, it just feels safer when everything is bolted together and covered up again.

With the engine on the bench I needed also needed to complete one other job.
The Digidash instructions state the the oil pressure sensor should be attached to the engine by a short section of high pressure hose to ensure that it is not damaged by the high frequency vibrations created by a bike engine.
So I needed to fit a -6\NPTF fitting into the port occupied by the existing low pressure warning switch. The warning switch is actually fitted into a thread adapter boss which is in turn threaded into the main oil gallery. I thoroughly cleaned around the area to prevent any grot falling into the main oil ways and removed the boss and switch.

I found that the NPTF thread in the boss was too small for my -6\NPTF fitting so I tapped it out a bit. NPTF Threads are tapered so if you tap them out you actually make the hole a big bigger, but you have to be careful not to go too far, or the fitting will never tighten up and seal correctly. I then, carefully cleaned, refitted and torqued up the boss and adapter to the engine
Again I used threadlock and again it needed to be torqued to 15nm.