Saturday, February 20, 2021

XK120 Fuel Injection & oil pump

I'm going to consider this post more of an interlude than an update.  I do continue to make progress but it has been slowed because I have been waiting for parts.  When I started the project, I sorted parts by mechanical, body, interior and electrical.  I started with the body and am now making my way through the mechanical.  Not that it was my original intent but ultimately, I'm making a bit of a hybrid (some might say a bastard) car.  If I were to start over today, I might do it slightly different but I am where I am.

In my last post, I talked about my struggles using a different set of main bearing caps and that I was having a hard time getting the oil pump drive to line up.  Having made a wedge spacer, I was OK with the alignment but not the spacing.  

If you look at the left side of the photo, you can see the wedge spacer I spent quite a bit of time sizing.  More important though is the gap between the drive and the drive gear in the bottom right.

Since I was waiting to get the oil pan back from the machine shop (more on that later), I had time to think about my oil pump setup.  The more I thought about it the more I didn't like it.  To do it the right way, I knew what I needed to do but I was quite frankly scared to do it.  While, I'm not sure exactly how the angle from engine to engine could vary that much, the way to fix my issue would be to machine my main cap to the correct angle.  Not having the proper alignment tools and not wanting to spend days shaving a few '000s off at a time, what could I do?

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Having a pretty good starting point for the angle I need, I decided the safest thing to do was print a main bearing cap.  Using my real one as a guide, I was able to draw and print one out fairly quickly (except for the 19hrs it took to actually print it).

My printed cap was the correct dimensions but I did have to hog out a section for the oil pump drive but the angle was really close.  A few minutes with some sandpaper and I got the drive to line up very well.  Now, I feel much better about milling off the surface of my main cap.

Using the printed cap, I was able to ensure the surface was 90 degrees from the drive gear.  Having this, I could angle the cap properly in the mill to reproduce the same angle.


You can see it under the baffle plate but I had to rebend the discharge tube because the angle of the pump changed enough to make the other one useless.  Speaking of baffle plate, I had to make that too and the oil pickup.  The pickup is not quite aligned here but ultimately, it will be flat with the pan.  It isn't free floating like the factory pickup but it will do the trick.

Here is the top down (or bottom up) view of the pickup and the baffle plate.  Not having any oil pump tubes (but 3 pumps) and not wanting to fabricate a pickup, I found one online that was close to what I wanted and just welded it to the end of my fabricated pickup tube.

Can't quite see it here but another fabrication I had to make was weld ears onto the front Main bearing so the baffle could bolt somewhere.  Does the customizing ever end?????


I had to fabricate the rear baffle plate that attaches to the pan.  Thanks to forums.jag-lovers.com for some great reference pictures.  View from the front of the pan showing the front mount.

Well, after 15-20 hours of fabrication and rework, I feel much better about my oil pump.  On to the next project.

Speaking of oil pans, what happens when you try to use a later model timing cover with an older model oil pan?  Answer: A trip to the machine shop.  I discussed this issue in my previous post but having decided to modify the later model timing cover to work with my period correct engine resulted in having to modify the oil pan too.  I discovered that a rope seal uses a slightly smaller diameter seal groove than a rubber seal (1/8").  Thankfully, having the correct size timing cover gave me something to give the machinist as a guide.
Not quite like the factory did it but having read somewhere that Jaguar actually machined the front lip off (the timing cover) to make changing the seal easier, I told the machinist to just worry about the diameter and not the lip.  Time will tell but the I am very happy with the result.

 With the front seal worked out and the baffles made, I just need to receive the oil pump o-rings and I can button up the bottom of the motor.  Never order something you really need with a low or out of stock item.  The vendor will hold the order until complete.  I think I'll order another set so I can wrap this up and test the engine.

Speaking of testing the engine, I've spent quite a bit of time working on my fuel injection since my last post.  While 3D printing parts I've designed helped me ensure they fit, when installed, it didn't help with maintenance parts.  I mentioned last time that I couldn't remove the valve covers using the XK150 water rail and would have to fabricate my own water rail.  Well here it is.

Hot off the mill.  I used a 2"x3" square aluminum so there would be enough room to use the Jag thermostat housing - far right of the picture.

With this design, I am able to remove the valve cover without taking everything apart.  Here you can see the thermostat housing attached to the front end.




As one last test, back in the car to see how everything works out.  Uh-oh, two problems.  

The radiator mount goes where I put the air box.  This is easily remedied in my final design, won't affect my dyno testing.  

Second problem, I removed the T-stat housing because it barely clears the radiator.  There is NO WAY a hose will connect between the rail and radiator.  Back to the drawing board.

 
I don't have it on the motor yet but doing some research online, I found some inline T-stats that I contemplated but felt like temperature control might be difficult.  I liked the design and concept so just made my own.  Not only did I make my own but I welded aluminum for the 1st time too.  Still need to clean everything up but I'm pretty happy with my work.


You can see from here, I cut the front of the water rail flush with the front water outlet from the head.  Welded my T-stat directly to the front of the rail.

The connection will be at a slightly different angle but should be very close to the factory connection.  I'll have to wait for the hose kit to arrive to be sure.
 
In addition to the mechanics, I have most of the electrical complete too.  All I need to finish is wiring in the O2 sensor and its ready to test.

Since I was spending time at the machine shop, I made the standoff for the tooth wheel at the same time.  Using my 3D printer once again, I designed the mounts for the timing pickup.  I missed the length by a little bit but that is easy to fix.  Change the design and press 'Print'.

Next post should include pictures of the interior and back to the body work.  Things are coming together.  Now, if I could just get the rear hubs of the axle, I could have the wheels back under the frame.