For anyone who hasn't taken on a project like this, the devil is in the details. Especially when, at the end of the day, the car can be worth upwards of $100K. I am trying to be as meticulous as possible and not go so fast I overlook anything. Since my last post almost a month ago, I have been doing a lot of little things. Here are a few of the things:
Engine:
A few posts ago, I talked about the pistons I found and how the weight was almost perfect. Well....
Knowing the head needed work, I wanted to get the block checked out too. Having 2 blocks (a 'W' and 'V'), neither the original, I was going to use the 'W' block which actually came from an XK150 because it seemed to be in better shape and was matched with the cylinder head. Even after discovering the block has some slight differences from the 120, it seemed the right decision.
Since acquiring the car, this was the first time I removed the pan to see exactly what it looked like inside. I didn't take any pictures but you aren't missing anything because there was nothing inside. It was literally just a block with the oil pan bolted to it. Makes it easier to take to the machine shop that way. Before loading everything up to take it to the machine shop, something told me I should check the bores again so I can tell the machine shop what to do. I have a set of bore gauges but I like to insert a new piston ring in the cylinder, ensure its level by pushing it down with a piston and then measure the gap at the end of the ring. If I measure at the widest point in the cylinder, I can see whether the block needs machined. Oddly enough, one of the things that came with the car was a brand new set of piston rings. I grabbed one of those and one of the pistons and 'what the heck!!!' The piston is not a 3.4L piston, its a 3.?? something. I really don't care if I can't use them.
That changes everything. I can't use the pistons, I don't really have any other parts for the 'W' block and the head will work on the 'V' block, I changed my mind and decided to go ahead and use the period correct block instead of the head matching block. What this does mean is I have to find a timing chain cover for the 'V' block because its slightly different than the 'W' block.
Having solved that riddle, the next thing I needed to do was find a set of main bearing caps. This is a bit tricky because caps are matched to the block. The block and caps are stamped with a code (I'm sure the code means something, day of the week, builder, something).
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| The 'V' block is stamped with P00 or POO and the cap number. |
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| Bearing Cap is JOR, not POO |
If you don't have the matching caps. it is almost impossible to use another set of caps without align boring the block. Its not easy finding a set of main caps for a 70 year old car but I was able to find a set. In the end, I think I might be able to get away with using them and NOT machining the block.
The first thing I did was install the bearings and crankshaft. I then installed the front, rear and middle cap and check to see if the crank would turn. At first it wouldn't spin but with just a slight amount of leverage, it did. Once I got it to spin, I could spin it by hand. For 1 final check, I used some plastigage to determine the clearance.
If you're not familiar with plastigage, its plastic that is a specific diameter. If you take pieces of the plastic and place it on the bearing or crank and torque down the caps, it will smash and spread out. You can then use the provided gauge to measure the internal clearance. I placed some material on each of the main caps, each side and top. All measured at .015", which is the minimum acceptable clearance. Just to be safe, I'm going to have the machine shop check them anyway but hopefully I can save a few bucks.
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| If you look closely, you can see the width of the plastic is the same as the .015 gauge |
One other thing I discovered is that an XK120 oil pump is hard to find. Buying new caps worked to my advantage because the caps are from a newer block and uses the more readily available pump.
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| With the newer type pump, all I need is the coupling. From first glance, looks like the pump is slightly out of alignment with the drive. Good thing I have access to a machine shop, if it needs some adjustment. |
Now, the engine is off at the machine shop:
- New valve guides (that allows for seals)
- Replace damaged tapped guide
- Check and bore cylinders (.030", I think)
- Clean and check for cracks
- Check and align bore main journals
With that taken care of, its back to the tedious stuff, sand blast, repair, prime. I think I have almost all the brackets, levers and mounts prepped. I haven't decided whether I'm going to paint or powdercoat. With it blasted and a coat of primer, I can still go either way. Its easy enough to blast back to bare metal for powder.
Oh yeah, and I finally attached the boot and bonnet sections to the side rails. Again, no pictures but soon it will be off the frame so I can finish the frame work and actually start building a car,
One last thing I'm working on. This started with my E-type but not wanting to disassemble and test on my working car, Snow White (fka XK120) will be easier and expand my commercialization possibilities.
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| Design is complete, will verify dimensions before making in metal. I might end up with the only FI XK120 in the world. |
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