It was kinda odd that the disassembly and cleaning "fixed" the problem.  There was junk in the water pump, but I can't see it stopping all flow.  We blew it out, scrapped a little junk off of the inside and reassembled.   What was not shown is that on the second start, the engine started getting warm...like close to 200 and then just as quickly settled down to 185 and stayed there - pretty reasonable temp.I am not sure that the thermostat wasn't sticking.  When we took the water pump off, we also pulled the thermostat and put the heat gun on it.  It took quite a bit of heat to get it to move, then it started working.  Maybe it is sticky/defective and takes more to open.The water pump was indeed the one that was on the engine when we removed it from the Weasel.  It doesn't leak, and after taking it apart, it was very clean inside.  I have a couple of rebuild kits, but at this point, I am probably going to pull the one off of the running Weasel engine since I rebuilt it last year. 

I don't want to spoil it Pierre!😍.....but a little hint....it is a 6x6.....

Patrick TiptonSince we did know much about the internal condition of the "disaster" engine, I just wanted to start it first and check the oil pressure before we went any further.  We ran it for about 30 seconds in total.  I would not run it any longer than that.  Oil pressure was a solid 55lbs.  I will hook up the radiator and really warm it up over the weekend.  After the engine has been warmed up, we can really check the compression etc....and see if it is going to be good enough as is to reinstall in the machine.  More next week!

The disaster was just that the original Weasel engine was in such terrible shape up top.  We were just exercising a little "creative license" there John 😀

The assembly oil/lube is petroleum based and does indeed just merge with the oil.  There is debris created when you first start a rebuilt engine...a little ring wear, a little bearing wear, bushings, etc....so you do want to change the oil after it has run a bit, although not after a test run.  In the case of the engine that we ran in the video, we just installed new valves and cleaned everything else.  We won't change that oil now, but rather install the engine into the Weasel and run it for a year.  We will change that oil during "routine" maintenance at some point in 2025.On the new engine, we will run it on the test stand for a few hours to make sure it runs right without leaks etc.  We will change that oil before installing it into the Weasel.

more...in next comment.

Appreciate it Daniel!

Don McKeown  Sorry about your loss Don.  As for the spent brass, how about melting it down into a plaque - ala a lot of post war rebuilding centers, that could honor Grampa and you and your son's restoration efforts? Alexander's work is impeccable!The engine assembly process is great fun.  The next episode is going to have more things to pay attention to....like setting end play on the crank and cam, etc.  Very satisfying work!

Definitely call the machine shop and ask them how well the block and crank were cleaned.  My machine shop tells me - "clean it" because he is a one man show and while he cleans cranks and blocks after working on them, it is mostly a manual process and he wants the builder to double check his work.  In shops with automated cleaning equipment, I think the risk is much less.  "Squeaky" clean is an excellent indicator - I would not worry but I would give them a hollar!  Thanks for the comments!

We are going to talk all about labyrinth seals next episode...darnedest thing ever!

You guys are cooking.  How is the hull coming along?

They do indeed look symmetrical, but it looks like both the block and the caps were machined very slightly off perpendicular so they only fit one way.  I am guessing intentional and very cool.