I'm still working on getting my '51 Plymouth to actually fire on 6 cylinders. From driving it and adjusting valves I got compression from 60-30-0-0 -60-60 to 60-60-35-0-60-60. 60 PSI on all 6 is enough to make the engine run okay as it starts near instantly and generally runs great other than the skip I actually did a leak down test and found the intake valve on #3 leaks pretty good ( 35 PSI ) and the intake valve on #4 leaks a lot. The rings seem to be okay but being I can't exactly hold pressure I'm not sure, but there isn't much air going out the tail pipe. I also found that the #4 intake valve seems to stick up just a little with a borescope. I ordered intake and exhaust valves for both #3 and #4 cylinders, NOS valve stems, retainers and keepers to eliminate all possibilities that way. If the valve seats are in decent shape, can I just lap the new valves in? Normally I'd drop the cylinder head at a machine shop and have new guides and seats installed/ cut but being valve in block, I don't have it that easy. From reading the plymouth manual, I know doing some of this stuff in car was common/ expected back then. And how can I test the rings? Is the timed liquid test accurate? If the rings are bad or if there is light damage the manual says that I can hone out light imperfections and only to re bore if it's out of taper or out of round tolerances, which are quite generous it seems. Stuff I know wouldn't fly at a machine shop today. Hopefully tonight I'll have the head pulled for a second time
There is no reason you can’t fix/overhaul most everything in the car with the correct tools. If you’re removing the head and pan and your crank is fine. I would remove all of the pistons and rods, clean up all the bores with a glaze breaker and finish with a carbon ball. Tape or rubber hose the rod Journals and turn the crank in the hole your glaze breaking to have the most space for the glaze breaker home. Have a pan under the engine (I like 3’x3’ white plastic for washers and dryers) and I squirt with kerosene or diesel fuel when doing the work. Put in a new set of rings…cast iron rebuilders are best. You can have up to a .030” gap and be just fine. I can’t remember the flat head 6 valve guides but a good lapping will do wonders wwith ne seals. Don’t worry about the width on the valve seats it not a race engine. You can actually roll in new main bearing with the crank in place. Egge can supply you with all the parts if you can’t find them online. I knew guys in the 60’s who did jobs like this every weekend for extra money.
I pulled the head and really inspected the bores and they look good. Filled the suspect bores with wd 40 along with one known good cylinder and they all held the oil for hours. Intake valves on 3 and 4 are pretty bad. 4 doesn’t hold back liquid at all and 3 holds a little. If I get time tonight I’m going to pull the valves on those cylinders and see if the seats need cutting. I have the new valves coming.
I'm having a heck of a time getting the springs compressed to get the keepers out. I'm using a Sunnen valve spring compressor that looks very similar to a KD model 700. It has no model number and is Patent pending so I'd guess it's pretty old. The problem I'm having is that to squeeze the valve spring, the tool is effectively loosened all the way and it has a spring to keep it from falling apart but the spring has less tension than the valve spring so it does nothing. If I put the tool in I think upside down, I can have it so the 'feet' rest on the sides of the lifter bore, and push up on the retainer with the topThe downside is, it just opens the valve. Can I bolt a plate or something across the valves to hold them down? There are head bolt holes that would work. I'm thinking the pre punched steel stock that hardware stores have. Quick and easy if it'll work This is the same tool as I have. https://www.ebay.com/itm/3267263035...5qiXtgSrI8ZzNbu4Z_5HoxuY9oQI5BVEaAgq8EALw_wcB
I visited this website http://flatfenderfever.com/id8.html where they are working on a jeep 134 using the same valve spring compressor so I know I’m using it correctly. Just doesn’t seem to open wide enough. The only other thing I can think of is catching a loop of spring vs the bottom retainer with the tool. That should allow me to push the retainer up and get the keepers. Not sure that’s the right way to go about it though.
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