Old school engine work

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.