Flat head combustion chamber

It was a 1965 American 330 2-door sedan.  The only options it had were radio, heater, reclining bench seat, and automatic transmission.  The only thing I did a little different than the average owner might is that I ran premium fuel, and set the timing to the premium fuel spec in the owner's manual.  I drove it to work until the car was 48 years old, finally retiring it due to body rust from 48 years New Jersey winter road salt.  It had only clocked 120k miles, but the head was never off the engine, the trans was never out of the car, and it still ran great the day I retired it.  Once it warmed up, I ran it pretty hard.  It would use about 1 quart of oil between 4,000 oil changes.

I've also had two 195.6 OHV engines and ran one of them over 200k miles.  Of course I kept the head torqued on the OHV.  The two biggest differences between the OHV and the flathead are power, and weight.  The OHV 195.6 is pretty heavy for it's size.  My 1964 440 hardtop, with it's automatic and tall gearing, would run 85 MPH all day long.  My 1960 Rambler 6 4-door hardtop and my 1963 Classic 660 2-door sedan were very peppy for mid-size cars with such small sixes.

In both engines, I ran 10-30 oil in the winter, and HD30 oil in summer.  I always warm up my engines by driving gently, and after a hard run, always let them idle a bit before shutting them off, which oils the cylinder walls.

I've had about 8 Ramblers over the years, and got excellent service out of all of them.

The Nash/Rambler/AMC flat-head is pretty bullet proof. No special maintenance needed. The only thing hard to do is adjust the valves. Supposed to be done every 8K or so, but most people just don't mess with them unless they start to make a noticeable amount of noise or they start to feel a power loss. They loosen slightly over time due to wear. They are just hard to get to with the motor in the car! If you ever pull the motor for any reason, ADJUST THE VALVES, even if the head never comes off. Do it while you can get to them easy! It takes a contortionist with the engine in the car from the top. Easiest way is to get it up on a lift so you can remove the steering linkage and K brace, but it's still tough. The OHV needs head bolt maintenance mainly due to the conversion nature of the design.

Other than adjusting valves in car, the only thing hard on the flat-head is taking that head off -- after it's been on for several decades. Some corrosion gets around the bolts in the holes. The first one I ever had to take off was due to a piece of lock washer falling down a spark plug hole. Landed on a piston and got embedded in the aluminum, knocked against the top of the chamber (got all the way to the tight part of the chamber). Sounded like someone inside with a hammer trying to get out! NOTE: blow/clean top of engine BEFORE pulling sparkers out!! I ended up using a steel wedge around the sides to get that thing off (over 100K, been on for 18 years... my first, a 61 back in 1979). I was concerned about damaging the sealing areas, but I worked it in a little at a time all around until it broke loose. Had to get it about 1/2" up before that happened! Luckily no damage. Head was shaved 0.020" just to true it up, block never pulled. It didn't need that much, machinist recommended it since it did need a small amount taken off (0.005-0.010... don't recall exactly). Today I'd soak those studs with PB Blaster or something for a couple days before trying to pull the head, and then I might try pulling the studs instead. Definitely use the starter with a good battery and the plugs in with all nuts off to see if that will break it loose first.

     Using your .045” ruler as equivalent to a compressed head gasket then from the block deck to the top of the combustion chamber is the .358” shown in your photo 

Assumptions: 1 that the valve upper corner is flush with the deck

                      2 That your cylinder head has not been milled

The exact numbers are not that important ..but the lesson is to check carefully if you decide to do any of the following:

     Mill the head

     Deck the top of the block

     Use a thin head gasket

     Decrease valve lash

     Install a high lift cam

     Over rev and float the valves

     … The way I drive nowadays the last one is irrelevant :-)

     

Good insurance is a lump of modeling clay on the head of both valves ..Next rotate the engine 2 full turns then dissect the clay for an exact measurement of valve to head clearance 

I did some more math that may be possibly useful but will post it later

Thanks Again for all the photos ..They are great!