MTFCA Forum

Just some updates on the progress (or lack of) on the Orville Enyeart engine built for Andy Mounce. I've posted before, but as originally built the bore was 3.8750" and the stroke was increased to 4 5/8" by using a Model B crank and grinding the main and rod journals offset to Model A specs and using a 7" connecting rod. The engine when I got it appeared to have broken a ring and destroyed what I expect were custom Egge pistons as well as scoring the already oversize bore. I had Joe Bell pour new babbitt and the engine was sleeved to standard, now the engine is only 204 cubic inch. A lot of close fits with the cam shaft and the connecting rods when you move everything down and close to one another. I'll post more as work progress (rods are out for babbitting), hoping that by this time next year the engine should be together. I would like to solicit some advice on:

A good source of "custom pistons"
Distance the top ring should be from the deck
Source of solid copper head gasket
Suggested bearing side clearance , seen if everywhere from no less than .002 to .024

Ross Pistons will build you anything you want----for a price of course.

I bought these custom 7.5 to 1 pistons for my Fronty head with Model A crank and rods in 2019, at that time it was just under $800, and I know they have had a couple price increases since then. That is pistons, with pins and rings. I'm at 191 cu. in. on my engine with a 3.780" bore.

As far as copper gasket---are you talking for a normal flathead or overhead? I just bought a overhead copper gasket from Lang's

Bearing side clearance? For crankshaft thrust or are you talking for rod side clearance on crank? Crankshaft thrust around .004" is good, side clearance on rod to crank at least .005" but more (alot more) isn't so much an issue, unless it's pressurized oiling. All this stuff has to work together the more complicated it gets.

Solid copper head gasket for stock head. The intake valves are almost 1 5/8" in diameter so they interfere with a "standard" head gasket. Looking for side clearance on the rods between the crank throws on a pressurized oil system. Thanks

I’ve got a handful of these solid copper gaskets available. They are .040” thick and were designed to clear 1.720” valves on both sides. The pic shows the solid gasket on top of a new steel sandwich gasket

Kevin, email sent, that looks like the ticket, thanks

Last update for this year, the snow is starting to fall and the shop is not heated (intentionally)! Coincidentally, the engine was originally built in California and in a runabout way it's returning there. Joe Bell (Tiffin OH) for the babbitt and machine work, Dan McEachern (Alamedea CA) for the oil pump & spacers, Kevin Pharis (Orangeville CA) for the sold copper head gasket, Dude Green (Yuba City CA) for the rod work, Ross Pistons (El Segundo CA) for the pistons. Enjoy

Quarter inch piston rings can touch the top deck. Eighth inch piston rings should stop an eighth inch from the top. Either way the BOTTOM of the top ring should be about a quarter inch from the top of the cylinder. One thing you do NOT want is for the top ring to try to snap out if some of the Babbitt in the rod cap suddenly knocks out, allowing for the rod and piston to jump a bit higher. A jump of an eighth inch is not uncommon. If the bearing can allow for a quarter inch jump? Significant other damage will likely have already happened before the ring can snap out at speed. I did see an engine once that did that! Not a pretty sight.

Lubrication also gets iffy at the very top of the bore.

Looks Nice!


I put an internal center chamfer in the rods and mains (Babbitt) for full circumference lubrication and as a bonus it throws up enough oil to the pistons.

Hank

You have a special head gasket because it has big valves. A friend of mine had a flathead motor with 1 3/4" intake valves and he blancher ground the top of the block and the cylinder head, put contact cement between them, put it on, bolted it down and it ran like that without problems for a number of years. When he decided to change the cylinder head he unbolted all the bolts, took them out and it ran and still didn't leak water. Finally, he had to get under the back of the head to get it off.
Nick

I forgot to mention Orville Enyeart lived a couple blocks away from me. My dad and I were friends with him through the Long Beach Model T Club.