320 Combustion Chamber volume

[Jyrki]

Has anyone measured the combustion chamber volume of a 320 head?

I'm trying to figure out how much chamber filling would be needed, after going to a 3.594" overbore (350 cid), shaving the head .125", and shooting for 9:1 CR with flattop pistons.

[pmuller9]

You need 89 cc in the chamber including the head gasket thickness for 350 cu in displacement with 9:1 compression.

Figuring on a 3.5 in round chamber it would be 0.56 inches deep.
Subtract for head gasket thickness brings it closer to 0.5 inches in depth.
Here is an aluminum chamber we did for the 263 S8
It is .375 deep


AlumChamber.jpg

What were you thinking about using to fill the chambers?

Paul

[Jyrki]

Actually, I'm open for good suggestions. Some say it could be welded with a nickel rod, some suggest brazing with brass, and some suggest making a mold and cast the part out of bronze, and screw it in place.

I was asking for the actual CC as I don't have a spare head to measure, and the OE ratios are with a domed piston (of unknown volume)

[Jyrki]

Paul, have you run that head yet?

[pmuller9]

Actually, I'm open for good suggestions. Some say it could be welded with a nickel rod, some suggest brazing with brass, and some suggest making a mold and cast the part out of bronze, and screw it in place.

If you weld the chamber, you can install hardened valve seats and will be a lot more stable than a screwed in piece.

The down side of welding the head is the head needs to be preheated as much as you can before welding. You could construct an oven with a removable top so you can weld while the head stays heated. It could be something as simple as stacked furnace brick with an oven heating element in the bottom. Could even weld up a steel box with 8 inches (Or more) of good insulation on the outside and heating elements on the bottom with a circulation fan. The better the insulation factor the hotter the oven will be.

I was asking for the actual CC as I don't have a spare head to measure, and the OE ratios are with a domed piston (of unknown volume)

The 1936 320 had flat top pistons with a CR of 5.9 making the combustion chamber 134 cc including the thin steel head gasket.
If you look at the combustion chamber depth it averages about 0.85.
If you figure an average diameter of 3.5 inches you have a 134 cc chamber which verifies the 1936 spec.
I don't have a 320 head that I can cc.

Paul, have you run that head yet?

The project got put on the back burner because we took on the job of recreating a Hydroplane that raced in the 1960s called the “Miss Marion Bluegrass”. It ran in the 7 liter class and was driven by Earl Wham. The original engine was a blown alky 427
The project was started this past January. The first part of this effort was to duplicate the original trailer which we finished just a couple of weeks ago in time to pick up the wooden hull that was built over in Seattle Wa. It will take the rest of the year to finish.

Paul

[Jyrki]

I think I might have to remove my head and check the valves and seats. I'd make the injector bores at the same time. Would also allow me to check the cylinders and pistons. I'm now running a thick composition gasket, so would swap a shim gasket while at it.

I would not fill the chambers at this point, but just make a mold, to figure out my options. We'll see.

[Bob]

What valves did you use?!

[Jyrki]

Original exhaust valves, BB Chevy (Manley Race Flo) for the intakes