The Stovebolt Site Forums The Shop Area Engine Shop 216 dome pistons

I could use a little help/ information. I have a 1946 Chevy pickup with a 216. Parts are hard to come by and very expensive. Got a buy on six brand new .030 piston for my 216. Got them from my ups lady open the box and to my surprise they are slightly domed not the flat top I was thinking I was getting . They are for a 216 and marked for 1937 to 1953 216 . What is it with these pistons and will they work in my stock 216. Why are they domed. Help and information greatly appreciated and needed. Thank you .

Any chance you can post a photo of the pistons?

Davie Boy, May also help if you can post whatever part number/source information you have to better ID them.

What does your chamber look like?

I have several pictures of the pistons but I am not computer savvy and have not figured out how to post them. My son is coming home from college this holiday weekend. I will have him do it. As usual 🥹

Is there an advantage to the domed piston?

My dad ran dome pistons in a 1941-53 engine, and had to use two head gaskets to keep the pistons from hitting the head.

Problem solved!

These are EGGE pistons according to the box. Part number L1018-6.030. Good place have delt with them before. But no answer from phone calls or email requests.

It's a quench engine. Adding gaskets in a later 216 head to prevent P-H contact destroys this.

If it may help a little, below are pics of the 1937-40 216 domed piston and the 1941-53 216 flat top piston to show a comparison. In looking through the 1929-53 Chevy Master Parts Catalog, the head casting and the casting design changed between 1940 and 1941. 1937-40 216's used head casting# 838773. 1941-49 216 & 235 and 1950-53 216's used casting# 3835517.

A description of the cylinder head assembly from the 1941 Chevy Shop Manual (pg 161) says:

"The cylinder head has been completely re-designed, increasing the compression ratio to 6.50 to 1, and the horsepower to 90. At the same time the possibility of detonation has been decreased. The combustion chamber has been especially designed for use with a flat top piston that provides exceptionally compact combustion volume on the exhaust valve side where the spark plug is located."

"On the inlet valve side the head is machined so that, except for a shallow recess in which the inlet valve is located, the bottom face of the head over the piston is flat and is separated from the piston top dead center by the thickness of the cylinder head gasket only."

FWIW, I would suggest you check and confirm the casting number on your 216 head to be "838773" as that is the head designed for use with your new domed pistons.

DO NOT try to machine the domed piston flat to work with the later model head. It looks OK, but after only a few hours or operation, a hole will appear in the center of the piston. Yes, I tried that- - - -no, it didn't work!
Jerry

Gdads51 is 100% correct. Thank you for your help. Looks like I have set of new dome pistons that are pretty much worthless for me. Pity. Live and learn. Thanks again.

If you can’t return them to whoever you got them from, post an ad offering them up in the Truck Parts For Sale forum. There’s a very good possibility you may find a ‘Bolter in need.

If you need some help tracking down flat top pistons, send me a PM. I have a bunch of leads that could help you out and maybe save you some dough to boot.

If you're willing to rebore your 216 .060" oversize, standard bore 235 aluminum pistons will be a drop-in fit. They have the same wrist pin diameter and compression height as a 216 piston, and the aluminum pistons will be a lot easier on the Babbit rod bearings- - - -lighter piston weight, better acceleration, and 8 cubic inches more displacement to boot. Your "216" becomes a 224 that way. It was a very common modification back in the dark ages during an engine rebuild, in the 1950s.
Jerry

Thanks for all your help people. Finally got it all worked out. The box part number is for flat piston but it has domed pistons. Luckily I talked to these people and they are going to take them back. I am going to take a break fro this situation for a while Makes my hair hurt. Thank you for all your help

Good to know they are working to resolve the issue! All is not lost!!! Thanks for coming back and updating on what's going on and your hair might hurt less if you stop trying to yank it out - lol.
Been There - Done That way too many times.