Found a set of old but never used pistons for my 283 build, never heard of the company and can't find any specs, but they were cheap and domed which I was looking for. Domed 283 pistons are not too easy to find here on the wrong side of the pond... Anyone have any info about them or used them? The box says April '84 and part.no P399. Any help appreciated! Sent from my iPhone using The H.A.M.B. mobile app
Looks very similar to the Egge pistons shown here: https://www.corvetteforum.com/forums/c1-and-c2-corvettes/2149054-1957-283-pistons.html Egge discontinued them some time ago.
Safeguard pistons were made in Marinette Wisconson, Also makers of Badger pistons ,still in business today.
Two things stand out, at least to me. First the dome, what is your intended usage for these? If you are going to use them on the street you may want to check your final compression ratio and decide if you have the necessary octane available for them. They look to be the taller dome that was used on the ‘61 fuel injected 283 that was 11-1 c. r. with the 64CC , 1.94 intake/1.50 exhaust heads. The second thing is the valve notches, be sure to check the valve to piston clearance. The notch in the top circumference denotes “front” and I would not use the old hot rodders trick of freeing up a couple of horsepower by switching sides since they are a cast piston. The wrist pins are likely offset to the major thrust side and if you install the pistons with the notches to the rear you will be increasing piston slap. Also, regarding them being cast, they should be fitted with a relatively tight clearance, maybe with a high limit of .002.
Thanks all! Sure looks very close! Does anyone have measurements of the Egge pistons? These domes approx 0.21 high and 2 3/4" across at the widest point behind the valve reliefs. Wish there were a easy way to cc domes... Skickat från min iPhone med H.A.M.B.
Your totally correct Fordors, I need to figure out the dome cc so I can check if they're useable for me. It'll be one step above a mild 283, looking for around 10.5 in compression, cam will probably have duration around 220 @ 0.50. Have both Power-Paks and 1.94" double humps, will see which ones will work best. It'll probably end up in my '53 Chevy, looking for that early sixties, nose in the weeds, high school feeling with scavengers and the sound of a fairly wild 283... Skickat från min iPhone med H.A.M.B.
If you want to CC the dome you might put a piston in the bore, no rings necessary, and wipe grease around the circumference to seal it. You mention a dome height of .210 so have the piston .250 down in the bore. CC it and then compute the volume of a cylinder 3.935 X .250 and convert to CC's, subtract the CC value you measured in the bore and you will have arrived at the dome volume, but that will not account for the valve notches which will be relatively minor, maybe 3-4 CC's. You might consider machining a bit off the domes to arrive at a proper compression ratio. You do not want to use the small chamber Power-Pack heads.
Fordors knows of what he speaks! Also, double check before machining dome (any way you can) for thickness.
Thanks guys! Sounds like a good method Fordors, haven't bored the block yet as I'm not 100% yet that I'll use these pistons but I'll do something similar. I guess the better flowing and slightly larger double hump heads is a more logical choice... Skickat från min iPhone med H.A.M.B.
I use a wrap around ring compressor with some tape around the ring land area and the top of the dome flush with the edge of the compressor. Figure the volume of the cylinder to the flat of the piston and subtract the volume of the liquid you added to fill the compressor to the top. If your careful this should get you within 1 cc of dome volume.
And, they are cast pistons that probably have steel plates helping to support the pin bosses. Most of these 265/283 pistons had a right bank and left bank set. There's still a NOS set of similar "301/.0125" pistons on that auction site we all know and love. Price is a little steep at $320.00 plus shipping. I am Butch/56sedandelivery.
Finally got around and measured them! (Yea, my engine build isn't exactly prioritized...) They're +12cc which makes em 11:1 with 64cc heads. Skickat från min iPhone med H.A.M.B.
You can control CR with gasket thickness. Cometic makes many different ones. You can also message the top corners smooth to eliminate hot spot; this will also lower the CR slightly.
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