Hemibear426 Posted February 12, 2021 Report Posted February 12, 2021 Our new pistons have paint marks (dots) on the underside of the pin area on one side. Any idea what this mark signifies? Quote
kencombs Posted February 12, 2021 Report Posted February 12, 2021 I've seen a few new sets that used a paint mark to indicate oversize. I guess it's easier to see when packaging than the stamp on the top. Quote
Hemibear426 Posted February 12, 2021 Author Report Posted February 12, 2021 Can a piston be put on the rod the wrong way? Quote
Hemibear426 Posted February 12, 2021 Author Report Posted February 12, 2021 Photo of piston paint marks. Orientation? Quote
JBNeal Posted February 12, 2021 Report Posted February 12, 2021 Paint marks like that remind me of quality control acceptance marks for shipping. Piston orientation and std/oversize# are typically stamped into the piston top to survive the combustion during service life, for future service reference, especially for a visual check when the head is removed. 2 Quote
Sniper Posted February 12, 2021 Report Posted February 12, 2021 I don't think those paint marks have anything to do with piston orientation either. Not sure we even need to worry about that. The industrial manual doesn't even say anything about it. Only one I have handy right now. Quote
Hemibear426 Posted February 12, 2021 Author Report Posted February 12, 2021 I'm beginning to agree that these are not orientation marks, but then I found the following: From Ed Packer's book "Manual for Plymouth Owners", 1950, "When putting the piston back on the rods, the slotted side of the piston must be opposite to the metering hole in the big end of the connecting rod. When placing the rods in the engine, the metering hole must face toward the camshaft side of the engine." I have seen the slots in original pistons he is talking about. These new pistons do not have the slots so I believe I am pretty much worried about nothing. Thanks so much for all the responses, Mike Beyer 2 Quote
Sniper Posted February 12, 2021 Report Posted February 12, 2021 If I was going with new pistons, and I likely am, I'd get with The Freewheel Tony Smith and have him set me up with a set of modern design pistons and rings. Probably a 10hp gain just from less friction, lol. Not to mention less strain on the rods due to lighter weight. Actually, if I could swing it I'd ship the 230 to him and tell him to build it. The man is a craftsman. 1 Quote
Hemibear426 Posted February 12, 2021 Author Report Posted February 12, 2021 Great recommendation. Where is he located? Any contact information would be greatly appreciated. Mike Quote
Sniper Posted February 12, 2021 Report Posted February 12, 2021 He doesn't do engines anymore, unfortunately. Long story, but basically the facilities he had access to is no longer available to him. He's on Facebook as The Freewheeling Tony Smith though. Quote
Adam H P15 D30 Posted February 12, 2021 Report Posted February 12, 2021 2 hours ago, Sniper said: If I was going with new pistons, and I likely am, I'd get with The Freewheel Tony Smith and have him set me up with a set of modern design pistons and rings. Probably a 10hp gain just from less friction, lol. Not to mention less strain on the rods due to lighter weight. Actually, if I could swing it I'd ship the 230 to him and tell him to build it. The man is a craftsman. Might as well use a set of 218 rods and 0 deck the pistons... Quote
Dartgame Posted February 12, 2021 Report Posted February 12, 2021 I'd contact the piston manufacturer and ask them what the paint marks are there for - just in case - but it probably makes no difference. 1 Quote
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