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Identifying forged internals from the oil drain hole
I'm just now starting to look at a project car I picked up last month and am trying to identify the internals of the engine. The car has been sitting for two years so I am draining all the fluids and prepping to fire it up. The oil was dark but clean when I drained it. While I have the oil out, I was going to stick my cheap inspection camera up the drain plug hole and verify the previous owners claim of forged internals. So far I haven't got a good angle yet on the counterweight parting line to see if its got the crisp mold line of a cast crank. The head of the camera is big and I can't turn it much inside the pan but I haven't given up yet. Are there any other markings that might give it away if the crank is forged from this viewpoint? How about identifying the rods and pistons if they are forged or not? I've attached a few lousy pics of the underside of the pistons. I will be pulling the plugs shortly and taking a look from there as well.
The crank can be verified by the shape of the notch on the rear flange. The likelihood of a forged 455 crank are slim as they are fairly rare. 330 cranks are the only small block forged cranks
From what I know all Olds connecting rods are forged. Dunno what that buys you performance wise, though.
Factory cast and some aftermarket cast pistons have a part number on the bottom side whereas many aftermarket forged pistons have the number engraved/stamped on the top.
I’ll go with L2323 Speed Pros on the pistons. Skirts look too thin to be cast.
I dont know, they just don't "look" like forged pistons. Here is the skirt on an original GM piston out of a 69 Olds 400, pretty thin. Only way to tell for sure is look at the top and see if there is a part number on it.
Thanks for the initial thoughts all. I'll try and pull the plugs tonight for the piston tops and hopefully get a shot of the crank as well. The rods definitely look cast to me. I'm expecting to find all cast though the previous owner claimed forged, but I'll be pleasantly surprised to find otherwise!
Here are some pics of the top side of the pistons. If there are any markings, they are covered by carbon deposits. Bernard, do you have any insight as to what is the tipoff that these are cast pistons? It would be great to know the different ways to tell between cast and forged. For the crankshaft, this definitely looks cast to me. Note the crisp casting line and the raised, cast lettering in the pics. I assume that if this was forged, any markings would be stamped. Out of curiosity, do the numbers on the side of the rods indicate their origin? Are these factory stock markings? I'd like to gain some knowledge while I have the opportunity. Thanks everyone for your info, hopefully this will help others in the future if they are looking to identify these things as well.
[QUOTE=Natedawg;1144878] do you have any insight as to what is the tipoff that these are cast pistons? It would be great to know the different ways to tell between cast and forged./QUOTE]
Nate,
Its really kind of hard to describe the difference but once you have seen them side by side it is not hard to figure it out. Cast pistons typically have a much rougher surface on the areas that are not machined. Cast pistons will sometimes also have a steel insert in the inside, that is a dead giveaway. I will try to find a couple of forged and cast pistons ad take a picture side by side.
December 26th, 2018, 01:31 PM
