I have a question which I can't find any resourcing to help me out. I have an old set of TRW L2352 pistons to use in my 406 build. All 8 pistons are marked "front" pointing to the right if you look straight down on them. These piston do not have a centered pin. They are offset. Does anybody know how to install them into the bore? If I follow the "Arrow" and based on the pin offset the passenger side of the motor would have the arrows facing to the front of the engine and the drivers side would be facing to the rear. I'm really confused about this. Speed pro offered me no assistance as they said they were made by TRW. Anybody have experience with this piston? Thanks for your help. This 406 will be going into a mini ram 1987 Vette conv.
400 SBC pistons all (8) marked the same direction with arrow? How to install?
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The arrow always faces to the front of the block. The trick is the rods. Each rod on its big end has a noticeable chamfer, one side is larger than the other. The bigger chamfer always faces into the crank pin end radius where it blends into cheek. Another is the big chamfer points out of the pin never at the other rod.
Since number one cylinder is the leading side with the piston arrow always facing to the front then all the odd number cylinders 1, 3, 5, 7 orient the piston arrow forward and the big end‘s biggest chamfer also faces forward. The even number cylinders trail in order of the odd number cylinders so 2, 4, 6, 8 have the piston arrow facing forward with the rods big end biggest chamfer side facing to the rear of the engine. Get this wrong and the rod bearing will seize on the chamfer of crank pin journal. A sure fire sign of this is if you cannot turn the crank assembly in the block after installation of the pistons and rods to the crank.
The down side of press fit pins is get this backwards and disassembly of rod and piston usually ruins the piston.
Check your set up, then check it again and when your sure it’s right check it again before joining pistons to rods.
Bogie
Since number one cylinder is the leading side with the piston arrow always facing to the front then all the odd number cylinders 1, 3, 5, 7 orient the piston arrow forward and the big end‘s biggest chamfer also faces forward. The even number cylinders trail in order of the odd number cylinders so 2, 4, 6, 8 have the piston arrow facing forward with the rods big end biggest chamfer side facing to the rear of the engine. Get this wrong and the rod bearing will seize on the chamfer of crank pin journal. A sure fire sign of this is if you cannot turn the crank assembly in the block after installation of the pistons and rods to the crank.
The down side of press fit pins is get this backwards and disassembly of rod and piston usually ruins the piston.
Check your set up, then check it again and when your sure it’s right check it again before joining pistons to rods.
Bogie
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15,340 Posts
One needs to note that I’m talking Chevy SBC, other engines have different configurations that need to be figured out. The basics are the same but the actual cylinders will differ SBF numbers right side 1, 2, 3, 4 so here the big end largest chamfer faces forward, cylinders on the left side of 5, 6, 7, 8 the large chamfer faces to the rear.
So it’s important to know the beast you’re working on as the cylinder order of who is number one that is usually the front most cylinder of most forward bank. And of course how the cylinders are numbered bank to bank.
SBC Gen I and II
SBF ‘Windsor’
So this needs to be thought through as it isn’t one way satisfies all engines.
Bogie
So it’s important to know the beast you’re working on as the cylinder order of who is number one that is usually the front most cylinder of most forward bank. And of course how the cylinders are numbered bank to bank.
SBC Gen I and II
SBF ‘Windsor’
So this needs to be thought through as it isn’t one way satisfies all engines.
Bogie
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6,017 Posts
To add to this, the engine only turns one way. The piston doesn't know or care if it's in the RH or LH bank, it only knows that the crank rotation loads the same side of the piston. The pin offset is related to engine rotation direction, NOT which side of the block it's in. This is why the arrows all point the same way, the are SUPPOSED to.
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