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New to the site and looking for some help figuring out what way the rods go back in. Tangs to the left or tangs to the right?? I took the engine apart about 7 years ago and have finally got it all ready to go back together but did not mark anything Have sorted through mismatched caps and bearing clearances and have the old rods ready for new pistons but need to know how to orient the rod. No oiling holes or dimples to look at just bearing tangs to go buy is all I can tell? Any help is appreciated!
Thanks for the reply - I have read that too since my question. The problem is all the videos I've seen of these 403's coming apart - all the tabs are pointing to the rear of the engine. This does not jive with all large chamfer facing the cheek of the crank. What do they say about hindsight - 20/20. If ever I do this again to another engine - everything with marked upon disassembly. I may just have to buy new rods to be sure.
Tabs on an olds rod should go outboard. That is, while rotating, they come closest to the oil pan rail. So left bank is opposite of right bank.
Like Mark said, the important part is making sure the largest chamfer goes towards the closest edge of the rod journal, and the tangs should offset the bearings *away* from the edge of the rod journal.
I haven't done it in an olds, but usually if you put one or both in backwards there won't be enough side clearance and it might even lock up. But depends on the details of how the crank is ground and the shape of the bearings.
Thanks so much for the input - in my quest to figure out what side is the chamfered side I notice what I believe to "contact" with ? on two of the rods. I've emailed Dick Miller Racing and hes going to recondition and identify rod orientation for me. (Well assuming he's not 6 months backlogged) See pictures below. I also included one that I "mocked-up" (dreaming) the engine in the car. I'm defiantly anxious to get it running but will not short-cut anything.
Last edited by Bill X_R; February 21st, 2023 at 02:34 PM.
Also note that if you're using normal press-fit piston pins then the orientation of the piston also matters. Most pistons have a "forward" indicator - this is to ensure the combustion thrust is on the correct side of the piston. Hopefully the assembler paid enough attention to make sure the rod and piston alignment agrees.
Some pistons don't care which way they go, or they have valve reliefs that force a certain orientation instead of the thrust. Just depends.
Also note that if you're using normal press-fit piston pins then the orientation of the piston also matters. Most pistons have a "forward" indicator - this is to ensure the combustion thrust is on the correct side of the piston. Hopefully the assembler paid enough attention to make sure the rod and piston alignment agrees.
Some pistons don't care which way they go, or they have valve reliefs that force a certain orientation instead of the thrust. Just depends.
Thanks - the pistons I bought have relieves - so that part is clear. I'm going the recondition route - Rick Miller wanted 500 for reworking my rods and hanging the pistons. (Not a bad price but 4-6 weeks and new rods are 600) or I can get some "Federal Mongol?" reconditioned for 300. I'm not going to be running high RPM and the car is out maybe a couple times a year.
February 19th, 2023, 12:28 PM
I took the engine apart about 7 years ago and have finally got it all ready to go back together but did not mark anything 
Have sorted through mismatched caps and bearing clearances and have the old rods ready for new pistons but need to know how to orient the rod. No oiling holes or dimples to look at just bearing tangs to go buy is all I can tell? Any help is appreciated!
