Quote:
Originally Posted by sdbob
Interesting about Federal Mogul didnt know that. I have 16 rubber rods I spent rainy Saturdays taking out of early 60s Pontiac engines in the late 60s. I had a 65 421 I rebuilt about 1970. Resized the rods, cast pistons,valve job. Ran that engine approximately 6 yrs. Took it to 5800 many times. When I pulled it apart to use the block. I noticed for the first time, the engine had 7 of the wide flange rods and 1 cast rod.The engine when I bought it out of a wrecked 2+2 seemed original, it had about 60 k when I bought
it. I still have those rods and pistons in a box
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it's all in the heat treat. requires the skills or tutelage of an educated metallurgist. they cut the parts up, polish them, look at the grain structure under a microscope. then adjust/modify the heat treat process to get the grain structure needed for the strength required. so you take a little piece of the cut up rod, heat treat it in a small oven the size of a microwave, and then hardness test, polish/grain size cert it WITH PICTURES of the grain size. the camera is built into the microscope. until it's right. then you stick to that formula for the big run of parts, where the oven is loaded with a fork lift, with a big overhead garage door, and the quench tank is as big as a swimming pool. it's a whole different ball game. I did it for years in jet aircraft engine production of parts. the cutting, polishing, heat treat, loading/unloading the big oven, in the lab and out in the shop.
those rods you used were simply forged and not heat treated to save cost. on the early short stroke Pontiac engines 1955-58 they'd survive. they were marginal for a 389 w/3.75" stroke. they were too weak for a 421 with 4" stroke. that's why the SD421 went to it's own heat treated forged rod and won Daytona with it a few times. the 421 HO rod was a cheaper non-heat treated part to save money on street cars and blew up in their face. then they came out with cast rods across the board that were strong enough under 6000 rpm for the strokes used...but barely for the 428/455.
the reason Pontiac went to a cast rod, is they could made a stronger cast part in huge quantities, that was much cheaper to make than a non-heat treated forged part, and much cheaper than a heat treated forged part.
it was common approach back in the 1970's if you built an engine using factory GM, Ford, Mopar, AMC rods, to hardness test the rod top/bottom/center, and discard any rods that tested soft, and use the 8 best ones out of what you had or could get. we should all still be doing it NOW, no matter what forged rods are used.
the problem is, if you're buying CHINESE rods, you're trusting THEM on another continent, to do all the above competently, in your best interests. good luck there. that is a risky proposition. Chinese basically hate Americans and are an inch away from going to war with us in the South China Sea right now. are they checking every single rod for correct hardness on a Rockwell tester ? lol !!
#2, Pontiacs are all about the nostalgia now, let's face it technology has advanced, there's new engines out now make Pontiac V8 seem like a Model T. If we're always pushing the latest greatest, watch what you as for, cuz the then the electric car makes the gasoline V8 totally obsolete, and you have no Pontiacs at all.
if the HOBBY becomes drag meets and car shows with rows of cars with Speedmaster Chinese engines carb to oil pan, and Chinese sheetmetal, then it's all over but for the cryin'.... it becomes the silver dime, quarter, half dollar, dollar that no longer had any silver in it after 1964- totally irrelevant.
I'd put more confidence in what I can make and get done here myself, than what someone in China can make for me. The dollar store approach to engine building is not my cup of tea.