Technical > Matt Shaff's Engine Shop
LSM Engineering
cad500justin:
I called Schneider and a local cam guy here in the Bay Area and they both said it’s fine to run on roller bearings. There isn’t a special heattreat as long as it’s the right blank. Logically I would’ve called LSM, but steve is a dick and doesn’t return calls or emails.
Alan, this is an 8620 billet cam (according to redline racing cams), I bought this blank still in the rounds from a guy that does tractor pulling with a big caddy. He had LSM make a handful of these blanks all at once to save money, especially since it has a special nose on it to drive a Hilborn pump.
I chose to run roller bearings because Cadillac engines oil their cam bearings very poorly (my old 90lb seat pressure single valve springs on a .600 lift cam had problems wiping them out) and to make matters worse the block I had already had a scarred up cam tunnel from a zealous guy removing the old cam bearings. This motor will have springs that are 800lbs on the nose and will get a dry sump oil system just for overkill. Shooting for easy 7.60’s on alky NA. And into the 6’s on nitro down the road a little.
denverflatheader:
8620, alloyed steel, very good! It’s a high performance camshaft with the more expensive time consuming heat treatment termed carburizing providing more reliability. My guess for all out drag racing “fuel” engine, fuel delivery issues number one engine killer. Number two oil delivery issues. Both of these cause engine parts failure. Valuable you’re aware and taking steps to address your engine’s specific oil deficiency.
Switching to dry sump with adjustable pump speed (as opposed to wet sump fixed oil pump speed) is expensive and best assurance to make your Cadillac engine survive, along with any block modifications to improve oil passages with the boosted pressure/flow. Roller cam bearings extra insurance with higher spring pressures, oiling concerns or sustained high rpms. Anyone who selects a vintage engine to build and run has my respect.
cad500justin:
Update, he begrudgingly answers emails when you tell him that you’re disputing his credit card charges. Funny how that works.
He said that he did not make a mistake on the price, and after a long detailed email in which I mentioned that if he had returned even one of my 10 phone calls or emails we wouldn’t be doing this dance and I asked again if the cam was setup for rollers, I got.
“This is not worth the time to fight over. We will credit you 800.00”
I personally wouldn’t let him grind a cam for my lawnmower at this point. Once I get my pistons I’ll degree every lobe ad make sure it’s skippy.
denverflatheader:
From reading your update, guessing you still have concern on the camshaft journal's hardness. As I wrote earlier, the camshaft lobes must meet the 48Rc-58Rc Hardness (Rockwell specs). For the cam journals using roller cam bearings, not aware what numbers the industry standard requires. You would need to contact one of the larger camshaft companies for answer.
If you have interest, there’s a simple way for you to check the camshaft journals Rockwell hardness yourself within a 5 unit range. Available are Professional Pick File Sets to check for Rockwell Hardness between 40Rc and 65Rc. Starting with the 65 pick file, you would pick and try to scratch the cam journal surface. If scratch mark appears, the pick file is harder and the material is softer than 65Rc. Move to the next 60 pick file and repeat, if no scratch mark, the pick file is softer and the Hardness is between 60Rc and 65Rc. You now have an estimate of the Rockwell “c” Hardness within 5 units.
If there is a local machine shop close to you, they probably have a set of these Rockwell Hardness Professional Pick Files; plus if they’re racing friends, just share your camshaft story and check away. A set of these files typically cost $150-$250 based on quality.
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