Quote:
Originally Posted by mgarblik
My advice trying to run this combination is to pay very close attention to the oiling circuit. I haven't worked with the MR1 specifically, but have built many IA 2's and stock blocks. With the 3.25" main housing bore, there is less block and more hole, if you get what I am saying. That's why everyone prefers the 3" main for high power applications and and a 2.750 would be even better with a good enough crankshaft. Fortunately, you have a Scat crankshaft which has decent main oiling holes and pretty good chamfers. I don't think an Eagle would survive over 6200-6300 RPM with their awful "divot eyebrow" type of main oiling. You didn't state what HP you intend to produce with this engine, so I have to guess. If you intend to make in the 1200 HP range, a Pontiac based oiling system with an accumulator should be OK. IMO you need .0035 main clearance and perfect housing bores to keep it alive. The primary issue with a 3.25" main bearing is bearing speed and heat. You need the extra clearance to keep flushing oil through the mains and remove heat. I think you need to plan to keep your RPM's around 7000-7200. If your planning to make big horsepower, north of 1500 HP, your going to need to upgrade the oiling system with a pump capable of at least double the flow rate of a Pontiac pump. At a very minimum, a Titan pump if your going to stay wet sump or a dry sump system. Good luck with the build.
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I must irritate that this is intended to be a drag week / power tour car, so reliability on the street is more important than max effort. I plan to make it as reliable as possible and increase power accordingly. So I dont have a magic number that I must hit... it will make what it makes within the limitations of reliability. Cooling systems will be abundant. I will have oil coolers and trans coolers with thermostatic by-bass valves w/ dedicated thermostatic controlled fans and a large triple pass radiator. The goal is to have a cooling system thats able to maintain a set temp no matter what the engine or transmission are doing. Although these systems will add significant weight, its all part of the plan to maintain predictable running temps.
The plan is to run up to 15-20lbs boost on E85. So where ever that takes it will determine the power output. The 72cc E-heads flow over 320cfms and have been ceramic coated combustion chambers and exhaust ports. I am guessing that I will be running 800-900HP pump gas (6-8lbs) and between 1,000-1,200HP on E85 (15-20lbs). At that point I will only run what I can stick to the ground.
Will be running a Luhn Performance Oil pump and pick up. .035 seems like an awful lot for daily driving on the street. I was initially intending to run .025 on both rods and mains. The plan is to target 6500RPMs however I know it could easily take more RPM. This makes for a good topic though... I like the idea of more oil for increased cooling, just not sure if that much clearance is good for a daily driver capable of cruising hundreds of miles a day.
The original plan was to use a factory cast iron 455 block... If I hadn't already had the completed balanced 3.25" rotating assembly I would have gone with a 3" main block... However I do feel that I am definitely better off with the MR1 block over the 455 block.
Thanks for the input....
SPEED SAFE, NICK