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Old 02-03-2010, 12:34 AM
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Default v8 2 stroke build

hi all im planing to build a v8 2 stroke engine from scrach lol . i might sound crazy cus who would build a v8 2 stroke engine completey from scrach . well i would lol. im most likey goin to run cbr600 pistons and make my own con rods and fit berings too. in order to do this i need to make my own crank shaft. so if i use the cbr pistons and if i make it the same stroke as a cbr600 ill end up with a 1200cc 2 stroke v8. this thing will scream and be a rocket on the right applaction. lets see how i go.

thanks. Dan
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Old 02-03-2010, 12:36 AM
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your biggest expense is the block
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Old 02-03-2010, 12:40 AM
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Quote:
Originally Posted by BriggsTwins View Post
your biggest expense is the block
im goin to ither make one at tafe on the mills or i will fab one up and machine sleves to go in it with the transfor ports in the sleves
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Old 02-03-2010, 02:26 AM
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change of plans i cant find my cbr600 pistons so i was thinking of buying pocket bike components such as: pistons, rings, conrod, cylinder, maybe cranks and mod then to accept 2 con rods per jernal and joining them all together. then all i need to do is make a bottom end and sort out ignition. i think a 400cc 2 stroke v8 would be kool to say you built it lol.
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Old 02-03-2010, 03:23 AM
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The old 318 "Screamin' Detroit" diesel engines were 2 stroke V8s.
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Old 02-03-2010, 07:00 AM
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Smokey Unik experimented with building full size 2-stroke/V8 race engines back in the 60's.
He said: Twice the power at half the weight.
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Old 02-03-2010, 09:23 AM
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so you are gonna make 4 2stroke harleys hunh? i definitely want to see it. are the cylinders going to be removable? i had two cox free flight engines, i thought of making a v-twin from. never did it. anyway, pistons sre around 20, i don't see the cranks available on partsforscooters.com. you should be able to find donors in the scrap yards. i paid 35 for one with no body. engine was good though
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Old 02-03-2010, 01:35 PM
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I'd say grab some L/C sled engines, use the jugs, pistons, heads, carbs etc and machine your own bottom end and crank.

I hope you know your way around a machine shop, because making an 8 journal crank/crank case for a two stroke is going to be a job and a half.
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Old 02-03-2010, 01:45 PM
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wouldn't it be a 9 main journal? if it fails spectacularly, thats some heft that will be flying. there are some guys in germany making v12 and radials that are r/c airplane sized. they seem to work great.

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Old 02-03-2010, 01:50 PM
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i hope you know cnc.... that's a ton of milling

and if you have two pistons per crank case doesn't that mess up the fuel and air delivery?

you will be making your own crank... that's that
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Old 02-03-2010, 01:52 PM
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Yea i would think with a two stroke, two rods per journal would mess up fuel air...but i dont know. I've always seen multi-cylinder two strokes with sealed crank cases for each cylinder.

Mike, why would you have 9 journals in a 8 cylinder engine? that makes no sense.
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Old 02-03-2010, 01:55 PM
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sealing each piston to itself...
a true v8 i don't think is possible
more like two banks of in-lines or a compact in line

you would be better off making something like a v4 at first
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Old 02-03-2010, 01:59 PM
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the crank has to be supported on each end. if running 8 slots for pistons, you need 9 journals (for the crank to rotate). since he was saying run 2 per, that would be 5.
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Old 02-03-2010, 03:18 PM
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hmmm, look at it this way, if you make the block and cylinders as four strokes then all you have left to for is make the heads which is more simple than fighting with crankcase pressures and fuel delivery... using jugs off of a bike, all you have to do is machine the fins away from one side to join them together, and get a NICE cooling system for it

timing and camshafts would be greatly simplified but you still run the issue of making a system to feed oil, Intake manifold and having a decent set of bearings...
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Old 02-03-2010, 03:27 PM
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cam shafts??? what cams?

are you talking about a two stroke with valves? that would be plausible, but the head work would still be hard

probably more hard than case work

and the valves would be opening twice as many times as the four strokes so he would get valve float sooner, right?

then again he could have a two stroke like the Detroit so that the only valves are for the intake
(possibly supercharged two stroke)
(but then he would have to go with dry sump)
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Old 02-03-2010, 04:21 PM
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Quote:
Originally Posted by TurtleMann14 View Post
cam shafts???
then again he could have a two stroke like the Detroit so that the only valves are for the intake
(possibly supercharged two stroke)
(but then he would have to go with dry sump)
the valves are for the exhaust the air goes in through the cylinder wall and then the fuel is just injected in to there... just sayin.
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Old 02-03-2010, 04:30 PM
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:/ guess i had that a little backwards

you sure? idk it would just make more scence to me if the exhaust went out the ports on the cylinder

i can't find anything on it
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Old 02-03-2010, 04:32 PM
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nope why u think the detroits NEED a super charger to run.

http://static.howstuffworks.com/gif/...two-stroke.gif
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Old 02-03-2010, 04:34 PM
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alright you win, but here is another thought

what if you did revers it? would it run better?
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Old 02-03-2010, 04:37 PM
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probaly not the piston goes up pushes gases out while theres air on the botom then it keeps goin up valves close injector goes and bam...
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