Box Stock

What cam is this?

95 shaw said:
Or, the cam gear was twisted with timing set 1 tooth off on purpose.
Such things are done on claimer type engines. A degree wheel will tell the stpry.
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Possibly, It did run great with the original cam one tooth off. I took that cam out and installed a 310 lift cam, that cam with the new Mikuni carb got me 2nd place in modified this weekend. Towards the end of the race the engine would start surging, it would hit around 6500 rpm and kinda fall on its face then it would shoot up to 8300.
 
Update: I got in touch with the guy that put the engine together. He said he had the timing off one tooth so the motor would run cooler. ?‍♂️
 
I asked him about the cam and he said it was supposed to be a .308. I bought it off Facebook so I really wasn’t expecting him to do much about the cam. I picked up a used .310 lift cam this weekend from the kart shop for 40 bucks.
 
Yep lol that’s what he said. I am starting to question everything about this motor. What is also questionable is the fact it is a predator block with a clone crank and .020 longer arc rod. He said this combo makes a stroker motor. From my research this combo would destroke the engine.
 
The dot on the crank is very close to correct position 5 teeth from center of keyway, that would put the valve events at 15* retarded. No matter what the builder said as you can discredit that as soon as he said he did it so the engine ran cooler. I would strongly suggest it was jostled on disassembly and pushed back in place out of time. I don't have the time or effort to draw out a valve timing chart 15* retarded but think about where that puts the overlap period in regard to TDC and that wasted spark on the exhaust stroke.
 
karting62 said:
Yep lol that’s what he said. I am starting to question everything about this motor. What is also questionable is the fact it is a predator block with a clone crank and .020 longer arc rod. He said this combo makes a stroker motor. From my research this combo would destroke the engine.
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Correct , hey as long as you didn't pay too much you'll be alright.
 
You should of put a small mark on the crank as a reference to where the crank gear dot was. That way it would rule out gear rotation the next time around . Just as a reference.
 
Good idea ovaltech, I wish I would have done that. I lined everything up dot to dot so I will check it after running for a while to make sure the gear isn’t spinning.
 
I'd like to see what other parts are in this thing to be spinning 8500rpm... me thinks your tach is not reading correctly....
 
I took it apart to see what all is inside, it is predator block, clone crank, ARC .020 longer rod. Flat top piston in the whole .042, .310 cam, 14cc Honda head, 26 lb springs, stock valves, stock pushrods. Mikuni 28mm flat slide carb on alcohol. I was running a 12/64 gear.
 
I just ordered a JRPW level 10 head for it. 32/28mm valves 16cc, 42 lb springs. Chromolly pushrods. With my budget I had to go with champion rockers instead of ratio rockers. I am curious to see how much more power it will make.
 
With a stock cam these engines will run with the cam a tooth off in either direction. One better than the other of course. I couldn't get 7600 rpm out of it but it would turn over 6k
 
poboyracer said:
With a stock cam these engines will run with the cam a tooth off in either direction. One better than the other of course. I couldn't get 7600 rpm out of it but it would turn over 6k
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I ran mine 6400rpm when it had the stock cam in that was set one tooth off. When I put the .310 cam in it I lined it up dot to dot.
 
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