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Smilin Dave's Dream Build.
#1
From time to time smiling Dave says he's going to put a stroker crank in his mighty muscle Mc10 and blow everyone right off the track.   I recently discovered something that would make Dave's MM Mc10 look like a girlie man's toy.

Last summer I bought a ratty Mc30 parts motor because it had a decent Max Torque clutch on it.   It had no manifold so it was easy to see that the upper intake ports had been butchered beyond hope.  I finally pulled the clutch off recently and was going to sell the motor on ebay for practically nothing.  However, I noticed that the head gasket was pretty thick so I decided to take the motor apart before I put it up for sale.  I pulled the head, turned the motor over and the top of the piston popped out of the cylinder by about 30 thousandths.  The piston ran down the cylinder 1.8 inches!  Someone (once upon a time) had put a +50 piston and a MC70 crank in the engine.

At room temperature the crank was too big to remove through the unmodified side cover hole.  At a really high temp I was able to persuade the crank to exit the block with some assistance from a tire thumper like the truck drivers use.  I suspect that installing the crank would go easier because the block would have expanded and the room temperature crank would be a bit smaller than my superheated one I pulled out.  It's pretty likely this stunt would work in MC 40's & 45's too.

To avoid the temptation to make a budget busting pilgrimage to Wiseco the next time I'm in Ohio, I sold the piston on ebay.  The difference in pin location between a stroker piston and a regular 6.1 piston is quite remarkable.  I hate to think how much a few custom pistons like that would cost.  

When ebay settles down from PTSD from two major hurricanes and firestorms without end, I will sell the crank.  It wasn't going to and won't go in the MC40 I was planning to put together for Bushnell for sportsman before I found out that now any 6.1 mac goes.  At 230 pounds I don't think there's much I can do to a single carb mac to stay within sight of the skinny guys anyway.

I had no idea that 1.835 cranks had worked their way into the super series 6.1 because I started karting just before the Mc90 marked the end of the super 6.1's.  If you see smiling Dave scarfing up Mac 30s, 40s, and 45s you will know he has abandoned the MM Mc10 for a supersized super mac.

Smokey
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#2
I enjoy reading about how people spent the time to make something work that gave them and edge as long as it was not illegal.  And since I don't know what the rules were back in the day I am guessing this was "pushing the envelope" an expression that you don't hear anymore. 

Ingenuity and innovation is what is missing, lacking, void, no more gear heads, people that like to experiment with the unknown.  I haven't found the word I want but the young people today, if they cannot buy it off the shelf they don't want to mess with it.  They think that the 10 of a second happens because they want it so bad it will just happen because they are a good guy.   

They don't want to put in the time and experiment doing different things at the track because they got "better things to do".  The cause and effect thinking is just not there.  When I tell people after they spin out on the track and go in reverse, that they should toss the chain when they come in because now they have a link that has been stretched and it will beat the clutch sprocket to death because it will no longer seat in the valley any more.  And it will ruin the axle sprocket but the clutch sprocket will go first because it is making almost 6 times as many rotation as the axle.    Yes, it is a pain in the ass to change the chain but it is cheaper than buying two new sprockets.
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#3
daves motor already has stroker crank and is like .070 over ..lol.. sept I herd he blew it up ..??
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#4
Fun and interesting thread.......
Jim Waltz, West Sacramento, CA
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#5
There is no way a stock Mc70 crank can fit through the side plate hole of a 30 block without modification of the opening. I have seen people machine material off the cranks to get them to fit so look close at the crank before you offer it for sale as a buyer would not be happy if they buy a crank and discover that part of the counterweights have been trimmed off. Another comment, you can't install a 70 crank without also installing a rod from a 70 or one of the other large displacement engines. If you use a Mc 30 rod with an unmodified 70 crank the wrist pin bosses will hit the counterweights. If the rod is a Mc 30 or any of the 6.1 ci model rods and the piston clears the crank then that is more evidence the counterweights have been machined off on the outside edge.
Steve O'Hara
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#6
I'm sure smiling Dave will appreciate this information as soon as he figures out how to put a MC10 sideplate on a MC30 to make it look like the MM mc10.

Blaine
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#7
I'm afraid Dave's dream may be shattered.  Readers of the "old" forum must be reading these threads.  There are two Mc40s offered on the other forum for a mere $495.00 each.  Sorry Dave.

Smokey
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#8
BROTHER.
BUILD A FAST ENGINE AND EVERYONE GOES TO SAYING I'VE BEEN CHEATIN.
truth be told i only ported the motor.
i had been wanting a mc10 to port and i traded three sets of original mcculloch engine bolts for what i was told was an un runnable mc10.
i figured the parts i'd get were worth the trade.
long story short the block and everything else was fine except for a huge bore.
i figured the block was on it's last hurrah so i followed jim butlers direction for porting a block.

came out nice and then sat about two years before scott k. talked me into letting him build it.
something about me being slow on projects and finishing was discussed i think.
he built it as bullet proof as his usual motor and painted it all nice.
i was annoyed about the paint as i wanted it to look ratty.
it was supposed to get a stroker crank but scott had never done one scratch build back then so it got a stock 1.5 which stayed in it ever since.

it sounded great but i had a carb issue first try the high wasn't working.
even so was pretty fast.
well it turned out the carb issue was the main problem i'd have with that motor.
  when i finally resolved backwards installs, mis built parts, clogged passages and worn out diaphrams it went pretty good.
so good that i had to wait for the other guys to catch up occasionally.

anyway i stuck the piston and haven't found a new one yet.
for some reason the longer it's sidelined the bigger the legend of stroker kranks and cheater stuffs gets.
it's always been a legal motor built as per specs laid out over fifty years ago.
it'll sure be embarassing to the guys yelling cheater motor if i stick it back together again.
i might just have to pass a few guys again then easily pass any tech you'd like to use.

as for a cheater mc40 not a huge issue to add the bigger crank i think. you'd have to cut a relief in the hole the crank passes through so it would fit. maybe a little relief grind inside the block to allow the counter wts to pass or shave the counter wt and deal with a shaky motor.
a mc10 block i bought from steve miller had a mc93 crank jammed into it.
took me hours of fiddling before i found the angle to get it out without hurting the block.
that one got rebuild and chris m. ended up with it last i heard.

anyway theres lots of radical interchange and mods these motors can have but why bother if it only makes a ten second motor?
if a motors been cut i'll build a modified but if it's original porting i prefer to leave them stock just mho.
aa already cut mc30,40,45 can easily be made alot faster with a nice nine port job maybe raise the exhaust a smudge and open it up.
no need to add additional stroke from a mc101 or mc70-75-90
do that porting right and most mc91's would have trouble staying with it.
Cool
Dave L.
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#9
Well put Dave, but remember what one of the purported moonshiners on TV always says.  "It ain't illegal if you don't get caught".   Actually it's just fun to tease you once in a while about your mighty muscle MC10.

Smokey
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#10
you never know teasing me might get me off my lazy butt long enough to put it back on the track somehow.
Big Grin
Dave L.
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