Mc5/Mc49 crank

ted johnson · Post by **ted johnson** » Wed Jan 19, 2011 11:11 am

Who can tell me the difference between the Mc5 and the Mc49 crankshafts? Thanks! Ted

david a luciani · Post by **david a luciani** » Wed Jan 19, 2011 12:22 pm

i'd like to know myself since they seem to be the same to me.
i know all the saw cranks went over to ball bearings shortly after the mc5 was replaced.
maybe mcculloch had a big backstock of them and promoted the mc49 class as a way to sell off the overage?
dave

ted johnson · Post by **ted johnson** » Wed Jan 19, 2011 1:14 pm

Here on the site, the IPL sheets for the Mc49C are missing the key sheet that actually shows the P/N. I assume that the Mc49M/C has a straight crank like some of its larger cousins, so that P/N wouldn't be the same as for the Mc49C.

david a luciani · Post by **david a luciani** » Wed Jan 19, 2011 4:33 pm

hi Ted,
i think you're right as i have a 3/4 shaft mcculloch crank that i can't identify.
never bothered to check it's stroke maybe when i get a spare minute.ha ha ha ha ha.

dave

Terry Bentley · Post by **Terry Bentley** » Thu Jan 20, 2011 12:17 pm

The Mc 5 crank has longer keyways cut like all of the early motors thru Mc 7 or Mc 8. The Mc 49 should have shorter key like 90 series. The Mc49MC replacement crank has ball bearings on both sides. The 1-60 series of chainsaws is correct for Mc5 and directy interchangable for 49c/e.

ted johnson · Post by **ted johnson** » Thu Jan 20, 2011 1:39 pm

Thanks, Terry. The longer keyways shouldn't matter. I actually have an Mc6 here that belongs to a buddy of mine. It has a 1-3/8" crank in it for some reason. I may try to buy it from him if it looks good when I get the engine apart. TJ

Scott Kneisel · Post by **Scott Kneisel** » Thu Jan 20, 2011 7:17 pm

I have an original Mc5 crank Mac # 50756. It has very narrow counter weights and the larger key slot.

I have had both the 49 M/C crank with the 3/4" PTO shaft #89139 and a 49C crank in the past and from what I recall is that they both had larger counterweights than the Mc5 and the taper pto did have the smaller key slot.

I think the 49C used the same crank that was used in the Mac 640 chainsaw but I have no documentation saying so. That crank was P/N 50756A which is a revision level higher from the Mc5 crank.

The 49E crank is P/N 90891 which has a LH pto thread and no key slot. That is the crank to get!! If you can find one...these "Mc49 class racers" are gulping all of them up!!

All were 1.375" stroke.

I predict that the Mc49 may be the most desired engine this year and probably the most expensive.

Personally I think we should start and Mc5 & 6 class....What do you think about that?

I'm out,
Scott

david a luciani · Post by **david a luciani** » Thu Jan 20, 2011 7:31 pm

yay, let's do an open mc 5 and 6 class.
that would be a blast and might have some interesting motors being built!!
dave

Paul Booth · Post by **Paul Booth** » Thu Jan 20, 2011 11:13 pm

Come to the Land of Lincoln Vintage Event at Springfield Il on May 27 and 28,2011 and run the Mac 49 class. This will be our 3 RD YEAR running the mac 49 er by themselves. Very good class and they have a ball. Consider adding it to your event. Come join us for a fun filled Memorial Day Weekend Event
Paul Booth Land of Lincoln promoter

ted johnson · Post by **ted johnson** » Fri Jan 21, 2011 9:14 am

Good info on those cranks, thanks, guys. I'm down for the Mc5/6 class. Just remember, a thin ring Mc6 will eat a thick ring Mc5 for lunch! The displacement difference seems to mean less than the compression ratio, carb and thin ring difference. We had an Mc5 back then with a thin ring piston and a compression boost and an HL93 carb that won lots of junior class races against all comers.

Mc5/Mc49 crank

Mc5/Mc49 crank

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Re: Mc5/Mc49 crank