rearenginekarts.com

I need a Mac 1.375 stroke crank for an Mc5 or Mc49. Must be in good condition overall with no bad threads or keyways. Mac 5 rod needed too.
Also need early aftermarket 3d port intake manifold. I'd prefer a Hovey 8-reed or an early Van Tech. Not interested in the manifolds that do not feed the third port separately.
Please look thru your stuff! Thanks. Ted Johnson

ted,
all these mcculloch saws will have the correct crank for a mc5:
mccolloch s250 - 300 - early 250 - 1-62 - 1-63 - 640.
i know i have a 640 i just robbed a inner flywheel cover from and the crank looks great.
was gonna put it in my mc5 i have but theres no hurry for me so if you want it p.m. me.
the later con rods fit fine in a mc5 but if you're wanting the correct 55009 con rod i have a couple i'm sure.
have several early manifolds i might sell .
dave

Dave, I was just getting ready to revise my ad when I saw your reply. Scott K. is taking care of the crank issue, but I still need a rod. Are the 91 rods the same length as the Mc5? Pin Dia. the same? (It's been 50+ years since I messed with an Mc5..., so I don't remember) If so, I'll use one of Ron C.'s rods. If the '5 rod is a different length, I'd like to purchase one. I DO plan on using the thick-ring piston, but I don't know if the block R.C. has is standard bore. Write me at my home email: nosnhojkart@yahoo.com, or call me at 505 869-6233 and we can talk about manifolds/rods. I also have several of those Go Power phenolic reed petals you wanted. TJ

Survey time..... the McCulloch IPLs and every Mc 5 I have seen has the spark plug on the exhaust side and there is no opening in the shrouds for a plug and no rubber boot. Today I communicated with a fellow that has a NOS Mc5 and he says it has shrouds like the Mc 6 and later motors. Anyone know the history of the Mc 5 that can shed some light on the two versions? When and why the change?
I have seen some motors referred to as Mc5/6... did McCulloch actually sell a motor identified as such or is that just a description someone made up?
Another question.... do any of you old timers actually remember seeing a Mc45D in person back in the mid 60s or an ad for such a motor? I can't find any reference to such a motor in any magazine race results or ads from the era but I don't have that many magazines from then to study.
Thanks to anyone that can still remember clearly that far back
Steve O'Hara

Hi, Steve. Our first Mc6 had the early plug boot that was yellow, and fit closely around the plug, but it was on the flywheel side. I never saw any REAL Mc5's with a plug boot. The first Mc6's were factory converted Mc5's and the blocks were Mc5 blocks. Mac added the Mc6 marking behind the Mc5 stamp. I can't remember if there was a slash (Mc5/Mc6) or no slash. Also can't remember if it was Mc5/Mc6 or Mc5/6. I only saw one or two of these, and it was 50 years ago! I also knew a guy that said he had a thin-ring Mc5, but he was fulla hooey! I don't believe any true Mac 5's had the plug boot, but you know McCulloch. They could've run out of the solid shroud and used a saw shroud-maybe it was the very end of the Mac 5 run. Mac decided (late '59-early '60)that the plug was washed by the incoming charge better if it was on the f/w side. It also cooled the plug better. The saws were changed at that time, too. The kid who lived across the road from us bought Dad's Mc5 (it only had maybe 2 weekends on it, and had been sitting on the bench for months), and Dad converted it to an Mc6 for him. Dad left the plug on the exhaust side, and the beast ran like the wind. Lanny won his first Brevard Co., FL championship with that motor on my old dead axle Bug that we converted with a Reed Eng. kit. We put the new axle hangers under the rails at 40" wheelbase, and the thing looked like a jackrabbit! TJ

Steve,

i have a mc5/6 block that is stamped that way by the factory.
possibly tomorrow when i'm in the shop i'll see if i can get pix.
of course that might be the mc6 i sent dick teal so it may be in his hands now.
anyway i'll track it down and post a pix.

i'd heard from a chainsaw guy that the mc saws heads were turned because the plug wire had a nasty habit of giving spark shocks to the operators.
he grouped all the early saws in this thought but futhur research indicates it was just the d44 with center plugs.
if you ever run one of those early saws with a center plug you'd see how close your hand is to a bad jolt.
i suspect mcculloch got rid of excess center plug heads by selling them as mc10 kart motors but i have no paperwork on that.

the best explanation came from a fellow at the big one i chatted with for a while.
he's been a mcculloch dealer and racer in the day.
he said they moved the plug and cut the hole when the stroke was increased because the plugs fit better.
as the stroke change was minor i only half listened.
the deck wasn't raised till the mc7 came out , at least by me eyeballing the blocks to see.

finally i have a few hand cut shrouds that have saw marks from where the original closed shroud were cut open.
the holes that were drilled for access to the allens in the head are in each corner of those.
one of them has an original mc5 sticker on its side not the top but that shroud was not mounted on a motor .
so the sticker could have been moved somewhere in the past though it looks original.

Dave

Guys,

I have more than one block that has 5/6 stamped on it. I'm in the process of putting together a kart like I raced in 1960 with dual Mc6 engines. I found 7 blocks or engines that finally ended up giving me 3 good engines. Dave helped me with a few of the pieces and Vince did the machining work. I don't have any information on why they are stamped this way but it's pretty clear that they probably had left over Mc5 engines. The 5 was a pretty poor performer and wasn't selling very good. The 10 was pretty good but the 6 was better than the 10. I consistantly beat a pair of 700 West Bends, a Merc outboard and a Diston at the local race track.

The kart in the picture is a 1959 Fox similar to the 1960 that I'm working on; it has Mc5 engines on it. The picture was taken in the summer of 1960 by Bob Lapke's dad and developed in 1961. Developing pictures later was common back then.

Dick Teal

I have an article from a Mechanix Illustrated How To Do it Encyclopedia copyright 1961 .
It says

" Not long ago I saw Bob Palmini as he was leaving the Agoura, Calif. Raceway.
He was excited as though he had just struck oil in his back yard. Pointing to the kart he'd just loaded on his truck he said , " that Power Products engine ! we came in third in a field of 28 McCullochs and we're just getting the hang of it !It's smooth as silk . Man, it's the comer "

I was told that this made McCulloch bring out the next gen Macs early and this is why there were 5/6 blocks as the current motor was the 5 and the 6 was the next gen motor.
Other than the book I have and what I was told . This is all the info I have .
Any Thoughts ?
Brian

Brian, McCulloch basically told us exactly the same thing about the reason for hurrying production on the Mac 6. TJ

Hi,Here's some food for thought,The first pic shows two blocks stamped Mc5 but the one on the right has an X over the 5 and is stamped Mc6 in the round part of the block. The second pic shows how McCulloch stamped the Mc5 & 6 on the same block. The third pic shows a motor sold as a Mc5 but there are X's over the Mc & 5 and is stamped Mc6 in the round part of the block. It has the solid shrouds (no rubber spark plug boot) Mc5 crank & piston w/thick rings,metal screen over the flywheel & early Tillotson carb. Carl