Mac 1-80 crank seals?

[Dean Richards]

Hey all, I know this is off topic for karts but I figured someone on here would know. I am restoring a Mac 1-80 chainsaw and was wondering if anyone knows what number crank seals are used? This saw has the gear reduction and looks like a bear to get apart. Just want to get seals before I took it apart so I would remember how it goes back together. Thanks, Dean

[Kurt Bogerman]

Not sure if the 55A (1958 gear drive saw) used the same seals, but, for whatever it's worth, the 55A uses two 102940 seals.

Also, Applied.com, for example, allows you to specify dimensions and lip designs, etc., in order to cross reference seals. Might be worth a try?

[David Luciani]

the answer to your all your questions are already posted.
theres a seal interchange chart and everything in the motors section.
you guys REALLY NEED to read some of the past articles and posts on this forum that are about mcculloch motors.
that's why i go to the trouble of indexing and moving threads around so they can be found faster.
lucky for you i have a few minutes so here ya go one more time.

the 1-80 1-70 use the exact same block and crank as the mc10.
the s44a s55a s55 s44 are earlier versions of the 1-70 and 1-80 blocks with a lighter crankshaft counter wt.
THEY ALL use the same bearings and seals throughout the motor.
so mc10 seals/bearing fit those motors and vise versa.

i forget the exact number, later i'll look it up but there are modern seals that fit.
pretty sure they're part of the standard set of 3 seals all the mcculloch motors we use require.
in the mcculloch resources section it's listed somewhere and in the old forum it's listed about a zillion times.

a little factoid.
the mc 1-80 or 1-70 is exactly correct motor to build a mc10.
there is zero difference between them and a mc10 as they shared the same casting.
many 1-80's are former 1-70's with the 1-70 x'ed out.
 many mc10's are former 1-70's or 1-80 with the saw numbers crossed out by the factory.
the most common crossed out saws are the ones with 1-70 and 1-80 crossed out and restamped mc10.
mc s55a and s44a can also be made over into early mc10's but will have the lighter crank wts thus more vibration.

ALL these saws require a d44 center head, shroud, long wire coil, and outer cover to become identical in appearance to a mc10.
there are tiny differences in the shroud cover but very few people know what to look for and i'm not telling!

if you want a fast mc10 you'll need to swap out the piston to a thin ring kart version.

hope this helps.
d

[Dean Richards]

Kurt thanks for the help, I appreciate your assistance.





Not sure if the 55A (1958 gear drive saw) used the same seals, but, for whatever it's worth, the 55A uses two 102940 seals.

Also, Applied.com, for example, allows you to specify dimensions and lip designs, etc., in order to cross reference seals.  Might be worth a try?

---

Dave, Didn't mean for anyone to go out of there way to help me out, just thought someone would know off the top of their head. I did go on to the Mcculloch engine section and seen an interchange chart, but didn't see anything about 1-80,1-70 or a mc 10.  seen stuff for mc9 and 91. Maybe I am just missing it. I have rebuild some mac chainsaws and working on some kart motors but I'm not knowledgeable enough on these engines to know what seals will work on the different engines. On this particular saw I am not looking to convert this to a kart, just get it running as it was meant to be. I appreciate everyone's help on this forum. Thanks, Dean.

the answer to your all your questions are already posted.
theres a seal interchange chart and everything in the motors section.
you guys REALLY NEED to read some of the past articles and posts on this forum that are about mcculloch motors.
that's why i go to the trouble of indexing and moving threads around so they can be found faster.
lucky for you i have a few minutes so here ya go one more time.

the 1-80 1-70 use the exact same block and crank as the mc10.
the s44a s55a s55 s44 are earlier versions of the 1-70 and 1-80 blocks with a lighter crankshaft counter wt.
THEY ALL use the same bearings and seals throughout the motor.
so mc10 seals/bearing fit those motors and vise versa.

i forget the exact number, later i'll look it up but there are modern seals that fit.
pretty sure they're part of the standard set of 3 seals all the mcculloch motors we use require.
in the mcculloch resources section it's listed somewhere and in the old forum it's listed about a zillion times.

a little factoid.
the mc 1-80 or 1-70 is exactly correct motor to build a mc10.
there is zero difference between them and a mc10 as they shared the same casting.
many 1-80's are former 1-70's with the 1-70 x'ed out.
 many mc10's are former 1-70's or 1-80 with the saw numbers crossed out by the factory.
the most common crossed out saws are the ones with 1-70 and 1-80 crossed out and restamped mc10.
mc s55a and s44a can also be made over into early mc10's but will have the lighter crank wts thus more vibration.

ALL these saws require a d44 center head, shroud, long wire coil, and outer cover to become identical in appearance to a mc10.
there are tiny differences in the shroud cover but very few people know what to look for and i'm not telling!

if you want a fast mc10 you'll need to swap out the piston to a thin ring kart version.

hope this helps.
d

[David Luciani]

i wasn't annoyed or put out by your question just grumpy in morning after lots of travel.
anyway my point is if you read all the mcculloch info many of your questions are already answered somewhere.
on your specific question i think a little more depth should be explored.
so here ya go.

mcculloch built basically two types of motors.
the kart numbers i know by heart here they are
the super series motor mc10,20,30,40,45,70,75,100,101
and the standard series motor mc5,6,7,8,9,90, mc49, 91,92 93
with the exception of the mc70 and mc49 they all have removable heads.

the saw numbers are fuzzier and mcbobs site for that info is long gone maybe someone will chime in with that info??

on saws and karts
the super series motor uses two ball bearing on the crank has a shorter crank shaft .
generally , the super motors are longer in stroke and have bigger bores to the same year standard motors.
the biggest exception to that is the mc10 mc6 which were the same specs which mcculloch quickly learned damaged sales to the more expensive mc10.
the standard motors mostly came with one roller bearing and one ball bearing on the crank.
the actual crank is longer side to side and the bore/strokes smaller than supers in matching years.

there are some people who would argue the super motors with same bore and stroke as the standards are faster because of the ball bearing on both sides.
i have no opinion on that myself.

the saw motors are a little more complicated.
at first ALL mcculloch motors in both series had removable heads.
that changed in the saw section pretty early and most came with fixed heads in later years and eventually all of them were fixed heads.
at the same time mcculloch moved to ball bearings on both sides both standard and super.
these were manufacturing tweaks aimed at simplifying assembly at the factory and cutting costs.
by using the identical bearings and seals on all the saws repair parts were simplified and buying costs were cut .

the super series motors always to my knowledge came with tapered crank pto's through the entire production of these saws.
the standard series in early years were made with tapered pto's but evolved to the so called stub crank which is a left threaded pto crank that the saw clutch simply screws onto.

this was great in production and worked well in the saws.
for us it created a problem because the threaded crank pto is hard to mount up a go kart crank.
the standard saws are interesting to karters because they are great to make over into a mc49 clone motor .
it is doable with a max torque clutch designed for that application or by making an extension shaft.
there is other mods that can be done but that's a different subject.

on all mcculloch saws and kart motors throughout the conn rod bearings are the same.
the conn rods themselves are interchangable to some degree though the older conn rods will not work in the newer motors because the stroke swing is greater.
the newer conn rods fit up perfectly to every crank but attention has to be paid to conn rod matching length.

the pistons fall in two catagories the early end sealed exhaust bearing style and the later covered exhaust bearing style.
the early motors also came with a sealed conn rod pin with an open bearing or possibly it was a hop up part.
the open bearing was added because it has the advantage of better lubrication.
pistons from sAWS DIFFER FROM KART PISTONS IN THE PISTON RING. THE SAWS HAVE COMPARATIVELY MASSIVELY THICK RINGS WHILE THE KART MOTORS BARELY CAN BE SEEN THEY ARE SO THIN.
DANg caps lock!!

the parts interchange between saws and kart motors is pretty good within each series.
all super outer covers and shrouds covers fit all super motors.
the inner covers also interchange with the exception of the rod driven points of any mc10 style early motor.
those motors will possibly fit up the later super inner covers but you'd need to add a pointless ignition to the motor to get it to run. 
the standard covers interchange from beginning to end with the exception of the early mc5's which had a closed top and reversed head.


all mcculloch separate heads will bolt onto all un fixed head mcculloch motors.

con rods interchange as explained above .
same with pistons but the bore and which style piston the motor requires is the main consideration.
saw pistons will work in karts motors and the reverse is also true.
piston pin to deck height must match unless you are modifying motor and know what you are doing.
performance will be damaged if you put a thick ring piston into a kart motor.
if you have a modified earlier motor newer pistons can work with correct pin to deck matching and extra ports.

flywheels fit up to every motor but dwell degree must match up or be compensated for on build.

 coils are identical with the exception that earlier motors often need a longer wire but coil wires are fairly easy to replace.

saw stuffers were all over the place interchange is poor at best. 
kart stuffers vary between super and standard.
early aftermarket kart stuffers were often closely fit so care should be made to ensure fit before purchase.

the saw manifolds came in several styles and are interchangable in the same series motor ie: most 250's fit up to others.
the kart manifolds were two distinct main styles early small carb and late big with little differences in performance year to year.
there are some casting changes which define earliest to latest in small carb design and in large carb design there is a single year shorter manifold (bad design).
there are a few manifold variants outside the two main styles.
a slanted manifold ,a aftermarket manifold installed by factory both effective and several dual manifolds useful only if you are building a factory correct motor.

exhaust on all mccullochs is the same size flange and bolt spacing throughout. interchange is excellent.

saw/kart points and condensor with the exception of mc10 match within series ie super series points standard series points.

all connecting bolts on main connections heads , intakes , exhaust have same thread pitch on all saws and kart motors.
stuffers being the exception they are all 1/4 /20 on all saws and kart motors.

i think thats everything.
one last point early standard motors in saws always are clutched supers are mostly gear drives.
only in later years were the supers pull starts.

hope this is useful
D