Mac 125 special rods

[mcbob]

I noticed the other day when Tom responded to one of my many questions he spoke of a long rod to suit the 101, now i recall that there is mention of such a rod in the IKF book of spec's covering the Mac 49/ 91 and 101 engines ...... now the question is the mention of a 125 rod a typo error or was it a rod that is different to the normal assortment of 101/SP125 rods that i am aware of ????

And if the above is true was it a way of a quick method of stroking this engine.

McBob.

[steveohara]

Bob,

You must have written that question after indulging in a few of those jumbo Foster's.
Surely you know that the rod length has nothing to do with the stroke.... assuming we are talking about engines.
FYI, the center to center distance on the rod used in the 75,100, 101 is longer than the center to center distance on the rod supplied in the 101A, 101A/A, B, D, M/C
The later model pistons had the wrist pin moved down in the piston so the dimension from the center of the big end to the top of the piston comes out the same for both setups thus it is possible to replace the older, longer rod with the newer version and use the modern pistons in the older model engines.
One other thing, the older rod used the larger diameter wrist pin.
Regards,
Steve O'Hara

[mcbob]

Hmmm musta been thinking of strokin' the wrong thing your right Steve what the dickens was goin' through my burnt out grey cells ........... thanks for setting me straight .......... and thanks for the tech advice.

It must have been that tinkering with the enemy that got me off line and outta wack ( read as Benders )

McBob.

[mcbob]

Well here's another and in the words of an Australian politcan " Please Explain " the 200cc rod ?




McBob.

[Dan Flanders]

He Bob-
Probably referring to the B Reed class which ran two 100cc Mac 90 series motors...Thus the 200cc Mac reference.

[Rob Voska]

Anyone have a length dimension on these "long rods"?

[Tom Smith]

about + .100"
there is nothing special about the long rods

[Russ Smith]

No Aussie would be caught dead drinking Fosters.

[mcbob]

Ya dead right Russ we call it gin's xxxx ...... if ya git ma drift ................

McBob