Old crankshafts

[speedyk50]

Hi all! I have a technical question …
I have 3 old crankshafts for 18 Johnsons (FD11 – 1957 …). They are all not good for service as they have some pitting and lines that you can catch your fingernail in which will destroy bearings in no time. I hate to throw them out without knowing if they could be salvaged by regrinding them down to a specified depth and then using an oversized needle bearing set. This in turn may – depending on the clearance in the cages may cause interference or …..??? I have a new one (after a long search) so these are surplus and I hate to throw them out.
Just curious!
– Ken Speed – Member AOMCI
p.s. I still have my Big Bee and 20h for sale.

[dan-in-tn]

Ken, we use to have the cranks rebuilt on larger late model engines, but it was fairly expensive. That’s why it was always larger engines with just one or possibly two journals. You can’t just turn them down because the crank is hardened for roller bearings. Grinding it down would remove this surface hardness and leave the crank too soft for needle bearings. The reason the whole crank is not hardened is because it would be too brittle and break. People have asked this question before and even tried the procedure you mentioned, but it doesn’t work. Thank goodness we have many old engines to choose from, at least on the OMC side of Classic collecting.

Dan in TN

[speedyk50]

Thanks Dan. Never considered that. You are right that there are plenty of good ones out there and perhaps some NOS – only until the day you go looking for one. 🙂
Thanks for your reply Dan
– Ken

[garry-in-michigan]

In the truly rare Antiques with anti-friction bearings a bronze bushing bushing insert was tried as a substitute for unobtainable rollers. It resulted in a 10% horsepower loss. This a resulted in an increased effort to find or produce oversized rollers.

[jw-in-dixie]

You can always find alternate uses for ruined cranks. 😉 JW in Dixie

[johnyrude200]

I’ve been slowly accumulating a collection of cranks where the driveshaft is seized up…still waiting to figure out what I’m going to do with them all. I’ll come up with something creating eventually!

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