Panhead cases question
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Stage IV
Joined: Oct 2020
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From: Colorado
Panhead cases question
So I have a set of right side 55 cases and was gonna buy a repop left side 55 case. I feel like I hear a lot that it's hard to make a crank unless the cases exactly match. How hard would it actually be? Is this a legit thing or is it just my engine builder not wanting to do with it? Thanks in advance for any answers
Stellar HDF Member
Joined: Aug 2020
Posts: 3,159
Likes: 2,202
From: College Station, TX
I think it largely depends on the quality of the reproduction case and how well it lines up with the right side. That's one reason the case halves are matched from the factory.
The 1955 big twin uses timken bearings (I believe it was the first year for that), but the right side uses flat roller bearings. It is critical that the left and right bearing races are aligned, so if the right case bearing race is not properly aligned when the case half was cast, it could be problematic when setting up bearing clearances and end play. That being said, it's been done more than a fair amount, so it can be done.
The right case bearing race is lapped to size using a lapping tool that works off the alignment form the left case to maintain the alignment between the bearing races.
Perhaps the shop you are working with has not done a lot of this and is not comfortable with the process. A lot of shops seem to not want to work on the older engines.
Paul
The 1955 big twin uses timken bearings (I believe it was the first year for that), but the right side uses flat roller bearings. It is critical that the left and right bearing races are aligned, so if the right case bearing race is not properly aligned when the case half was cast, it could be problematic when setting up bearing clearances and end play. That being said, it's been done more than a fair amount, so it can be done.
The right case bearing race is lapped to size using a lapping tool that works off the alignment form the left case to maintain the alignment between the bearing races.
Perhaps the shop you are working with has not done a lot of this and is not comfortable with the process. A lot of shops seem to not want to work on the older engines.
Paul
Tourer
Joined: Apr 2007
Posts: 411
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From:
The cases never match. Not only do you have to do the line bore but also the gasket surface & the motor mounts. Everything needs to be checked. It can be a PITA. The last set I did was an Evo. Couldn't believe how far off they were. Took more than a hone to get those bearings in alignment.
If new cases are available but them. It's better to start with a matched set.
If new cases are available but them. It's better to start with a matched set.
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,048
Likes: 990
super +1
machine shop charges will exceed what you are expecting. yes, with $$$$$$ it can be done.
i have found that hd shop will not touch even newer models. they will do minor things like boring and such but a case up not so much. they would prefer you to seek an independent shop. i had a friend with a 1975 fx frame up restoration and he had night mares with it and the shop had to completely redo all of their work, they didn't even test run it. he brought it to sturgis to sell and the engine locked up. choose well, choose well
machine shop charges will exceed what you are expecting. yes, with $$$$$$ it can be done.
i have found that hd shop will not touch even newer models. they will do minor things like boring and such but a case up not so much. they would prefer you to seek an independent shop. i had a friend with a 1975 fx frame up restoration and he had night mares with it and the shop had to completely redo all of their work, they didn't even test run it. he brought it to sturgis to sell and the engine locked up. choose well, choose well
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