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E: Engine Cylinder liners

Cyborg

Well Known and Active Forum Website User
VOC Member
Unsure about the history of these cylinders, but they are still standard bore and would be within limits if I used NOS pistons. Plan is to bore them .020” over and use modern low expansion versions. One of the reasons the liners were removed was because the oil feed holes were too high. In fact everyone I have measured it too high. Unsure at this point if I will use the feed holes at all, but will reinstall the liners 180 degrees, so new holes can be drilled at the proper height and then oil supply can be shut off or not. I’m assuming these are factory liners, but haven’t seen ones removed in this condition (printing still visible). The carbon buildup didn’t amount to much and cleaned up with some aircraft paint stripper, so no abrasive required. Contact between muff and liner looks better than usual….Finnish on the muff bore looks a little strange, almost like there was some vibration on the cutting tool? Then honed to size? Anyway… look good enough to use. It took a fair amount of heat to get them to drop, so that was a good sign. Comments…suggestions…liner looks original?


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Bill Thomas

Well Known and Active Forum Website User
VOC Member
I would use more piston clearance than what they say,
In case the barrel is not fully square on the case ?.
Cheers Bill.
 

Cyborg

Well Known and Active Forum Website User
VOC Member
Assuming you measured the bore of the muff and the OD of the liner and are happy with the fit.
No… I have my head firmly planted in the sand at the moment. I already have a surplus of door stops. The length of time in the oven that they took to drop was a record, so was trying to just base it on that. Thanks for ruining my day.
Anyone care to offer up the minimum interference fit required?
 

Bill Thomas

Well Known and Active Forum Website User
VOC Member
No… I have my head firmly planted in the sand at the moment. I already have a surplus of door stops. The length of time in the oven that they took to drop was a record, so was trying to just base it on that. Thanks for ruining my day.
Anyone care to offer up the minimum interference fit required?
6 thou ?.Liner to muff .
 

Bill Thomas

Well Known and Active Forum Website User
VOC Member
But If I was doing away with the oil hole, Like my next job, I would allow more piston clearance.
For me say 5 thou ?, But I have never used modern pistons !,
I am still on 10 thou race clearance, With old Specialoids !!.
Things are actually straight on this one. Cylinder deck is square to the crank… within .001 over 10”. Measured by the local
 

Cyborg

Well Known and Active Forum Website User
VOC Member
6 thou is the generally accepted interference. I just did a set of std pistons in the current project at 3 1/2
We’re you able to use the cylinders that came with it? Who did your cylinders?
I tried setting up a cylinder in the mil, but I have to use the quill and the knee to get the boring head all the way through. Without power feed, it would be a gong show and I’d need to come up with a better cutter. Did the last one in the lathe and it turned out surprisingly well, but risky due to the lack of rigidity. May have to do the walk of shame…..
 

Robert Watson

Well Known and Active Forum Website User
VOC Member
You know who did my cylinders. He has a jig for putting them in the lathe, with or without liners, and cut the oring groove for the base seal at the same time, I just got a dozen of the orings by the way.
Muffs dropped of the liners around 250 degrees, pretty much no contact left so went 30 over on the liners and standard bore.
 

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