Custom starter bushing questions

[bnam]

I just rebuilt an engine for a friend. His starter was fried when his engine seized after the last rebuild elsewhere. When we pulled the starter to send it off for a rebuild, the bushing pulled out along with the starter. The transmission is a 6V, starter is 12V. The bushing is nominally the correct one for this conversion - outer dia ~16.5, ID ~11, but it is loose in the case as well as on the shaft. I measured the shaft of this starter, and it measured only 10.8mm OD vs spec of 11. The new starter in my 65 Ghia confirmed the 11mm spec.

So, we need to make a bushing that is a bit smaller than what is available from the parts vendors. Searching for standard bushing specs (for this 12V into 6V application) didn't shed much light, but from one vendor's site I got the following:

OD - 16.8mm (the bushing that came out was 16.6mm OD)
ID - 11.1mm
L - not mentioned, but saw 12.5 mentioned somewhere, but two bushings we have are 14mm each.

Questions:
1. What is the gap/tolerance we should leave between the shaft and the bushing. For a 10.8mm shaft, should we do a 10.85mm hole in the bushing or should it be 10.9mm?
2. What is the "correct" length for this bushing?
3. What grease would you recommend? Was planning to use wheel bearing grease. I read about using graphite, but not sure we have an easy source for it.

Thanks,
Byas
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1971 1302LS Convertible (RHD) owned since '74
Click to view image
1965 Karmann Ghia Coupe - under restoration
1966 Fiat 1500 Cabrio (with 1600 Twin cam)
1952 Citroen TA 11BL

[modok]

.05mm would be a good minimum clearance IMO
this type of thing.... is not going to be clean or perfectly aligned.

[EVfun]

If the new bushing stays in the transaxle I'd just run it. You are taking about the starter gear pushing back about 0.3mm and just 0.2mm more than intended (8 thou). I've seen trashed flywheel ring gears, but then the starter bushing was way more hogged out than that.

My exception to this would be if you have a more serious performance engine. In that case I would consider another starter that doesn't have a worn shaft, or if the transaxle is loose I'd run one of the self supporting (autostick or aftermarket) starters.

The problem with making your own custom spec bushing is that you are creating an issue that will follow you around for future maintenance work.
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[Dale M.]

Forget the bushing and go to a Autotrans (self supported) starter.....
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“Fear The Government That Wants To Take Your Guns"
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
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All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...

[bnam]

Had the starter rebuilt by a Bosch specialist - cost $20. The bushing will be ready tomorrow- $4~5. Importing an auto stick starter will cost about $500. No contest.
Byas
_________________
1971 1302LS Convertible (RHD) owned since '74
Click to view image
1965 Karmann Ghia Coupe - under restoration
1966 Fiat 1500 Cabrio (with 1600 Twin cam)
1952 Citroen TA 11BL

[bnam]