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Proper interference fit for rod -piston pin bushing- install #2534413
08/10/18 11:51 PM
08/10/18 11:51 PM
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo Offline OP
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domingo  Offline OP
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Lima, Peru
What is the reccomended interference fit for a rod -piston pin bushing- install?

0.0015" or would 0.002" be better????

I dont wanto to just drive em at room temp because I dont want to risk shaving them off as they get driven in, and loosing some of that interference fit that will make em stay in place.

I was planning on installing them by dipping the rod in boiling water and putting the bronze bushings on dry ice.

Then driving them in with a stepped driving tool turned to the exact dimensions for the bushings im gonna be driving in.

I am thinking this would be the better way to do it to achieve a better and more snug fit -when they get back to room temp- without any damage to the OD of the bushings, and then hone them to size....given I dont have access to a machine shop that has roller burnishing tools locally.

Last edited by domingo; 08/10/18 11:53 PM.
Re: Proper interference fit for rod -piston pin bushing- install [Re: domingo] #2534427
08/11/18 01:04 AM
08/11/18 01:04 AM
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Bend,OR USA
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Cab_Burge Offline
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Bend,OR USA
I would do one like you want to and then try finishing it and see what you think of the results up
I shoot for looser(.0010+ per inch of pin size up) on the pin to bushing clearances do to wanting to rev it above 5000 RPM with no worry up twocents


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Proper interference fit for rod -piston pin bushing- install [Re: domingo] #2534436
08/11/18 01:23 AM
08/11/18 01:23 AM
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Washington
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madscientist Offline
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Washington
If you are talking press fit into the rod you only need .0008-.00010 and no more.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Proper interference fit for rod -piston pin bushing- install [Re: domingo] #2534440
08/11/18 01:29 AM
08/11/18 01:29 AM
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Downtown Roebuck Ont
Twostick Offline
Still wishing...
Twostick  Offline
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Downtown Roebuck Ont
No bushing in a press fit rod that I'm aware of.

Kevin

Re: Proper interference fit for rod -piston pin bushing- install [Re: domingo] #2534461
08/11/18 02:41 AM
08/11/18 02:41 AM
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Posts: 9,670
Lima, Peru
domingo Offline OP
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Im talking about installing a bronze bushing on the small end of the rod.

Question for the machinists in the forum.

How much interference fit to use if indirect heating the rod in boiling water and puting the bushing in dry ice before driving it in.

Re: Proper interference fit for rod -piston pin bushing- install [Re: domingo] #2534468
08/11/18 03:18 AM
08/11/18 03:18 AM
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Washington
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Originally Posted By domingo
Im talking about installing a bronze bushing on the small end of the rod.

Question for the machinists in the forum.

How much interference fit to use if indirect heating the rod in boiling water and puting the bushing in dry ice before driving it in.


If you have .001-.0015 press that's plenty. I have never ever heated and rod and frozen the bushing to install them.

There is no reason to either of those things. I put a little oil or even anti seize in the bore and push them in. We had a little press for doing crap like that and it broke one day. So I carefully used a vise with soft jaws and pressed them in.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Proper interference fit for rod -piston pin bushing- install [Re: domingo] #2534512
08/11/18 11:29 AM
08/11/18 11:29 AM
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New York
polyspheric Offline
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I read about using a full floating bushing 100 years ago, and it made my head hurt.


Boffin Emeritus
Re: Proper interference fit for rod -piston pin bushing- install [Re: domingo] #2534522
08/11/18 11:58 AM
08/11/18 11:58 AM
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo Offline OP
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Full floating like early flathead ford rod bearings? Ha. I guess it could work...or not????

Re: Proper interference fit for rod -piston pin bushing- install [Re: domingo] #2534685
08/11/18 05:55 PM
08/11/18 05:55 PM
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Rio Linda, CA
John_Kunkel Offline
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Rio Linda, CA
I think .0015-.0020" press fit would be OK and the heat/cool installation method will work OK but, in an ideal world, the best way to final size the ID of the bushing is not to hone it but to burnish the inside by pressing a correct size steel ball through its bore. This not only sizes it but expands it against the rod bore much like installing an intermediate shaft bushing.


The INTERNET, the MISinformation superhighway
Re: Proper interference fit for rod -piston pin bushing- install [Re: John_Kunkel] #2534802
08/11/18 10:31 PM
08/11/18 10:31 PM
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Posts: 9,670
Lima, Peru
domingo Offline OP
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domingo  Offline OP
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Lima, Peru
Originally Posted By John_Kunkel
I think .0015-.0020" press fit would be OK and the heat/cool installation method will work OK but, in an ideal world, the best way to final size the ID of the bushing is not to hone it but to burnish the inside by pressing a correct size steel ball through its bore. This not only sizes it but expands it against the rod bore much like installing an intermediate shaft bushing.


Living in Peru and playing with old musclecar engines, far from an ideal world!

So I guess I will go with 0.002" interference and the heat/cold method. The machine shops down here dont have burnishing tools, I asked at several and they dont even know that tool exists. Reconditioning some old rods from a rotating assembly thats already balanced to those rods. I have other engines with H beam rods and brand new internals, just not this one. Just trying to make things work and not end with a time bomb.







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