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Engine basics => Engine set up tips => Topic started by: Tom Schwartz on March 14, 2013, 08:01:04 PM

Title: New piston for B40
Post by: Tom Schwartz on March 14, 2013, 08:01:04 PM
I removed my sons B40 from his P 40 to do some cleaning and inspection. Long story short- I found the small end of the con rod had worn out. I ordered a new piston / rod assembly from Brodak but even after cleaning all the Castor deposits from the liner it will not go in, way too tight. Is this common? Can I hand fit the piston to the liner by using some kind of compound? And by the way.... which way does that oil hole on the big end face  ??? Guess I was sleeping when I took it out.
Waiting for warm weather in PA
Thanks
Tom
Title: Re: New piston for B40
Post by: Brett Buck on March 14, 2013, 08:34:42 PM
I removed my sons B40 from his P 40 to do some cleaning and inspection. Long story short- I found the small end of the con rod had worn out. I ordered a new piston / rod assembly from Brodak but even after cleaning all the Castor deposits from the liner it will not go in, way too tight. Is this common? Can I hand fit the piston to the liner by using some kind of compound? And by the way.... which way does that oil hole on the big end face  ??? Guess I was sleeping when I took it out.
Waiting for warm weather in PA
Thanks
Tom

   Normally, piston and liner are a matched set. You can't generally mix/match them. Can't you use the original piston with the new connecting rod?


    Brett
Title: Re: New piston for B40
Post by: Chris Wilson on March 14, 2013, 09:39:21 PM
If you do a search of the site there is mention of how tight fitting the Brodak 40 is so perhaps its meant to be the way you have it.

And it seems that Brodak do not sell matched sets of pistons and liners so they must be very confident with their CNC machines!
Title: Re: New piston for B40
Post by: Brett Buck on March 14, 2013, 09:42:12 PM
If you do a search of the site there is mention of how tight fitting the Brodak 40 is so perhaps its meant to be the way you have it.

And it seems that Brodak do not sell matched sets of pistons and liners so they must be very confident with their CNC machines!

   You mean "someone in the Crimea's" CNC machines?

    Brett
Title: Re: New piston for B40
Post by: Chris Wilson on March 14, 2013, 09:47:59 PM
As far as the oil hole orientation goes, I would be far more interested if there is a radius on one side of the big end journal - if you have one then the radius goes up against the crank web.
Title: Re: New piston for B40
Post by: Tom Schwartz on March 15, 2013, 08:05:25 PM
If you do a search of the site there is mention of how tight fitting the Brodak 40 is so perhaps its meant to be the way you have it.

And it seems that Brodak do not sell matched sets of pistons and liners so they must be very confident with their CNC machines!



This is so tight, the piston will not reach the top of the liner. I will probably re-use the original piston, that was still in good shape.
Thanks
Title: Re: New piston for B40
Post by: Dick Pacini on March 15, 2013, 08:27:20 PM


This is so tight, the piston will not reach the top of the liner. I will probably re-use the original piston, that was still in good shape.
Thanks

I would give John Brodak a call or send him an email.  He will most likely offer a solution.
Title: Re: New piston for B40
Post by: Clint Ormosen on March 15, 2013, 09:50:52 PM

This is so tight, the piston will not reach the top of the liner.



If your trying to push it up by hand, then no it won't go to the top. That's as it should be. Tight.
Title: Re: New piston for B40
Post by: bob whitney on March 15, 2013, 10:50:10 PM
i bought a piston for a B25 ,when i got it it would fall through the liner   ,i talked to John at the KOI  and he had me send him my P/L and they fit a new piston to my old liner and it runs good , i also broke a 25 crankshaft after i deiselizd it and he replaced the crank free of charge  give him a call
Title: Re: New piston for B40
Post by: Mike Greb on March 16, 2013, 03:43:27 PM
Last summer i bought a 25 liner from brodak, but he was out of the piston and rod assembly.  I found a store that had an piston assembly , but the piston would not even start in the liner. By selling the Liner and piston separably there is a low probability of the parts fitting right.