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Engine basics => Engine set up tips => Topic started by: HemiGTX on November 14, 2021, 11:19:26 PM

Title: Fox .15x piston/rod removal
Post by: HemiGTX on November 14, 2021, 11:19:26 PM
Hello,

I have a never-run .15x that was fairly frozen with dried assembly oil.  I crock-potted and oiled it up and it turns  but is still not snapping over freely.  There appears to be some dried oil between the case and crank, as well as  wrist pin, that must be cleaned off.

So I removed the head and rear cover, scribed a mark on the case and liner.  The liner was easily removed but try as I might, I could not remove the con-rod from the crank pin.

Is there a technique I'm missing?  Not holding my mouth right?

Title: Re: Fox .15x piston/rod removal
Post by: kenneth cook on November 15, 2021, 02:47:20 AM
            Press the pin forward, the back wrist pin hole is tapered for a press fit. This is how it's written in the manual.
Title: Re: Fox .15x piston/rod removal
Post by: HemiGTX on November 15, 2021, 05:47:34 AM
Thank you for the response.  I am having difficulty removing the piston/rod assembly from the case because I can't get the connecting rod off the crank pin. 

My assumption is that the connecting rod is not sliding freely on the wrist pin, and therefore isn't providing enough movement for the rod to come off the crank pin.  Is my assumption correct?  Should I soak the engine longer in the crockpot to attempt to free up the connecting rod on the wrist pin? 
Title: Re: Fox .15x piston/rod removal
Post by: Peter in Fairfax, VA on November 15, 2021, 01:19:51 PM
You are using an Allen wrench to pull on the rod, correct? And, are you pulling the rod back with everything hot?
Title: Re: Fox .15x piston/rod removal
Post by: BillP on November 15, 2021, 08:42:48 PM
It's a new engine and tight so you aren't getting any help from wear. Have you tried to get any side to side wiggle on the crank to wrist pin? My guess is it's a typical fox crank that needs more effort than seems reasonable. Some are just way more difficult compared to others. I bent a screwdriver blade to hook the crank tightly and make the tight ones easier to yank off. Best results are with crank at 5 or 7 oclock. Let us know what you find.
Title: Re: Fox .15x piston/rod removal
Post by: HemiGTX on November 15, 2021, 10:17:22 PM
Thank you one and all.  With more soaking I was able to work the con rod back on the wrist pin and ultimately off the crank pin.  The con rod was really frozen on the wrist pin and required a bit of time to get cleaned up.  Engine is back together and ready to break in.  It will ultimately go on on a Akromaster  Thanks again, everyone.
Title: Re: Fox .15x piston/rod removal
Post by: Mike Greb on November 21, 2021, 06:34:23 PM
It is fairly common to have the connecting rod glued to the wrist pin with dried castor oil.   It takes a lot of crock-potting, heat, penetrating oil or all three to get some unstuck. Until the wrist pin is unstuck, a motor probably won't come apart.