Hi Gang:


    I recently pulled the head on an older Fox .25, 50's, to check for binding after a crash.  Now I can not get the head screws to enter the holes in the case with the cylinder in place.  The holes for the head screws are slightly covered by the cylinder flange thus preventing the screws from starting into the holes.
 
    Possible suggestions for a solution are:

   Grind notches in the cylinder flange to provide clearance for the screws with the trusty Dremel Tool or ?

     Any other suggestions?

                                                                                                Tia,

                                                                                                Frank
                                                                                                         

    Hi Phil et. al.:

    No, I did not mark the crankcase and sleeve when I removed the sleeve from the engine.  The reason is, it will only properly line up one way with the ports correctly oriented.

     There are no notches in the flange of the liner to clear the head screws.  One can see that the flange covers a portion of the head screw holes and the inital assembly scratched the lip of the liner with the threads of the screws.

     I guess that it is time to cut light notches in the liner to facilitate assembly.

    Any more suggestions?

                                                                                                 Tia,

                                                                                                 Frank

Frank,
Sounds like you found the cause of the binding after the crash. If you have the liner out can the head go onto the bolt hole? This could be just some off set holes from the factory. Or the hit caused the cylinder to egg shape and once the bolts are out it moved out a couple thousands. If the piston moves freely without the head on you could drill out the head bolt holes to get them lined up. I do this on Fox 35's all the time. Some of the heads have holes in the case that are just a little tight and will cause the engine to bind as the head is tightened. For my stuff I run a # 30 drill through all the head holes (I have also opened some of the backplate holes to a #29 drill). This usually does it.

Best,           DennisT


 

Hi Frank,

Glad that the head bolt mystery is cleared up!   I love the old .25 as a stunt engine, but I did pick one up which was bolted to a VooDoo.   I thought it might have been used for slow combat........  the engine seems to be almost as strong as a Fox .35, and seems to run just a touch better, also.

I tried one of the "new" Fox .25 which had the "bolt on" carb/venturi and it definitely does NOT run like the old .25.  Couldn't even get it to run in a dependable wet 2.

BIG Bear
RNMM/AMM