OS LA 65 Cover Plate Question

[Andy Mutziger]

Hi All,
I'm  hoping the collective knowledge base here can have an answer for my following question:
Is the OS FP 60 cover plate (OS26027000) a compatible  replacement for the OS LA 65 cover plate (26507000)?
Thank you very much in advance, Andy

[Andy Mutziger]

I know the FP 40 cover plate works for the LA 40 & 46. Thinking the same might be true for the FP 60 and LA 65 plate, correct? Thank you, Andy

[Brett Buck]

You might be the one to find out and let us know but, if all else fails, The plastic back plates on the LA series can be successfully sealed with RTV and attached with large area flat washers under the bolt heads.


Motorman

   Thats true, but I haven't seen anyone have problems as long as then didn't over-tighten them. Once you do, it distorts, starts leaking, the "solution" is to crank down on it harder, then it cracks near the bolt holes. The best solution is to *leave it alone* since you only have to take it apart after a crash, but apparently, no one can resist the urge to unnecessarily disassemble their engines. The next best solution is to gently just nip it tight when only when necessary, the least desirable is to clean everything with acetone, put a big bead of silicone around the tenon, then use fender washers and crank down on it.

    Brett

[Andy Mutziger]

Thanks for the input Motorman and Brett.  Hopefully  the 60 cover plate will work. If not, now I have some insight. Cheers Andy

[Brett Buck]

Those two post were just about diametrically opposed. How could you glean what to do from that?

   They were highly complementary, as far as I can tell. You told him how to work around a broken part, I told him how to not break the part in the first place.

   Brett

[Steve Helmick]

One thing I noticed about the .46LA was that the threads for the backplate screws (into the crankcase) were only tapped as deeply as the factory needed them, and no more. Maybe not as deep as you might need if you change to the metal backplate or non-factory screws.

It might be a good idea to compare the depth of the backplate as well, even if the bolt pattern is correct. A set of feeler gauges could be useful for checking both screw depth and comparing plastic/aluminum backplate depth.    Steve

[Andy Mutziger]

Thanks again for the input. I reached out to Horizon Hobby which is the US OS rep and they identified the following differences:

"The 60FP backplate is not a compatible replacement. The 60FP uses M4x10 backplate screws, the 65LA uses M3x12.

Thank you,
Rick V.
O.S. Engine Technician

Horizon Hobby, LLC"

Steve, you called it.
Cheers, Andy

[Tim Wescott]

   ... The best solution is to *leave it alone* ...

I just want to mention that I took this advice about ten years ago, and I have a plastic-back 25LA and a plastic-back 46LA, both of which are just fine.

... the least desirable is to clean everything with acetone, put a big bead of silicone around the tenon, then use fender washers and crank down on it ...

Interesting.  My first guess if I had one that was distorted would be to use a little bead of silicone (or whatever Permatex seems to be compatible with nitro, castor and methanol) and tighten it to original specs.  Or replace with new, if I could find one.