Hello,

Recently, a friend gave me a OS Max-H .40 RC engine.  He bought it about 1985. I ran it on my test stand and everything appears fine.  Good, strong engine.  I didn't tach it but lots of RPM with a 11/4 prop.

Anyone have an opinion on how this engine might be for CL use?  I thought about making a venturi for it to replace the carb.  The carb base O.D. measures .510 which is quite a bit larger than the LA carb/venturi. Would .283 (LA .40 venturi I.D.) for the I.D. of the venturi work?  Maybe just lock the carb full open?

Any advice appreciated.

Thanks,

Joe

I have a few of these motors (most are older than yours) and they seem to run best and draw fuel with ~ .260" I.D. venturi and the O.S. Needle Assembly .20-.25 FP-S  Manufacturer Stock# 22311000. I believe the O.D. of the spraybar is ~ .136".

http://www2.towerhobbies.com/cgi-bin/wti0001p?&W=000443397&I=LXCR49&P=K

Thanks for the information on the OS Max-H fellas.  I didn't see any markings (other than "OS Max-H" ) on the engine.  I'll have another look.  The person that gave the engine to me had it mounted in an RC trainer so I doubt that it is a pylon model.

Just thought it might make a decent engine for CL use.

Thanks again for the help.

Joe

Joe;

If you have the Max-H .40 with just "Max-H" on the side, then you have a great engine for general work.  Any of the guys who make venturis can provide you with a properly sized setup that will run great.  One thing to note, though - the diameter of the hole that the carb or venturi goes into requires that you use a long bodied NVA.  The best that I have found are the long Super Tiger type  sold by Len Neumann.  I believe Randy Smith can get these as well.

My fuel of choice is 22% lube (50-50 castor/synthetic), 10% nitro, B-Y&O 11-5 prop.  On a scratch built Oriental that I shortened the nose about .375", it trimmed out with almost no nose weight needed.  Fuel usage is right at 4 oz for the pattern, so you might want to look at a slightly larger tank to be safe.

The Max-H 40 is a great engine.  Good luck with yours.

V/r

Bob

Hello,

Recently, a friend gave me a OS Max-H .40 RC engine.  He bought it about 1985. I ran it on my test stand and everything appears fine.  Good, strong engine.  I didn't tach it but lots of RPM with a 11/4 prop.

Anyone have an opinion on how this engine might be for CL use?  I thought about making a venturi for it to replace the carb.  The carb base O.D. measures .510 which is quite a bit larger than the LA carb/venturi. Would .283 (LA .40 venturi I.D.) for the I.D. of the venturi work?  Maybe just lock the carb full open?

Any advice appreciated.

Thanks,

Joe

Sorta off the topic, but not really..............

I have a basically brand new 40 H "P" pylon engine with a busted ring.  I would dearly love to turn this one into a stunt engine!  Does anyone know where a "stunt" sleeve, piston, and head (if necessary) could be found?

Thanks
Bill <><