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Engine basics => Engine set up tips => Topic started by: Ty Marcucci on September 22, 2008, 04:39:22 PM

Title: OS .40 H series
Post by: Ty Marcucci on September 22, 2008, 04:39:22 PM
 D>K
Title: Re: OS .40 H series
Post by: Just One-eye on September 22, 2008, 04:49:36 PM
All of mine predated the ABC era, had steel liners, so I suppose the rings were iron ones.  I had some different versions.  Most seemed to only have a single BB, at the rear end, although one of mine came with a front BB as well.  They vibrated VERY little, unlike the Max-S 35s, which vibrated "some". 

I've had three Max-H 40s, and a couple of H-35s.  The 40s I had were very nice for stunting, with a lovely 4-2-4 break, and good power.  All could fly a 35-size stunter in a rich enough 4-stroke that you seldom broke to two-stroke, and only then, when you REALLY needed it, much in the way I loved to use Tigre G21-46s, although the 4-stroke rpms were too high for 11-6 props (which were my choice for the G21-46s), and I used 11-5s for my Max-H 40s.  One of my H-35s probably was a "Combat Special", not clearly marked as such, and wouldn't run in a breaking run at all. 

Title: Re: OS .40 H series
Post by: Steve Holt on September 22, 2008, 10:27:15 PM
There were at least 3 versions of the Max H 40.  One had a "P" on the case and was timed for R/C pylon racing.  One version had an "S" on the case and was timed for U/C stunt.  Most of the ones I have seen have no marking other than the Max H on the case and were the standard R/C engines.  All ran very differently.
Steve
Title: Re: OS .40 H series
Post by: Brian Hampton on September 22, 2008, 11:35:09 PM
There are two basic versions of the Max-H, the later one had twin ball races and a larger transfer port and was mainly an RC sport engine. The earlier version was usually a single rear ball race except for the P (pylon) engine. The early version came in 4 types, the standard RC just marked as a 40, the stunt marked as 40S, pylon as 40P and rat race as 40RR (I think, it might have been just 40R). The letter was stamped underneath the 40. The P and RR use the same crankshaft and I only know this because there's a NIP one on ebay here in Australia right now. I have an S version but I've never used it. It's easy to tell the difference between a single and twin ball race because of the different prop drivers that are used. The single ball race prop driver extends back inside the crankcase where a bearing could be fitted. AFAIK they all use a ringed piston.
Title: Re: OS .40 H series
Post by: walter weatherford on September 24, 2008, 11:01:21 AM
The single rear bearing model of the 40H had a longer stroke and smaller piston OD.  THE reason I know is I am still trying to find a piston for my 40H with the smaller OD.
Title: Re: OS .40 H series
Post by: Bill Heher on September 25, 2008, 11:06:03 AM
I have one that I converted from R/C with a .280 venturi and a ST needle valve assy. Is there any difference in the timing between the S and the R/C? 
Mine has no letter under the 40, and I took the carb off so I'm sure it was an R/C. Will it run the same  "S"  4-2-4?

Which would you put in an Oriental, the old non-schneurle Max-H described above , or  a  .35 FP-S ?

I have a new .35 FP-S  that I was planning to use, but I like the idea of running a rich setting with plenty of power. It gets hot down here in FL, so I like extra fuel / oil to pull the heat out of the old iron motors.