I was the winning bidder on an FP40 on the Bay, only $17.95 for it, and when it got here today, I see that it's not an FP at all, but a Max H40P.  I looked at the OS history, and it appear this is an R/C pylon racing engine from 1967.  does anybody here have any experience with this engine?  I can see some possibilities for this engine, but don't know what it's running characteristics are.  I'll bench run it soon to get some idea, but would appreciate any input from the folks here.  Thanks! 

Jeff

That was made as an OS 40H and was a good stunt engine, the Pylon version..not so much

Randy

Thanks for the info Randy.  Good thing I fly R/C too!

Hi Jeff,

I have had one of those H.40P since my R/C days close to 30 years ago.  Put it on a Sweet Stick and hold on!

It is a "hot" engine, even for later times.

BIG Bear
RNMM/AMM

That was made as an OS 40H and was a good stunt engine, the Pylon version..not so much

Randy

Hi Randy,

What sort of run did the stock .40H-Stunt have?  A wet 2 or a true 4-2?  How about props for the .40H-S?

Thanks
Bill

Does anybody know offhand what connecting rod will fit this one?  The big end is wallowed out...

Don't you just love Ebay?

Usually I do!

Thanks Randy, I would appreciate that.  I can't find any part numbers in the O.S. part listings.

I just picked up a new in the box OS MAX 40H RC.  A couple of questions.  How can I tell what model of 40H this engine is?

There are two versions, old and new. The early version has a small transfer port and is the one that came in 4 variations. The OS timeline has a photo at http://www.osengines.com/history/osm640/osm-1964-max-h40rc.jpg

The later version has a much wider V shaped transfer port and was basically just an RC engine although it was probably available as CL with just a venturi fitted with no change to timings. Photo at http://www.osengines.com/history/osm640/osm-1972-max-40rc.jpg

From memory the two types had different bore/stroke so it's likely that the conrods were different as well. The letters stamped under the mount are probably only of interest to OS themselves (could mean anything) because two otherwise identical engines can have different markings. At a guess it might be a code they used to indicate the month and year of manufacture but I've never been able to make any sense from them (meaning I haven't cracked the code ).

Brian-Thanks for the info.  My 40H is the 1972 version.

Jim

Randy-I was having problems posting the photos but Tim Wescott explained why. I am now able to post these photos.

Jim

Hi Jim

You can use that one in CL Stunt, with a 265 venturie and 157 spraybar, you my want to use a lower pitch prop that a ST maybe a 5 or 4.5 pitch with a 11 to 11/34 inch diameter, Sometimes a 12 x 5 would be OK, depends on what plane your pulling
I would use 23% oil fuel with 1/2 castor, start with 5% nitro and go from there.

Randy
Randy