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Engine basics => Engine set up tips => Topic started by: RDJeff on July 03, 2012, 03:02:51 PM

Title: OS Max H40P
Post by: RDJeff on July 03, 2012, 03:02:51 PM
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
Title: Re: OS Max H40P
Post by: RandySmith on July 03, 2012, 04:52:15 PM
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
Title: Re: OS Max H40P
Post by: RDJeff on July 03, 2012, 06:55:18 PM
Thanks for the info Randy.  Good thing I fly R/C too!
Title: Re: OS Max H40P
Post by: Bill Little on July 03, 2012, 07:06:46 PM
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! LL~ LL~ LL~

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

BIG Bear
RNMM/AMM
Title: Re: OS Max H40P
Post by: Brian Hampton on July 03, 2012, 09:03:30 PM
The H40P was similar to the H40RR (Rat Race) except it was the only version of the first H40's to use twin ball races. All the others (including the RR) used a single rear ball race and a different prop driver that extended back into the crankcase where a ball race could be fitted. They're completely different to the later H40 which had a much larger transfer port.
Title: Re: OS Max H40P
Post by: Bill Little on July 03, 2012, 09:40:48 PM
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
Title: Re: OS Max H40P
Post by: RandySmith on July 03, 2012, 10:35:04 PM
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

Setup correctly it would do either  4/2  or wet 2, they had the power similar to a ST 46,  Prop depended on what plane, A 11 x 6 or 11.5 x 5 would work well on planes of the era.

Randy
Title: Re: OS Max H40P
Post by: RDJeff on July 05, 2012, 09:29:51 AM
Does anybody know offhand what connecting rod will fit this one?  The big end is wallowed out... :-\
Title: Re: OS Max H40P
Post by: Joseph Lijoi on July 05, 2012, 10:26:02 AM
Does anybody know offhand what connecting rod will fit this one?  The big end is wallowed out... :-\

Don't you just love Ebay?
Title: Re: OS Max H40P
Post by: RDJeff on July 05, 2012, 02:32:49 PM
Don't you just love Ebay?

Usually I do!
Title: Re: OS Max H40P
Post by: RandySmith on July 05, 2012, 03:20:46 PM
Does anybody know offhand what connecting rod will fit this one?  The big end is wallowed out... :-\

Hi

I have thousands of new parts for older OS  engines I can look for you if you want me too, I may have a new one

Randy
Title: Re: OS Max H40P
Post by: RDJeff on July 05, 2012, 06:54:18 PM
Thanks Randy, I would appreciate that.  I can't find any part numbers in the O.S. part listings.
Title: Re: OS Max H40P
Post by: Jim Catevenis on July 30, 2012, 06:16:37 AM
Randy - 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?  The only markings, other than the H cast in the case are the letters RV stamped on the bottom of the mounting lug.  Also, what size venturi would be optimal for stunt and does this engine require any mods for stunt?

Thanks
Jim
Title: Re: OS Max H40P
Post by: Brian Hampton on July 31, 2012, 11:35:34 PM
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 :) ).
Title: Re: OS Max H40P
Post by: RandySmith on August 01, 2012, 09:44:47 AM
Randy - 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?  The only markings, other than the H cast in the case are the letters RV stamped on the bottom of the mounting lug.  Also, what size venturi would be optimal for stunt and does this engine require any mods for stunt?

Thanks
Jim

Hi Jim
Can you post a picture of your 40?

Randy
Title: Re: OS Max H40P
Post by: Jim Catevenis on August 03, 2012, 03:48:50 AM
Brian-Thanks for the info.  My 40H is the 1972 version.

Jim
Title: Re: OS Max H40P
Post by: Jim Catevenis on August 05, 2012, 06:29:25 AM
Randy-I was having problems posting the photos but Tim Wescott explained why. I am now able to post these photos.

Jim
Title: Re: OS Max H40P
Post by: RandySmith on August 05, 2012, 11:22:26 AM
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
Title: Re: OS Max H40P
Post by: Jim Catevenis on August 06, 2012, 05:21:00 AM
Randy-Thanks for the information.

Jim