Will a HS40 crank in a H35

markus

Well-Known Member
#2
No the crankshafts do not cross during that era. Rod and case side journal is larger on the HS and the taper for the flywheel is different as well.
 
#4
Matching a crankshaft to a specific Tecumseh engine is a friggin nightmare (been there, done that) as Tecumseh had so many variations of their crankshafts and flywheel tapers.
Michael
 

markus

Well-Known Member
#6
Thanks Markus. I am still looking for a crank for the H35 (green 1971 Rupp Scrambler) and considering other options.

Bill T
If your really dead set for the H35 and willing to loose the HS40 as an engine (not many people are willing to do this) you can use a late model H35 block and transfer your early hS40 crank, sidecover, and flywheel/ignition over, if its a lighted/charging coil flywheel you will need to use the shroud from the HS as well because it has to have the studs for the recoil). As of 1983/84 they "stroked" the H35 matching the HS engines. and some of them even used the same crankshaft that the HS40 used at that time and got the larger HS rods as well. still use the H35 cam, lifters etc..

the 34755 a and b blocks were like that and you would want to find one of those if you could as the casting is still fairly smooth enough that when painted they still retain the 1970's look. Plus they still used the larger exhaust valve. They discontinued that block though while they were still in business and offered the 36562 as an alternative which by that time was used on their H30/H35/ and H40 engines till the end. it has the smaller exhaust valve (usually comes with it) and the casting is usually very rough as tec quit painting engine blocks by that time so it may not smooth out under paint too easy and be noticeable. also the later the block they usually are not drilled and tapped for the magneto so that will have to be done as well (pretty sure its that way on the 36562) They are dimpled though in the correct spot.

If you were to do this, set the timing same as an HS engine not what the H was. I have mocked up/fitted parts to verify, but I have never pulled the trigger on a finished build so I don't know how well they run. was going to but the early HS parts are needed around here right now. The later engines run better than the earlier ones, but they also have 2 more pounds of flywheel on them.
 
#7
I have 2 crankshafts. The one in the H35 engine has a damaged keyway and was either made for a no roller bearing side cover or has a sleeve pressed on to it.

The engine came without the roller bearing side cover.

The second one I purchased off Ebay was supposed to be for a H35 Rupp minibike and NOS. It has the 3/4 by 3 inch PTO but has an undersized rod journal measuring about .851 in diameter. Plus I doubt it is NOS.

I have a two Rupp worthy engines. One Ruppized newer HS40 which runs good. The other is an original HS40 out of my purple Rupp Roadster 2 and needs rebuilding.


At this point I guess I should rebuild the HS40 so I have 2 working engine and watch Ebay for the proper H35 33085 crank.

I had though abut buying a used HS40 off ebay and using the end cover and crank but based on what Markus said I'm not going to do that.

I am also thinking about either a Honda GC160 on the Scrambler or a Westbend 820.

Bill T
 

delray

Well-Known Member
#8
ok, reason i ask was i work with a guy that had a problem with his 8hp kohler for his cub tractor. his rod journal was .020 under and no one made a rod that was .020 under. only standard and .010. so he found a place that would reweld material back up on the crank and grind it to standard size again. crankshafts for his engine are starting to get little harder to find and pricey and it was a crank with a live pto shaft on it.
price was just under $100 to repair it. might be a option in the future for some of us that want to restore a original engine for any small engine project. like they say there not making this stuff anymore and slowly starting to get harder to find parts(crankshafts)
 
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