Tecumseh H50 Stroker

#1
This all started when I bought a couple of rods from Kevin ( Sixpac440 ) for a very reasonable price . So I've decided to try and build an engine around these rods , of course I'll only be using one of the rods for this build. I believe the correct number for the rods are 36972K




Big THANKS to some of Tecumseh Guru's on this forum for posting in old threads ! Google works miracles sometimes ..:laugh:
[MENTION=5969]markus[/MENTION] [MENTION=339]delray[/MENTION] [MENTION=10091]125ccCrazy[/MENTION] [MENTION=3072]ole4[/MENTION] [MENTION=44698]Sixpac440[/MENTION]

Tecumseh H50 short block bought off Ebay , this is not the Tecumseh H50 Motorsports block . Its a stock bore , stock stroke , points type engine . But it does have the bearing side cover .


 
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#2
Going to use an H60 crankshaft that will accommodate either of these rods and stock h50 piston for this build . I got the H60 crankshaft from (jeep2003) Bryan on here. Thanks Bryan !


H50 crankshaft at the front , H60 crankshaft at the rear




First problem being the H60 crank must have came out of a bushing block or side cover . H60 crank at the pto side is to lose in my side cover bearing from the H50 crank . Notice the raised area on the H50 crank to accommodate the Tec bearing ( Hoover A-205 or A-208) .



Knowing I would have to find a correct bearing to fit the H60 bushing crank or use a bushing type side cover .



After much searching on the Internet and on this site I was just about to give up on the correct bearing. Finding an old thread on H50 Tec engines 125ccCrazy had posted and Briggs bearing that would work with the H60 bushing crank . Both the Tec and the Briggs bearings were Identical in measurements except for the ID . Tec bearing ID was 1.025 and the Briggs bearing was .998 , perfect press fit for the H60 crank .


Both bearings OD : 2.045
Both bearings width : .598
Tec ID : 1.025
Briggs : .998

Tec Bearing : Hoover A-205 or A208
Briggs Bearing : 692007
NTN Bearing : 6205


Yes the Briggs bearing I paid $24.00 for actually was a NTN 6205 . There's a sucker born everyday...:laugh:
 
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#3
First things first I need to get the crankshaft rod journal opened up and turned down to work with the billet rod . After talking to Mike Clements Sr. I new the crankshaft rod journal needed to be turned down to .998 to accept the rod bearings that fit in to the billet Tec rod. But I had to get the width of the rod journal opened up to. H60 crankshaft will be sent to Crankshaft Craftsmen in Detroit to get this done.

 
#4
I know the rod journal needs to be turned down to .998 , but I need to figure out how wide the rod journal needs to be widened. H50 stock rod width measures .855 and the stock rod journal on the crank measures .875 . That's .020 side movement for the stock rod , or .010 clearance on each side of the stock rod.
Billet rod width is .940 so I need to at least have the sides of the H60 crank rod journal opened up to .960 for side clearance. I'll probably go to .970 for the side clearance just to be safe .






 
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#5
I know the 5.3cc/.060 stroke won't make an Oooh in to an AAAH, but CC can easily offset grind, take the excess all from the inside.
Then you can run it proud of deck and/or thin the lid a little for weight reduction.
It's great to see the Tec getting some performance love!


Oh, and just for fun, have you got an HS crank or block around for a comparison?
 
#6
Thanks FirePowerMinis and I'll keep that in mind ! :grind::hack::lol::lol: I do have an HS50 that is ready to be built and will get some side by side pics for comparison .
 
#8
Thanks ole and I'm glad the Briggs bearing worked out to .

H50
Stock bore : 2.625
Stock stroke : 2.25

H60
Stock Bore : 2625
Stock Stroke : 2.50

So by using the H60 crank in the H50 block I will gain a 1/4'' more stroke .
 
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delray

Well-Known Member
#11
When might we see some finished Engines on this Site? LOL.
that's funny you say that. almost all flatheads I have seen built on this site seem to never get finish,because they run into problems or what every....:doah: or say they got it running and then disappear from the web site with out any proof they really run? when it comes to modified flathead engines.
 
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delray

Well-Known Member
#12
Ond
tecumseh h50 short block bought off ebay , this is not the tecumseh h50 motorsports block . Its a stock bore , stock stroke , points type engine .
you say it's a points engine. I wonder if you can dig up a aluminum flywheel off another H-motor. i'm pretty sure they made them on the early model H's
 

delray

Well-Known Member
#13
OND
After much searching on the Internet and on this site I was just about to give up on the correct bearing. Finding an old thread on H50 Tec engines 125ccCrazy had posted and Briggs bearing that would work with the H60 bushing crank . Both the Tec and the Briggs bearings were Identical in measurements except for the ID . Tec bearing ID was 1.025 and the Briggs bearing was .998 , perfect press fit for the H60 crank .
you will be surprise how many different bearings you can find and fit your application......:thumbsup: kind what I did too,just search for the size I needed for my bushing style crank that I wanted to modify into a bearing crank and wallah…...:thumbsup:
 
#14
Sent the H60 crank out today ...going to Detroit . I hope these guys get it right the first time ! I should of had it sent to [MENTION=9664]cheezy1[/MENTION] and had him take to the crank shop ….then I know it would have been right when it was returned or Bill would have kicked there A$$..:2guns::deal:
 
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#15
that's funny you say that. almost all flatheads I have seen built on this site seem to never get finish,because they run into problems or what every....:doah: or say they got it running and then disappear from the web site with out any proof they really run? when it comes to modified flathead engines.
Mine runs .lol
 

delray

Well-Known Member
#17
nice, well we know for sure we have two documented modified Tecumseh small blocks running. funny thing you two guys are the only ones I found. both you guys did a very good job on your builds with posting and a video running. OND will be another one when he is done with his build.....:thumbsup: it just seems like when I was doing searches for performance up grades on hs-motors I stumble across a lot of unknown finishes builds.
 
#19
I know the 5.3cc/.060 stroke won't make an Oooh in to an AAAH, but CC can easily offset grind, take the excess all from the inside.
Then you can run it proud of deck and/or thin the lid a little for weight reduction.
It's great to see the Tec getting some performance love!


Oh, and just for fun, have you got an HS crank or block around for a comparison?
Here you go ! H50 on the left and HS50 on the right .



 
#20
Here you go ! H50 on the left and HS50 on the right .

]

Beauty. Thanks! Plenty of crank to reduce to fit the HS, but I see there isn't much room in there. I better pull one down and see how tight it gets. Hard to believe that under 2" is all the stroke that'll go in.
 

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