A small block that might run...

#1
You guys made me drag out the HS40 I had sitting (courtesy of [MENTION=1406]minibikin'[/MENTION]). It needed some TLC and a 3/4" PTO crank to replace the 1" PTO. Nothing else fancy....:laugh:
 

delray

Well-Known Member
#2
nice pete,where is that one going...…….:scooter:
i would see a lot of toro and some sears snowblower engines with 1 inch cranks.
 

cfh

Well-Known Member
#6
OND, on those 245 cams, are those hard to find? also do they really change the performance of an HS50? and what other stuff do you do? i would imagine a different connecting rod?? thanks!
 
#8
Quick (HA!) Rebuild

Spent the weekend rebuilding the HS40. Here are some pics and details:

Deep Scrub of the Case:



Light hone of the cylinder. Valves were pretty gunked up and those were cleaned with Blaster, and a little fine sanding. I used 220 wet with a piece of 4x4 1/4" aluminum angle to dress the surface of the block and true the gasket surfaces for the intake and valve cover.

Piston got same treatment with Blaster, rings removed and reseated after cleaning. Valve face and seats honed with fine compound. The head bolt holes were retapped and cleaned before final assembly.

The "new" 3/4 PTO crank needed to be cleaned and polished to remove surface rust. The crank gear for the cam actually had to be moved to be flush with counterweights, as less than 50% of the two gears made contact. Springs reinstalled as they were removed, after serious gunk removal.


More assembly next post.
 
#9
Every Tecumseh Hater's Nightmare--Ignition

Tecumseh Points Ignition install is always tricky.

Backer plate and polished intake manifold on. Note bump cam installed. I did lap the taper with the flywheel beforehand.


I completely disassembled the coil and removed surface rust both inside and out. The points air gap is set at 0.020 at the high point of the bump cam. If this air gap is not correct (even a tad off), the timing will be way off--you won't be able to get a solid ohmmeter reading. This took a dozen tries to finally get as my fingers are just too big hold the points and tighten!

Here's the poor man's dial indicator set up:
The timing is set at 0.035 BTDC with both valves closed.


Once the ohmmeter toned, I fine tuned the timing so the needle was just moving and buttoned her up.


A new variable speed throttle was installed. Installed a known-to-be-good carb and roughly set the governor up.


Head and shroud went on and ready to get outside and test!
 
#13
Runs good! No smoke, blue or black. :thumbsup:
Sounds good Pete , but I knew it wood ! :thumbsup: Man that was a quick build ...:laugh:
I was anxious that the engine was too abused as I tore it down given the carbon build up and gunk in the valve spring chamber, but was pleasantly surprised--it truly all is in the engine timing: if it's off just a tad, then you got unburnt fuel mucking up the works. And, Eric, somebody had to have a small block running this year!:laugh:

This'll bring the little ARCO alive. I think the 40s are the best of the small blocks. Off to the coater for the shroud and miscellaneous parts tomorrow...
 
#14
So Pete you've been following along huh ...lol :laugh: I knew one of three or four of us could get one, at least one built ! Its been a good year ! Pics of finished bike please ???
 
#16
So Pete you've been following along huh ...lol :laugh: I knew one of three or four of us could get one, at least one built ! Its been a good year ! Pics of finished bike please ???
Sounds real nice pete....:thumbsup:
Yes, I follow along....Brian amazes me with his detailed notes on these engines and you ain't half bad yourself!:thumbsup: I'll pull the bike out later this week and dust it off (and pull the H35) and post a few shots. It's one of my early builds.
 
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