H35 with a Billet Rod

[Phil1958]

i was puttering the afternoon away with an H35 block and an ARC6282 billet
connecting rod, the billet rod fits the H35. Slick! it will need some
fitting so it passes the cam, the oil dipper will need a hair cut too.
this rod is the one for the 5.5hp tecumseh OHV, it also fits the HS50.



another thing i noticed is that this H35 has an aluminum cylinder, the
other H35's i worked on recently had sleeves. the skinny i hear on honing
aluminum is that i shouldn't. bore up to the next size and get a new piston.
any advice would be appreciated here. if you, or if you know someone, who
can do cylinder work on these beauties please chime in. advice is always much
appreciated. :thumbsup:

this engine will be used on my winber parade ride. i'm hell bent on bringing
something this year.:laugh:

thanks

H35 - 45772Z

DOM - 02120CE0025

Engine Family 2TPXS,1561BA

Disp = 156cc

 

[CarPlayLB]

Phil,
first of all, I know very little!
A buddy gave me a stuck Briggs 5HP that had been in the rain for years with intake valve open. The rings were rusted in place and nothing would move! I hammered the piston out and used a flex-hone and cleaned it up. There are two different types of hones based on the material you're working on. I had nothing to lose here, so I honed the aluminum bore. Never had done it before, but it is very easy. Engine fired on the second pull (I know you Tec guys aren't used to that!) and is one of the best running motors I have! If it just needs a clean up, I'd hone it! ....and if they are close enough in size, you can use my hone!

 

[Phil1958]

2 things:

1 - H35-45772Z shows up as a side popper on hahahahahahahahahahahahahahahahaha.com. hmm, someone swapped a blower housing on me!

2 - jeff clark did this with a side popper and used an HS50 crank and cam. i sent the H35 cam to isky to see if he can do anything with it.

 

[markus]

isn't the stroke different between the H35 and HS40/50 :shrug: did you rotate all the way through to see where the piston sits at TDC

 

[roccosbike]

This H35 your building, do you have a picture of the flywheel to this motor? I have a 1970 H35 and was wondering if one of those con rods would fit it and now im real curious. I will be checking the fitment for sure now. My H35 is steel sleeved and has a swing away compression release cam.

 

[Phil1958]

isn't the stroke different between the H35 and HS40/50 :shrug: did you rotate all the way through to see where the piston sits at TDC

i'm using the H35 crankshaft so the stroke hasn't changed. the piston looks close to
being flush with the deck but no measurements yet. the front connecting rod bolt has
interference with the block so something has to change there. the existing oil dipper has
to be removed and replaced with something close to the stock dipper. i don't know, this
may work.

 

[Phil1958]

This H35 your building, do you have a picture of the flywheel to this motor? I have a 1970 H35 and was wondering if one of those con rods would fit it and now im real curious. I will be checking the fitment for sure now. My H35 is steel sleeved and has a swing away compression release cam.

i'll post a pic of the original flywheel tomorrow. it is one of those heavy cast iron flywheels using the coil
mounted above the flywheel. the finished article will have an aluminum flywheel.

 

[fistfullabar]

Check my speedway build got a whole part on billet rod in HS40.

 

[Phil1958]

This H35 your building, do you have a picture of the flywheel to this motor? I have a 1970 H35 and was wondering if one of those con rods would fit it and now im real curious. I will be checking the fitment for sure now. My H35 is steel sleeved and has a swing away compression release cam.

 

[owend]

That would be really cool if you got it to work Phil!

 

[Phil1958]

there is interference between the block and rod bolts. looks a relief cutout
will be needed if i can't find any low profile caps screws to replace the rather
long screws that came with the rod.





i'll bet that there will be cam shaft interference too.

 

[ATKRIDER]

i'll post a pic of the original flywheel tomorrow. it is one of those heavy cast iron flywheels using the coil
mounted above the flywheel. the finished article will have an aluminum flywheel.

Not sure what your plan is here but to use a OE aluminum flywheel I am pretty sure Tecumseh never made an H or HS with aluminum wheel and external ignition. Pretty sure your block has the bosses to mount a early points type internal stator/magneto but odds are they need to be finished drilled and tapped like all of the other late model H35's I have seen which is No Biggie but than you will be faced with the fact your crankshaft has the wrong taper for those early ignition set-ups. Your crank taper will measure .740" on the big side and .640" on the small. A early points aluminum wheel is .740"-.540". Not going to work as is. Just giving you a heads up.

As far as the aluminum bore. IF it is straight and round say within .015" it can and will need to be honed. Plain and simple.

The bore should be 2.500" so if it is straight and round than get a 2.5" silicon carbide flex or ball hone in 400 grit and use ATF as a lubricant and hone away. From YEARS of experience trust me that you do NOT want to get carried away here. Anything more than 6 down/up full length strokes (Keep the comments to yourself) and you will start changing the size/shape of the bore and there is no going back. If you want a perfect cross hatch than practice on a junk block or something before just having at it. I tend to keep the hone RPM kind of slow-like 3-500 RPM.

Aluminum is funny shit when you start honing/sizing/resizing. If you use something like kerosene or stoddard solvent the hone will stick to the aluminum like glue. Motor oil doesn't work very well either, for whatever reason.

 

[ATKRIDER]

You must have posted the pics of the rod interference as I was typing or I would have addressed this as well.

Is the rod connected to the piston in the above pictures?? Curious because something seems wrong here-like the entire reciprocating assembly.
Anyway if the rod IS centered in the bore in the pictures than probably your best bet is to relief the block and maybe wack some of that bolt head off at an angle-

 

[Phil1958]

You must have posted the pics of the rod interference as I was typing or I would have addressed this as well.

Is the rod connected to the piston in the above pictures?? Curious because something seems wrong here-like the entire reciprocating assembly.
Anyway if the rod IS centered in the bore in the pictures than probably your best bet is to relief the block and maybe wack some of that bolt head off at an angle-

the rod is connected to the piston, here is a pic of it at tdc. (markus was asking about that)
the piston is in backwards, but this is all fitting stuff together.



here is the block stripped, i will be using the internal points mount for a hall effect sensor, i
have a feeling that the points will recoil so badly that they will be impossible to use as a tdc
indicator at running rpm. i'm using a kettering ignition with a micro driving a FET driving an
external coil, something to play with. next to the block is the piece of aluminum that will
eventually be the flywheel.



thanks for the help on the honing, i will refrain from using more than 6 full strokes! :laugh:

 

[ATKRIDER]

Sounds like you have it covered. Actually I f'ed up and the bore shouldn't vary any more than .0015". Forgetting that one zero is a HUGE OOPS!!
Sorry-
I shouldn't give advice after a few beers-

 

[OND]

Hey Phil, Is this a H35 side popper engine ? I hope you get this worked out I have a H35 side popper I need to build for the build off, Thanks and I'll be watching this thread for your updates. :thumbsup: This is some good stuff !

 

[ATKRIDER]

Oh and since we are on the subject-
It appears just from looking at the picture that the piston to bore clearance is excessive. I have a sneaky suspicion that this thing is going to be getting an oversize piston.

But than again my eyes are no bore gauge-but I sure would check it with one. Just my opinion.

 

[buckeye]

Man, bunch of great info I have no idea how to use. Sounds good anyway.:laugh:

 

[markus]

when did they downsize the exhaust valve on the 3.5's :shrug:

 

[Havasu Dave]

The ignition system sounds interesting. Are you going to be able to run the timer chip with a variable resister to have dynamic timing available? That would be a big improvement for those running those fancy cams.