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hot rodding for the fun of it..

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waynebrown

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Curious what type of 'hot rodding' modifications could be performed to a 2 cyl 2 stroke 50 TLERE?
I used to see some guys running the mini hydros and such with heavily modified engines, and curious what may be more or less
'off the shelf' stuff I can do to tweak more git from this?

I actually have a couple donor units, and am about to try my hand at boring my first engine in about 20 years. Going with a block that already has a cracked sleeve, just to prove to myself I can recall how to center the boring bar, etc.

Would decking block and head serve well enough to increase compression? I've only seen pistons 0.010, 0.020, and 0.030 larger, but none state the compression ratio, and none seem to have port alignment done to skirts.

Any suggestions on where to find go-fast info?
 
Boring adds very little HP(1-3hp) unless you increase cubic inches such as taking it from 3.1 ci to 3.6...The trick for making horsepower on a 2 stroke is increasing engine intake volume and transferring that into combustion area.Your engine is a good example as with a simple carb swap it can be detuned to a 40hp or if a 40hp it could have been turned into the 50hp just by increasing CFM intake. If you can find a old Land & Sea 50XRS front intake you can really make a some hp as this converts front of engine to V4 dual reeds and dual 2 barrel carbs either from a OMC or Merc engine our choice. This plus some added finger ports to cylinder and piston,extra compression from head shaved,addition timing can get ya near 70hp at prop.These mods will make the engine only good for light weight boats with total weight under 700lbs. Flywheel balancing will be required for RPMs over 6100.
 
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faztbullet said:
Boring adds very little HP(1-3hp) unless you increase cubic inches such as taking it from 3.1 ci to 3.6...The trick for making horsepower on a 2 stroke is increasing engine intake volume and transferring that into combustion area.Your engine is a good example as with a simple carb swap it can be detuned to a 40hp or if a 40hp it could have been turned into the 50hp just by increasing CFM intake. If you can find a old Land & Sea 50XRS front intake you can really make a some hp as this converts front of engine to V4 dual reeds and dual 2 barrel carbs either from a OMC or Merc engine our choice. This plus some added finger ports to cylinder and piston,extra compression from head shaved,addition timing can get ya near 70hp at prop.These mods will make the engine only good for light weight boats with total weight under 700lbs. Flywheel balancing will be required for RPMs over 6100.
Click to expand...

I know they made a 60 HP 2 cyl, I assumed they achieved with additional carb bore and jetting as bore and stroke remains the same. I've already done a little tweaking by resurfacing head, and shaving off 0.005, which brought compression up 7 to 9 psi. I haven't tried yet to find the point of diminishing return with this engine type. I would like it to remain reliable enough to take out the grandkids, but hot enough to satisfy the gear head in me.
Some sick part of me wants to see expansion pipes hanging off this thing though.. :|
 
Your motor is already making right at 60hp as the old 60 was powerhead rated and your is prop rated,,you got about 55hp at prop.
If your going to try and bore a block you will need a offset bit and holder to reach bottom of cylinder and clear rod slots..
 
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faztbullet said:
Your motor is already making right at 60hp as the old 60 was powerhead rated and your is prop rated,,you got about 55hp at prop.
If your going to try and bore a block you will need a offset bit and holder to reach bottom of cylinder and clear rod slots..
Click to expand...

Good info! Thank you.
Offset bit and holders I have, my boring bar has an adjustable feed rate, can you suggest a feed speed to start?
As stated earlier, going to try on a ruined block just to get my hands back in it. Not expecting any miracles by any means. If I can keep it centered and make it round, the fundamentals are still there. The rest is muscle memory (I hope).

What grit honing stones are commonly used? Anything out of the ordinary?
Off the wall, anyone have CNC files for a billet block?
 
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