Aluminum cylinder

[bertsmobile1]

Walt is quite right , I should not need to "me too" his posts.
Cool bore engine can not be bored out oversize successfully.
Briggs use the same size piston is engine that are all iron, alloy with iron or steel liners, alloy with chrome plated bore and all aluminium
Thus +20's and even + 40's are available.

Boring is done in thous from .5 up to around 15.
Honing is done in hundredths of thous to clean up the ridges left by the boring bar or clean the glaze off worn cylinder walls, replace the cross hatching or to size very accurately.
Honing .010" off a bore wall by honing would be near a whole day of machining and wear out a complete set of stones.

 

[upupandaway]

....don't waste your money on it. ...

I agree with Walt. An aluminum block is not just bored and honed, it needs treatment for long life. Annodized(or the like) Nikesil(common treatment) or the like original treatment in it is lost when you bore it.
Personally to keep cost down, u can get a used one for 20$ and transplant the motor if u want.

 

[jp1961]

I've researched Briggs "Kool Bore" technology. From what I gathered on the web, the piston and rings were chrome plated and the cylinder just plain aluminum (sort of opposite of a chrome cylinder/aluminum piston setup).

Anyhow, you could find a good used engine for your friend, or if somebody could reasonably bore the cylinder .020" over, it may make a good winter project.

Regards

Jeff

 

[sgkent]

honing a cylinder out or boring with a cutter are two forms of oversizing cylinders. The problem with aluminum is that the honing stones load up with aluminum when more than just a little is removed. Keeping the stones wearing evenly is most important when honing. I used a Sunnen cylinder honing machine for years. Back when Chevy tried aluminum blocks the solution to over size was use a cutter then press in a steel cylinder and hone it to size. That won't be cost effective on a small engine unless it is a one of a kind museum piece. Buy a new engine or a low hour used one.

 

[7394]

Example: Chevy Vega....................Need I say more..:thumbdown:

 

[SidecarFlip]

Example: Chevy Vega....................Need I say more..:thumbdown:

Actually, the Chevrolet Vega had a Nikasil plated bore, not plain aluminum and it worked well so long as the coating didn't get scratched or nicked. If it did, the engine became an oil burner. Nikasil was and is a common liner in motorcycle engines even today. Nikasil (Nickle-Silicone impregnated bores work just fine actually.

Saying more is saying less in your case.

 

[sgkent]

they sagged and blew head gaskets. The over bore and steel sleeve was to put the steel a few thousands above the desk so it really crushed the head gasket. The trick conversion was a Buick V6. Personally if I wore out an aluminum BS engine I would just hone it to get a cross hatch, gap new rings and pray for the best. The small shop that over bored lawn mower engines died a long time ago. Yes there are people who do it but the cost is high compared to the gain. Usually one can find a used mower, pressure washer, edger etc that is being parted out over a broken drive shaft, pulley, gears, pump yada yada and the same engine as you have is $80 - $125 to take it off the guy's hands.

But if one does bore the aluminum make sure the guy does a lot of them because if the cutting pressure is too high the cylinder will be more wavy when done than it was before it was bored.

 

[SidecarFlip]

they sagged and blew head gaskets. The over bore and steel sleeve was to put the steel a few thousands above the desk so it really crushed the head gasket. The trick conversion was a Buick V6. Personally if I wore out an aluminum BS engine I would just hone it to get a cross hatch, gap new rings and pray for the best. The small shop that over bored lawn mower engines died a long time ago. Yes there are people who do it but the cost is high compared to the gain. Usually one can find a used mower, pressure washer, edger etc that is being parted out over a broken drive shaft, pulley, gears, pump yada yada and the same engine as you have is $80 - $125 to take it off the guy's hands.

But if one does bore the aluminum make sure the guy does a lot of them because if the cutting pressure is too high the cylinder will be more wavy when done than it was before it was bored.

We took a Vega Hatchback, tubbed it, put in a 350 chevy 4 bolt with a hair dryer and a turbo 400 and ran consistent 10's with it. Even drove it on the street once in a while.... Those were the days...lol

 

[7394]

We took a Vega Hatchback, tubbed it, put in a 350 chevy 4 bolt with a hair dryer and a turbo 400 and ran consistent 10's with it. Even drove it on the street once in a while.... Those were the days...lol

Yep, I put a 327 in my vega wagon, long ago, after it became an oil burner. :thumbsup:

 

[sgkent]

y'all kinda snuck up on folks I bet who thought they were racing a Vega.