Overboaring the 295

[Monsterezgokid]

Originally Posted by DOOmsman

Have you checked the pin hight in both pistons?

The crank rods for the 295 and 350 are the same one, same P/N from ezgo, so the needle bearing that comes with the piston will fit the rod properly. The complete pistion kits come with a new wrist pin, made for the pistion that they come with.
So everything should fit like a golve

Originally Posted by Goat53

don't know if it applies to these engines but we used to go up 1 size on the rings and leave the bore stock , then press the ring into the bore and keep adjusting ( grinding off 1 end ) until we had .007 ring gap in the cylinder , by the time the engine warmed up the rings all but had a complete seal ,,, more compression , less blow by , more bottom end torque . ,,, those were lawn mower engines ,, 4 cycle ,,, should work on these also . The 'stock ' ring gap was around .025 to .030 , don't know what the stock gap in the ezgo engines is havn't been working on them that long .

I read in the ezgo engine rebuilding book, they say that they specify a (0.008-0.016) ring gap for the top ring on the 295cc, and a (0.006-0.010) on the 350cc. however just below that chart, they have a "upper Limit" wich states a max (0.040) clearance..

But sounds like your ideal would work, just as long as you dont make it too snug, then you will have some major issues of ring binding.

I can scan the page if you all want to see it?

[DOOmsman]

In snowmobile engines the wrist pin is placed higher (closer to the crown) as strokes get longer to cut down on piston scuff is the reason I asked. Keep us posted, very interesting project.

[pizzamaker]

this is weird! i'm building a 295 with .50 over 350 pistons this weekend, this is the fourth one that i have done and they make a good power.

[pizzamaker]

make sure that you take the time to check your deck height, the deck height on this one is -.097 so this block will have to be decked.

[IMG]http://i320.photobucket.com/albums/nn343
/pizzamaker_photos/deckhieght.jpg[/IMG]

[Monsterezgokid]

Originally Posted by DOOmsman

In snowmobile engines the wrist pin is placed higher (closer to the crown) as strokes get longer to cut down on piston scuff is the reason I asked. Keep us posted, very interesting project.

I see where your geting too now.. You make a good point..
I havent ordered the 350 pistons for this project yet, so when i do, ill measure it up and see what the differences are in the pin distance..

And pizzamaker, you engine looks nice. did you use a high temp paint/engine block paint for painting the block? Looks sharp





One thing i would like to look into (maby for this project, but just for general knowlege) is stiffer valve springs, and whatever else i can do to make this engine beable to hold up to higher rpm's. I know that a proper shaft balance would help, but do any type of high performance or forged connecting rods exist out there?. I remember reading about a member here who has a performance 350 or something like that, which he uses in his go kart. But he never really expained the setup on that engine.. i would guess that those internal parts would be a custom thing?

I know im geting kinda off topic here, im not looking for a true high performance tire screecher for this one motor, but would consider doing fun performance thingys on other motors. And just to see what others have done for performance goodies.

With the motor im working on, i planed on doing a complete rebuild, so i thought why not just go with some added umph on stuff that i would be replacing anyways.

[pizzamaker]

i don't see the need for stiffer valve springs for what most people are using these engines for, you want to end up with something dependable! ez go 4 cycles are hard on valves to start with so stiffer valve springs will only shorten the life of the valves as well as the cam,rockers etc your rev limiter will come on way before you can float the valves! the oil being low or to hot and the ring gap being to tight is the leading cause of rod/engine failure [my opinion] along with the old style valve keepers blowing off. the squelch factor [the distance between the top of the piston and the highest part of the combustion chamber] in the head is were a lot power comes from! thats were the block decking comes into play. if you can get this distance down to .025 to .035 it will compress the fuel to burn with greater power. over all compression, cam,carb jetting, exhaust,etc,etc all need to play together to make HP.
some do not agree but 15HP can and is being made without a ton of money or time.

[calvindj]

hey pizzamaker, just joinedthe club yesterday. have been serchin & askin on B U forum for a month about 295 mods. i see where you've built several and i'm build one now. my question is can i safely fit a .50mm over 350 piston in that block? my buddies that work @ ez-go here in augusta say no & you say yes, so help me out a little please. i'm great at buidin car engines so get as technical as you want. i really would like to keep up with my 350 buddies.and how can i acheive those 15 horses? Calvindj

[rusty]

Welcome to the forum calvindj......................

[spled77]

Should we use a 350 head gasket with this MOD? And a 295 gasket kit or is the 350 gasket kit the same?

[pizzamaker]

Originally Posted by spled77

Should we use a 350 head gasket with this MOD? And a 295 gasket kit or is the 350 gasket kit the same?

yes, use a 350 gasket set