Power Crater vs Flat Top

We can't help it if you didn't adjust the timeing and had the wrong clearance on your 2 stroke.

We can't help it if you use soft rods, weak pistons or poor design. All of your failures are a result of your own thoughts and actions.

You're full of bs pank. You've got a different argument than you had last time on this subject. Had anyone other than Marty posted the same things you wouldn't give 2 hoots.

It's easy to see how little you know.

Ever look at an m&w and see where the top ring is located? Better yet show us.

I bought a wd45 that was not running. When I pulled the engine apart I found flat top pistons in it with every ring land broken. It was a work tractor, my guess is someone unknowingly overhauled it with the wrong parts.

The pistons were .380" down in the bore if I rember correctly. I'd have to measure a piston sometime and figure it, but that's way to much compression for cast pistons and low octane gas.

I set my M&W's up to be 11.25 :1. I took right about .050 0ff the top to get the quench height.   I think I trimmed the original 70cc bowl out to 88 or 90cc which didn't take that much other than take the little vane out of them, taper the sides and true up most of the bottom. Then with the valve relief machined in I think the total volume was something like 92cc.

I buy a few gallons of 114 race gas and blend with a little 92 for it. It probably went to 6 or 8 pulls this summer, dad and my hired help take it out if there's time. I went to a couple with it a few times and try to find a kid to drive and let have some fun.    


Edited by wi50 - 21 Nov 2012 at 11:54pm

mlpankey wrote: That wasnt the question. The question was is your quench after running the same as it was or did the turbulance errode the piston top. I also have picture of turned down pistons that were heavily pulled and they broke after third season. Would have lasted longer if sit in the barn and only made two pulls a year.

What's your point? Turned down pistons broke. Detonation kills. Another failure.

M and W pistons are quite thick and have a huge dish to start with. Others are not so well suited.

That wasnt the question. The question was is your quench after running the same as it was or did the turbulance errode the piston top. I also have picture of turned down pistons that were heavily pulled and they broke after third season. Would have lasted longer if sit in the barn and only made two pulls a year.

Edited by mlpankey - 21 Nov 2012 at 6:13pm

Wi have you had the head off that motor so you could see if there were any errosion of the piston top caused by the tight quench. We tightened a two stroke up it ran like a scoulded dog but when we tourn down for a freshening we saw our flat top had a slight dome from the errosion of the piston edge shaping its self to the cylinder fire ring creating a poor mans dome in the two cycle world.

I have Powercrater pistons from an AGCO 175 kit in my WC with a 4" crank and all WC components (carb, intake, etc).  M&W dyno at Old Threshers put her at about 32 horse for what it's worth.  My WD has WD45 powercrater pistons on a 45 crank and all 45 componets, made 50 on the same dyno the year before.  Wanted to run them both this year, but didn't get the chance.
AaronSEIA

It comes from the compression increase when people install the flat top pistons for a 4" stroke in an engine with 4 1/2" stroke.

I've see some discussion about flat top WD pistons giving more power to 226 engines than the Power Crater Pistons. Is it only because of the higher compression or was the Power Crater a bust?