Pistons

Flathead8

New member
I have heard to use Weiseco and Burris Pistons, but have heard Weiseco likes to burn up or bust apart, almost if they cannot handle it....Any help would be greatly appreciated. Thanks!
 

jhucks03

Member
Never had trouble with a Wiseco in my Modifieds. I guess maybe if your running a load of nitro. What class are you running? Assuming a stocker-type, either one would go for a long time. However, I thought you could only run Briggs piston (not sure because I think they upped the bore to .050).
 

Flathead8

New member
I'm running in "stock-appearing" class, if that helps, I haven't memorized all the rules and regulations down on what I can and can't do with the engine
 
In that class you can do anything inside as long as it appears stock from the outside, so basically an open but with a stock looking from the outside carb. The carb is your limiting factor as the stock carb can only be bored to around .750 and have enough strength to last a little while. You need to check an see if the Cyclone carb is legal ,it's looks somewhat stock but was not built out of a stock carb and is much bigger than what a stock can be. As far as pistons and rod's are concerned you need a longer than stock rod , 4.500 would be good and the appropriate Weisco to go with it. Weisco's will not burn up or break. Jon
 

Flathead8

New member
Thank you Jon,
I have an Arc rod, I don't remember what it is off hand, the carburetor has an imprint of GForce with the three squiggly lines under it. I have an aluminum flywheel with an 8* offset key. Have a red high top coil, and a .10 over piston. The cam is where it gets me, I don't have any idea on how to figure out if it is stock or even what it is. Is there any numbers that would help figure that out? And they call it "eyebrowing" or "eyelashing" the intake and exhaust parts so there is a better flow from valves to piston and vice versa...
 
Sounds like a bored stock carb, # 8 key is quite a bit of advance for the timing, must be a big lift cam if it matches the ignition timing. If the engine is together you can check lift by measuring off the deck at max lift and get an approximate number. If cam is out of the motor then measure the full length of the lobe top to bottom then subtract the base circle, which can be measured 90 degrees from the first measurement and get you close. A stock cam will only have .233 lift . The rod length will determine what piston pin height you'll need. You may have a stock length rod, ARC made a lot of them as they are used in the stock class. If it's stock length it will be marked 3.870 or 3.875. Jon
 

Flathead8

New member
Thanks again,
I'll make sure to figure out what's all there! Should I make a grove from the sliver of block between the piston and intake and same for the exhaust side, because there isn't any on the block. And should I smoothen out the exhaust port to get rid of the internal threads inside the block? Flathead8
 

jhucks03

Member
Leave exhaust port pretty much untouched, a reducer would even be better. You can cut the eyebrows, but I'd say you have quite a few easy bolt-on power before you go hacking the block.
 
Releiving the block by removing the eyebrows between the valves and cylinder make a big difference in flow and is worth the time.
You say you have an aluminum flywheel, is it an aftermarket type such as ARC or a stock Briggs (lawnmower) wheel? The Briggs wheel is very dangerous to use.
The G force carb is one supplied by Dover, he can give you the specs, it may be a stock class carb and for stock appearing should be bored to .750 and a thin butterfly installed.
If you intend to run over 7500 RPM a long rod is in order, either a 4.475 or 4.5" length should work, the 3.875 rod runs out of steam at the high RPM range. -- Chuck
 
That is not a billet wheel it's some kind of casting, don't run it , consider it a lesson learned. You would be much better off with a stock 5hp wheel if you can't find a billet that fits your budget. Stock wheel can turn high 7's low 8's with no problems, anything much more than that you need a billet to be safe. Jon
 
That looks like a cast aluminum Briggs flywheel. I recommend you NOT use that flywheel as they more likely than not will explode at high RPM. They were used in lawnmower applications (verticle shaft) at RPM's of around 3600 where a heavy flywheel was not needed due to the weight of the blade. -- Chuck
 

CarlsonMotorsports

Premium User
What's amazing is that that particular ebay seller has been selling these cast aluminum flywheels (calling them racing-Briggs flywheels) for several years now and getting big bucks for them.

Take that flywheel off and throw it in the trash can before someone gets hurt or worse!



There is no problem with Wiseco pistons. Some of the very best that money can buy. Just make sure that you buy current inventory....There are sellers on ebay that still have new "in the package" Wiseco pistons from 20+ years ago. I got a bunch of these older pistons in a buy-out a couple years back and they certainly aren't the same quality as the newer forgings. Same goes with Burris pistons. The newer stock is very good.

Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cuts
www.CarlsonMotorsports.com
765-339-4407
bcarlson@CarlsonMotorsports.com
 

Flathead8

New member
What's amazing is that that particular ebay seller has been selling these cast aluminum flywheels (calling them racing-Briggs flywheels) for several years now and getting big bucks for them.

Yeah, that is what I thought when I had that flywheel was delivered. It sure did look like an aluminum cast. That had kind of made a bit furious that I got jipped out! oh well, we live and learn. But it's a good thing I didn't run it, hopefully others won't either.
 
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