So many posts about pinch on here, so let me clear up some misconceptions about pinch...
When the engine is new, the pinch is tight so that the piston will wear into the size of the sleeve and create a good "seal." When the engine is still new (1/2 gallon or so) it will not have full RPM because the friction is holding the engine back. After the pinch has been reduced (maybe 1 gallon or so), the rpms will be very high, and you will have maximum power. After that you will not feel much pinch, but the engine will run for a LONG TIME. This is the maximum for the engine, between 1 gallon and 4 gallons. Some go longer than others, but most will give good performance for 5 gallons or more. We've had freak engines go around 9 or so.
So what am I saying? Pinch is over rated! Don't be so preoccupied with the way the engine feels, just pay attention to how it runs. If it idles and the tune is consistent, you have a winner. We spend all our time trying to get rid of the pinch to get max power, and I read about guys worried because the pinch is gone. Send it to me and Cody will run it.
If you run Team Orion engines, it has the highest quality materials and high silicon piston material. It will maintain the seal longer. It's not some cheap engine that once the pinch is gone, it's done..
The only time you have to worry about the engine losing compression is if you are way over 300 degrees or lost your air cleaner. Then you have problems. Also, the maintenance of the engine is important, keeping clean and fresh air filters all the time. Also, grease the ends of your inner air cleaner sponge. Most of the engines that get ruined suck dirt underneath on the inside closest to the carburetor. That's where the dirt gets in between the housing and the foam.
Here's some tips for long engine life:
- ALWAYS turn the car on it's side when you put in or take out plugs to keep dirt out. If possible, clean inside the head around the plug with the compressor or motor spray as well.
- Be a fanatic about clean air filters! Check often and change frequently.
- Grease the ends of your inner filter sponge.
- Don't take the engine apart! I try as much as I can to never take the engine apart unless absolutely necessary.
Hope this helps the sportsman guys, and for the expert guys, it never hurts to have a refresher... I follow all these guidelines religiously. - PK