Q. What is the best cam you offer for the blue restrictor engine (WKA) and the purple plate (WKA). Is it a Floater cam ?
What should the valve spring pressure's be?, etc......
Please advise on how YOU test for coil bind on your springs... I have been using electronic fish scales to get seat pressures... is this method accurate? HOOK A BROTHER UP ! ! ! !

A. When dealing with any restrictor plate setup it is important to understand that there are limiting forces that greatly effect the performance of the motor, most importantly that piece of metal you just stuck between the carb and block. Well, since we can't do anything about that, let's talk about the things we can change that can give back some of that horsepower that was just robbed. These are the RPM ranges that we will be shooting for.

To achieve these results, follow these few golden rules.

 

Rule # 1: Start out with a good cam!
With this setup, we'll be producing enough RPMs to float the valves, so it's important to select a good controlled valve float cam for your application. Without hesitation we recommend the tried and true 95-3, it's just one tough little cam, and with it's proven track record we can rest assured it will help produce the HP we're after. 

 

Rule # 2: Increase your fuel flow.
This is the most crucial factor in this setup, unfortunately it's often ignored. By increasing the jet size of your carburetor you can help reduce some of the restriction that the plate has given you. Here are recommended jet sizes for the two plates.

 

Rule # 3: Increase the valve lash settings to .007" (intake) & .006" (exhaust). This will effect the opening and closing values of the cam, making the cam open and close LATER.  Since the plate will limit the operating (RPM) range of the motor, you will want to increase the lash (distance between the lifter and valve) to maximize the cams efficiency at the targeted horsepower range. 

 

Rule # 4: Adjust spring pockets for proper spring pressures. The recommended spring pressures (using 95-3) for plate motors are as follows...

For those of you who aren't familiar with spring pressure adjustment you can check out Controlled Valve Float.

And as for testing spring pressures with fish scales: do what you have to do, if you don't have access to a professional spring tester then the fish scale method is better than nothing. Just remember your results may vary!

 

Rule # 5: Adjust your timing. These are the recommended values for our particular setup.

 

Rule # 6: Lastly, choose a good exhaust pipe.
We recommend the following...

 

Well, that's that.  We hope you've enjoyed this months installment of "The DynoCams Tech Question of the Month".  Join us next month as we delve into other mysteries of Karting issues.