TOPIC: Proper Groove angle

Hello All,

After doing a number of grooves and seeing improvements on the emission side but not what I want on the performance/mpg side, I began to question the angle I have been cutting the groove. I believe the important angle is between the shaft and the throttle body plain. I noticed my large bit has a shiny mark close to the actual cutting portion. I think I am holding the bit to high, causing the bit to also cut into the back of the throttle plate itself. I know we are not looking for perfection here, but if I am close but not close enough - room for improvement.

Just a thought. I'm thinking of making some sort of "gauge" to check on the angle of the groove once made. I would hold this "gauge" across the groove, with the throttle plate wide open and look for gross imperfections.

Also - Dan Merrick mentioned cleaning the forward edge of possible burs and spurs. Would cleaning more of the groove itself and the trailing edge help or hinder. Are we looking for a sharp forward and trailing edge?

Thank you all for your help. I want to make sure my grooves DO make a big difference, not just a small change.

Scott

Well, I watched the training dvd again. The most important angle is the taper on the shaft to the body of the throttle body - keep it parallel. I will probably start by re-grooving our 2002 Olds Silhouette this weekend, paying close attention to angles. This will be a test of my theory - if performance changes. I will also double check all vacuum connections and seal problems.

Scott

Whenever you are not seeing power, the normal cause is vacuum related. You'll hear this from me time and again, until you start preaching it to the bathroom mirror!

Double check your vacuum before you start re-grooving. It is far better to be too steep than too shallow, for if the entire bit is not IN "The Groove" then it is NOT "The Groove"!

You're doing great, Scott!

Quit doubting your abilities and stick to the basics...

Groove
Vacuum
ECU

And in that order! Once the groove is done, ALWAYS look at the vacuum before anything else.

Ron

A ditto to what Ron said. Little things can mean a lot, but vacuum is the key. Providing your engine is healthy, if you can get the vacuum system leak free and plug that pcv at the intake you are going to see your desired results. Vacuum, vacuum, vacuum.

Hello Scott, please check out my last posting on the forums. It is the one that is a 1995 with a 5.7 throttle body injected.

A major relearning and preaching session to me and all the Gadgetman family on how important the vacuum and anything connected in conjunction to the vacuum of engine.

A little leak can take away from the little groove effects faster than the groove can improve.

Keep up the good work, and please as Ron said don't doubt your abilities. I know you will overcome this , just keep grooving and smiling.

God bless you, GadgetmanNebraska Aron Cheek

I'm posting to this old thread to get it in front of us again. Notice what Scott says about the bit angle. To restate it again--the bit front flat side is held against the throttle plate in the initial cut. You hold the Dremel flex shaft so the bit remains steady in all directions, and use moderate pressure to begin cutting straight down against the plate. Using the plate as a backstop, cutting straight down into the bore wall material. You keep going, until the TAPER of the shaft directly behind the cutter head touches the TB bore wall. Strive to hold the tool so the TAPER of the shaft is parallel to the bore wall. This might mean the flat bit end will not be exactly flush to the plate.

I will take the bit itself and hold it in the TB to get an idea of the angle position needed- so that the taper is as close to parallel w/ the bore wall, then see how close to directly against the plate this is.

The next cut, is a half-cutter ball width to the right. Keep repeating this way from left to right.

I'm just restating what was already said here, with a bit more detail.

Tracy G