SM Head Modifications on a budget

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My next step would be a quick and easy one…….

Clay in the sharp corner in the chamber that was left by the edge of the 15* cutter……..so it’s like the cut was made with a blade that had a radius on the OD.
It probably won’t do anything at this point, but it would be nice to have the chamber form more “correct” moving forward.

My take on where it’s at right now is……… the SSR is still in control at the higher lifts.
 
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PRH said:
My next step would be a quick and easy one…….

Clay in the sharp corner in the chamber that was left by the edge of the 15* cutter……..so it’s like the cut was made with a blade that had a radius on the OD.
It probably won’t do anything at this point, but it would be nice to have the chamber form more “correct” moving forward.

My take on where it’s at right now is……… the SSR is still in control at the higher lifts.
Click to expand...


He gained some area at the short side but now he has to learn how to use it. Now comes the challenge of trying to control the air to go where you want it to. It starts with bowl work and moves towards the entrance. Think 3D, think PAST the chamber, think center of cylinder bore not cylinder wall. This is the start of sleepless nights.
 
PRH said:
Well, you’re in charge……. What’s the next move?
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I would sure like to see a nice close up of the chamber around the intake valve. Don’t be cheap with the pictures. I can’t imagine a ridge in the chamber that is so bad it couldn’t be addressed with a 3/8 sanding roll. I really don’t like his choice of tooling
 
pittsburghracer said:
I would sure like to see a nice close up of the chamber around the intake valve. Don’t be cheap with the pictures. I can’t imagine a ridge in the chamber that is so bad it couldn’t be addressed with a 3/8 sanding roll. I really don’t like his choice of tooling
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Want the colors gone for the pictures?
 
I looked at a pic of a SM head that I prepped.
As it comes ootb there is already a sharp corner on the wall where the plunge cut and the seat intersect.
So, that’s just what the avg diyer is going to be working with.

IMG_3627.png
 
pittsburghracer said:
I would sure like to see a nice close up of the chamber around the intake valve. Don’t be cheap with the pictures. I can’t imagine a ridge in the chamber that is so bad it couldn’t be addressed with a 3/8 sanding roll. I really don’t like his choice of tooling
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Here's the pictures. There are no ridges in the chamber, other than that created by the plunge cut. A little chatter, but no ridges.

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Looks like the 15* bit you used for the top cut has a radius on it?
I guess I thought it was the one you posted a pic of previously that was squared off.
 
PRH said:
Looks like the 15* bit you used for the top cut has a radius on it?
I guess I thought it was the one you posted a pic of previously that was squared off.
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It was the one in the picture. It was square. There is a 105 degree sharp inside corner formed by the plunge.
 
My take on “bigger” valves being put into heads that are less than optimum in the SSR area is that it usually makes the shortcomings of the as cast SSR form more pronounced.
 
PRH said:
My take on “bigger” valves being put into heads that are less than optimum in the SSR area is that it usually makes the shortcomings of the as cast SSR form more pronounced.
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Sort of the same thing happens when the PRP is opened without changing the SS. It exposes the other problems. The factory sizes the PRP the way they do for a reason.

I watched a Youtube video with Curtis Boggs and Jeff Hammond. Curtis talked a bit about monitoring pressure differentials (pressure drops) in different parts of the port to help really figure out what's going on with these low port heads. I think that would apply here.
 
PRH said:
My take on “bigger” valves being put into heads that are less than optimum in the SSR area is that it usually makes the shortcomings of the as cast SSR form more pronounced.
Click to expand...
Exactly...the belly of the ST + IMO the valve job and transition into the chamber + lack of area around the valve is causing problems the bolt bulge and pinch won't cure.
 
Earlie A said:
Sort of the same thing happens when the PRP is opened without changing the SS. It exposes the other problems. The factory sizes the PRP the way they do for a reason.

I watched a Youtube video with Curtis Boggs and Jeff Hammond. Curtis talked a bit about monitoring pressure differentials (pressure drops) in different parts of the port to help really figure out what's going on with these low port heads. I think that would apply here.
Click to expand...
The pinch should really not hurt a port like this...even if it's a bit large. I really think it's the valve job/chamber hurting things. Still fun to see what the changes you make do. What's really fun is when you unlock or find what the port really likes. Then it's like magic and makes you feel all warm and fuzzy!
 
Do you remember a few weeks ago when it said in one of MY posts to remember three words. Push push push. Almost any head you look at will have what I refer to as a “Herman Munster” overhang at the short turn leading into the valve job. It’s hard to see in Brian’s pictures but on the left side you can see how he “pushed” Herman’s forehead back. This helps you shape the shortside and at the same time widens the shortside. Like others have said you may not have to widen the pinch, till you do. As you learn you will find you go back and forth finding the areas that need work. Those of use that have done this for years can aggressively attack each area from experience. Study this picture and think about how pushing this area back will benefit you. Remember as you lay down and “tighten up” your corners with smaller tools you are not only gaining area but access too.

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Someday when you are bored and have a stock port try these exact same mods on a port with a 2.02 valve.
 
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