SM Head Modifications on a budget

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Earlie A

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pittsburghracer said:
Well my thinking is especially with guys that want to buy their own valves is a 2.02 and a 2.055 cost the same right? The throat is already on the large size right? The valve job on Edelbrock and Speedmaster heads kinda suck from the factory right? Most guys want a local shop to check their heads out so I’m thinking for about the cost of a competition valve job if they could possibly pick up 15cfm would it be worthwhile. Is 15cfm there to grab. Just thinking outside da box.
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This conversation was started in another post and moved here to avoid the hijack. PBR’s post above sums up his idea about taking SM heads, getting a 2.055 valve job done by a machine shop, then making the other modifications and improvements at home with tools that are inexpensive and readily available. So basically, how much improvement can a guy doing his own head modifications expect to achieve? Should be a fun exercise.

I have one untouched port in a SM head that I purchased on Black Friday, and a box of SM 2.055 valves. These were all purchased for testing purposes anyway.

Since @pittsburghracer was gracious enough to volunteer my services for the testing, I will return the favor and ask that he serve as ‘mentor’ and suggest/provide an outline of the modifications to be made and an order for doing so (which step is first, which step is second, etc).

Here are the steps that I am considering, in no particular order. Please feel free to suggest additions.
*Valve job for 2.055 intake valve (must be done by a machine shop)
*Back cut angles on 2.055 intake valve (drill press and die grinder)
*Enlarge PRP width (die grinder and cartridge rolls)
*Bowl blend (die grinder and cartridge rolls)
*Head bolt bulge reduction (die grinder and cartridge rolls)

I intend to flow test between each modification to show the changes along the way.

Now PBR, give us an itinerary. What comes first and why?

The attached pictures show some similar tests I performed some months back. It shows the order that I performed some of these same tests on the same head but with a 2.02 valve.

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My thinking was since most guys like to have a machine shop check out their bare heads that would probably be my second stop. We have had plenty of members over the years that have enlarged “the pinch”. That I think should be the first step as many have done so. It can safely be opened to 1 inch by almost anyone with basic hand tools. So probably the first test I would like to see is opened up for a 2.055 valve with a 30 degree backcut on the intake. Then a 70-60-45-30-15 competition valve job. I’m not so sure members would feel comfortable working the common wall and removing the head bolt bulge but that would be an interesting 2nd test.
 
Edited,

Whatever it is, I have my popcorn ready.
:popcorn:
 
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Ant said:
You talking about factory or aftermarket heads for the testing? Or are these experiments going to apply to the majority of small block heads?

Whatever it is, I have my popcorn ready.
:popcorn:
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Reread the very first post.
 
Here's some preliminary information. From the factory with 2.02 valves, the throat measures 1.820 wide and 1.825 deep. We'll call the throat 1.823 diameter which is 90.2% of 2.02. The pushrod pinch measures 0.935 wide x 2.08 tall which is an area of 1.945 in². I'll try to remember to measure the port volume before grinding on anything.

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Something I slept on and thought I better post off it’s been so long since I’ve just opened the pinch without tubing I went from memory and thought you could go 1 inch safely on the pinch. I checked Shadydales website and he used the .950 figure. I wish I had time to check a head but I gotta beat the 90 plus degree heat. Maybe later.
 
I prepared the valves for the testing this morning. See the pictures below for the redneck back angle riga-ma-jig. This jig took 30 minutes to make and is plenty rigid enough and accurate enough for grinding back angles. It is NOT suitable for grinding seat angles. Each valve took about 1 minute to grind a 30 degree back angle. I tried to get the back angle and the 45 degree seat angle the same width. Each angle came out about 0.070" wide.

As can be seen, the jig consists of 2x4's, conduit clamps and woodworking clamps. The pneumatic die grinder and grinding stone are from Harbor Freight. It's nice to have a drill press like in the pictures because of the rigidity and the ability to move the valve up and down easily. Similar results could be achieved with a hand drill or an electric die grinder. Instead of the stone, a carbide burr or cartridge roll could be used. The important thing is rigidity and maintaining a fairly consistent angle between the valve and the cutting tool.

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You my friend need a few tools and if you think you are having fun now, just wait. My only regret is getting a couple of them so late in life.
 
Watching and thanks to both of u posting. I did my own redneck porting/cleanup on my x heads. Probably hurt them more than helped lol, time will tell.
 
Another cool thread. Thanks. Can you clear up the acronym "PRP" for a dumb ****, please?
 
pittsburghracer said:
You my friend need a few tools and if you think you are having fun now, just wait. My only regret is getting a couple of them so late in life.
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But the title of the post is 'on a budget'. Still trying to convince my wife that she really wants a dyno.
 
Earlie A said:
But the title of the post is 'on a budget'. Still trying to convince my wife that she really wants a dyno.
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Well there’s your mistake. You have to convince the wife that she NEEDS a dyno.

Need and want are different. Need means you have to have it. Want means yeah it’s cool but I can live without it.
 
Newbomb Turk said:
Well there’s your mistake. You have to convince the wife that she NEEDS a dyno.

Need and want are different. Need means you have to have it. Want means yeah it’s cool but I can live without it.
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Hush up or I'll convince your wife you NEED another smack in the head. lol
 
Newbomb Turk said:
Well there’s your mistake. You have to convince the wife that she NEEDS a dyno.

Need and want are different. Need means you have to have it. Want means yeah it’s cool but I can live without it.
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I've got to change my perspective.
 
Everyone has their own way of going about it……

I start with cutting the seats as the first step.
I feel the valve job dictates how you approach the bowl & chamber work.

I have a pretty steady hand and rarely have any serious “slips”.

Cutting seats for a novice, I would set the seat angle very slightly on the small side, with the understanding that the seats will need a final touch up after the porting is finished.

Baseline test- heads ootb
2nd test- recut seats for bigger valve(no porting)
3rd test- (stage 1)blend bowl and mild touch up of SSR
4th test- add back cut to valve
5th test- open PRP
 
Earlie A said:
But the title of the post is 'on a budget'. Still trying to convince my wife that she really wants a dyno.
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Ya but 90% of the guys are going to get their valves backcut by the guy checking out their heads and doing the competition valve job. You would be dangerous with a dyno. Lol. Wow I typed this out hours ago and forgot to push post. Damn phone calls.
 
pittsburghracer said:
Ya but 90% of the guys are going to get their valves backcut by the guy checking out their heads and doing the competition valve job. You would be dangerous with a dyno. Lol. Wow I typed this out hours ago and forgot to push post. Damn phone calls.
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May be safer than me driving a 10 sec car though.
 
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Here's the baseline data. Test 598 is the stock port tested with a single angle 2.02 Speedmaster valve. Test 597 is the stock port tested with another Speedmaster 2.02 valve from the same box of valves but with a 30 degree back cut from the Redneck back angle jig. Since the Redneck jig seemed to make some people cringe, I thought it would be fitting to test the Redneck valve against a 'properly' backcut valve. So, I got out the valve grinder and made the valve for Test 599, which is again the stock port with another SM 2.02 valve from the same box cut to 30 degrees.

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With all due respect to PRH and his input, which I always appreciate, I'm going to let PBR call the next shot since that was our initial plan and this whole thing is really his idea. What's next? PRP?
 
Let’s see what opening it up for a 2.055 valve with a performance 70-60-45-30-15 and blending into an 89% throat does for us. Then like I said most guys are capable of using snap gauges or a go no go fixture to open the pinch up to .950 without touching the common wall because we can always gain more area there later. Airspeed numbers at the pinch and short turn after the valve job but before opening up the pinch would be interesting. Then we could see how much the pinch mod calmed the port.
 
pittsburghracer said:
Let’s see what opening it up for a 2.055 valve with a performance 70-60-45-30-15 and blending into an 89% throat does for us. Then like I said most guys are capable of using snap gauges or a go no go fixture to open the pinch up to .950 without touching the common wall because we can always gain more area there later. Airspeed numbers at the pinch and short turn after the valve job but before opening up the pinch would be interesting. Then we could see how much the pinch mod calmed the port.
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I have a Newen 60-45-30 cutter that cuts an 0.059" 45 degree. What widths would you like to target on the 30 and 60?
 
Earlie A said:
I have a Newen 60-45-30 cutter that cuts an 0.059" 45 degree. What widths would you like to target on the 30 and 60?
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.059 is pretty wide to be considered a performance 45 degree seat. They are more in the .040-.045 area. My 70 and 60 are pretty wide on my cutter and thin as they come up. I’m assuming you are going to hand blend the valve job and short turn. Just to remove lips and blemishes
 
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