SM Head Modifications on a budget

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At higher lifts(velocities), I can see where the radius might be deflecting the air stream out sway from the edge of the valve……..where the thicker margin allows it to ride along that length before making the turn into the bowl.

One theory anyway.
 
This may be the last test prior to taking on Herman's forehead. I don't know of anything else to try other than a different valve job. To get a steeper top cut (which I think would help the separation issue), the valve would have to be sunk which would affect the throat, etc, etc. I think that will have to wait.

This test is the last thing associated with the first 5 steps, but it's really like step 5.5. For this test the ridges in the chamber that were created by the 15 degree plunge cut were blended away. The plug side was smoothed first and flow tested. There was virtually no change in flow. The short side corner was then blended away. The sharp inside corner was a little problematic to get rid of. In fact it is not totally gone. The finish cut in the chamber is a burr finish. No sanding rolls were used.

Final flow results after both blendings are shown. These blendings were a little helpful at low lifts and again at high lifts. There is an apparent decrease in the 0.500-0.600 lift range. With all the instability in that range I think these should really be ignored. All that is happening there is that the sharp ridges are helping to delay flow separation. The ridges are helping the port hold on a little longer before the balloon pops and the flow fully jumps the valve.

I guess it's time for some SSR work.

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Blended chamber looks like a wash, but does give very slight gains where it matters most.
 
This could be the last test in this series of trying to find the low hanging fruit when porting a Speedmaster head. I have prepared 3 ports in the same head with different valve jobs. All three ports have had the pushrod pinch enlarged until the brass tube was reached. All three ports have had the head bolt bulge fully removed. All three ports have had the chamber deshrouded to the gasket line on the long side.

Here's the differences in the ports:

Test 628 is port 3/6 with a 15/30/45/60/70 valve job and a 2.055 valve. This is the port used throughout this entire post.
Test 634 is port 2/7 with a 35/45/60/75 valve job and 2.055 valve.
Test 635 is port 1/8 with a 40/50/65/75/80 valve job and 2.02 valve. The intake valve on this port has been shifted 0.060" and the exhaust port has been shifted 0.080".

Flow results are attached. I think it's safe to say that in the hands of a novice porter like myself, 260-265 cfm is about all that is available from this head until the apex/short side areas are addressed. That was PBR's estimate from the beginning. He thought that there was 15 cfm available from some simple(ish) modifications. That proves to be exactly right.

It is interesting to note the areas in the flow curve where each of the three ports pull ahead of the others and also lag behind the others.

As time allows I plan to make simultaneous modifications to all three ports and track the progress. It will most likely happen in a new thread.

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I thought the goals were more along the lines of:

What I was hoping for was to see how close we could get to 285-290cfm with the least amount of work and cost for guys that can’t afford to pay for a full port job.
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But during this test we are testing things guys can do at home and probably send it out for a competition type of valve job. If we could find simple things a non head porter could do at home and get 285-290 out of it I think that would be great.
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PRH said:
I thought the goals were more along the lines of:
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I thought so too. Lol. 290 cfm is there to grab with a 2.02 valve so I was just hoping for a more simple way of getting there for some of our guys on a tighter budget. A good .300-.550 head that smoothly flows up to 290 cfm at .600-.650 can make some nice power that most guys would be satisfied with.
 
I’ve been miss quoted by a couple different guys in this post. I even copied and pasted a few times. And if you remember right it was an imaginary target set for do it yourselfers. We tried, we failed or should I say he tried we failed.
 
I kinda thought for a website that tends to get boring at times there was a lot of interest by several members.
 
I think he’s still going to go after the SSR, it might just be in a new thread.

My feeling is, he should just continue with the R&D in this thread.
 
pittsburghracer said:
I’ve been miss quoted by a couple different guys in this post. I even copied and pasted a few times. And if you remember right it was an imaginary target set for do it yourselfers. We tried, we failed or should I say he tried we failed.
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I certainly don't consider a ~15 CFM gain with the minimal invasive/risky work involved, a failure. This effort went a long way towards helping me understand how much each modification can be worth and in what part of the cycle they tend to affect performance. I'm looking forward to the next, more involved steps, whether they continue in this thread or a new one. Everyone seems to agree that all the glory is in the short turn radius but I'm still pretty fuzzy on what that ramp should look like when you are done and where the biggest gain can come, with the lowest risk of making a sprinkler. I've got a set of stock ProMaxx 171s I want to improve and when I look at the SSR I think I see where I'd want to start, but I'm probably wrong.
 
gzig5 said:
I certainly don't consider a ~15 CFM gain with the minimal invasive/risky work involved, a failure. This effort went a long way towards helping me understand how much each modification can be worth and in what part of the cycle they tend to affect performance. I'm looking forward to the next, more involved steps, whether they continue in this thread or a new one. Everyone seems to agree that all the glory is in the short turn radius but I'm still pretty fuzzy on what that ramp should look like when you are done and where the biggest gain can come, with the lowest risk of making a sprinkler. I've got a set of stock ProMaxx 171s I want to improve and when I look at the SSR I think I see where I'd want to start, but I'm probably wrong.
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I think he did a great job and thank him for doing all the testing. I’m sure he learned a few things too.
 
@Earlie A thanks for doing this work. It's very illustrative to me. My takeaway from this is that, for the average joe, there's better ways to spend time and money than trying to amateur port a set of heads. Just an awful lot of work for what amounts to maybe 10-15 CFM. I still believe this is a job best left to a professional.

Now....if we could get some old fashioned porting templates to take care of some of this... that would be a different deal altogether. But until that time comes, I'll just look elsewhere.
 
I know mean416 is working on a build that will be using RPM’s instead of SM’s.

As far the the in & ex port openings go, the SM’s have less obstructions.

Imo, it’s probably worth the time to remove the ridges/edges on the RPM heads where the cnc’d port openings meet the as cast runner.
I’ve also seen some RPM’s that had that edge be pretty pronounced at the PRP in some ports.

I like to get rid of the ridge there and blend it into a radius.
 
Mean416 said:
@Earlie A thanks for doing this work. It's very illustrative to me. My takeaway from this is that, for the average joe, there's better ways to spend time and money than trying to amateur port a set of heads. Just an awful lot of work for what amounts to maybe 10-15 CFM. I still believe this is a job best left to a professional.

Now....if we could get some old fashioned porting templates to take care of some of this... that would be a different deal altogether. But until that time comes, I'll just look elsewhere.
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If the plastic templates were available, do you think people would use them? The templates would have to be on the conservative side (to reduce porting mistakes) which would limit flow to say 270ish. We make CNC templates like that in our shop fairly often, so the work would be in digitizing the port on the front end. Making the gauges is easy. I just wonder if people would really use them vs the ease and safety of ordering a CNC head.
 
Earlie A said:
If the plastic templates were available, do you think people would use them? The templates would have to be on the conservative side (to reduce porting mistakes) which would limit flow to say 270ish. We make CNC templates like that in our shop fairly often, so the work would be in digitizing the port on the front end. Making the gauges is easy. I just wonder if people would really use them vs the ease and safety of ordering a CNC head.
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I tried the DC porting templates twice.

I threw them both away.
 
Earlie A said:
I can see that. And I can see a template manufacturer getting tired of the calls and complaints.
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IIRC, one glaring issue was the valve job they called out. Again, off my memory if you didn’t use a basic 45 degree 3 angle valve job it screwed up the bowls which screwed up the rest of the port.

Plus, in the case of the W5 head they didn’t call out the removal of the bolt boss in the port.

You can see on a flow bench that area of pinch is shoving the air across the port to the guide. String showed it so clear Ray Charles could see it happening.

Chrysler said don’t remove it, as it speeds up the air right there!!! That was a WTF moment for sure. I almost asked for a clarification but I declined to care what that dude said any more.

There was some other stuff too. Valve size is one of them. I can’t think of a single instance where I’d use a 2.02 valve in a W2 or 5 head. Ever.

I was looking to do 2.125 or even 2.150 if I didn’t have to move the guides.


So yeah, porting templates may work for basic stuff but if you are going to leave the 2.02 valve in a W2 or 5 head I’d but Trick Flows instead.

It’s a waste of the head.
 
Here’s how I look at it……..

If someone put out an instructional video on YT for a particular type of head…….something about 20-30mins long, that covered all the basic do’s and donts……that should be all the info someone should need to be able to make worthwhile gains.

If they don’t feel comfortable diving in after that level of instruction……..they should probably pay someone to do it.

Of course, a book would suffice as well………but with todays technology…..the YT video if far easier to bring to the public.
 
Well as a guy who's played with a die grinder a fair bit, but definitely not a head porter...

1. I'd use a set of templates and guidelines if it got me in the 280+ range with a set of edelbrocks. That's easily a 500+ HP head now.

2. If the video showed in detail how to address the short side and bowl areas, I'd go for it.

I'm not afraid of using a doe grinder and can do a good job with one, but I am afraid of screwing up a perfectly good set of heads in the process.
 
PRH said:
Here’s how I look at it……..

If someone put out an instructional video on YT for a particular type of head…….something about 20-30mins long, that covered all the basic do’s and donts……that should be all the info someone should need to be able to make worthwhile gains.

If they don’t feel comfortable diving in after that level of instruction……..they should probably pay someone to do it.

Of course, a book would suffice as well………but with todays technology…..the YT video if far easier to bring to the public.
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And its cheaper to do a YT video than to produce a book.

I prefer books but I love to read. I will watch a good video though.
 
I can see where a template would be beneficial in a few select areas like the short turn. Otherwise some specs/dimensions would suffice. Got to be a lot more careful with water in the old iron heads.
 
Earlie A said:
I can see where a template would be beneficial in a few select areas like the short turn. Otherwise some specs/dimensions would suffice. Got to be a lot more careful with water in the old iron heads.
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Haaaayup. My heads don’t match match because I was just making the ST a skosh wider and there it was. That little blister you see when you know you are screwed.

So I had to grab another casting and start over.

If it’s not a W2 head I don’t even consider porting on them.
 
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