2.055 Speedmaster Porting Progression
- Thread starter Earlie A
- Start date
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The other aspect of this is that guys like Earlie and PBR (rip), are getting heads to experiment with. I'm sure there are many castings in the graveyard before you really start producing worthwhile results. Better to buy some TF or Bloomers and move in with life, it'd be a lot cheaper
I'd just be doing a different type of bench racingYou don't need a flow bench.... For bench racing
Earlie A
Well-Known Member
I've tried many other combinations of valve angles but never shallower than a 30 degree final top cut. Yesterday I decided to try a 15/30/45 valve job and keep track of time. So yesterday morning the valve job was cut and the chamber worked over. Valve job was about 1 hour, but that included setting up a 15 degree plunge cutter with sharp corner (that's the only 15 degree cutter I have and I sure don't like the sharp inside corner it cuts), a 30/45/60 three angle cutter set for the 2.08 valve and individual 60, 70 and 80 degree cutters to form the throat. Before blending throat is 88%.
Cutting the chamber was about 1.5 hours.
Last night the pushrod and head bolt holes were tubed. That was about 45 minutes.
This morning the port was roughed in. Bowl was set at 95%, pushrod wall moved, roof raised, pinch enlarged, head bolt bulge removed and common wall flattened. Total time this morning 1.5 hours.
All that is left is the floor and the short turn and cutting the radius on the pushrod pinch to pushrod wall interface. I also need to go over the entire port with a double cut burr. Roughing was done with a single cut burr. There is probably about 1.5 hours of work remaining.
So total for 1 intake port will be slightly over 6 hours. Obviously if doing an entire set of heads with 8 intake ports the time per port could be reduced. Might be able to get it down to 4-4.5 hours per hole on the intake side?
It's also easier to build a middle ground efficient smaller engine than a highly efficient larger one.
I meant for a given HP and RPM, Eg.. you want a 500 hp @ 6000 rpm, most would build a 408, 500 hp x 5252 / 6000 rpm / .9 = 486 lbs-ft / 408 = 1.19 lbs-ft per cid is ruffly what you need, to build a highly efficient 360 you need around 1.35 lbs-ft x 360 = 486 lbs-ft x 90% x 6000 rpm / 5252 = 500 hp @ 6000 rpm.
PRH
Well-Known Member
I commend your efforts………but if spent that much time on heads like that, I feel like I’d end up working for peanuts.
Even at 4 hrs per cylinder it’s way more time(money) than most would be willing to pay……not to mention you haven’t touched the exhaust yet.
I’ll be looking forward to the flow results and the final time tally on those.
Using some RPM heads that got “stage 2” type porting(270cfm), retaining the 2.02 intake valves, on a basic 416 bracket build, I got 560hp using a very easy on parts SFT cam.
Those heads got about an hour per cylinder worth of porting.
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Earlie A
Well-Known Member
You have touched on this before and I agree. If you have any chance of making money porting heads, for most customers you have to shoot for 90% of the potential gains and call it good. That last 10% is time consuming.
PRH
Well-Known Member
Is that head you’re working on slated for the head dyno shootout?
Earlie A
Well-Known Member
Not the 15/30/45 unless the flow results shock me. I'm just trying it to learn. I EXPECT the extreme low lift numbers will be great and the mid lift numbers will suffer vs something with a steeper top cut. I have no idea what the high lift numbers will do. Conventional wisdom says a steeper valve angle and a steeper top cut is better at high lift and I believe that to be true when turbulence (separation) doesn't shut down part of the throat area. I'm curious to see what a more shallow top cut will do in a couple of areas of the chamber at high lift.
PRH
Well-Known Member
My prediction is, the flatter top angle will allow the onset of separation over the SSR to occur at a lower lift …….than if a steeper top angle were used.
ValiantRacing
Well-Known Member
Have you ever worked/reshaped just the chamber and then flowed the head?
Earlie A
Well-Known Member
Not without doing the valve job first.
ValiantRacing
Well-Known Member
What kinda of improvement did you see?
Earlie A
Well-Known Member
I’ll try to look it up when I get to the shop tomorrow but what I remember are pretty good gains at low and mid lift maxing out about 10 or 15 cfm at peak. Can’t get much more out of the Speedmaster until apex area is increased and the short turn reworked.
Earlie A
Well-Known Member
Here's an example of a stock 2.02 Speedmaster, then a 2.055 valve job, then a chamber deshrouding. For clarification, this test is from about a year ago and is not the same port being discussed earlier in this post. I think the valve job and the chamber blend in this example could be better as there is not much improvement in the mid lift flow. I would expect a little more there. The big takeaway for me with this head is that on the top end there is not much improvement that is easily available until you start working the whole port and short side.
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Earlie A
Well-Known Member
This thread is getting a little confusing and I apologize for posting flow numbers from multiple ports in the same thread. Now I am posting flow numbers from the 15/30/45 2.08 valve job that was cut in a port a couple of days ago. The floor and the short turn were finished this morning and flow tested. There is not much that I like about a 15/30/45 valve job. I didn't like the way the chamber looked. Compared to steeper top cuts the port sounded off from 0.050" lift and never improved. The 30 degree cut is only 0.050" wide so it's probably a little on the small side, but for my way of thinking this is just too much expansion too fast. Not a fan.
NC Engine Builder
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Looks like it could be viable on a low lift restricted deal, like some oval track deals.
Earlie A
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Could be. Mid lift flow numbers are decent. I think I'll sink the valve just a little to make the 30 degree cut wider and see what that does.
NC Engine Builder
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In some situations they only have like .410-.420 lift, but that's a totally different scenario than what your discussing here....cary on!
I could see it working pretty well with this grind in a limited stock class.
Howards Cams 712901-12 Howards Cams Hydraulic Flat Tappet Camshafts | Summit Racing
Howards Cams 712901-12 Howards Cams Hydraulic Flat Tappet Camshafts | Summit Racing
PRH
Well-Known Member
I know what you mean about the “sound” even when the numbers are decent.
The curve hung on better than I thought it would.
PRH
Well-Known Member
In simple terms, my take on that is the longer/steeper top cut allowed the numbers to continue to climb, then the SSR took over and with the valve that far from the seat, is back in control.
So in a way, that shorter 30 with the 15 top did cause the port to peak lower……. If not necessarily earlier.
So in a way, that shorter 30 with the 15 top did cause the port to peak lower……. If not necessarily earlier.
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