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Re: 572-13 head flow-by flow tech 2 [Re: Cab_Burge] #3064546
08/02/22 03:28 AM
08/02/22 03:28 AM
Joined: Apr 2016
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NH, USA
toddinNH Offline
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NH, USA
Originally Posted by Cab_Burge
I wonder how much actual CFM flows through the motor at or below 3/4 max lift work shruggy


A good 1D simulation like EngMod4T will show you that plus so much more. Buying Ricardo WAVE or GT-POWER might be slightly more accurate(you can plug in different burn models more easily) but unless an engine OEM are simply too expensive.

A curious person can learn more about ICEs in a few months with 1D software than a lifetime of learning via other means. It just requires careful measurements that most enthusiasts don't seem willing to collect.

Re: 572-13 head flow-by flow tech 2 [Re: toddinNH] #3064854
08/03/22 10:27 AM
08/03/22 10:27 AM
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So. Burlington, Vt.
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fast68plymouth Offline
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It would be interesting to see what some of the better modeling software would spit out for Gregs build with the two different flow curves plugged in.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: 572-13 head flow-by flow tech 2 [Re: fast68plymouth] #3064869
08/03/22 11:07 AM
08/03/22 11:07 AM
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Pattison Texas
csk Offline
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Pattison Texas
Originally Posted by fast68plymouth
It would be interesting to see what some of the better modeling software would spit out for Gregs build with the two different flow curves plugged in.

Yes it would, I'm gonna say it would like the back cut on the intake only, just my opinion


1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392

Re: 572-13 head flow-by flow tech 2 [Re: fast68plymouth] #3064890
08/03/22 11:54 AM
08/03/22 11:54 AM
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NH, USA
toddinNH Offline
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Originally Posted by fast68plymouth
It would be interesting to see what some of the better modeling software would spit out for Gregs build with the two different flow curves plugged in.


If Greg had the data to plug into EngMod4T I would run a few scenarios, but in order to to do so - and get something of value for outputs - requires hundreds of measurements; some of which aren't simple to obtain.

For a quick and dirty analysis of the two flow curves, Engine Analyzer Pro(free trial period) might price interesting. I'd do it, but I have wasted the trials on all my PCs and cannot locate the pertinent files and delete, restoring my boxes to the pre-trial state.

Re: 572-13 head flow-by flow tech 2 [Re: toddinNH] #3065088
08/04/22 09:02 AM
08/04/22 09:02 AM
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Shelby Twp. Mi
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Generally, the best way to gage a good cylinder head for a novice is to see if it performs on the engine. You've been lucky to have access to some good people in this build. (Larry and Todd etc) If the car doesnt run to your expectations probably the last thing I'd examine is the heads or intake. Just the same, we appreciate you sharing the pieces and some data you have on them!

Re: 572-13 head flow-by flow tech 2 [Re: HardcoreB] #3065155
08/04/22 12:32 PM
08/04/22 12:32 PM
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Las Vegas
Al_Alguire Offline
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Get that thing screwed together and in the car already biggrin


"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"
Re: 572-13 head flow-by flow tech 2 [Re: Al_Alguire] #3065177
08/04/22 02:16 PM
08/04/22 02:16 PM
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PA.
pittsburghracer Offline
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Originally Posted by Al_Alguire
Get that thing screwed together and in the car already biggrin




YaaaaaA. Winters coming. Lol 😂


1970 Duster
Edelbrock headed 408
6.143@110.85 mph
9.73@135.05 mph shifting at 6700 RPM
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: 572-13 head flow-by flow tech 2 [Re: pittsburghracer] #3065333
08/04/22 09:26 PM
08/04/22 09:26 PM
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Posts: 9,564
Frostbitefalls MN (Rocky&Bullw...
gregsdart Offline OP
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Originally Posted by pittsburghracer
Originally Posted by Al_Alguire
Get that thing screwed together and in the car already biggrin




YaaaaaA. Winters coming. Lol 😂

So true. Well, the crank came back, offset ground to 4.560 (yes, 4.560!)which fits the expensive pistons i bought for the -13 heads and a set of poweradder + Molnar rods that are 7.0 long. Makes 580 cubes at 4.50 bore. So i wait for the crank to get balanced and pistons and rods to get pin fitted. Then i can put it all together and hopefully dyno it to dial in the fuel curve. Maybe race at BIR mid september!


8.77 153 mph best, 3055 lbs 528 indy 440-1 alky
Re: 572-13 head flow-by flow tech 2 [Re: pittsburghracer] #3065533
08/05/22 05:01 PM
08/05/22 05:01 PM
Joined: Nov 2015
Posts: 683
Missouri
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jwb123 Offline
mopar
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Missouri
Originally Posted by pittsburghracer
Originally Posted by gregsdart
Originally Posted by pittsburghracer
It will be interesting to see how they stack up on the other flowbench.
it will for sure. Since you port heads, a little info on valve angles. No back cut on either intake or exhaust. I was told a back cut brought up the flow up to . 100, but a net loss occurred in the midrange. So i was told don't let anyone change that.





I went to a two day theory only class on head porting years ago and Darren Morgan recommended putting a 30 degree back cut on everything and his reasoning was it will never hurt and usually help. Like I said that was years ago so that thinking may have changed. He has some really good videos on YouTube that I have shared and guys really enjoy them. I have never watched them because by now I know how I want to go about it and after 100’s of flow tests Im kinda set in my ways. I prefer to do it at least on the intake valves. The 30-45 minutes that he spent on the exhaust side was worth the 600.00 plus the 300.00 I spent to take my son.


I also sat in a seminar by Morgan and I usually back cut all the intake valves. The way i have found that gives the best results is to grind the seats and then slap the valve in the head to get a mark where the valve will seat, then grind the back cut angle so you come close to the seat mark. I want the face of the valve to be at least .060 wide, so if perfect .030 on each side of the seat mark you got slapping the valve. If you just grind a 30 degree back cut on the valve and it is too far away from the seat area it does not give good results. I think you posted on speed talk as well. But you need to check the short side air velocity, if you increased the flow with a back cut you may increased the velocity to make the short side unstable at high lifts, I think Morgan talks a lot about velocity in the ports as well. I have found just a little work with a sanding burr will fix most issues like you describe.

Re: 572-13 head flow-by flow tech 2 [Re: jwb123] #3065656
08/05/22 10:52 PM
08/05/22 10:52 PM
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Bend,OR USA
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Cab_Burge Offline
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When working on motors and using "theory" please remember the valves open and close interrupting the air flow on both intake and exhaust sides.
My message is a flow bench doesn't do that so make sure you have before and after data from either an engine or chassis dyno or from the track with very similar weather conditions when testing before and after ALL changes twocents work
I remember meeting Jacko, an early SO CA very good head porter, in 1969. He had some aluminum 426 hemi heads he was working on for Mopars Direct Connection parts R&D department, he didn't have a flow bench and said he could see what the air would do under vacuum or pressure on the exhaust side.
I'm sure he used a big commercial vacuum cleaner with a smoke tipped sparkler on the intake side and would reverse the hose on the vacuum hose to make pressure on the exhaust side. shruggy
i heard later that he would drag out one of the blocks he had to mount the heads on to do his testing from inside the cylinders with an adapter to seal against the cylinder walls shruggy work
I was really lucky to be able to meet and get to talk to him for a short while, I was installing his phone service after he moved from the coast out to the desert bow


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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