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Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 08-November-2022 at 8:42AM
Originally posted by lynchster lynchster wrote:

Been doing all the research all over again with a better understanding of tolerances and consequences. 

1. Based on cylinder psi the calculator puts my compression closer to 10.4 -10.5

2. Three Howard Cams matched to 9.0, 9.5, and 10.1 wind up at just about 150 psi. 

3. According to George Pence the cast heads can manage 8.0:1 dynamic compression. Alloy heads 8.4:1.
I think his very informed opinions and his preference for sports car performance versus muscle cars lead to his preference for sub 8 dynamic compression ratios and higher lsa's.
I don't think he's wrong. The higher pressures don't lend themselves to the durability of factory produced and warrantied drivetrains. Piston rings would last longer and high stress abuse would crack these blocks 50 years ago.

4. I'm just guessing here and I could be wrong again. With the improvement of just pulling the timing to 6 degrees I could probably run colder plugs, better than 90 octane fuel, and jet the carb richer but for what? I'm still losing 10 degrees of timing, giving up a lot of power, and still stressing the engine.

5. I haven't found the specs for the cams Pence did but I suspect they're flat tappet designed. I wish I had a Dyno program so I could play with camshaft profiles. 
The one Howard's cam with a 69* IVC is close but I wouldn't mind tweaking the specs on it to drop a bit of lift and maybe shift the LSA a bit to get closer to 72* IVC. 
I called Howard's today and my springs are good for the .611 lift too but I don't know about piston clearance or the oil band height.
The guy also thought a 75* ICV was crazy. Obviously not a Cleveland guy. 😆

6. Not sure I want to do this swap myself just yet. Daily driver? Sure. Converted engine that cost more than most cars I drive not so sure.

7. Conflicting information:

Read psi for street cars between 150 and 200 psi. (WTF?)

Seen compression test on a Cleveland at 180 psi. Two cylinders were at 150 though.....

Feel free to throw out thoughts, criticisms....

   



What do you mean in your third point?  Are you saying that George is conservative or too aggressive on the DCR because he does sports car engines?  I am not really sure what you mean.  My engine has mid 7s for DCR and I wouldn't want too much higher than that, especially since 91 Octane is the best I can get. 

I agree with Rock, your DCR is too high. The way I see it is you have two viable options. 

First, replace the cam, which probably will move your power band, which is why I asked what gears you are running. I suggested asking George for a cam grind, but I didn't know his health was down.  It's too bad because he did help me out when I was doing my build.  In the end I used a custom grind designed by Tim Meyer.

Second, reduce the compression, either with new pistons, or by increasing the combustion chamber size like Rock showed above.  If you are pulling the intake, pulling the heads to work on the chambers might be not too bad of a job, but I can't say I'd want to go at the combustion chambers with a die grinder, I'd worry I'd mess something up.  Maybe you are up for that kind of work or there is some in your area that can do it?

Check you PMs, I will send you something else that might help you out.


Edited by 72FordGTS - 08-November-2022 at 9:57AM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote handsofstone Quote  Post ReplyReply Direct Link To This Post Posted: 08-November-2022 at 9:17AM
Chuck, 
   Billy Ray's Haberdashery and Tim Halstead on Facebook might have some tips as well. Billy Ray does some nice work and videos on youtube as does Tim. Not sure where Billy is located but if he is nearby it may be worth it to have him tweek the chambers to lower your compression to work with your current setup.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 08-November-2022 at 3:59PM
What do you mean in your third point?  Are you saying that George is conservative or too aggressive on the DCR because he does sports car engines?  I am not really sure what you mean.  My engine has mid 7s for DCR and I wouldn't want too much higher than that, especially since 91 Octane is the best I can get. 

I wouldn't say he's concervative or agressive. The longer LSA's he prefers would seem to indicate his tuning preferences. Not a bad thing, a preference.  

Figuring that the Boss 351 was running a similar compression ratio I'm not really considering dished pistols or redoing the heads. Since the block is studded that's pulling the engine and it's taken 17 years to get this together.

According to Pense the cast heads can support a dcr of 8.0 which seem to indicate cylinder pressures  in 160 range. I've seen other Cleveland builds in the 180 range. Mine is right there and it would indicate to me that there are too many compromises involved in that range.

I figure if Ford can offer a 10.6:1 Cleveland with a dcr in the 7.5 - 7.7 range in a production car I should be able to come up with a roller cam in the 7.5 - 8.0 range without killing it. 

Howard's offers an off the shelf cam  with an IVC of 69 that would theoretically put the cylinder psi at 162-ish. The centerline is 106 and the exhaust lift is .611.
I'm considering a design tha staggers the exhaust valve no higher than .600 and opening the lsa to 110 - 112.. I'm not sure how it works in practice but I think with a couple of tweaks I can get the PSI to 155-160 easily. The question being how does the altered cam timing effect the engine.











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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 09-November-2022 at 10:22AM
DCR's from 69* IVC

Static compression ratio of 10.4:1
Your dynamic compression ratio is 8.01:1
Your dynamic cranking pressure is 163.82 PSI


Static compression ratio of 10.5:1
Your dynamic compression ratio is 8.08:1
Your dynamic cranking pressure is 165.69 PSI

unfortunately you don't have any elevation to speak of to help out. i've been using flat sea level.
bumping you up to 1000' makes a difference but IMO you should plan for the worst

Static compression ratio of 10.4:1
Effective stroke is 2.61 inches
Your dynamic compression ratio is 8.01:1
Your dynamic cranking pressure is 158.48 PSI
Your effective compression ratio reflecting 1000' altitude, is 7.81 :1

Static compression ratio of 10.5:1
Your dynamic compression ratio is 8.08:1
Your dynamic cranking pressure is 160.34 PSI
Your effective compression ratio reflecting 1000' altitude is 7.88 :1

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 09-November-2022 at 12:33PM
Ok, now I understand what you mean about Pence's preferences. But even Rock said to keep the DCR at 8 or lower too.  One thing you have to remember when looking at DCRs from engines like the BOSS 351 and the other high compression engines from this era is they used higher octane fuels then that we don't have readily available today.  I liked Rock' recommendation of keeping DCR at 7.7-7.8 and from his math above the 69* IVC doesn't seem to do it.

I sent you a Google Drop Box download.  Not sure if you got it or it worked?  It might help you with the cam selection.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 09-November-2022 at 2:00PM
Thanks Vince
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 09-November-2022 at 2:22PM
Originally posted by Rockatansky Rockatansky wrote:

DCR's from 69* IVC


Now I know where the slight differences in pressure are! I've been using 300 ft. I'm at 450 but surrounding areas dip to 300. Weird going in because I just pulled the altitude out my head for consistent numbers.
I've made two phone calls this week and had rambling conversations with with a guy at Howard's. That cam at 112* LSA gets me to 71 IVC. My only concern there is the .611 lift on the exhaust side without the lifter bore sleeves.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 72 RS 351 Quote  Post ReplyReply Direct Link To This Post Posted: 10-November-2022 at 3:45AM
If you pay for a custom cam, the extra $100 gets you control over everything. You set the limits as you want them, and they should easily design a cam to meet them. If you don't want it to open the valves more than .600, you tell them that.

My refresh I'm hoping to use OEM type rockers, which have a general limit of .550", if I can run them to 6000+ rpm or a little more, that's a limit I will set for the cam.

Tell them what you require, it's their job to design it to work optimally within those. If you are having pre-designed cams suggested to you, then those are not going to be the best possible for your engine and vehicle.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 10-November-2022 at 10:55AM
I've been having fun with that calculator. LOL
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 10-November-2022 at 11:15AM

this is Brent Lykins cam page, i'm sure he can cobble a cam for you to make it all happen. just a heads-up Brent and George didn't quite see eye to eye. give him a call & rake it over the coals, if Brent's not your cup of tea we can pull a recipe from George's web page. i know there's a hydro roller or 2 in there somewhere and get it ground by Bullet. i'll start looking if i get a chance
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 10-November-2022 at 1:31PM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 10-November-2022 at 4:15PM
Thanks Rock!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 13-November-2022 at 6:31AM
Interesting experiment but I have no idea of the math behind it. 
In the dyno2000 program I took the flat tappet Boss351 Cam and flipped the same specs to a roller cam. That alone netted a 45 Hp / 36 TQ increase. I assume it's just in the projected cam lob profiles. ? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 13-November-2022 at 10:51AM
I think you are correct about the program making the assumption on the ramp rates of the cam lobes. The hp figures in the program aren't always the most accurate but what it is really useful for is comparing changes from one cam, head or other changes to another and the affect on the power curve etc. I did some stock do some stock engines with the program and got pretty close to the advertised figures (gross SAE numbers).
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 13-November-2022 at 11:17AM
Originally posted by 72FordGTS 72FordGTS wrote:

I think you are correct about the program making the assumption on the ramp rates of the cam lobes. The hp figures in the program aren't always the most accurate but what it is really useful for is comparing changes from one cam, head or other changes to another and the affect on the power curve etc. I did some stock do some stock engines with the program and got pretty close to the advertised figures (gross SAE numbers).

I did that with the Boss351 cam. Now I'm experimenting......LOL
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 13-November-2022 at 1:48PM
I picked 2 cams so far. One from George and one of the Howard's off the shelf cams 235245-12.  
                                      LIFT              DUR            LCA        ICL         PSI        DCR
George's cam 70* IVC   .544/.544    .278/.286         114        111        160        7.96 


Howard's        67*IVC    .576/.600   .278/.282         112        108        166        8.14
230245-12

Howard's -3    70*IVC    .576/.600   .278/.282         112        111        160        7.96   
230245-12

George's cam    396HP @ 6K       411TQ @ 4.5K   
Howard's  -3     405HP @ 6K       410TQ @ 4.5K


Howards   -4     405HP @ 6K       408TQ @4.5K  

These following are my assumptions based on how I understand what I'm looking at. Please feel free to correct if so inclined. 

Georges cam is 3* advanced                                  114 LSA / 111 LCA     70* IVC
Howard's 230245-12 is 4* advanced                       112 LSA / 108 LCA     67* IVC

I assume if I install the 230245-12 3* retarded        112 LSA/ 111 LCA      70* IVC
If that's the case taking out the whole 4* advance    112LSA/ 112 LCA       71* IVC

Basically losing 1-3 ft lbs of torque in a place I'd never miss it. 

The HP and TQ between Georges cam and a 3* retarded 230245-12 cam are just about identical until you get to 5500 and 6000 rpm where Georges cam falls of by 4HP/4TQ and 9HP/9TQ. Not very important picking one over the other in a street car.  

I find the lift differences and similar power curves somewhat confusing

The previous numbers were based off the Dyno2000 program with a dual plane intake and HP manifolds (they are large compared to most) w/ full exhaust

Large tube headers w/ full exhaust    453HP @ 6K      451TQ @ 4.5K
Add Single Plane                              490HP @ 6K      469TQ @ 5K   
Drop the exhaust                             503HP @ 6K      480TQ @ 5K  
 
 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 14-November-2022 at 1:16PM
factor in chain stretch and i think you'll get that 3* you're looking for fairly quickly. me personally i'd target at least that 72* IVC figure i came up with, it'd be a pisser to go through it all and still be on the edge
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 14-November-2022 at 3:00PM
Originally posted by Rockatansky Rockatansky wrote:

factor in chain stretch and i think you'll get that 3* you're looking for fairly quickly. me personally i'd target at least that 72* IVC figure i came up with, it'd be a pisser to go through it all and still be on the edge
Not too happy about it now but it is what it is. I'm just as concerned about going too soft as I am too hard. Disappointment is not what I'm looking for in a 17 year project.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 15-November-2022 at 6:12AM
How does it look if you retard the Howard's cam 6 degrees so it runs 2 degrees retarded?

This timing set allows for +- 8 degrees at 2 degree increments:


Can you post pics of the power curves?


Edited by 72FordGTS - 15-November-2022 at 6:55AM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 15-November-2022 at 11:54AM
Didn't even think to check at 8*. 😮
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 17-November-2022 at 3:59PM
Originally posted by 72FordGTS 72FordGTS wrote:

How does it look if you retard the Howard's cam 6 degrees so it runs 2 degrees retarded?

This timing set allows for +- 8 degrees at 2 degree increments:


Can you post pics of the power curves?

I had re read your post. I'm likely going to just swap the camshaft but I'm having a lot of fun with the program.
I retarded the cam 8* (in the program!). 
It flipped the cycles on the intake and exhaust. Likely more than obvious to someone who's studied camshafts. If I understand what I'm reading it would likely cause exhaust reversion. The intake closes at 68.3 but the exhaust is closing at 64.3. Most are closing in the mid to late 70's.
It does mathematically look better in the program. 
As it sits   392HP @ 5500 / 426TQ at 4000
8* retard  407HP @ 6000 / 411TQ at 4000 and 4500  
   
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lynchster Quote  Post ReplyReply Direct Link To This Post Posted: 17-November-2022 at 4:27PM
Originally posted by 72FordGTS 72FordGTS wrote:

Can you post pics of the power curves?
Apparently not the way normal people do.....

This is one retarding my cam 8* versus the 235245-12 retarded 3*. Not much difference on paper but the latter has slightly better vol eff.
The latter also has an exhaust cycle 14* longer 

Without dots is the cam I have -8*


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Post Options Post Options   Thanks (1) Thanks(1)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 19-November-2022 at 9:30AM
The retarding helps but it seems not enough.  From the DCR calculator at 300' it shows:

Static compression ratio of 10.4:1.
Effective stroke is 2.84 inches.
Your dynamic compression ratio is 8.12:1 .
Your dynamic cranking pressure is 165.15 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of PSI is 8.06 :1.
V/P (Volume to Pressure Index) is 144

Interesting seeing the power curves don't change that much between the cams.  What I actually wanted you to try was retarding the Howard's 230245-12 6 degrees instead of 3 degrees as you indicated above.  I think that might get your DCR to a safer range and not affect the power curve too much.  Runinng the Howard's 230245-12 at 3 degrees retarded seem to get the DCR close, so I thought 6 degrees might be right on the money.

Maybe Rock will have a better idea.
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