#21  
Old 04-03-2021, 01:43 AM
ta man ta man is offline
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What cylinder heads and compression?

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466 Mike Voycey shortblock, 310cfm SD KRE heads, SD "OF 2.0 cam", torker 2
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best et 10.679/127.5/1.533 60ft
308 gears best et 10.76/125.64/1.5471
  #22  
Old 04-03-2021, 01:43 AM
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2 400 ci Pontiac engines. First one has 13.5:1 cr and has peak cylinder pressure of 1350 psi. Second one has 9.5:1 cr and has peak cylinder pressure of 950 psi. @ 100 ATDC on the power stroke the 9.5:1 cr engine will have the same cylinder pressure as the 13.5: cr engine. Note for this example both engines have their peak cylinder pressure at 12 ATDC.

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  #23  
Old 04-03-2021, 06:46 AM
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To me there comes a certain point in solid roller lobe function where the only benefits your getting by doing so is reduced fiction and milage life.

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Old 04-03-2021, 07:10 AM
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Here’s a informative chart from DV’s second book on BBCs in terms of the amount of overlap needed, and the BBC is a lot like 455 in terms of its not so great rod to stroke ratio and it’s need for far better breathing’ heads to produce rising power above 5000 rpm.
.
And yes, overlap and the placement of the overlap plays a part in breathing that shouldn’t be overlooked .
I wish I could posted up the instructions bigger in my second picture for easier reading, but that’s the best I could do!
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!

1) 1940s 100% silver 4 cup tea server set.

Two dry rotted 14 x 10 Micky Thompson slicks.

1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.

Education is what your left with once you forget things!
  #25  
Old 04-03-2021, 08:40 AM
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I've asked Butler, and await their guidance. The ideas here seem to gel well, and that off-the-shelf might be probable.


I've associated low duration cams with pinging. And cam that are just a bit too much with ping-free operation on 87 octane. In this case i will have a 9.0:1 long block to place the Roller, and a 10:1 Spare to place the 236/244 Flat HYD per below.

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Old 04-03-2021, 09:17 AM
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Steve, can you repost the Chart ahowing the leftside Compression ration? Thanks!

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Old 04-03-2021, 09:19 AM
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Quote:
Originally Posted by steve25 View Post
To me there comes a certain point in solid roller lobe function where the only benefits your getting by doing so is reduced fiction and milage life.

Yes. With snowbirding across 720 miles each way, the goal is mileage life.

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12.24/111.6MPH/1.76 60'/28"/3.54:1/SP-TH400/469 R96A/236-244-112LC/1050&TorkerI//3850Lbs//15MPG/89oct

Sold 2003: 12.00/112MPH/1.61 60'/26"x3.31:1/10"/469 #48/245-255-110LSA/Q-Jet-Torker/3650Lbs//18MPG 94oct
Sold 1994: 11.00/123MPH/1.50 60'/29.5"x4.10:1/10"/469 #48/245-255-110LSA/Dual600s-Wenzler/3250Lbs//94oct
  #28  
Old 04-03-2021, 09:29 AM
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Opp’s, sorry!
Here it is for ya!
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!

1) 1940s 100% silver 4 cup tea server set.

Two dry rotted 14 x 10 Micky Thompson slicks.

1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.

Education is what your left with once you forget things!
  #29  
Old 04-03-2021, 10:55 AM
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Butlers will likely be suggesting those comp extreme marine profile I mentioned.

Looking at Vizards overlap chart we have been pretty far down the chart on some engines and still had milage in the 20s. Not saying his chart is at all wrong, but if you follow it to the T and are trying to get milage you will likely end up with a tractor engine. We have ran 70 to 80* of overlap and not seen much change in the milage. The cams all had pretty late EVO events.

Kind of what Stan posted, EVO doesn’t seem to drive the cylinder pressure that much. In very simple terms. Work=F * s. Force x distance. We have had better fuel economy increasing the (s) in that equation with the later EVOs, then paired the intake profile and overlap with the cid, compression and head flow. Don’t necessarily have to have a smooth idling tractor engine to get good economy.


Last edited by Jay S; 04-03-2021 at 11:17 AM. Reason: add
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Old 04-03-2021, 11:24 AM
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So, i am sold on the 4.21" Stroke for Street, and MPG mileage, even with towing (like any sort of incline-uphill). The matter of great MPG versus cubicfeet/mile is dealt with by gearing/overdrive and EGR. EGR is that neutral filler gas (nitrogen) that makes a 455 run on the air of a 326. Air//fuel ratio being locked to 12:1, EGR allows a rich enough burn for power and great MPG.

All that goes away when "flooring it"!

That said, and out of the way, the parameters to allow 87 octane fuel for making ping-free power and performance app to favor the low/medium compression with EGR from cam overlap. I have sketched some Driver-controlled EGR schemes to tune-in the best EGR while on the highway, to compliment what-ever the cam is-or-isn't doing well enough.


Last edited by Half-Inch Stud; 04-03-2021 at 11:34 AM.
  #31  
Old 04-03-2021, 11:36 AM
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Well I think that we can all agree that if a fuel mileage goal needs to met, then that will always come by means of average best numbers,

As in for example the most torque produced in the least amount of rpm between 2000 and 3000 rpm, with good power up to let’s say 4500 rpm for down sifted up stiff grade climbs and passing moves while towing.

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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!

1) 1940s 100% silver 4 cup tea server set.

Two dry rotted 14 x 10 Micky Thompson slicks.

1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.

Education is what your left with once you forget things!
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  #32  
Old 04-03-2021, 12:08 PM
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This thread needs the intended cruise RPM really bad.

Clay

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Old 04-03-2021, 12:15 PM
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Quote:
Originally Posted by tom s View Post
I have been REALLY happy with the Stump Puller!Have it in my 434 RA V.70 MPH at 1900.Tom
Would guess the stump puller lift is too high (can't remember it offhand) for HIS wants/needs. BTW - what lift are we talking about?? And..why the want for low seat pressure on a HR?? Heads already set up for that???

I also run a Stump puller in a low compression 455+ w/ low enough compression to run 87octane - and yes. A great cam. Aluminum heads, etc.

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Old 04-03-2021, 12:31 PM
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Quote:
Originally Posted by steve25 View Post
Here’s a informative chart from DV’s second book on BBCs in terms of the amount of overlap needed, and the BBC is a lot like 455 in terms of its not so great rod to stroke ratio and it’s need for far better breathing’ heads to produce rising power above 5000 rpm.
.
And yes, overlap and the placement of the overlap plays a part in breathing that shouldn’t be overlooked .
I wish I could posted up the instructions bigger in my second picture for easier reading, but that’s the best I could do!
Steve,
I don't have the book. But from working with David on his TMC / Torque Master Cam program (I did the computer programming). I would have to believe there should also be a LCA chart in his book also.

Stan

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Old 04-03-2021, 12:36 PM
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Quote:
Originally Posted by GTOLou View Post
Would guess the stump puller lift is too high (can't remember it offhand) for HIS wants/needs. BTW - what lift are we talking about?? And..why the want for low seat pressure on a HR?? Heads already set up for that???

I also run a Stump puller in a low compression 455+ w/ low enough compression to run 87octane - and yes. A great cam. Aluminum heads, etc.
This would be my choice something similiar..what I would want is to make the engine efficient at cruise and the higher lift will not hurt.
I'm not why the OP is afraid of lift..this isn't the old days..modern engines have lift.
If aluminum heads were in the budget..combined with a cam similiar to the stump puller with an overdrive it would be 20mpg plus at 70mph.

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466 Mike Voycey shortblock, 310cfm SD KRE heads, SD "OF 2.0 cam", torker 2
373 gears 3200 Continental Convertor
best et 10.679/127.5/1.533 60ft
308 gears best et 10.76/125.64/1.5471
  #36  
Old 04-03-2021, 12:56 PM
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Quote:
Originally Posted by ta man View Post
This would be my choice something similiar..what I would want is to make the engine efficient at cruise and the higher lift will not hurt.
I'm not why the OP is afraid of lift..this isn't the old days..modern engines have lift.
If aluminum heads were in the budget..combined with a cam similiar to the stump puller with an overdrive it would be 20mpg plus at 70mph.
While it does come down to lobe design. But in must cases the more lift for a given duration the more velocity and acelleration the valve will see. Mark put some limits on what he wanted for valve spring pressures.

Stan

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Old 04-03-2021, 01:14 PM
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Quote:
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Best results seem to be an asymmetrical intake profile with more seat timing, and the exhaust can be a symmetrical profile that is more aggressive and less seat timing. Usually see a drop in exhaust temps for heavy towing. It helps the exhaust valve spend extra time on the seat to transfer heat. .
^^^This^^^

Take a page from International Harvester, a typical cam spec for their 345 CID motor is 188/178 @ .050, lift .440/.395. I think overlap works out to around 39 degrees.

The 10 degree lower exhaust duration is specifically to promote heat transfer off the valve. You might consider adjusting the intake duration upward to match the increased displacement of the engine, but maintain the 10 degree lower exhaust duration

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  #38  
Old 04-03-2021, 01:27 PM
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Quote:
Originally Posted by darbikrash View Post
^^^This^^^

Take a page from International Harvester, a typical cam spec for their 345 CID motor is 188/178 @ .050, lift .440/.395. I think overlap works out to around 39 degrees.

The 10 degree lower exhaust duration is specifically to promote heat transfer off the valve. You might consider adjusting the intake duration upward to match the increased displacement of the engine, but maintain the 10 degree lower exhaust duration
I would be interested in what the intake port flow to exhaust port flow ratio is for that International Harvester engine.

Stan

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Old 04-03-2021, 03:05 PM
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This is what DV has in that same book Stan.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!

1) 1940s 100% silver 4 cup tea server set.

Two dry rotted 14 x 10 Micky Thompson slicks.

1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.

Education is what your left with once you forget things!
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  #40  
Old 04-03-2021, 03:33 PM
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Quote:
Originally Posted by steve25 View Post
This is what DV has in that same book Stan.
Steve,
Thank you

Stan

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