#21  
Old 03-04-2017, 05:07 AM
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Then the OP should run that cam and see if it works, that is the only way to know for sure with these things......Cliff

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Old 03-04-2017, 11:50 AM
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Bulter is building the engine correct? Why would he build a street engine that wouldn't perform as expected and be detonation prone? I would think with all of their yrs of experience they would have some what of a clue by now.

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Old 03-04-2017, 12:06 PM
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Lets look at it a little differently.

1. I'm sure we can all agree that the LSA is the amount of degrees between the center of the peak of the intake lobe, and the center of the exhaust lobe.

2. I'm sure we can also agree that both valves are not open at max lift at the same time. Therefore what is happening at max lift is not what's responsible for the power changes created from LSA changes.

3. I think we can also agree that power changes from LSA changes are due mainly to exhaust valve positioning at TDC during overlap. This reduces overlap.

4. I think we can also agree that intake valve opening is sooner with a narrow lobe sep angle. And that exhaust valve opening is delayed with narrow lobe seps. This keeps torque pushing on the crank for a longer period of time[crank degrees]. More torque being made.

5. So, with that being said, one of the tricks Harold did with these lobes is he not only made them non-symmetrical, but he also[and I probably shouldn't be saying this, but Harold is no longer with us, so it probably doesn't matter as much now]offset the lobes from the center of the cam core. No one else does this. By offsetting the lobes, it changes the exhaust positioning at TDC on a cam ground on a 110° LSA, to emulate a non-offset lobe ground on a higher LSA like 113°-114°. But at the same time, it positions the intake lobe more like a cam ground on a tighter LSA. This is how they get such wide power bands out of what some might call a narrow lobe sep. Now, when the piston is at TDC during overlap, the exhaust valve is closed a lot more than the intake is open. By advancing these offset lobes 6°, it gets the intake to exhaust lobe relationship to emulate a wider lobe sep. I know a lot of people won't fully understand this, but Harold was a very smart man, and had a lot of tricks up his sleeves. There are other things he did to these lobes, and his other lobes that I am not going to get into that has to do with valve action.

I just wish people would give them a try before deciding they are no good based solely off of what a cam card says. The cam specs in the books are really deceiving when it comes to these lobes. I just ask that before these are judged, they be tried first. After all, you can't say a meal sucks, if you never tasted it.

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  #24  
Old 03-04-2017, 12:07 PM
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Originally Posted by slowbird View Post
Bulter is building the engine correct? Why would he build a street engine that wouldn't perform as expected and be detonation prone? I would think with all of their yrs of experience they would have some what of a clue by now.
Yep, you would think!

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  #25  
Old 03-05-2017, 05:24 AM
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Bulter is building the engine correct? Why would he build a street engine that wouldn't perform as expected and be detonation prone? I would think with all of their yrs of experience they would have some what of a clue by now.
Yes, Butler is prepping the block, rotating assembly and build the heads to match the Voodoo HR cam with 1.65-rockers but I'll assemble the engine. Told them intended use of the car, trans, stall, gearing, and disired compression ratio. In the email I got back from them they told me that I had done a good job of selecting parts for the kit and that they would contact me if any questions arose during the time the short block and heads are being built. I'll check with them of they can short fill the block with Hard Block before the machine work. I followed grivera's advice and looked up the Harland Sharp rockers. Could not find a single thread where a HS rocker have failed. So I decided to get their Diamond series (400$ @ Jegs).

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  #26  
Old 03-05-2017, 05:56 AM
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Originally Posted by gtofreek View Post
Lets look at it a little differently.

1. I'm sure we can all agree that the LSA is the amount of degrees between the center of the peak of the intake lobe, and the center of the exhaust lobe.

2. I'm sure we can also agree that both valves are not open at max lift at the same time. Therefore what is happening at max lift is not what's responsible for the power changes created from LSA changes.

3. I think we can also agree that power changes from LSA changes are due mainly to exhaust valve positioning at TDC during overlap. This reduces overlap.

4. I think we can also agree that intake valve opening is sooner with a narrow lobe sep angle. And that exhaust valve opening is delayed with narrow lobe seps. This keeps torque pushing on the crank for a longer period of time[crank degrees]. More torque being made.

5. So, with that being said, one of the tricks Harold did with these lobes is he not only made them non-symmetrical, but he also[and I probably shouldn't be saying this, but Harold is no longer with us, so it probably doesn't matter as much now]offset the lobes from the center of the cam core. No one else does this. By offsetting the lobes, it changes the exhaust positioning at TDC on a cam ground on a 110° LSA, to emulate a non-offset lobe ground on a higher LSA like 113°-114°. But at the same time, it positions the intake lobe more like a cam ground on a tighter LSA. This is how they get such wide power bands out of what some might call a narrow lobe sep. Now, when the piston is at TDC during overlap, the exhaust valve is closed a lot more than the intake is open. By advancing these offset lobes 6°, it gets the intake to exhaust lobe relationship to emulate a wider lobe sep. I know a lot of people won't fully understand this, but Harold was a very smart man, and had a lot of tricks up his sleeves. There are other things he did to these lobes, and his other lobes that I am not going to get into that has to do with valve action.

I just wish people would give them a try before deciding they are no good based solely off of what a cam card says. The cam specs in the books are really deceiving when it comes to these lobes. I just ask that before these are judged, they be tried first. After all, you can't say a meal sucks, if you never tasted it.
Paul - I really appreciate you taking the time to answer questions and share your experiences in this thread! I read through the whole "505 build for the street" and "Noisy Hydraulic roller lifters" threads yesterday. I will make the modification of the lifter bores as you described. Your attention to all the little details in a engine build awesome. If / when I build another engine, I will definitely contact you to build it for me.

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  #27  
Old 03-05-2017, 06:39 AM
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Originally Posted by Burningbird View Post
Thanks for the "heads up" about the Scorpion rockers. I'll ask Butler which rockers they recommend for my combo. The Crower's is probably best, but is quite expensive.
Steve C, these heads have the new CNC heart shaped chambers. I live in Sweden were we still have 94-octane at the gas station and it rarely gets above degrees 80°F in the summer. I hope this reduces the risk of detonation. My previous engine, a 400 (406) with ported iron heads and 10.1:1 comp. run fine without any problems. I have tried to "copy" some of your engine combo with this build, but a little milder version than your's.
steve25, I hope the drivetrain will hold up, not too sure about the 295 Cooper Cobra's in the rear...
Let me help you in a way that I wish someone had helped me!

Back when I first returned to England I brought with me my prized 1987 GLHS Shelby Charger #116. It was fairly high strung anyway but I had the Shelby Stage II computer installed and 91+ octane was required to fend off detonation. In America this meant buying the higher priced fuel. Imagine my joy upon coming to England and finding the cheap stuff was 92 and the expensive stuff 97. Woo hoo, right?

Long story short, I discovered something AFTER the hole in my #4 piston appeared...

If you look closely at the octane label on a US pump you will see some interesting small writing. It will say something like:

87 octane R+M/2

Know what that means? There are a few industry standard octane tests. The older test is the "Ron octane" test. It always gives a higher number. The newer test is the "Motor octane" test. It always gives a lower number. US pumps show the average octane rating from these two tests. In the UK (and in Europe as far as I'm aware) only the Ron octane rating is used. In other words, the US "87 octane" fuel and the UK "92 octane" fuel were roughly equivalent. And my American "91 octane or greater" fuel requirement meant I should have been buying the 97 octane UK stuff.

Learn from my misfortune.

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  #28  
Old 03-05-2017, 07:34 AM
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Originally Posted by glhs#116 View Post
Let me help you in a way that I wish someone had helped me!

Back when I first returned to England I brought with me my prized 1987 GLHS Shelby Charger #116. It was fairly high strung anyway but I had the Shelby Stage II computer installed and 91+ octane was required to fend off detonation. In America this meant buying the higher priced fuel. Imagine my joy upon coming to England and finding the cheap stuff was 92 and the expensive stuff 97. Woo hoo, right?

Long story short, I discovered something AFTER the hole in my #4 piston appeared...

If you look closely at the octane label on a US pump you will see some interesting small writing. It will say something like:

87 octane R+M/2

Know what that means? There are a few industry standard octane tests. The older test is the "Ron octane" test. It always gives a higher number. The newer test is the "Motor octane" test. It always gives a lower number. US pumps show the average octane rating from these two tests. In the UK (and in Europe as far as I'm aware) only the Ron octane rating is used. In other words, the US "87 octane" fuel and the UK "92 octane" fuel were roughly equivalent. And my American "91 octane or greater" fuel requirement meant I should have been buying the 97 octane UK stuff.

Learn from my misfortune.
Thanks for your concern, sorry to hear about your engine failure. In Sweden we have 95 and 98 octane (RON). As I understand, in US the fuel is measured in AKI = RON + MON / 2. The 98 octane in Sweden is in reality little more than 98 RON, nearly 99 octane, which is equivalent to about 94 in the US (AKI). Both my Firebird -70 with 10.1: 1 compression (406 with 068-cam and Iron heads) and my Bonneville -60 with over 10:1 (389 with 066-cam/closed chamber iron heads) runs fine without detonation on our 95 RON. So I hope that my new aluminum heads with modern chambers and a much larger cam will cope with 11: 1 compression on 98 RON.

/Erik

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  #29  
Old 03-05-2017, 10:49 AM
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Originally Posted by gtofreek View Post
Lets look at it a little differently.

1. I'm sure we can all agree that the LSA is the amount of degrees between the center of the peak of the intake lobe, and the center of the exhaust lobe.

2. I'm sure we can also agree that both valves are not open at max lift at the same time. Therefore what is happening at max lift is not what's responsible for the power changes created from LSA changes.

3. I think we can also agree that power changes from LSA changes are due mainly to exhaust valve positioning at TDC during overlap. This reduces overlap.

4. I think we can also agree that intake valve opening is sooner with a narrow lobe sep angle. And that exhaust valve opening is delayed with narrow lobe seps. This keeps torque pushing on the crank for a longer period of time[crank degrees]. More torque being made.

5. So, with that being said, one of the tricks Harold did with these lobes is he not only made them non-symmetrical, but he also[and I probably shouldn't be saying this, but Harold is no longer with us, so it probably doesn't matter as much now]offset the lobes from the center of the cam core. No one else does this. By offsetting the lobes, it changes the exhaust positioning at TDC on a cam ground on a 110° LSA, to emulate a non-offset lobe ground on a higher LSA like 113°-114°. But at the same time, it positions the intake lobe more like a cam ground on a tighter LSA. This is how they get such wide power bands out of what some might call a narrow lobe sep. Now, when the piston is at TDC during overlap, the exhaust valve is closed a lot more than the intake is open. By advancing these offset lobes 6°, it gets the intake to exhaust lobe relationship to emulate a wider lobe sep. I know a lot of people won't fully understand this, but Harold was a very smart man, and had a lot of tricks up his sleeves. There are other things he did to these lobes, and his other lobes that I am not going to get into that has to do with valve action.

.

Paul, you explained this to me when I paid a visit and it's been hiding in my head ever since. I've been intrigued with the voodoo line of cams since that talk and have been wanting to try one.

  #30  
Old 03-05-2017, 10:56 AM
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As far as compression goes with the old bathtub Edelbrock chambers. So far my father has been running his 571 with these old 1st gen style edelbrock heads with 10.84:1 compression for the last couple years on this 91 octane cat pea they call gasoline out here. It's been running just fine and shows no signs of detonation. It made best power on the dyno at 34 degrees too. Conventional wisdom says these chambers need a lot of timing, but that just wasn't the case with this engine. It lost power with anything above or below 34 degrees. Even in the hot dry summer months here it's been fine. Choosing the right camshaft to work with it is key and I trust Bischoff knows what he's doing when he did this engine. The carb tune and engine temps will also play a roll. I suspect Butler will get Burningbird squared away fine, 11:1 really isn't that much of a difference.

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Old 03-05-2017, 12:04 PM
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On the engine dyno my previous 462 build with the older design Edelbrock chambers likes 37 degrees total timing.

Keep in mind Dave Bisschop's comments directed toward a 10.5 static compression ratio was a general recommendation. Again for engines leaving his shop to be used under all types of driving conditions, unknown gas quality, unknown camshaft parameters, and not knowing how the end customer would tune and operate the combination.

I agree under the right conditions it can be higher but he is like many engine builders that do not suggest pushing it for most people with a lot of unknowns. Personally I agree and don't push the compression on my cars for a limited increase in potential performance that may or maynot be noticed on a street car. Thus just my .02


.

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  #32  
Old 03-05-2017, 02:12 PM
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I have continually pushed the compression limit with the Voodoo cams. I have built several 10:1 iron headed Pontiacs with Voodoos, and so far the only that has ever detonated was the 10.8:1 428. And it only detonates in the heat of the summer. I told him that was pushing it too far, but he didn't want to get different heads, and decided he would mix race gas in the summer. Winter time, it runs great!

I built a 389 that was exactly 10:1 with 1964 closed chamber heads, with a smallish Voodoo[227/227 @ .050"]. Ran great on 91. Built a 10.1:1 413 with iron 670 heads, no detonation on 91. A few others that were close to 10:1. Just need to get the Voodoo degreed in the right place. And that is 6°-7° advanced. Have built many other brands with them also, while pushing the compression limit. How little hot exhaust gas that gets regurgitated back into the chamber during overlap is a key ingredient to them not detonating. That is far more important to detonation, than the closing point of the intake valve, IMO. I know that goes against the grain, but I routinely go against the grain, and like it! Scratches the itch's, you know!

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  #33  
Old 03-05-2017, 08:52 PM
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I have other engines here I push the limit with. My 302 is a true 11:1 with original iron heads and a slightly revised blue print of the original 30-30 cam. It's running great on 91 pump. A 406 sbc I have with 10:1 and iron heads and a modern tight LSA cam works fine on pump. My 454 with AFR aluminum heads and modern chambers will run on 89 with 10.2 :1 comp. I wish I pushed the compression up more with this one.

The one that bit me was the Firebird. We talked recently Paul about the compression it has with it's original iron heads. Always ran great on 94 octane back east but now with 91 octane for the last 10 years it's been sensitive in the heat here. So that is now getting a revamp.

I still want to go against the grain and try a voodoo cam Paul I don't mind experimenting.

  #34  
Old 03-06-2017, 12:57 AM
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Originally Posted by Burningbird View Post
Thanks for your concern, sorry to hear about your engine failure. In Sweden we have 95 and 98 octane (RON). As I understand, in US the fuel is measured in AKI = RON + MON / 2. The 98 octane in Sweden is in reality little more than 98 RON, nearly 99 octane, which is equivalent to about 94 in the US (AKI). Both my Firebird -70 with 10.1: 1 compression (406 with 068-cam and Iron heads) and my Bonneville -60 with over 10:1 (389 with 066-cam/closed chamber iron heads) runs fine without detonation on our 95 RON. So I hope that my new aluminum heads with modern chambers and a much larger cam will cope with 11: 1 compression on 98 RON.

/Erik
Looks like you are on top of the issue. Wish I had known.

Sam

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  #35  
Old 03-06-2017, 02:09 PM
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Just received that exact cam in the mail Saturday, will be going in my 461.

Doesn't Comp Cams own Lunati these days? Or am I mistaken?

.

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  #36  
Old 03-06-2017, 02:10 PM
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Recalculated the compression ratio and only got 10.8:1. This is with 4.211" bore, 4.5"-stroke, 87cc chambers, 6cc(?) dish/valve relief in pistons, 0.045" gasket thickness, 4.3"(?) gasket bore diameter and the pistons 0.005"(?) down in the block. Waiting for Butler to email me back about short filling the block.

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  #37  
Old 03-06-2017, 02:21 PM
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Originally Posted by HWYSTR455 View Post
Just received that exact cam in the mail Saturday, will be going in my 461.

Doesn't Comp Cams own Lunati these days? Or am I mistaken?

.
Looking forward to hear your opinion about the cam! My car is undergoing a complete overhaul and it will take at least a year before it's on the road again.

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  #38  
Old 03-13-2017, 04:00 PM
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Originally Posted by 'ol Pinion head View Post
Just a few thoughts... then someone can crucify me for bringing it up

An .060 455, I'd be concerned about cyl wall thickness. Would not a proper short fill of hard block, folllowed by block machinework, & an oilcooler make sense w/ any stock block with one of these 4.5" stroker cranks? 6.8 rods with 4.5 stroke is going to result in a 1.51 R/S....short skirt design custom piston, quicker cyl bore wear.
Just got an email back from Butler and they do not think it is necessary short fill with hard block with my application. Also asked about Mega-brace but that was not necessary either with the Lunati HR.

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  #39  
Old 03-13-2017, 06:47 PM
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I would imagine it is dependent on the power level you're shooting for.

My father was going that route with a stock block and 4.5" crank and with the power they were shooting for Tony Bischoff wanted to partially hard block it. In the end the block was junk anyway so he decided to go aftermarket.

  #40  
Old 03-21-2017, 08:57 AM
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I was thinking if I should use a windage tray on this engine. It has a stock type oilpan with a baffle (RPC 6-quart) and Butler's crank scraper. The only one that seems to fit a 4.5 crank with stock style pan is the one Spott Performance makes. Will a see a 10hp gain with a tray or is it just a waste of money on this 6000rpm engine?

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