Thread: BBF 528 Pump Gas Engine: 737HP & 672lb-ft Torque

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528 Ford Specifications

• Bore: 4.42"
• Stroke: 4.30"
• Rotating Assy: SCAT cast crankshaft, H-beam rods, 36cc "D" shape dish Diamond pistons, King bearings, balanced
• Heads: Blue Thunder 74cc, ported, +.100" Ford Racing valves, 3-angle valve job, 10* locks & retainers, 1.625" dia. springs, 230 lbs seat
• Compression ratio: 9.8:1
• Rockers: Miller 7075-T7 aircraft aluminum, 1.7 ratio
• Camshaft: Billet steel roller, custom ground for this engine combo. Lobe = 0.4550" / .4170", LSA = 109* Dur@.050" = .266 / .278, Lift at valve = .757" / .709"
• Roller Lifters: Morel
• Block: D0VE-A with Boss 429 bulkheads, thermocleaned and mag checked, High Flow Dynamics Stage 1 oiling mods
• Bearing clearances: mains = .0035"; rods = .0030"
• Timing Chain: Ford Racing double-roller with billet gears and 9-position keyway
• Carburetor: Holley 4500 Series Dominator, 1150 cfm
• Distributor: MSD breakerless
• Oil Pump: High Flow Dynamics Stage 1 prepped Melling M84DHV
• Oil Pan: Armando's 10-qt jet boat pan and pickup
• Intake: Edelbrock Victor 460 with Dominator carb flange, ported to Blue Thunder intake port size

This engine was dynoed at Westech, which is the same facility where the recent Engine Masters Big Block Shootout had their engine finalists tested. Results were 737HP @ 6300 rpm and 672 lbs-ft of torque @ 4600 rpm, and 95% of peak torque was sustained all the way up to 5900 rpm. A torque curve that flat obviously extends well below the 4600 rpm mark but I don't have the data because the facility focused on pulls from 4600 rpm & up due the customer's applicaton of the engine (jet boat). I was not in attendance of this session and could not make several requests and changes on the motor during the pulls.

Also, I'm pretty sure there's still more HP in it. Due to some top end oiling debugging from the start of the day, some valve train parts were changed out by the dyno operator for the sake of getting to the pulls, and the replacement parts installed by the facility--I feel certain--cost the top end about 11-14 HP. Additionally due to the time constraints, trials of carb spacers were never evaluated and I think we might have found another 9-12 HP there (the posted results are without a plenum-increasing carb spacer!). In other words, this engine could have conceivably generated as much as 760 peak horsepower on pump gas.

Bottom line is, when the day was over and the customer had his requested 700+HP, he felt we that delivered and so there was no need to search for any more.

Also, I want to emphasize the fact(s) that this engine recorded 737HP with a very conservative 9.8:1 compression ratio and one carburetor.

Honorable mentions go out to:

• Chris Straub (Straub Technologies) for camshaft consultation. Our customer wanted 700HP / Pump Gas / Reliable, which is a tall order and we wanted to be sure we met his needs. I turned to Chris for this build because he profiles camshafts for a lot of big name professional competition engines and he obviously calculated a profile that works excellently with this particular engine combination.
• Charlie Evans (Evans Racing Engines), because I must have called Charlie 4-5 times to discuss the approach I wanted to take porting these Blue Thunder 74cc heads and also discussed with him several valve train hardware options (BT heads ship bare). Charlie provided a lot of insight.
• Van Heskett, my engine building partner, for his never ending patience over this motor build. Of all the engines that we build together, I vehemently insisted this engine have special attention and it was mocked up countless times, while we tried different valve train setups, different valves in the heads, different crankshaft and connecting rod bearings, etc.

528Insalled_2.jpg

528Insalled_1.jpg

Paul

ADynoSheet.jpg

HPTQ_Chart.jpg

Note the strong and stable torque curve. This build was for a jet boat, so the dyno pulls were from 4500 rpm and up, but one early pull, where the oil was just changed from petroleum (engine break-in) to synthetic (pulls), was a lighter pull from just 4000-5500 rpm, and even down there the lowest torque number is 96% of the highest. So now we know that the torque band is diesel flat from at least 4000-6500...and based on this analysis, it's pretty safe to say that the flat torque extends well below the 4000 rpm mark.

I think this particular build shows clearly that all this attention to details can pay off big time at the dynomometer.

Paul

Some very good numbers, Paul!!!! The one I find particularly interesting is the Air/Fuel ratio-----how do you keep it so stable???? Who's your carb guru???? By BG won't stay that steady, and you don't even want to know what I paid for that dog!!!!!!

Originally Posted by Paul Kane

528 Ford Specifications

• Bore: 4.42"
• Stroke: 4.30"
• Rotating Assy: SCAT cast crankshaft, H-beam rods, 36cc "D" shape dish Diamond pistons, King bearings, balanced
• Heads: Blue Thunder 74cc, ported, +.100" Ford Racing valves, 3-angle valve job, 10* locks & retainers, 1.625" dia. springs, 230 lbs seat
• Compression ratio: 9.8:1
• Rockers: Miller 7075-T7 aircraft aluminum, 1.7 ratio
• Camshaft: Billet steel roller, custom ground for this engine combo. Lobe = 0.4550" / .4170", LSA = 109* Dur@.050" = .266 / .278, Lift at valve = .757" / .709"
• Roller Lifters: Morel
• Block: D0VE-A with Boss 429 bulkheads, thermocleaned and mag checked, High Flow Dynamics Stage 1 oiling mods
• Bearing clearances: mains = .0035"; rods = .0030"
• Timing Chain: Ford Racing double-roller with billet gears and 9-position keyway
• Carburetor: Holley 4500 Series Dominator, 1150 cfm
• Distributor: MSD breakerless
• Oil Pump: High Flow Dynamics Stage 1 prepped Melling M84DHV
• Oil Pan: Armando's 10-qt jet boat pan and pickup
• Intake: Edelbrock Victor 460 with Dominator carb flange, ported to Blue Thunder intake port size

This engine was dynoed at Westech, which is the same facility where the recent Engine Masters Big Block Shootout had their engine finalists tested. Results were 737HP @ 6300 rpm and 672 lbs-ft of torque @ 4600 rpm, and 95% of peak torque was sustained all the way up to 5900 rpm. A torque curve that flat obviously extends well below the 4600 rpm mark but I don't have the data because the facility focused on pulls from 4600 rpm & up due the customer's applicaton of the engine (jet boat). I was not in attendance of this session and could not make several requests and changes on the motor during the pulls.

Also, I'm pretty sure there's still more HP in it. Due to some top end oiling debugging from the start of the day, some valve train parts were changed out by the dyno operator for the sake of getting to the pulls, and the replacement parts installed by the facility--I feel certain--cost the top end about 11-14 HP. Additionally due to the time constraints, trials of carb spacers were never evaluated and I think we might have found another 9-12 HP there (the posted results are without a plenum-increasing carb spacer!). In other words, this engine could have conceivably generated as much as 760 peak horsepower on pump gas.

Bottom line is, when the day was over and the customer had his requested 700+HP, he felt we that delivered and so there was no need to search for any more.

Also, I want to emphasize the fact(s) that this engine recorded 737HP with a very conservative 9.8:1 compression ratio and one carburetor.

Honorable mentions go out to:

• Chris Straub (Straub Technologies) for camshaft consultation. Our customer wanted 700HP / Pump Gas / Reliable, which is a tall order and we wanted to be sure we met his needs. I turned to Chris for this build because he profiles camshafts for a lot of big name professional competition engines and he obviously calculated a profile that works excellently with this particular engine combination.
• Charlie Evans (Evans Racing Engines), because I must have called Charlie 4-5 times to discuss the approach I wanted to take porting these Blue Thunder 74cc heads and also discussed with him several valve train hardware options (BT heads ship bare). Charlie provided a lot of insight.
• Van Heskett, my engine building partner, for his never ending patience over this motor build. Of all the engines that we build together, I vehemently insisted this engine have special attention and it was mocked up countless times, while we tried different valve train setups, different valves in the heads, different crankshaft and connecting rod bearings, etc.

Attachment 25211

Attachment 25212

Paul

Paul,all I could think of was this would be great in a "Pro Street" application.
Then I saw the name Chris Straub.
There are two people out there If I need to ask questions about cam profiles.
Chris is one of them and one of the most educated people in the world of camshafts.
The other is Harold from the former UD cams if you can ever get a hold of him.
How many hours are you getting out of the valve springs?

Phenomenal! Also interested in the spring open pressure and how long they can hold up.

-Chris

Originally Posted by Dave Severson

Some very good numbers, Paul!!!! The one I find particularly interesting is the Air/Fuel ratio-----how do you keep it so stable???? Who's your carb guru???? My BG won't stay that steady, and you don't even want to know what I paid for that dog!!!!!!

Dave,

Thank you. Believe it or not, the carburetor is an out-of-the-box Holley 1150, zero upgrades (other than air & fuel jets). I think the bsfc's might have been a little better with a fancy carb, but this customer was on a budget and we carefully spent the time and money where it was needed the most.

The a/f looks stable, at least in part, because the pulls are from 4500-up and the main metering circuits are already delivering and going strong.

Paul

Originally Posted by erik erikson

Paul,all I could think of was this would be great in a "Pro Street" application.
Then I saw the name Chris Straub.
There are two people out there If I need to ask questions about cam profiles.
Chris is one of them and one of the most educated people in the world of camshafts.
The other is Harold from the former UD cams if you can ever get a hold of him.
How many hours are you getting out of the valve springs?

Thanks Erik! Chris and I have been acquainted for quite some time but our shop has not regularly used his consultation services. It seems that Chris and I see eye-to-eye on a lot of things both inside and outside of business. From a professional standpoint I found working with him real easy and very beneficial.

In regards to the valve springs: I repeatedly spelled out to the customer that just because this is a pump gas engine does not mean that it is maintenance free. I stressed to him that high dollar, high power engines require a great deal of preventative maintenance and told him that he can expect to pull his heads once a season to touch up the valve seats, and that between such servicing he should have available an on-the-head valve spring checker.

In fact, this is why I publicly thanked my parter Van in regards to valve train setups (above post). For example, at one point I pushed to try springs with a 2.100" installed height, hoping that by not squishing the spring so far with the valve open (relative to installed height) that our pleasure boating customer might get more life out of them/less chance of breaking a spring. Unfortunately, due to valve angles relative to rocker stud location, the taller spring moved the tip of the valve too far inboard (toward the rocker stud) and the roller tip of the rockers was mis-positioned over the stem tip, in effect. Bad geometry. Therefore, 2.100's were pushing it with these heads in this application and so we squeezed out a 2.030 installed height and things look good.

Bottom line is: if you can afford such an engine, then you can afford the maintenance that comes with it, incuding R&R-ing valve springs, etc. Valve train is obviously one area that can rarely be overlooked when it comes to maintenance. Most else in this build we managed to make relatively maintenance free.

Paul

Originally Posted by skids72

Phenomenal! Also interested in the spring open pressure and how long they can hold up.

-Chris

Chris, I don't remember the open pressures off the top of my head. How long can they hold up? As noted just above, valve springs are the big maintenance part of this engine (valve train, actually).

I wanted to try cryogenically treating the springs in the interest of improving reliability; timeline was tight (customer wanted his boat in the water this season) and so I suggested to the customer that he buy a second set of springs asap and that we send them out for treatment.

Paul