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HP500 Just in case...

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axapowell

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Discussion starter · #1 · (Edited)
Well...it's been a long learning curve and a very opinionated one at that, but as of today I ran my first of two motors on the dyno. I know that the conversations and debates have been many and somewhat heated on what works and what doesn’t. I’m not posting this to prove anyone right or wrong, but just to say this is what I did and what the results were. So there is NO confusion these are the first results and I haven’t done anything for a tune yet, except set the timing, idle mixture, and idle. I ran the motor for about 30 minutes yesterday and today between idle and 3000 rpms to break it in a little before we pulled it today. The engine was run on a Dynomite dyno SAE corrected with dry dyno headers, no accessories off the crank except the water circulating pump. A Holley blue pump for fuel, 89 octane pump gas (low specific gravity), and we are in upstate New York, so the dyno room before we started was 65 degrees Fahrenheit.

THE ENGINE:
1999 Chevy 502 (HP500) Carbed
Standard bore, re-ringed with file fit rings deglazed and honed
Stock steel crank and rods, stock JE pistons, all checked for balance
New cam, main, and rod bearings
New Melling HV oil pump, screen and drive
New Crane 168741 hydraulic roller cam and stock style lifters (dog bones and spider)
New Crane Gold 1.7 rockers on the exhaust valves
New Crane Gold 1.8 rockers on the intake valves
New Manley .080 push rods to length
New AFR 315cc Fully CNC Ported Magnum BBC Head
With tulip inconel exhaust valves, spring upgrade and hard anodizing
New Spark Plugs NGK (6239) R5671A-10
Stock Dart 6200 intake manifold
Stock Holley/ Mercury Racing 800cfm carb
Stock Mercury distributor with modified rotor (for Crane Box) and stock wires
New Crane HI-6M ignition box
New Crane LX92 coil

That’s the parts list, again I haven’t tuned this motor yet and these are the preliminary results:

RPM HP Torque
2500 247.7 517.3
3000 313.1 547.7
3500 389.2 582.3
4000 426.2 560.2
4500 506.6 591.0
5000 586.8 615.6
5100 598.4 615.7
5200 605.8 613.2
5300 615.5 608.9
5400 620.4 604.3
5500 623.5 594.6
5600 628.5 588.9
5700 630.2 582.1

I plan on maximizing this current setup, breaking the motor in for at least another hour of dyno run time, and then bolt on the all of the accessories and running the motor AGAIN wet with the marine exhaust manifolds. I will then tune the motor again for optimal horsepower and torque.

There were quite a few people who claimed this combo would not work. I wanted 625 horses out of my 502’s and so far I have done that. I plan, at this point, to run my Mercruiser/ Gil manifolds and risers, but may change my mind before these engines go back in the boat. I would like to see if there are any reversion issues on the dyno. I’m still on the fence over this and refuse to pay the BIG money for CMI’s. With all the research I’ve done, it looks like they will be OK, but I will hold My opinion until after I run the motor wet with the Gil’s.

Thanks to all who have helped me to this point and to my patient engine builder Rick Brush from RPM Performance for letting me interact so closely with him in his shop. When I stop by to help, he values my input and your opinions. This wasn’t my first high performance engine with Rick, but it was my first marine engine.

Thanks again all,
Dave
 

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#6 ·
I did th echart with all the engine specs, and now I see that its hard to read the HP/Tq numbers, so here is just the chart. I know I'm posting a lot of DD stuff, but its the first time I've gotten a total combination here that I was able to plug into DD and compare to a real dyno run. Plus, I've gotten a lot of grief about DD being a computer "toy", and this example sure shows that it works, and works very well.
 

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#7 ·
Congratulations. Gotta' love the AFR's. :bigsmile:

Be interesting to see what the Gills do to this since Partsguy (on another thread) was pretty adamant on what / what not they can support.

I know I'll chersih the info.

BTW: Are your Gill's the tall risers or the early style short risers ?
 
#8 ·
very good results,very typical,great job
i would love to see a couple more pulls
1. w/ just a spacer added 1-2"
2. spacer and a bigger car,say 850 dp w/ choke horn cut off

i'd bet you get another 25hp outer her. :D
 
Discussion starter · #9 ·
Lots of questions:

Jetting is from the factory as far as I know.. I haven't cracked open a bowl to check them yet. I have them in my notes, but not here.

Compression ratio is close to 8.30 to 1...Stock compression was (I think 8.5 to 8.75) with a 118 cc head, the AFR's are 121 cc. I would guess around 8.30 to 1. I'm sure someone here can calculate it for you (and Me).
 
#16 ·
Very nice numbers from a 502, and I too will be very interested to see how it does with the Gils. I know partsguy has a lot of dyno experience so I don't doubt his claims. One thing I noticed is the -10 spark plugs you are running. On the dyno they will be OK, but in the boat those will load up an foul with a mild motor. They are very cold and some -8's would be better and possibly even -7's. I would bet there may even be a 5 HP gain in the hotter plug and your optimal spark timing will be lower with the hotter plug. Thanks for posting the results and keep us posted!!

Craig
 
Discussion starter · #17 ·
On the jetting...Here is what Mercury Racing told me I had, based on my serial numbers. (I think it's the same for all HP500's)
Primary Port 81 Starboard 75
Secondary Port 89 Starboard 93
 
#18 ·
Diamond Performance said:
Those AFR Heads are great, what cam did you use?
Click to expand...
some 20yr old camshaft design from what i've read before on here. :laugher: :laugher:
crane 741

i agree w/ wette vette on the spark plug.

did you say what your total timing was??if not,can you say,please.
 
Discussion starter · #19 ·
Wette Vette you know I couldn't remember if they went up or down on heat range, I have a set of -9's to put in with a gap of .040. I'll get some -8 and -7's comming to try as well. THANKS
 
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