HP500 buildup questions
 

I am in the process of upgrading the original Mercury Racing HP500's in my 1999 Formula 353 Fastech and need some advice.
The boat is running 79 MPH on GPS and our goal is 90 MPH which I believe will require about 650 HP output from each motor.
We are running Bravo 1.5 drives (I know - another weak point but that's a whole different conversation) mounted on factory installed extension boxes spinning 30P Bravo 4 blade props.

We did a pre teardown dyno run and although the motors were tired, we were surprised they ran 530 HP on the stand.
My engine builder has recommended we stay with the original 850 carbs and Dart intakes and will port match them to the new Merlin heads we are installing.
Internally, we are basically replacing everthing except the crank. The BBC pistons and rods with Manley pieces, Inconel valves and hydraulic roller valvetrain components for ease of maintenance.
The 502 blocks were decked, bored and honed so they are now 516 CI. Due to durability and cost, we want to avoid blowers and run on pump gas.
We are stuck on whether to reuse the exising camshafts and exhaust with these upgrades in order to acheive the 650 HP goal.
The motors came from the factory with GIL exhaust manifolds and silencer tips with rubber flappers.
This is a major concern since I have read numerous articles on water reversion issues with high overlap cams in this application.
If we move to headers we will tack on 7-10k to our rebuild costs which is not in the budget plus they typically are not a reliable as the GILs.
I would welcome any comments and recommendations on the pieces we have chosen especially in the camshaft and exhaust area.
Thanks!

You won't be getting 650hp with the stock Crane cam's. I would look into a custom grind for the motors.

The Gil exhaust is fine up to about 600hp (so I've heard)

The stock HP500 carb is only a 800 cfm.

Can you post up the dyno sheet from the stock hp500 pull. That would be some great info to have on here. I know I'm curious.

Dave

Inquire with existing owners
 

Someone with your hull and set up that can run 90, and then find out what it took for them to get there. Maybe an eye opening development.

[QUOTE=Joe308;3389212]I am in the process of upgrading the original Mercury Racing HP500's in my 1999 Formula 353 Fastech and need some advice.
The boat is running 79 MPH on GPS and our goal is 90 MPH which I believe will require about 650 HP output from each motor.

650 will not get you another 11 mph. As a general rule it takes 18 to 20 hp for each additional mph. On a twin engine boat, only hp increase of one engine counts. So if you get 650 hp out of new engines likely will see 5-7 mph increase.

I do not think you will get 650 with stock cam and heads.

Look up rmbuilder on this site and contact Bob, he is one of the best at designing custom cams. If you give him all your information he can get the best set up for your engines.

BLOWERS,,, Whipple ,,, or buy a complete rotating assy and convert it to a 540cu motor....merlin heads are a bad choice,,,castings are all over the place for alignment,,,Dart Pro1 CNC 335 heads and a 240 248dur 621 632 lift cam and you will go 90+ all day,,, also carb is to small,,,,,,, you can run blowers on pump gas 89 or 93 just depends on how much boost you run,,,,,you can get an Eagle crank and H beam rods that will be fine for this build since your on a budget to build it to a 540,,, do not get headers,,, they all leak,, Stainless marine III is the way to go

This might help.
http://www.offshoreonly.com/forums/g...-build-up.html

Try sending to axapowel(l) I believe he did what you are trying to do a couple of years ago. I made a couple of try at searching the thread with no luck. Keep us all posted.

Thanks for your replys, heres the dyno run on the original motors - they may have been "touched up" about 6-8 years ago but they were indeed tired and the internal components did not impress us.
It appears I cannot upload images so here it is from Excel. Peak HP 537 @ 5300 rpm, torque 581 @ 4100 rpm test conducted last January @ 60 F with headers.

EngSpd EngTrq EngPwr Fuel A Fuel B FulA+B BSFC A/F_O2 AirTmp
RPM lb-ft Hp lb/hr lb/hr lb/hr lb/hph Ratio degF
3500 560.2 373.3 85.4 80.9 166.3 0.445 14.9 59
3600 554.3 379.9 85.3 84.3 169.6 0.446 14.9 59
3700 563.6 397 85.5 82.3 167.8 0.423 14.7 60
3800 568.5 411.3 87.5 84.7 172.2 0.419 14.3 60
3900 578.8 429.8 90.1 89.3 179.4 0.417 14 58
4000 581.2 442.6 92 93.3 185.3 0.419 13.6 57
4100 581.2 453.7 93.9 95.9 189.8 0.418 13.3 58
4200 578.8 462.9 97.4 100.7 198.1 0.428 13.2 59
4300 578.3 473.5 99.3 99.9 199.2 0.421 13 58
4400 576.3 482.8 103.2 109.9 213.1 0.441 13 59
4500 571.9 490 103.7 114.2 217.9 0.445 12.9 58
4600 574.4 503.1 106.7 114.9 221.6 0.44 12.7 59
4700 571.9 511.8 110.2 122.4 232.6 0.454 12.6 59
4800 560.7 512.4 110.9 122.2 233.1 0.455 12.5 59
4900 561.2 523.6 114.3 123.2 237.5 0.454 12.5 59
5000 546.5 520.3 114.9 122.1 237 0.456 12.4 59
5100 546 530.2 120.2 121.2 241.4 0.455 12.3 59
5200 536.8 531.5 129.6 126.7 256.3 0.482 12.3 61
5300 532.4 537.3 126.5 128.2 254.7 0.474 12.3 60
5400 521.6 536.3 131.1 135.4 266.5 0.497 12.3 61
5500 501.6 525.3 133.6 132.9 266.5 0.507 12.3 60

Joe, got your PM. Thanks Augie!

Here's the deal. First of all I have tweaked the set up a little since 2006. In 2008, we bored, honed and decked both blocks to 509's (.030 over), upgraded the rods, pistons, oil pans, pick ups, oil coolers, and the entire fuel system. We are making the max HP for this small cubic inch. The speed is the real proof. I had the boat set on "kill" and ran into the 90's consistently. After denoting a piston at the end of 2008, I decided to back it down a little and again address the fuel system.

So, here we are today with a pair of 509's:
JE Custom Pistons (Teagues recipe)
Manley Rods H-Beam 6.385
Crane 168741 hydraulic roller cam
Crane roller lifters
1.7 ratio roller rockers on the exhaust, 1.8 on the intake
AFR 315 CC CNC'd heads with tulip inconnel exhaust valves and hard anodized coating for marine use
Hardin 10 quart pans with their offshore pickups
Hardin 18" x 3" oil coolers with the stock HP 500 oil filter mount with the thermostat
Mighty Demon Marine 850 Carbs
New this year Merlin intakes for marine
KE mechanical fuel pumps off of the sea water pump
CMI Elbow tops with bunged tail pipes for tuning, FAST wide band O2
XR drives on Imco Boxes
Sportmaster -2" shorties with a 1/2" spacer

I am down to two sets of props and last year decided to turn the props back to outward for handling around the dock. Props are Maximus 5 blade 28 pitch with a 15 5/8" diameter (cut down from 15 7/8") diffusers removed. Second set (faster) 32 pitch Mercury Bravo One 4 blade, also labbed, with the diffusers cut back. Brett at BBlades has the specs, if you use him, you can tell him it's ok to use my set up, it should get you close.

Anything else, just ask!

Dave

Couple more things...
Crane Hi6-M Ignition boxes with Crane coils
Stock distributor for the pick up only
Isky Tool Room Springs (9905)

With the CMI's wet, we were in the 650 range!

That's about it for now, ask if you need anything!

Dave

Hey Dave,

Thanks for the info - you are way ahead of me!!!

We are presently stuck on the cam / exhaust situation with the stock GIL exhaust not liking any bigger cam than already installed. We were planning on cutting out the silencer baffles from the tips and using the existing GIL setup but when I emailed Hardin tech support (who bought out GIL) they said do NOT use the GIL manifolds with any bigger cam or HP than the stock ones that came in the HP 500s. They recommended a dry pipe exhaust. Since I can't (won't) spend 10 grand on 2 sets of CMI headers I'm looking for alternatives and someone said there might be a suitable manifold offering from Stainless Marine.

According the the specs I had Merc racing fax me last summer the original HP 500 cams were 339/352 lift and 284/292 duration.
I came across a August 2003 Merc service bulletin online stating revised duration numbers of 222/230. I wonder if they did this to fix the reversion issues??? Anyway, my motors were done once before, so I'm really not sure what was swapped out. I know they had roller top end but when my builder torn them down before sending to the machine shop he said they only had std BBC connecting rods which I though was odd. I thought they had Carillo or Manley rods - maybe the last builder pulled them or they didn't come with them?

Anyway, let me know what you think about cam / exhaust situation.

Thanks!
Joe

HP 500's came with stock Chevy rods. They are fine up to about 600hp. As for the Cam, listen to Merc, I tried the Gils on the dyno back in 2006 and it did show some signs of reversion plus they killed the hp. I have had NO problems with the CMI's, but I am in fresh water too.

You may want to rethink the blower option. You could easily get 650 with a small blower and low boost. You could also continue to run the Gil's!

BTW I run 89 pump gas!

Dave

My builder hates blowers and wants to keep me as maintenance free as possible. I thought of the options of blowers or headers but we're into these motors for 20k now and adding either of those will probably tack on another 10k.

thats quite a difference, I'm guessing your numbers are advertised duration vs. duration @.050.

Great ideas guys, keep them coming....

Sounds like a nice project except the Merlin heads, did you buy them yet? If not maybe re-consider for soemtheing that will make more power. wags382/jeff wagoner built up his 382's hp 500's and made a honest 600 hp turning accesories BUT he used afr heads which flow considerable more than the merlins (easily 20%+). He has since turned motors into 540's and makes hp in the mid 650's and has his 382 formula in the high 80's, Smitty

Here is a similar thread on almost identical project
http://www.offshoreonly.com/forums/g...5cc-heads.html

Custom ground cam from Cam Motion
 

Seeing how my HP500 blew the head gasket, I am now in the same boat.(pun) My builder in TX recommended a Cam he always uses on HP500's. Better than original and corrects for reversion, also more efficient and power. Here are the numbers, hope they make sense: Cam - LSA 112, 226/234 @ .050 duration, .600 lift for hyd roller. He said the Crane pt# is 168731, but Crane sold to someone he does not know. Hope this helps.

You might be right on the cam specs being at .50 duration - that is indeed quite a difference but I couldn't find original published specs to compare to the 2003 service bulletin. As for the heads my builder likes the Merlins - are the AFR's a lot more expensive?

I'm sticking with stock heads, new Comp cams springs P/N 929. I was told the HP500 motor is pretty much bullet proof left stock. He will zero deck the block, heads and intake for just a little more compression and HP, also to correct for burn in block.

I was surprised that my HP500's had std BBC connecting rods. Merc racing was nice enough to fax me a few pages from their manual last year and I see diagrams showing both std BBC and Carillo style rods. Wonder if the real "racers" got the better internals?

Carbed 500hp's have the Gm rods. The second or third year of the 500EFI they started getting Manley rods.

Hey Dave,
Dean here, how's life in A-bay? Running 89 octane, what is your C/R?? I can get a killer deal on some AFR heads, I'm just trying to decide which size to get.....
Thanks,
Dean

I hear AFR came out with a cast iron head, but are all you guys running AFR's aluminum? We're probably going to stick with heavy metal. :)

9.25:1 minus the aluminum heads, easier to dissipate the heat, so net around 8.75:1.

You will also save 60 lbs. per motor.

Dave

Mine are 305...CNC'd from AFR to 315cc.

Dave

Dave,
Thanks for the info, I'll try to PM you today. My mom and step-dad, who lives in Potsdam, wants us to come up for a summer vacation, maybe we'll bring the boat, and you can show us around A-bay.....

Would be happy to give you the "Tour". If we plan it out right, I can get a few of the OSO TIBBC together for a gathering!

Dave

The AFR Aluminum head (Anodized) are a great investment. Also look at Stainless Marine exhaust. Will make the power and last. Less expensive than CMI and no leaks.

The biggest thing that will hold your build up from making really good numbers is going to be the world heads, they are STONES compared to afr's
http://racingfeed.com/downloads/chevy_flow_data.pdf
The merlins flow 320 intake/201 exhaust at .600 lift
The afr 315's flow 380 intake/296 exhaust at .600 lift
I built my first 540 almost 10 years ago running a procharger m-3 and I used MERLIN heads, the motor did not even break 700 hp under boost , when I freshened it a few years later I made 950 hp after switching to the afr's and a cam 1/2 size bigger than previously (designed by Bob Madera/RMBUILDER). Now, I know you are not building a blower motor BUT head flow is head flow and Merlins almost identical to out of the box rectangle port factory heads. Its no secret that heads that flowed 30% better than my Merlins were a big help in gaining 35% more power, this hold true in normally aspirated applications too, it WILL help make the difference between you making 540 hp and being dissappointed and making 650 hp and being satisfied, Smitty

Smitty,
Are your AFR's CNC ported like AXA's? I have alos talked with a couple of engine builders who say the some of the oil passages are too small on AFR's? Smitty what are the Part numbers of your AFR heads, and are they the Hard anadized ones you run in salt water?
BTW, Impressive motor!:drink:
Thanks,
Dean

I agree, plus exhaust. The two very important components in a successful build.

Hard anodized and inconel exhaust valves are a must too.

I just freshened up my heads, with the exception of a valve spring change in 2008, and all that needed to be done was exhaust guides, seals and a valve job. I chose to replace the Isky Tool Room springs while I had them apart. So, longevity is looking pretty good. As for the Crane roller lifters, 31 were still good! 1 was on it's way out. So lesson learned...250 hours, replace the litters too!

Dave

Dean, my heads are 315 cc intake runner cnc ported with hard anodizing and inconel tuliped exhaust valves. I am also running Isky tool room springs. I did NOTHING with the oil passages and have never had a problem. Out of the box my blower motor made 950 hp with them, they reccomend against additional porting but last time I freshened my motor I had them ported even more to match some of the mods to my intake/cam package and with a bigger cam than before I made 1115 hp. As far as the part number I am not really sure but I can tell you that RMBUILDER/Bob Madera is a distributer for them (585-654-8583) and can usually sell them to a guy for a price equal to or below the best deal you can find on them on the net short of buying used ones and he buys so many of them that he can get them faster than most suppliers. He also is a expert at cam design and supplies custom ground cams to optimize these afr head packages on most motors again at a price for what most of us would pay for a cam from most supply houses. I am very happy with them and the cam he supplied to me, Smitty

good advice sm gen 3s, the dart are better, but if you already bought the merlins have jim v go thought them carb, I would go with a custom 1050, nickerson or cfm carbs. I ran a 850 bg and picked up 4mph with a nickerson 1050. motor is a 509 with gen 2s, merlins, dart intake, isky cam over 600.do port match also if you could buyoval port intakes and have them blended to match the rec ports on the heads thats more hp. good luck.

Hey Dean, if you're up here look us up, Dave and I are both at Hutchinsons. If you end up here boatless you can spend the day with us on the River.

If you're missing the north country check out the Raquette River action videos on the TIBBC thread in the Formula forum.

There are 2 sets of flowed Dart aluminum heads sitting on my builders shelf ready to go, but we discussed this and think its best to stick with the bullet proof iron Merlins for now. He had some pretty hefty porting work done on them and we want to see what they will bring on the dyno. Now as for the cams, the ones we pulled appear to be original Merc racing (engraved MHP300 16-20-98) on the ends, but the grind number stamped on the billet is foreign to me (169516 98D2 A). We mic'ed em and they appear to be similar to the Crane 169621 grind, but I'd like to know what these are. As of now, we are leaning towards using with the Crane 16HR00004 cams (what Crane indicates were used in the HP525) for the new motors (610/632 lift - 235/244 duration @050). Any thoughts?

Thanks guys
 

RE,
Thanks for the generous invite, I'm working with HQ, (the wife :drink:) right now on summer vacation plans. As soon as she releases the 2011 Ferry summer vacations schedule I'll know better when we will be coming. If we don't bring a boat, I'll have plenty of gas monies!:drink::ernaehrung004:

Now back to our regular HP500 programing.......

Ttt

Those are the stock Merc carbed 500HP cams. The MHP 300 designates that. I forget what the Crane part # is, but they are not 169621's. Those are for the 500EFI. The stcok carbed cams were ground a 110 lob sep and reverted water easily.

The 525EFI cam is a good choice. Its a Crane 168741 ground with a 114 lob sep.