PDA

View Full Version : BLAWKHAWK COMBO



DON N.
10-28-2001, 04:37 AM
IS THERE A WEAKNESS OF SAY THE 1996 BLAWKHAWK OPTION COMBO,THE 502/BLACK HAWK DRIVE VERSES THE 502/BRAVO 1 . PLEASE HELP ME I,M LOOKING. :(

HP 600SC
10-28-2001, 06:38 AM
Yes the Blackhawk drive had a high failure
rate. In other words They blow up alot.

DON N.
10-28-2001, 11:50 PM
DID THEY OVER HEAT ON LONG RUNS ? OR MAYBE THE DRIVE OVER REV FROM LEAVING THE WATER ?
I SAW A 22' CLASSIC ADVERTISED WITH THESE OPTIONS. SHOULD I AVOID THIS SET UP ? I LIKE DRIVING THEM BETTER THAN WORKING ON THEM.

THANKS FOR THE RESPONSE. :confused:

FASTEDDIE
10-29-2001, 04:34 AM
Don,
Mercruiser stopped manufacturing the Blackhawk drive.It was obvious to them that the drive wasn't right. Stick with the Bravo One and you can't go wrong. :eek:

HP 600SC
10-29-2001, 05:43 AM
Exactly.

Woodsy
10-29-2001, 07:20 PM
Don,

There are alot of myths and legends regarding the Blackhawk drive. The pro's and cons of these drives have been extensively debated on this forum. I have done quite a bit of research on them, talked to a few Blackhawk owners, and came to the following conclusions.

1. The Blackhawk drive was usually mounted too low in the boat for it to work properly. Many were replaced by unbolting the Blackhawk and mounting a Bravo 1. This is not a fault of the drive, but a fault of the boat design. If you want to talk to someone knowledgeable about the Blackhawk and how to set it up, ping Waleyetwo (he has a repowerd X-18 with a totally stock 350 MAG MPI/Blackhawk setup that runs in the mid 70's... think of what he could do if he actually got some horsepower into that old boat. (hint hint Steve!) You can check him out at www.donziclub.com (http://www.donziclub.com) as well. The guy who helped him build the boat is Tom Davis, another lake Winni Outlaw, and he also really knowledgeable.

2. As far as the drive being unreliable, well, thats not so true. When the drive was positioned correctly, and so far, the only boat I have found was the Scarab P-29, it lasted as well as a Bravo. It has the same internals as a Bravo 1, actually the propshaft is beefier, but there are no reliability issues. If it is mounted correctly!

3. The biggest problem with the Blackhawk drive was corporate liability. It is an extremely fast drive setup. It runs loose & fast, just like an Arneson. Although the Arneson's prop setback makes the boat think it is bigger than it is. Donzi sold the 22 Blackhawks and with the drive too deep (x-dim) they porpoised when going at anything less than 60 mph. They were also extremely fast. 78mph in a 22' Classic is really moving. Thats with the drive set too deep. With the drive positioned correctly, a 22 Classic with a 502MPI/Blackhawk setup will do over 80. You need to know how to really drive your boat, to be SAFE in this setup at high speed. Selling an in experienced person that kind of a ride without training can result in some serious lawsuits...

4. Because of the above mentioned reasons, corporate liability and improper placement, not to mention the Blackhawks considerable cost, Mercury stopped production. There are plenty of Blackhawks available, just look over on OSO. They can be had for pretty good prices.

I would not shy away from buying a Blackhawk equipped boat, but I would go into it with my eyes open. If you don't like the Blackhawk drive, you can always sell it to me!!

The reason it was coupled to a 502 MPi setup was because you needed the fuel injection to get the idle to a consistent 900 rpm. Even at that idle speed, trying to dock a Blackhawk is a challenge because of the tremendous amout of water they pushed. You should watch one idle in a no wake zone... it's moving pretty good. :D

Woodsy

BigGrizzly
10-29-2001, 09:57 PM
The blackhawk drive if set up correctly will over heat. The Donzi Blackhawk Edition was set up correctly and would over heat. The X demention was correct on that model. Because its a dual prop the unit isn't as strong as the Bravo( counter rotating gears). The surface drive is too close to the stern which causes the biggest part of the problem with the counter rotating props. I know a man that scattered the black hawk drive, replaced it with a Bravo with a Imco shortie and picked up 3 mph on the GPS no other changes. The shortie was set up to the right demention( with a spacer). he said it handled better and had much better slow speed docking. Liability is not what caused them to stop production. Cost and drability did. One more small point It takes more horse power to turn a Blackhawk drive than a Bravo. I wanted one but changed my mind after some research. I have too much hp for the drive. If they were that good they would have been OEM on all high performance boats.
This was not the case. Get the Bravo!! Beleive me if it was that good Ted would have it on his boat, he uses only the best or doesn't use it!

Randy

CDMA
10-29-2001, 11:42 PM
I really think the Blackhawk was a great idea despite some of its possible short comings. All the shortcomings aside Wayletoo's( steve marr) x-18 runs mid 70's all day and he has seen 78.3 with 300hp. Talk about efficeint. While I do not pretend to be an expert if you look close at the stern of Steve's boat then the stern on a 22 blackhawk you see that his blackhawk is mounted significantly higher on steve's. It makes me wonder if in fact the drive was too low on the 22. Again not an expert just conjecture. Also with a surface drive that close to the the transom, with relatively little trimming ability, the drive height is a SIGNIFICANT factor. More so than a non surfacing application. Another factor that always amazed me was how you could control a blackhawk boat. I mean the point if this whole thing to is remove as much area from under water as possible. In doing so you gain speed but shouldn't handling suffer? As Woodsy pointed out the Arneson gains control by being over 3 feet long but the Blakhawk does not have that luxury.

I have to say that at this point I have yet to see a drive combo that I really like. While Bravo's, SX and king Cobra's are undoubtedly strong drives I am not a huge fan of the whole I/O thing. Sounds sort of hypocritical from an I/O owner and for sure they are 90% of the time the fastest and easiest option for a high speed boat. They are just so complex, so many moving parts, so many 90 degree turns. You are asking one realatively small unit to be your driveing force, transmission and steering. Another issue is bellows and all the thru hull holes an outdrive has. I am really hoping this Arneson thing I am doing will get me to what I am looking for. It just is so simple and bulletproof. Not to mention the efficeincy should be tremendous. While there are disadvantages to this drive as well: primarily low speed handling and inability to trim I hope these negatives will be overcome by the advantages. I guess only time will tell. My goal would be to gain 10 - 15 % over a comparable powered 22. So a 454 mag would run low 70's, a 502 over 80 and an hp 500 over 90. These number may never pan out but that is what I am shooting for. If I need to add rocker to get there so be it. My boat already has 8-12 additional layers of glass in the engine compartment floor in case I decide to go such a route.

Chris

A minor update for all those interested. The glasswork in the engine compartment is done : 8-12 layers on the floor, gussets, 1/2 inch ply across the parts of the transom that did not have 1 1/2 of ply already. The engine compartment has also been sanded primed and painted using a PPG product called delta c/o Scott Pearson. Really tough paint. Primarily used in fleet applications. Finally in the engine compartment the boxed aluminum stringers are in. The dash has been rebuilt as well as the floor. Every piece of hardware was removed. The boat has been completly sanded for painting. And 75% of the filling needed is done. I figure 2-3 more working days and I will be ready for primer.

Dr. Dan
10-30-2001, 04:54 AM
CDMA, engine compartment sounds great, got any pics? Look forward to seeing it finished...Doc :cool:

Woodsy
10-30-2001, 07:27 AM
BigGrizz,

I have to respectfully disagree with you. A Blackhawk runs no hotter than a regular Bravo 1. They actually share the SAME internals. As for your Dual Prop argument, take a look at the Bravo 3... same setup as a Blackhawk, pushing really heavy boats... very few lower unit failures. Donzi did not set the Blackhawk properly in the boat. It is a surface drive, and it needs to be near the surface. If you notice, an engine hatch on a BlackHawk edition is nice & flat like the hatch on a Bravo. Why? Because Donzi did not raise the motor up to the proper X-dim for a Blackhawk. If you put a Blackhawk on a 22, you will need a bubbled hatch like an older 18 Classic. I am not hear to start a flame war, and I do agree that cost was/is a big factor in the death of these drives. To utilize the performance potential of a Blackhawk, a boat manufacturer would need all new molds. Not to mention, raising the engine up 6 or 7 inches vertically will change the center of gravity in the boat in a negative fashion. all of this costs huge money. Most manufacturers, Donzi included, did not want to make the investment in time or money to utilize the tremendous potential of this drive. If they had, a 22 Blackhawk edition would have cost almost 100k. The Blackhawk drive has more patents than almost any other drive since the original Volvo units. It is a tremendous piece of engineering, and Mercury spent alot of time and money engineerring that drive. It works, very well, when set up properly. Donzi did not set it up properly. Steve Marr's X-18 is almost as fast as Geoo's with 1/2 the HP. Geoo's pushing 600hp and has seen the mid 95.2 and I still think there is a little more left there, Steve's X-18 with the 350MAG MPI/Blackhawk setup runs mid to high 70's all day with a 6 year warranty. IF Steve puts some power in his boat, it will be just as fast as Geoo's. If you get the chance, take a ride in Steve's X-18. You will change your mind about the Blackhawk.

Woodsy

CDMA
10-30-2001, 09:14 AM
Woodsy,

I agree with most of what you say but just to throw out: A surface drive puts significantly more loads on the drive than a similar unit run in a completely submerged manner. This is due to some pretty wicked vibrations that surface drives create. Another thing that I could see contributing to the increased heat was that there is very little drive left in the water and that of course leaves very little cooling from the water. Maybe a big drive shower would have helped that...

Also keep in mind Geoo's boat ran almost 80 with about 400 hp. Remember that as speed doubles drag is multiplied by 4. Not to mention the faster you go the harder it is to create bow lift.

Just my simple minded thoughts.

Chris

PaulO
10-30-2001, 04:17 PM
Wow! Now here's a thread that we can all appreciate. Good points on both sides. I, too did the Blackhawk research. I was looking to put one on my 20' Cigarette. I think that the truth lies somwhere in between here. I had not heard about the overheating problem but, that makes sense. More friction due to counter-rotating shafts, less drive submerged in the cooling water. I think the speed is there if set up properly and that means big x-dim. Although I don't disagree with Woodsy on the speed potential I do have to say that from mid-seventies to 95 mph is an astronomical jump!
Now, two more things:
1. Proper setup for a surface drive means that not only does the prop need to be in the exact right spot in relation to the surface, you basically give up all means of artificially introducing bow lift. In other words, there is no leverage for trim to work in lifting the bow. So, you need rocker and you need proper weight palcement astern to creat natural bow lift.

2. You can't justify the purchase of a Blackhawk even if you agree with all of Woddsy's positive points because of the props. Propsets for these things are scare and ultra-expensive. 2 grand is not uncommon for a used set. You also don't have the flexibility in prop design you have with a bravo.

Great debate!

One word conclusion: Outboard!

PaulO

blackhawk
10-30-2001, 06:47 PM
I did my research before I bought my boat and the best info I received was from talking to people that actually own or owned a blackhawk drive. Basically, everyone that had one liked it and said it was MORE reliable than their bravo powered boats. I think what killed the production was putting in on the wrong type of boat (no rocker) and the cost. Mine has worked awesome (knock on wood!!!) and definitely pushes the boat very fast. Plus it is an absolute thrill to drive because of the bow lift. I am going to tear into it this winter just to check everything over while the motor is out (damn gimbal ring!) I am no expert on the drive but I can tell you that it's fast, looks cool as hell at WFO and is a thrill to drive and ride in.

BigGrizzly
10-31-2001, 12:44 AM
Geoo's boat is a 430 rocket block with over 600 hp and rall about 88 mph Then he put on a large NO2 Kit to go 95. he also broke his front engine mounts in doing so.his boat is significantly lighter than a 22 hull.
Donzi built the boat around the drive so it has a rocker hull. The 350 has less torque and hp potential than the 502, so less heat is built up. Example, the heat exchanger on by 351 is 28 X 5 (400+hp)inches and the 502 is 60 X 6 inches (698 hp) for heat disapation this puts a tremendous load on the boat and outdrive.
How can it be stronger and more reliable than the bravo if it has the same internals. As fot the Bravo 3 that is different inside than the blackhawk ad used on different type boats and lower rpms.
Steves boat is nice and wish him a lot of luck with it. But be real its a small lite boat and center of gravity is higher than standard. 600 lbs up over 6 inches than stock, thats not for me. Merc made it to keep the C.G. low. The people I know don't love it when it is changed to a Bravo.
If its so good why didn't offshore racers use it. The answer, it wasn't.
If you think the 80 mph barrier is that easy to break, then jump up to the pump. I did and I broke it with change with a fat TRS and trans. However the cost was high, tenfold what 75mph cost. Ask Geoo how much it cost to go 80 than ask Frank, I won't tell you(wife reads Donzi net). The data is in and the bad out-weigh the good.

Randy