I just had the gears changed
 

In my bravo 1. Went from 1.36 to the original 1.5. First time out and after a few minutes of running, I could hardly get it out of forward. Pulled drive off and checked operation of the cable and dry shift action of the drive. Both seemed fine. Carefully put the drive back on and made sure the cable went in correctly and the same thing happened again. Seems that I can dry shift it fine on the trailer, but hard as hell at idle. Anybody got any ideas?

Hey Brad,
Hows it been going? The only insight I can give you on this problem is that, and you probably know this already, the drive is not designed to shift while the engine is not running. When you say dry shift on the trailer is the engine running or not? The drive should be difficult or near impossible to shift while not running. If is easy to shift there may be a problem with the shift yolk and detent ball inside the drive. Its under the inspection cover at the back of the drive.

If you have been shifting it without the engine running you can bend or break the drive cable. You can also break or bend out of adjustment the mechanism that connects the drive cable with the shift cable from the helm.

These are some simple things that come to mind. You are probably are aware of them all.

When you changed gears did you have to go into the top of the drive where the clutch cones are?

By the way I have the big Mercruiser service manual for the Bravo drive. If you need anything from it let me know. I can copy and fax to you.

Drop me a line when you get a chance and fill me in on your progress with the boat. We just bought a new boat!

Ron
[email protected]

Hey Brad, What happened to spinning a smaller prop faster? Now with 1.5's? Your speed and rpm's will be interesting.

Never did use a smaller prop. Went with many advice back to 1.5 gears to get the motor in it's power band. Run's like a raped ape now!

RJCardinal,
I thought it was a little strange when I could shift it without engine running. Never could do that before. I'm a little woried that I might have already damaged cable by having to use so much force to get it in and out of gear just to get it back on the trailer. I'm pulling the drive off and taking it to the "doctor" saturday morning. I had a local change the gears, but I should have taken it to the MAN. It's a long haul to Rowlett though.

What boat did you buy? I'm going down to your neck of the woods the weekend of the 11th. We're leaving the night of the 8th. I don't think my drive will be fixed by then so I doubt I bring the boat with me.

I agree....
 

For motors that like to run in the 5800 rpm plus range the 1.5 ratio is the best choice as long as you can prop it. Some of the crazy HP guys are making these days don't warrant 1.5 ratios because there isn't enough prop available to hold them down. How much HP did your 540 make? Are you using a Bravo prop? I run a 29 Spinelli on my 210 Sport. I am currently getting ready to try some other props since Spinelli closed his doors. I need a back up plan in case something bad happens. The Hammer has a similar hull to the 210 so I may try whatever type of prop you are using first. I turn the 29" 6300 rpm through 1.5 gears.

I am running a bone stock 29" mirage + now. Haven't encountered smooth enough water to see what top rpm (long enough to wind it out) is with the new gears yet.

Motor made 865 at 6000rpm.

Wette vette,

Your numbers indicate over 20% slip. WTF?

97.8 MPH on GPS is what I have seen at 6300 RPM. Approximately 15% slip. Spinelli props tend to have higher slip factors than merc props. I haven't run a merc prop on my boat since I installed the current motor. I run a 2" shotrt bravo and have a hard time getting on plane with 3 blade props. A few years ago with much less motor I tried a 25 Mirage and could barely get on plane with the short drive. I turned it 6000 rpm and radared at 87 MPH, which is only 8% slip. It would be interesting to see what a labbed 29 Mirage would do on my boat now. Having the GPS on board will make trying new props fun and easy. I would say with 865 HP you should be easily in the triple digits. I would bet 6000 plus rpm on the marage once completely wound out. Pretty awesome!!!

It would be nice to try that prop on your boat. Have you tried any others with the current setup?

Do you have any before and after numbers for the short drive?

You must have some real HP to turn those kind of numbers. What kind of engine?

Thanks.

BTW
 

I can barely get on plane now. Hate to think what a shorter drive would be like.

I have only tried Spinelli props on my current set up. I started out with a 27 Spinelli made for me when I was running the standard drive height. I built a 12:1 compression iron head 496" and went with the SS drive at the same time. I know the SS drive made a world of difference in driveability, but since I did a motor at the same time I don't know how much speed it gave me. I am now running a nastier 498" Chev and have only had the Spinelli props on there. The current motor has 13.2:1 compression, fully ported Dart 325 Pro 1 heads, 2.3 / 1.88, Comp solid roller cam w/ 272/280 @ .050" and .714" lift., Jesel rockers, CMI exhaust, and a Nickerson stage 5 1050 on a Merlin intake, MSD ign, WPM full hyd steering, Dooley pan, etc. I have no idea how much HP the motor makes. I am just glad to see someone else going way faster than a 21' made was ever made to go. I love the acceleration of a small boat with big HP.:D

Nice Motor!
 

What kind of gas do you run it on? How does it idle?

What do you mean a world of difference in driveablilty?

That kind of acceleration is sweet! I just don't know how long my drive will like it!

By the rpm you are turning and the type of motor, I wouldn't be surprised if you were making more horsepower than my blower motor. Kind of makes me want to rip that blower off and put some new pistons in!

The official fuel of NASCAR
 

110 leaded at our local Union 76. I picked up 15 gallons the other day and it cost me $52.00. I have a buddy that lives on the lake where I boat that buys it 300 gallons at a time and then sells it to us at his cost which is about $2.80/gal. I figure for what a blower and another carb would cost I can buy quite a few gallons. Before the short shaft the natural bow lift was a little excessive. It would chine walk if you trim it to much, and bow steer if you don't trim it enough. It had a very small sweet spot and it was not easy to find. With the short shaft the boat runs flatter and you can trim it more without excessive bow lift. As far as the idle quality with the big cam it can be a little bit of a pain around the docks, but it's no big deal. I think if the tail pipes weren't under water it would idle much better. On the trailer it will idle at 1000 rpm all day. Drop it in the water and that idle drops a little and it gets tempermental at times. I wish would have dynoed the motor. I figure 700 HP plus as a conservative estimate. I am looking forward to trying some different props and seeing if they stack up to the Spinelli. Let us know how you do with your new gear ratio. My guess you need to turn that 29 at least 6100 to get 100 MPH at 10% slip. Let us know how it does. Drive safely!!

I wonder if av-gas would work in a motor like yours? Mine idles horribly. I need one of those harpoon guns the navy uses to fire a rope to the trailer 100 yards out and kill the motor and pull myself in! The lurching makes it very hard to handle at the docks. It lurches from about 200rpm to 1600rpm!

The reason I ask about the av gas is that I can get it easily and cheaply near me, but I wouldn't know where to find "race" fuel. I think If I had it to do all over again, I would build a milder version of your motor with more cubes. This is my second blower motor and my fourth motor in this boat, and I have to say that I had the most fun with the N/A motors.

If I hear a loud boom sometime, I may be asking for your combination!

I would not run av gas in my motor.
 

There is definate difference between leaded race fuel and 100 LL av gas. Av gas is probably good for about 11.5:1 compression. Jdnca1 has a 10.25:1 aluminum head 632 naturally aspirated with 2 quads on a Dart tunnel ram. He is using a very long duration cam. The motor idles at 600 rpm all day long and made a little over 900 hp at 6500 rpm. He runs 92 octane and shows no sign of detonation. His 26 Carerra runs high 90's, low 100's all day long, and he hammers on it. It is really an awsome motor. I would like to build one like his with a single, big Nickerson dominator carb and around 12 to 13 compression. I will save that combo for a safer boat.:D You must be running a B & M blower to have all of that surge. The guys I know running Weiand and Littlefield don't have that problem.

You hit it on the head,
 

It's a B&M 420. Knowing what I know now, I would never have bought one. It's too small for this motor. It's turning almost 25% overdrive to make 8lbs boost through a superchiller. Was talking to a mechanic that just pieced together a clone of an HP900sc said that his engine didn't nearly surge so much with a littlefield 10-71. I'm sure the motor would make more power too with the bigger blower. It all stemed from my need to fit it into a small boat. I was not aware a year and a half ago that you could use a B&M pulley setup on other blowers, as that is the only belt system that has a chance of fitting in my boat.

I am at the point now of just trying to have some fun with the boat, as I have spent all of last summer debugging this motor (will NEVER skip the dyno again). Maybe this winter I will either sell the boat, the blower for a larger one, or build a nasty N/A engine like yours!

One thing that did surprise me on the dyno, was how much low end torque this motor made. That really translates into seat-of-the-pants acceleration. You said that your boat really accelerates well too, so maybe this is not much of an issue.

My boat pulls very hard from 3500 to 5800 rpm. Below 3500 there isn't much going on. I am hoping to get a new boat in the next couple of years. I would like to get into a light cat type hull and build a 540 very similar to my current 496. I like the Cougar 22, WPM 23 with a standoff box, and the 22 Daytona. I think these boats would still accelerate like my Baja and should be faster. They will definately be safer. It will be a couple of seasons before this happens. My wife says when she gets a new house, I can get a new boat. I guess she's the boss.:) Be sure to let us know how your prop testing goes with your new gear ratio. If the 29 doesn't work out I may be interested in taking it off your hands. I am also planning on trying a 28 Bravo lab finished, and depending how that goes a 30 lab finished. I know CP perf has a pretty good exchange policy so I may just use them until I get what I need nailed down. I need a good spare for my Spinelli since he went out of business.

I saw the want adds...
 

You must have had a bad weekend. I see you are selling some parts. What ya got planned? Let me guess, bigger blower, dominator carbs, and a cam change. New exhaust too. Maybe you better go back to the 1.36's.:D

110 Gas - Maybe you can save a little...
 

Was reading the posts betweem you and Brad with great interest, I happen to notice that you mention what you were paying a gal for 110. Why dont you drop in at Knolls on route 12,Michigan City and check out your price with them? I havent bought any this year but last year it was costing 132.00 a drum (55gal) The first drum I had to buy the drum, $20.00 from then on just trade an empty for a full one, I dont know what kind of prices they have this year but its worth a try. I still have some left from last year. I just use a little at a time just to make sure that I have at least 93 octane. Hope this helps you. I also have lab 30 and 32 props both left and right that you are welcome to use. just give them back the way you get them, Your small shallow lake scares me!!
Let me know if I can be of any help to you.:D :D :D
eliminator219

Wette vette
 

I'm not sure yet. The motor seems to be dialed in and running good, but I'm not happy with the driveability of the boat. Guess I'm turning into an old fart!

Pulled the drive and have it over at a shop. I'm afraid that the bad shifting might have done some damage. Will know today.

Les,
I finally figured out who you are. I remember well the day you were at Pine Lake with your new 26 Howard Cat and you asked me if I would take your boat for a ride so you could take pictures. I was all over that. :D It looks like you have an Eliminator now. What model, motor, and how fast? I know your Howard ran great. Why did you sell it? Pine Lake is small but there are about 4 or 5 other local racers that have a lot of fun out there trying to out do each other and our boats are really too small for Lake Michigan. I may be taking you up on your offer to try your 30 lab prop sometime this summer. Good to chat with you.

Craig AKA WETTE VETTE:D

Brad
 

I know what you mean sometimes. It could be a pain fighting it around the docks. I imagine if you accidently shift into gear at the wrong time with that blower surge it could do some clutch damage. The 865 HP isn't the best thing for it either. Hopefully it is minor and you will be boating again soon. Keep us posted on where you end up. Oh ya I got the cam specs Erson recommended for a 12:1 plus compression 540" with ported cylinder heads. 278/286 @.050 114+4 install with .731" lift.
You will need that good fuel to run this combo.

Well, I just talked to the mech and the news ain't good. Looks like the clutch and the bottom of the gears are damaged. I'd like to know what caused all this!

I'd also like to get a hold of desktop dyno to do some checking.

BTW, I currently have the Dart 355cc CNC heads. I hope they wouldn't be too large for a N/A setup. I think the trick for me would be to get the idle quality reasonable and still get the most out of the motor. If I can get a N/A motor to idle around 800rpm reliably, then max out everything else that won't endanger that idle, I think I'd be happy. I don't care how high within reason the rpm is where it makes peak power, don't mind running expensive fuel (as long as I can find it). This would lead me to think of 11 or 12 to one compression. The cam is the biggest question and unfortunately, the desktop dyno can't answer idle quality questions.

What are the specs on your cam??

272/280 @ .050 on 112 + 4 installation. .714" lift. My heads are fully ported 325 pro 1 Darts w/ 2.3"/1.88 valves. Keep in mind this cam is for 498" My next motor is going to be a 12 - 13 comp. 540 and the cam I mentioned in the last post was desinged by Steve Tanzi at Erson cams. He used my current set up as a basis for the 540. Your heads flow a little more than mine which usually means less cam to achieve the same results. I think your boat is still light enough for those 355 heads to work great. You will want to spin 6000 to 6500 rpm if you really want to take advantage of your full head flow potential.

Brad;

The current cam I run in a Merlin 632, 10.5:1 comp, dart 360 fully ported and polished heads (flow 422 @.800 lift), dart tunnel ram with 2X775 race Demons. Comp 280/288 @.050 115 centerline, .785/.760 lift. Motor idles @900-1000 in neutral and 600rpm in gear. The 632 wanted more cam on the dyno 2yrs ago so I stepped it up last summer. My original specs were Erson 272/278 @.050 114 centerline, .772/.740 lift. As you could guess, this cam idled even better. I think your 355's will work great on a 540, coupled to a 1150 or 1250 Dominator you shoulod have a Nasty set-up. The key to idle is to keep your velocitys up, thats why I went with small carbs on my tunnel ram. I agree with Wette Vette, 11.5:1 should be no problem on 100LL aviation fuel. If you have an interest I would sell you my old Erson cam cheap, I have no use for it. One lobe has some very slight damage from a lifter going, but nothing a $75.00 regrind can't fix. :cool:

For reference I know someone running a Merlin 540 with similar cam as mentioned 1250 Dominator, dart ported 345 pro 1's, 10.25:1, that made 774hp @6700.