Allison SS 2000, should I lower or raise the motor?

[St]

Hi!

I have been running my SS 2000 comp (center steer) with merc 280, sportmaster 1.87 fat shaft and lightning et 14,5"x30" prop for three years now.

I have been running 106-108 mph (on the limiter) with perfect balance.

This spring I hade to raise my motor to make it fit in a garage. Afterwards I lowered the motor down to the same height as I thought it was before. When running after this maneuver I don´t think the balance is as good as before.

It leans to the left when I reach 100+ mph and when I trim up to make it fly straight it feels like the nose goes higher an higher until I don't dare to carry on. It even feels like I have to make a long long right turn at 100 + to balance the boat. Earlier the boat leaned to the left when running with too little trim, but when I trimmed up a bit it was all perfect. And when I trimmed too much it started to lean to the right (which never happens anymore)...

Obviously the engine height isn't exactly the same as before (should have been more careful when changing the engine height). Question is: Do you think my motor is lower or higher than before considering the characteristics described above?

As for now when measuring the engine height, I would say the prop shaft is 3/8" above the pad (don't know exactly how it was before but I know for sure it was above the pad). My bet is that it was even higher before but I don't dare to raise it even higher with stock pad and stock sport master risking blowout at 108 mph.

At speeds lower than 90 mph I can't really tell any difference from before.

What do you guys think

Thanks in advance!

//Oskar

 

[whipper]

Your higher than before. Hence the paddle wheel effect at 100. long turn, lean ect.. I would try lower it that wont hurt as much as raising it. Look at it that way. Try one bump take it for a spin. If still uneasy try another bump take it for a spin. Keep doing this untill it feels comfortable again Then mark your gage and cylinder to be sure. Some times with the mark on the gage you can obviously bump and it went up or down but the gage still reads the same.

Ive done what you did a few times. She flys fast as heck to a great speed then ooops something doesn't feel right!! haha Real nice for hole shot and mid range up high though!!

another thing is the guys running 110+ with your setup probably are running higher but just got used to it. also require less trim and prop selection may change running higher. I remember a guy with a 280/260 ecu SS that runs 114+ tell me he had to really take the lift out of the top end prop because at over 110 she was ready for lift off and {spooky}!! took many trips to the prop shop to find a prop to run those speeds and heights. Jay Leach and few others are who you need to speech with about that.

 

[St]

Thanks for the input guys. I will start by going down 1/8 and than go down even further if necessary (still think I'm pretty close to the previous engine height due to the fact I didn't raise the engine very much therefore can't be that far away).

Too bad I don't have a hydraulic lift and a lift indicator. That would help for sure.

Still confused about the effects when running the motor too high. I thought that if you raise the engine, the more the prop will paddle the stern to the right which would make the boat turn left and to compensate you would steer to the right which would make the boat lean to the right when running straight forward....And if lowering the motor, prop would paddle less to the right but instead you get more of the circling forces form the propeller (pushing the left side of the boat down) and the boat would lean to the left. This is the reasoning that made me think I should raise the engine..... Have I got it all wrong?

Thanks once again!

Cheers!

 

[ally2dextreme]

Hi,do you feel comfortable at those speeds? Would you like to go a little faster? Let me know ,I have a few ideas and an assortment of props and gear cases.... Just let me know

 

[whipper]

From the last ss how fast thread it sounds like the gear case and prop combo needs to be matched like a science to run over were your all ready at.

 

[ally2dextreme]

From the last ss how fast thread it sounds like the gear case and prop combo needs to be matched like a science to run over were your all ready at.

If he's run 108 on the limiter I conclude 1,he can drive pretty well as it hits the limiter it unloads the boat and gets hairy,2:with more prop is more speed the same prop with my small 1.78 gearcase would be a great start