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View Full Version : Will a 290 take the rpm's......?



Blewbyu
05-18-2000, 03:37 AM
I have a '74 X-18 with a 5.7 H.O. ZZZ crate motor that came out of the box @345hp-then was warmed additionally to 385hp.Will turn 5800 on the outer trim pin, but I usually run one pin in to keep it in the water, and that drops rpm to about 5400-5500.The o/d is a 270 with a 290 leg.
Burning question- will this o/d remain fairly dependable when fed a reasonably regular diet of high rpm's?
(Running a Spinelli Bros 15x22 Custom prop with a "supercup" on the trailing edge).Would like to know what kind of preventive medicine I should give it besides regular gearoil changes?

Jamesbon
05-18-2000, 08:31 AM
This may ease the pain or worry you more. My neighbor has a 24 Cigarette with a 290 and a high compression 502 that turns anywhere from 4700-7500 rpm depending on which prop he uses. (15 x 24, or 16 x 30) We ran it on both props for a few months, then about a month ago, we got it airborne, re-entered the water, I throttled it up again, and it acted like it was in neutral. The reason why it acted like it was in neutral was because the main shaft in the drive split clean. I was surprised that the drive lasted as long as it did, so my thoughts are that you should be okay. The Volvo is a very tough drive.

Nathan
Jamesbon@ij.net

GEOO
05-18-2000, 08:57 AM
I ran my 290 with a 383ci @ 5500rpms no problems in my X-18. I used RedLine Lube in the drive.
What speeds are you running? That's a hot motor!! GEOO

Blewbyu
05-18-2000, 01:40 PM
Geoo- I haven't radared or GPS'd the boat yet-but with two people in the boat and 1/2 tank of gas we just barely pulled by a big Formula weekender type boat that had twin 502's. He had a very accurate paddlewheel speedo on his Lowrance X70A FF- and he was doing 71-est our speed at 73@5400 rpm.
Which Redline product do you use- the MTA lube or just the syn. motor oil?
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Regards-Jeff

GEOO
05-18-2000, 02:09 PM
I looked it up in my file. I used Amsoil 10W-40 (synthetic oil similar to Red Line). GEOO

Blewbyu
05-18-2000, 03:19 PM
Thanks Geoo! Amsoil not easy to come by here, but I will grab some Redline.
Re: the motor.....see my latest post:PN for Dependable HP.......gotta tell you, this motor ROCKS! And it's really sanitary-no chrome and no leaks!
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Regards-Jeff

rayjay
05-18-2000, 05:08 PM
Just a note about AMSOIL, which I sell in the HONDA Motorcycle Dealership that I am a partner in. AMSOIL is (and has always been) motorcycle rated, which is something not many other commercial "car" brands are. What does this mean? Well most modern motorcycles have one sump for the engine and trans, and therefore require an oil with long polymer strands with high shear strength, just like a gear oil. The gears of a motorcycle's trans, just like an outdrive, tear up the polymer strands of most non-gear or non-motorcycle rated oils. Also, because of air cooled motorcycles which have extremely hot areas that the oil comes in contact with, motorcycle rated oils are better at maintaining their lubricating ability after being subjected to high temperatures. I have used it for years and found it is good stuff! This is not a plug for AMSOIL as there are also other good brands of oil out there, but at the moment I am not going to change until another brand proves better in our race bikes.

rayjay

Forrest
05-19-2000, 10:00 AM
The Redline folks (http://www.redlineoil.com/) recommend Redline MT-90 to replace 10w40, and MTL to replace 10W30 where recommended in gearboxes. I run MT-90 in my 280 drives on my Magnum.

Nathan, that vertical shaft in Volvo-Penta outdrives are designed to break "clean" under the most severe shock load in order to save the gear box from damage.

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Forrest


[This message has been edited by Forrest (edited 05-19-2000).]

Blewbyu
05-19-2000, 09:57 PM
Thanks Forrest! I looked on the Redline site- and tho they gave all their product info-there wasn't any to reach them by phone or email for tech help.
Re: The vertical shaft. Looks like it skinnies up quite a bit in the middle of the shaft. Surprising it survives the abuse it gets from Donzi owners! (In most cases.....).
Regards, Jeff