raising a pylon

Although a full rebuild is years away, I was daydreaming today about modifying my engine. Seems like an easy way to gain a some horsepower is by adding an aluminum dual plane intake and a carb spacer. The problem is, these mods may not fit under the motorbox.

If I were to raise the motorbox a few inches to accomodate the go-fast parts, it may be in the way of the rope when its attached to the pylon.

My question is- would it be possible to remove the pylon and put in an appropriate spacer (steel?) to gain a few inches? What problems may be encountered?


Is it summer yet?

BKH, thanks for the advice.

I'm well aware that these boats are made for pulling- I think the term is "water tractor." Theres nothing wrong with more power though! The motor has 1150 hrs on it now, so a rebuild may not be out of the question a few years down the road. At that time, it would make sense to add better performing parts, especially if the added cost is not signicantly more than stock pieces. Of course, low-end torque would be the name of the game.

I'm just trying to have a little forethought. Projects for this spring include some floor repair and new carpet. A new interior is soon to be ordered (probably installed next fall). I'm gonna have the shop add a few extra inches of carpet to the bottom of the motorbox skin, just in case. If any changes would be needed to the floor, now would be the time to do them.

Top speed is only 41 right now, so a little more would be nice for barefooting, especially 1-footers. I know this hull has some potential- Ive been in a '95 with a GT40 that could do an easy 50

Last 2 owners say it always ran that way.   Pulls strong, just not a lot of top end. I plan to check the timing once I get it in the water.

Thanks for the compliments guys. I'm not looking to change the boat much. I agree its a looker and plan to keep it looking original- which is why Im going with a factory interior, etc.

Is it true that the pylon is glassed in? The posts I read implied that it was only bolted to the floor and hull.

I'm baffled by an original brochure I have on the '86 Ski Nautique. It has a one page performance report. I'll quote the write-up:

"The Ski Nautique 2001 runs 34 MPH at only 3000 RPM, while a 4000-RPM setting pushes the speedometer to a brisk 44 MPH. At full throttle, the 2001 reaches 47 MPH at 4250. Acceleration is crisp with the 351 cubic-inch engine pushing the boat to top speed in exactly 10 seconds".

I have a new engine and I only push 42 MPH. I don't know if their test was going down the rapids of what. 47 MPH at 4250 RPM's??? Oh well, I can live with 42.

your 90 maybe different then my 87, but in 87 the pylon is glassed in. I know because I'am redoing my floor and the plylon is loose so I have to reinforce the glass around the bottom of the plyon. just take a mirror and a flash light and look under the floor infront of the engine, you should beable to see the bottom of your pylon,.. it is bolted around the engine frame that sits on your stringers by two large "U" bolts.

all you other slow pokes should ski/board on good clear canadian water..my old girl has hit the 47 mark before.one time my dick head friend got my spare prop recuped,motor wound up to 5500 rpm and the speedo was over 50. engines are worth more than props.. that prop went buy buy.

cheers

the speedo's aren't very accurate after about 40mph use a gps and it will tell the truth about the speed. Also balance the motor and it's no problem turning 5500 rpm.

DavidF, thanks for the tip. Great advice, as usual. I'll take a look at it first hand, and go from there.

The pylon on the 90 sits in a cup that is glassed into the floor. In the bottom of the cup is basically a "finger" sticking up a couple inches, maybe an inch in diameter. The finger sticks into a negative "divot" in the bottom of the pylon. The pylon is not glassed in. The aluminum frame that holds the engine has a crossmember between the stringers made of aluminum. Through it are two MASSIVE U-bolts that wrap around the pylon and are secured by giant bolts (3/4 inch?). If you loosened these bolts, the pylon would probably pull straight out. I never have, but I'm pretty sure of this. It is tough to see because the crank pulley is right in your way. You have to check those bolts annually to make sure they don't loosen up.

Rick, I will have to check on that longer trick pole. The boat already has EI, so no worries there. I have the 1.23:1 tranny, so I'm already running a 14x16 prop. I'm adding an Acme 612 this spring.

M3, thanks for the description- I guess you would know exactly what setup I have! That gives me a perfect idea of what I would have to do to raise it.

88, I'm primarily a slalom skier, so adding that longer pylon from the Airs doesnt really appeal to me. Im just looking for 2-3". Thanks for the tip though!

There is absolutely no indication that the engine needs a rebuild anytime soon- it runs strong and was very well maintained (thanks M3). These ideas just keep me entertained until its warm enough to actually work on the boat!

Specifically, I'm looking at the Weiand Stealth, which looks to be fairly tall. I've heard its 2-3" taller than stock, though I cant find height numbers on the stock manifold. The stealth is 4.37" in the front and 5.06" in the rear.

Ive got a carb spacer (stock) on there now, which is where the PCV is plumbed in. I'd like to add a blended carb spacer in there instead, or in addition to what I have. I also plan to add some sound-absorbing insulation, which will take another inch of height away.

The shorter flame arrestor is an idea, but it would be nice to have a little more room, if possible.

I'm not expecting much from an intake alone- but a little extra (especially on the top end) would be nice. When I do a full rebuild in a few years, I think a 393w would be a pretty nice motor for a ski boat.

Or as a non-permanent solution you could get this from Lake Elmo Sports. It is pretty common for show skiing. http://www.lakeelmosports.com/index.php?main_page=product_info&cPath=19_52&products_id=98&zenid=4f83e65bade2223ca8ebddd7045fca9b

It slips right over your stock pylon. Made for doing 360's around the boat.