1989 292 sr1
 

Does anyone know what the distance between drive centers on a 1989 292 sr1 should be?
I'm ordering hydraulic steering, but just want to double check my measurements b4 getting the cheque book out. :evilb:
Thanks
Matt

Re: 1989 292 sr1
 

Off the top of my head (at 5:30 A.M.) I think the center on my '89 311 was 34 and some fraction inches. Measure the tip to tip at the front of your drives and then propshaft centerline to centerline at the rear. They should be the same or very close, depending on toe in or out. You can also double check by measuring grease zerk to grease zerk on the upper part of the outer transom plate above the Merc decal. Also measure center to center of the cap on the drive where the zinc is bolted to the bottom of the cavitation plate on the upper housing on the drive. I think these numbers should all be the same.

Re: 1989 292 sr1
 

Thanks reddog! I measured 34 3/4, but the silent thunder box gets in the way a bit and the light was failing so I want to check my measurements.
:cool:
Matt

Re: 1989 292 sr1
 

You might want to check for a previous thread on hydraulic steering on Formulas. I know there can be a clearance problem with the silent thunder and the rams. I don't know of a good solution to this problem.

Re: 1989 292 sr1
 

On my 89' 311 it is exactly 34 and 1/2 inches measured from the front of the drives. The propshaft, center to center is 34 and 1/4 inches so I have a slight "toe-in". I am going to make them equal as with props turning "outward" when under "load" the props will tend to provide a "toe- in" via the resistance of the water so presently when at speed my drives "toe-in" is actually more than 1/4 of an inch.

Re: 1989 292 sr1
 

I'm going with Rams mounted between the drives, and using IMCO end caps, which If I mount the tie bar on the lower bracket and the rams on the upper will give me the maximum clearance, more than if I use wing plates anyway. I will also consider mounting an extra microswitch to limit travel if necessary, or even ditch the silent thunder platform if I have to. I consider good steering a must, but the silent thunder/swim platform combo is just a nice to have and can be sacrificed.

Re: 1989 292 sr1
 

I just finished a 379 (per Cuda Count) project on my boat which included ditching the Silent Thunder Box and going with Stainless Marine tips with the internal flappers.
I like the looks of the "classic" offshore boat and have always HATED those rectangular exhaust tips.

Between dropping the box and swapping to an Eddie Marine Thunder aluminum exhaust system, I lost over 400 lbs of dead weight right over the props. Docked, the boat now sits over an inch higher out of the water at the stern, so I just dropped an inch on my "X" demension. At least "it" thinks so. The first time I fired it off on the hose it was all worth it.-

Re: 1989 292 sr1
 

Yeh, I was watching your progress with interest. Unfortunately I boat exclusively in salt water, I'm pretty nervous about aluminium exhausts, plus on a pair of 330hp 7.4's I doubt a performance exhaust would make much difference unless I start changing the heads too, which the budget won't stretch too this year. I do know where there's a pair of bulldogs for sale though :D

Re: 1989 292 sr1
 

Do you mind me asking which tips you went for? Are they the 4" straight flange straight end with the internal 'super flap'? They look sweet.

Re: 1989 292 sr1
 

Had an 89 272sr1(same beam) and the measurements(I was trying to find headers that would fit) was 34.5" center to center on the nose.

Re: 1989 292 sr1
 

My 311 is 34.5" center to center. Should be the same.

Re: 1989 292 sr1
 

Thanks guys! Parts ordered!
Now, what's next on the list..... :D

Re: 1989 292 sr1
 

when we gona get some WOT's ?

Re: 1989 292 sr1
 

I boat in the Gulf of Mexico, no problems with aluminum exhaust systems as long as you remember to ALWAYS flush your motors good after running in salt. Anyone who "trailer's" their boat around salt water use aluminum trailers exclusively.

In any motor, any time you can make it "breathe" better you are going to increase it's performance. Obviously some motors much more than others, but you will see some increase. Particularly over the stock Mercruiser manifolds, as they are just one big cavern inside and the exhaust gases end up just bouncing around all over the place until they ultimately find their way out. Plus you save 85 lbs. per motor.

Re: 1989 292 sr1
 

Stainless Marine. Love'em. Got them from "Trick Marine" here on OSO. And they are exactly as you described.

Re: 1989 292 sr1
 

Soon as we get some warm weather. Can you order some please. Low 70's would be perfect.

Re: 1989 292 sr1
 

Nope. You're toed-out dude!! :p

Re: 1989 292 sr1
 

Slightly toed in worked best on my twin 242.

Re: 1989 292 sr1
 

Third, so if the distance of the leading edge of the drive is greater than the distance between the propshafts (center to center) that mean's I'm "towed out"?????

I was misinformed. I was told that "in or out" was depending on the propshafts center to center, not the leading edge. Thanks for the correction.

What would be the best thing to do???? Increase the propshaft "center to center" distance over the leading edge distance. I think I'm starting to get confused.

I've got "outward" turning props so the way I understand it, the "prop torque" or whatever it's called, will cause the centerline of the propshafts to "diminish" slightly, is that correct?
Or do I have this azz backwards? Now I'm really confused.....not hard to do. :D

What is the ideal set up? Or is it one of those things you just have to keep screwing around with????

Re: 1989 292 sr1
 

for the terminology, think toe in/toe out as if you're looking at the front tires of your car.
Front of gearcase measures farther apart than propshafts= toe out and vise versa. 1/4" or more toe "in" most often is the setup to have. It's most often neutralized (gearcase over it's length made parallel to the bottom ;) ) by the water pushing to the outside (moreso against the inside leading edge of the gearcase) off the V shape of the hull after it leaves the bottom. It's not hard to picture in your mind's eye if you think about the forces at work, and the way a V-bottom displaces water, and how it wants to find it's way back.

Re: 1989 292 sr1
 

no, outlaw...with props spinning "out", your props are trying to "walk away" from each other as they bite thus thus maintaining a "toe in" (remember; leading edge of the gearcase is the "toe"). Just don't forget the forces of the water leaving the bottom of the boat as above. Adjust w/tie bar length.

Re: 1989 292 sr1
 

Now I don't know if mine were toed in or out. I do know this. The drives were a quarter inch closer together at the nose cones, than they were at the prop shaft. The 242 wasn't counter rotating. The tie bar made the biggest difference of all as far as the handling went.