Formula78

Ok, according to desktop dyno the small block is going to make 350hp and 425ftlbs tq (as a conservative estimate, DD can not run good numbers for an extreme energy cam, VERY agressive ramp angles). Well, I only have an 898 (260) drive!! With no budget for upgrading the drive I figure I will run it (read: baby it) until it can run no more. I'm just wondering what an experience like a drive failure is like? Is it all internal damage or am I going to blow gears out of the case, sieze the input shaft, rip the transom off and sink or what?

Biggus

The 898 drive has a very small lower vertical shaft and usually will break where the spline enters the upper gear housing. (there is an o-ring groove that is a weak link). Not usually catastrophic but it will leave you dead in the water. The lower gear set is pretty weak also.

On a postive note, an Alpha One lower will bolt right on to your 898 upper. The Alpha lower has a much thicker drive shaft.

Kurt

marinetrans

Ya, Biggus is right. The new re-man merc alpha 1 is the way to go. It has a bigger bottom gear set, no o-ring in the vertical shaft and has merc's heavier duty 1.50 gear set in the upper. The housings from merc have that awesome merc finish too.

Big Block Billy

The guys are right ! Sell your pre alpha drive(s) to someone with a 305 in a cabin cruiser on e-bay, and get an alpha. I've heard that the uppers are not as strong because not heavy enough bearings and gears are used and heard that the cases are different and also not as strong. Iv'e experienced all of the problems related to these drives. The driveshaft going to the lower does have an o-ring groove that weakens it. It is on alpha's until about 1990. One time a drive shaft sheared in two on me in this spot. Whatever you do, make shure the gears are shimmed correctly. Before owning the tools , I took that lower to get a new driveshaft and after about 2 days of boating the pinion sheared the bottom of the driveshaft and grenaded the case. Either they did not inspect parts enough, or did not touque properly or shim right. Alpha's can take 400 h.p. if and only if done right. I'm running an alpha on a 21' baja hull with a 454 330hp. 1.32 gears and no problems what so ever. I really can spank this boat all day every day and it can take it. I have discussed this in another thread in greater detail. That boat is for sale soon(must sell) Actually the boat went much faster with the 1.32 than the 1.50 drive with the same 23 pitch mirage. No noticeable difference out of the hole either( I couldn't believe it) , but it is a light boat. I feel that reducing the propshaft rpm by using 1.32 gears in the upper, puts less stress on the tiny little pinion gear. BBB

Formula78

Thanks for the input! Unfortunately a new drive and transom assembly is not in the budget. I am already spending too much on the motor. Looks like I am going to have to baby it (a lot) for the season. If I could just swap a drive, I might have been able to do that, but an Alpha does not bolt to the 898 housing I have.

JaayTeee

Get a Alpha/MR lower, it will
bolt right up to your 898 upper.

I did this about in 1989 ( after breaking
a gear in the original lower)
in a 19' boat, ran various engine combo's
from 300hp to 400 hp, without any problems.

I saw the old boat last fall, it still had the
original upper on it.


jt

GLH

A big bill.

Big Block Billy

Maybe you should buy a good used transom assy on e-bay and rebuild it with a transom service kit. This way you know its good. That's what I do. Every once in a while a good deal comes along and I grab it. If it gets too expensive I let it go, I wait for another similar item.
If it were my boat and I was to keep it, I'd buy the lower and install it and then find a good deal on an upper and transom assy. But actually I'd just go downstairs to my basement and find the parts I need B.O.A.T. Break out another thousand ! Ok, not everyone is a parts hoarding maniac like me !
Your awesome engine will do you no good when the drive takes a dump, but it will keep the battery charged so you can listen to the stereo while awaiting a tow
B.T.W. the newer transom assemblies are much better and stronger also. Around '85 or so they have a 3/4" water fitting that flows alot more h20 than the 5/8 found on older units. Thay also have a better designed steering tiller arm shaft that is less prone to loosening up. The MR setup is part of the infancy of outdrives.BBB

Fountain38SC

That's what happened when wime went.

p4-33

You might also think about adding Towing Coverage when renewing your Boat/US membership this year.

Makes the Big Bill not so Big.

Brian