New to me 88 454 alpha one drive flush questions

[Alleykat0498]

Had the boat about a month, its a 88 mach 1 23' condor with a 7.4 and a first gen alpha. To make a long story short less than 10 minutes after replacing the gimbal and bellows, the lower went. Snapped the vertical shaft right under the impeller housing. The boat was used in salt quite a bit so obviously I expected a failure at some point. So.... I bought a used complete unit for 200$ issue is the new unit has a 1.6? ratio and my old unit has a 1.32 ratio. My upper is in good mechanical shape, but has very fine metal in it. I've already flushed with some atf with the cap off and rotated the bearing etc. and plan on flushing with some diesel fuel before separating the cases. Im very skeptical that its even possible to remove all of the fine material by flushing.


So my list of questions are:

1 has any one had success flushing the upper after a failed lower?
2 has any one had success with a 1.50 sei unit for any extended period of time behind a BB, Im concerned about operating temps due to the slower pump speed.
3 should i just drop the coin and have the unit disassembled and resealed or order the sei?


Thank you in advance

 

[alldodge]

Had the boat about a month, its a 88 mach 1 23' condor with a 7.4 and a first gen alpha. To make a long story short less than 10 minutes after replacing the gimbal and bellows, the lower went. Snapped the vertical shaft right under the impeller housing. The boat was used in salt quite a bit so obviously I expected a failure at some point. So.... I bought a used complete unit for 200$ issue is the new unit has a 1.6? ratio and my old unit has a 1.32 ratio. My upper is in good mechanical shape, but has very fine metal in it. I've already flushed with some atf with the cap off and rotated the bearing etc. and plan on flushing with some diesel fuel before separating the cases. Im very skeptical that its even possible to remove all of the fine material by flushing.

So my list of questions are:

1 has any one had success flushing the upper after a failed lower?

Your not going to be able to flush the drive without complete disassembly

2 has any one had success with a 1.50 sei unit for any extended period of time behind a BB, Im concerned about operating temps due to the slower pump speed.

There should be no problem with the drive. SEI puts out a very good product and have heard no credible evidence to the difference. Your year 454 came as a 300hp and the alpha has no issue with that hp and in todays figures you will be a bit less.

3 should i just drop the coin and have the unit disassembled and resealed or order the sei?


Thank you in advance

If your sure the drive you bought is in good shape I would use it. Just going to need to decrease pitch on the prop. Now if your not sure I would go with the SEI and then you have the no questions asked warranty

 

[Bondo]

Ayuh,.... Welcome Aboard,.... I'd probably go with a new Sei in 1.50:1,... the 1.32 is obsolete,......

The cost of Labor kinda kills rebuildin' drives anymore,...
'n parts ain't cheap,...

 

[Tail_Gunner]

I have the same combo..snapped a lower drive shaft off like a toothpick hit a rock of course. Anyway's one full summer on a SEI and thing's are good

 

[Alleykat0498]

Thanks guys. Unfortunately my 454 is far from stock, head work etc. It's estimated around 400hp. The unit I've purchased works fine, but I lost over 20 mph throughout the rpm range give or take a few. Running 30 mph at 4000rpm with through hull and a big block just isn't gonna cut it. Guess I'll take my chances flush the crap out of my good 1.32 upper and see how long she holds up. Guess I'll find a donor with a bravo set up this winter.