MerCruiser ALPHA ONE 1.32 Gear Ratio Upper Unit on a GM 5.0/5.7

[Bondo]

Wasn't someone looking for one of those drives a week or two ago................

Ayuh,..... More like a month or so, I think,......

 

[kenny nunez]

The pre Alpha just means to me any of the drives that used the spring loaded pin to keep the pinion gear properly engaged.
I am told that a Ford engineer was consulted and the first thing he said about the spring loaded pinion was”That is not going to work”!

 

[achris]

The pre Alpha just means to me any of the drives that used the spring loaded pin to keep the pinion gear properly engaged....

So, the Mercruiser-1 and the 'R' drive.... But the MR is also 'pre-Alpha' and that doesn't have a pre-load pin, so there's the problem. Calling anything 'pre-alpha' is confusing.... It basically means any drive made before 1986, of which there are at least 16...

It's better to use the proper designations for the drives than some generic name that actually means nothing. Did you read that thread I posted at the end?

Chris....

 

[jbutler67]

I can post a picture of the complete drive and gimbal housing.

Boat is a 1986. Engine was replaced Outdrive is newer too. These serial numbers are on the following

A550024 on housing (stamped in metal)

A553024 on transom assembly (see picture)

 

[jbutler67]

Pictures of complete drive and housings.

 

[achris]

I can post a picture of the complete drive and gimbal housing.

Boat is a 1986. Engine was replaced Outdrive is newer too. These serial numbers are on the following

A550024 on housing (stamped in metal)

A553024 on transom assembly (see picture)

The transom assembly/gimbal housing is 1986. The engine is 1998... But I can't find anything on that drive number, 822756... The pictures are definitely not a Gen II drive, it's either an MR or an Alpha One (which are the same in everything but name)....

So yes, you're looking for a replacement Alpha One, or parts for....

Re-reading your original post, you're looking to buy a second (spare) drive for the boat, to replace one that was stolen, yes?... Finding a good 1.32 drive is going to be difficult, at best... However, there are plenty of good 1.5 drives around, and as your 1.32 appears to be in excellent condition, you'd likely get as much for it as two 1.5s... See where I'm going?... Get yourself a couple of 1.5s and check the revs (using a calibrated tacho) and see where you sit... From the photo, that looks like it might be a 17" prop, and with the 1.32 I suggest it's a bit on the big side. Moving from 1.32 to 1.5 would require a shift in prop size of 2", roughly... that equates to about 400rpm at the top end. If that prop is right at the bottom of the rev range with the 1.32, it's likely to be just about spot on with a 1.5.....

Anyway, that's my way of thinking. Let us know what rev you make at WOT now (and the pitch of the prop) and we can help see what's what...

Chris.........

 

[jbutler67]

Thank you Chris! Yes, looking for a second (spare) drive to replace the one that was stolen.

The current prop is 15” pitch.

End of of season here. But I now have plenty of info to shop for a 1.5 to replace the one that was stolen. (As rare as the 1.32s are, I’ll continue to watch EBay and Craig’s List to see if a 1.32 pops up for sale in my area. )

Thsnks again all.

 

[jbutler67]

I’m 90% sure current drive is a 1.32 given factory sticker. Any harm in popping the top cap and counting the teeth?

 

[alldodge]

I’m 90% sure current drive is a 1.32 given factory sticker. Any harm in popping the top cap and counting the teeth?

No harm at all as Walt mentioned. Should be 20 on top and 16 on bottom

 

[Walt T]

COUNT THE TEETH.. Remember our high school football coaches..... NEVER ASSUME ANYTHING.......You will make an ass out of u or me. This is SO true in customer service. Rule #1 Everybody lies. Rule #2 I limp and have a bad attitude to customers. Rule # 3 All customers lie
Just call me Dr. Houseboat

 

[QBhoy]

Agree with AC Chris that a 5.7 is just fine I’m that boat. Plenty mass produced boats bigger out there doing just fine with that engine.
But the issue is definitely that drive. The prop would need to be ridiculously low pitched. Would be a nightmare.

 

[jbutler67]

For “20 on top, 16 on bottom” is “top” to the right and bottom below the bearing?

 

[achris]

For “20 on top, 16 on bottom” is “top” to the right and bottom below the bearing?

:thumb:
20 teeth on the 'drive' gear, attached to the input yoke. And 16 teeth on the 'driven gear', at the bottom of the housing.

Chris.......

 

[jbutler67]

20 teeth on drive gear. 16 on the driven gear. Got it thanks. Raining here today. Will check tomorrow. Thanks again.

 

[jbutler67]

Confirmed today. It’s 20 over 16. (Had to drain some of the gear lube to see gears but worth it in order to confirm.)

Now I can start my search for a rebuilt Alpha One with a 1.5 gear ratio.

Thanks again everyone for your help.

 

[jbutler67]

Can someone go into detail about pro's/cons of installing a 1.32 outdrive on my small block. Boat is a 22' formula with a 5.7L engine. Ive seen a million postings about going from 1.32 to 1.47 on big blocks and the dangers posed, but I cannot find any advice on going the opposite direction. Any help would be appreciated!!

I can give the reason I am going from a 1.32 to 1.50... which may provide SOME insight. But, I'll leave it to those with more experience to provide the specific details.

With the 1.32 (which is for a bigger block engine?) the engine works to get up to speed. It's almost like trying to accelerate a car from a dead stop by using 2nd gear. You can do it, but engine works hard until it gets up to a certain speed. It will get up to speed but the engine works to do it. So, I have to believe it is not the best thing for the engine. Plus, it makes the boat more difficult to maneuver at slow speeds, like when docking.

 

[alldodge]

Can someone go into detail about pro's/cons of installing a 1.32 outdrive on my small block. Boat is a 22' formula with a 5.7L engine. Ive seen a million postings about going from 1.32 to 1.47 on big blocks and the dangers posed, but I cannot find any advice on going the opposite direction. Any help would be appreciated!!

Your hyjacking a thread, please start your own thread