Lookin' for documentation,.....

[Bondo]

That Mercruiser has never used reverse rotation motors,..... with Alpha drives,......

Over the years, I swear Don S told me that Merc never used reverse motors, but did do reverse drives,...... So I posted that at a Jeep forum I frequent,....
Then I was called out with this;

I have a 350 Mercruiser Chevy that was originally a reverse-rotation engine. It was one of a pair (cw/ccw pair) that had Alpha outdrives, so Mercruiser did build reverse-rotation engines. I built it back as a normal-rotation. The difference is the camshaft, and the reverse-rotation cam gears. The reverse-rotation engine uses direct-drive gears (like a L/F134 Willys) instead of a chain-driven cam.

So, is there any documentation that backs up these contentions, either way,..??
Would an Alpha drive even work, spinning it backwards,..??

 

[tpenfield]

How much do you have wagered on this?

I think @Scott Danforth is a good resource on this question.

 

[Bondo]

How much do you have wagered on this?

I think @Scott Danforth is a good resource on this question.

Ayuh,.... No wager, but I need to be Sure, before I respond,.....

Another question I found on another forum, that instantly brought Scott to mind was,.....
Will flow water direction, vs: oil flow direction, affect how cool the oil will get in an oil cooler/ heat exchanger,..??
Same direction, vs; opposite flow direction,..??

 

[tpenfield]

My recollection (not sure if it was from Don) is that the reverse rotation engines were used only for a few years, but not sure when. Otherwise, it was all done in the outdrive.

As far as verifying, the problem is most of what is searchable online is hearsay rather than factual sources.

 

[Bondo]

My recollection (not sure if it was from Don) is that the reverse rotation engines were used only for a few years, but not sure when. Otherwise, it was all done in the outdrive.

As far as verifying, the problem is most of what is searchable online is hearsay rather than factual sources.

Ayuh,.... My recollection is, reverse motors were used Only in Inboards, 'n not I/Os,....

 

[dubs283]

Ayuh,.... My recollection is, reverse motors were used Only in Inboards, 'n not I/Os,....

Yes. At least as far as I know and have seen in the wild.

Mercruiser never sold a RH rotation engine as a sterndrive package. All sterndrive oem packages are LH rotation engines. Can't say as for any Lake X trails but as far as general public market availability your looking at LH rotation

Straight inboard/v drive packages often had one LH engine and one RH engine. Most often the port motor is LH and stbd is RH. I have seen boats with the opposite (port RH and stbd LH) but it's rare and it has been obvious the motors were out of the boat at one time. Maybe someone goofed and installed backwards?

An alpha standard rotation drive would work in front of a RH rotation engine with a prop swap and remote cable adjustment but not for long. Using the reverse gear for fwd travel under load would chew it up pretty quick. If you've ever taken a counter rotated alpha apart it's pretty obvious how this would happen. Pretty sure merc doesn't make any counter rotated alphas anymore as a bravo will work counter rotated much easier, bravo drive doesn't care which way it rotates, just need the right prop(s) and remote control connection

I can't say as there is any publicly available documentation about sterndrive engines being only LH as most consumers wouldn't understand the concept.

This sounds like a question for my merc TAM, if he ever decides to visit the shop......

 

[dubs283]

You got me thinking this a.m., Bondo. I've thought about it a little more and I can say with almost 100% certainty the quoted text in post #1 is BS.

All alpha style drives from MC-1 to Gen 2 must have LH rotation engine input because of the cut of the gears.

Every gear in an alpha style drive is rotating when the engine is running regardless of gear position. The gears are not straight cut and must rotate only in one direction otherwise they'd fail rather quickly.

No way mercruiser would manufacture reverse cut gears for a handful of "standard" rotation drives to be behind a RH rotation engine.

If the gears were straight cut it'd be fine but they are relief cut to reduce noise/vibration and are designed to have input rotation from a LH rotation engine.

As far as the sea water pump operation I've no clue if it would pump correctly behind a RH rotation engine

 

[Scott06]

Ayuh,.... No wager, but I need to be Sure, before I respond,.....

Another question I found on another forum, that instantly brought Scott to mind was,.....
Will flow water direction, vs: oil flow direction, affect how cool the oil will get in an oil cooler/ heat exchanger,..??
Same direction, vs; opposite flow direction,..??

in a heat exchanger the cooling water and medium being cooled need to flow in opposite directions, if they flow in same direction it won't cool. the hot oil needs to be presented with increasingly cooler water as it moves through the heat exchanger and at most it will get to 10 deg above the cooling water temp

 

[alldodge]

Manual 1 list Merc II and III were built for LH and RH motors
Not Alpha

 

[Fun Times]

At one point I thought Merc did (maybe it was sea ray/the white drives?) then I always read no but maybe it's to early in the morning but is this site suggesting it happened and to run a right hand prop? https://www.perfprotech.com/blog/tag/engine-rotation

Edit: The following says all MerCruiser GM models 1974 and later show the stern drives to be (LH rotation), https://docplayer.net/30580333-Mercruiser-gm-engine-code-identification.html

 

[Scott Danforth]

I know that OMG had some reverse rotation. many inboards did. Not sure on Mercruiser. However I can ask some grey-beards that may or may not still be in Fond du lac

@Bondo , yes, in a shell and tube heat exchanger, you get about 75% the cooling if you reverse the hot side direction. however on most applications, the cam and oil pump flow the same, the circulating pump is different

 

[Bondo]

Thank you very much gentlemen,......

I think I'll lead my response in the Jeep forum, with the 2nd link posted by

Fun Times​

Then finish it up with a link to this thread,.....
Again, Thank you all,....

 

[Scott Danforth]

Bondo, shouldn't Jeeps be getting Cummins 4BTAA diesels?

 

[alldodge]

Bondo, shouldn't Jeeps be getting Cummins 4BTAA diesels?

No, 6.7's

 

[Scott Danforth]

No, 6.7's

They don't fit... However the LDV8 would

 

[Bondo]

Bondo, shouldn't Jeeps be getting Cummins 4BTAA diesels?

Ayuh,.... But,.... At -35* last winter, my '97 7.3l started, but gelled up 3 times in the 3 miles to the shop,........
Did what needed to be done, but with inconvenience,...

'n the whole idea of buyin' the Jeep, is for a back-up, to make it to town in an emergency, no matter what the conditions,....
As much as I Love diesels, my boats are gas, 'n I can live with this little V6 in the Jeep,.....
As little as I run it, keepin' it full of ethanol free gas ain't a big deal, just like the boats,....