Mercury V6 Pinion Height

**chubsta** · 12-27-2020, 04:27 AM

Why is it that foward gear needs to be installed in the gear housing when checking pinion height.
Can you leave it out when doing this.

**Tcatrett** · 12-27-2020, 10:13 AM

The older tool lines up in fwd gear bearing. The newer tool in the housing. Could maybe use the newer tool that way.

Originally Posted by chubsta

Why is it that foward gear needs to be installed in the gear housing when checking pinion height.
Can you leave it out when doing this.

**chubsta** · 01-09-2021, 06:33 AM

Thanks for the reply.
I have the newer tool.

**Aaronhl** · 01-09-2021, 02:04 PM

What's the part number of the new tool and can you post a picture?

**chubsta** · 01-10-2021, 03:45 AM

91-74476 Is the tool I'm using.
Not sure how to post a pic.

**Capt.Insane-o** · 01-10-2021, 10:19 AM

The fwd gear helps center the tool.

**chubsta** · 01-11-2021, 06:47 AM

I agree you need foward gear in place to check backlash once pinion height is set.
I was looking at the newer style tool and wondered how foward gear was needed.
All good.
Thanks.

**Aaronhl** · 01-11-2021, 04:44 PM

Originally Posted by TEXAS20225

one of these tools is on ebay 303512049283 also im assuming your setting all tolerances with mercury's preload kit as you know all drive shafts ( one bearing) jump up when started and all settings measured and adjusted while lifted

Is there a lower priced option?

**Capt.Insane-o** · 01-11-2021, 07:13 PM

I can't even tell you how many thousands of dollars I have in set up tools from speedmasters up through the number drives.

**TEXAS20225** · 01-14-2021, 12:10 AM

its kinda like your trade mark i have not built all the case's that have been invented by different motor producers but i have built so many Mercury v6 out board lowers they are uncountable

**Chaz** · 01-14-2021, 09:16 AM

Tex, you and the Captain are our resident go to guys for lower units ..

But I'm gonna go by the threads title Mercury V6 Pinion Height and go with .025 +/- .0005 ..

**wolfgangb** · 01-14-2021, 10:05 AM

Originally Posted by Chaz

Tex, you and the Captain are our resident go to guys for lower units ..

But I'm gonna go by the threads title Mercury V6 Pinion Height and go with .025 +/- .0005 ..

Subscribed - and I am always amazed at how nicely the SM gears can mesh, when set up correctly, contrary to the way they come from the factory. They just seem to throw the components together, with total disregard of their own manual`s requirements and the odd design changes which mother Merc introduces without telling anybody about - e.g. splines in clutch area and counter-splines inside clutch.
We have had new SM lower units here which twisted driveshafts or lost a pinion tooth within just two hours.
And, it starts with the dimensional quality of the casings, and ends in that the set-up time becomes unpredictable - like between 3 hours and 3 days.
Rgds, Wolfgang (South Africa)

**Bigchris090** · 01-14-2021, 01:50 PM

Hi all,

Sorry to jump in on this thread. I'm pulling my old gearcase apart out of boredom in lockdown. The pinion gear and forward gear both have missing teeth, the casing is pretty beat up inside... Will this matter?

Chris

**TEXAS20225** · 01-15-2021, 11:23 AM

i once bought a Torqmaster 2.5 case from a guy in FL. he shipped it to me claimed it was good when i got it as with all case's or blown blocks i bought i took it down all the way and it had 3 teeth missing from the pinion the guy said he did not know it and it had no loose pieces mixing with the oil so go figure he either ran it like that or cleaned it up so a customer did no know it was junk right away! of course it will affect it replace all gears that are missing teeth just my .02 something i did for years ive loaded plenty of consumer gears in sportys and torqmasters with big propshaft by having small shaft reverse gear ground out to 1.40 id so big carrier and shaft could still be used yes i know Brinell hardness it not same but everything else is

**Chaz** · 01-17-2021, 11:57 AM

Originally Posted by wolfgangb

Subscribed - and I am always amazed at how nicely the SM gears can mesh, when set up correctly, contrary to the way they come from the factory. They just seem to throw the components together, with total disregard of their own manual`s requirements and the odd design changes which mother Merc introduces without telling anybody about - e.g. splines in clutch area and counter-splines inside clutch.
We have had new SM lower units here which twisted driveshafts or lost a pinion tooth within just two hours.
And, it starts with the dimensional quality of the casings, and ends in that the set-up time becomes unpredictable - like between 3 hours and 3 days.
Rgds, Wolfgang (South Africa)

The ones I have done were in the .060 ~ .070 range .. checking as I took them apart. I can see gaining .005 ~ .010 as they initially bed in and wear over time. But more than twice what the spec call's for is ... just poor workmanship.

A good place for a 9" Ford to live is right around .010" . I don't care how expensive the parts are you use , there is always some runout when setting up backlash. I never go over .010 on the loose side, which can put the tight spots down around .003 or .004 . Guys have said , man thats too tight. I tell em to leave the wheels in the air run it in high gear a few minutes. Then put one burn out and a pass on the car . Pull the chunk out , bring it back and lets measure it again .. if it's still too tight , I'll give you your money back. If I'm right , you pay me again .. no one ever took me up on my offer.

So sometimes, (ok - always) you have to use common sense and experience when assembling .. anything , because mass produced parts have quite a bit of tolerance stacking. The more parts to a given unit ... the worse it gets ...