Yanmar 3QM30F transmission options

[sv_bruadair]

Hi guys,

So we're here in Bocas del Toro Panama thinking we may not go anywhere any time soon. We had an issue with our damper plate and replacing it with a new one has fixed that particular issue. But now our friend and mechanic says that we should really think about replacing our bearings in the transmission as it does make some grinding noise.

After talking with Barbara at Golden State Diesel and with the folks at Yanmar it appears that parts for our Kanzaki KH18 gear box is being phased out. For example a couple of the bearings are no longer available, on one of the three shim kits are available, some of the springs, spacers and other small parts are no longer available either.

So we're trying to decide if we should spend the money and replace what parts are available, specifically the bearings and seals and see if that will improve the noise issue in our transmission. This is noise we've lived with for the past four years, though now it's slightly more pronounced. We're told by a Yanmar dealer that a rebuild on our KH18 would run about $3500 and only parts that are available would be replaced and using the old parts for parts no longer available. Kind of pricey.

So another option has been presented. After doing some searches on this site and a few other message boards I have learned that the folks at MER Equipment have made a custom bell housing to allow the replacement of the KH18 with a ZF25M. Total cost for the new tranmission, bellhousing, adapter and new coupling is $2100.

So I'm wondering if anyone here has had any experiences with MER Equipment or if anyone has made this change to the ZF. One of the issues is that the new gear box has a ratio of 2.74:1 rather than our current 3:1 so I suspect a new prop will be in order.

Also curious as to thoughts, pros and cons, of making the change to the ZF25M.

Damon and David
sv Bruadair
www.bruadair.us

[sv_bruadair]

In researching some old posts here I see that John Gratton has actually used MER to replace his KH18 with a Hurth 250 (now ZF25M). John made this change in 2004 and I was wondering if anyone knows how I can get in contact with him to get a bit more information.

Thanks in advance,

Damon

[sv_bruadair]

I've been in contact with Mark at MER Equipment, he's the same guy that helped John Gratton three years ago adapt a Hurth 250 (now ZF25M) transmission to the 3QM30F. Below is some information Mark had to say.



Hello Damon,

Unfortunately you will have to modify your existing engine mountings because the adapter plate used does not have a pattern for engine mounting brackets.

You should be able to re-use your new damper plate; the spline configuration is the same on both transmissions.

Actually you won’t need the 31406 adapter and the SAE #4 housing adapter has the cut out to accommodate the ZF25M. So the transmission will bolt up to the #4 bell housing adapter and the prop coupling bolts up to the transmission output coupling.

I have an old KH18 core upstairs that I took a look at and you will have to have new mountings made locally; no one makes a housing adapter that has mountings incorporated into the housings.

The housing adapter I’m selling you has an offset so it actually pushes the transmission back about two inches; you shouldn’t have any problems with the input shaft bottoming out into the flywheel.

Thank you

Mark Miller
Parts Manager
MER Equipment
338 West Nickerson
Seattle, WA 98119
1-800-777-0714
Local 206-286-1817
Fax 206-286-1917
Direct # 206-957-6503
merequipment.com



And a second email from Mark reads


Hello Damon,

The parts will weight approximately 75 pounds to ship.

Sorry but we don’t have any pictures of prior installations.

As far as engine bed modifications; I’m not sure; it depends upon your application and how deep or wide your existing engine bed is. I have no way of determining that one.

ZF doesn’t really have a dimensional page on these components; you might suggest to whoever is doing the work for you that they try to utilize the housing bolt circle in order to manufacture mounts for your Yanmar.

Shipping to California would be approximately $50.00 via UPS ground.

The difference in ratio may or may not be an issue; the difference is not that much; you may actually be able to push the boat just a little faster.

Best regards

Mark Miller



Just wondering what other's thoughts are on this subject.

Damon

[mitchk]

[sv_bruadair]

[sv_bruadair]

[mitchk]

I have my transmission out of the boat and removed from the engine, I am going to replace the seals however I am looking for a special spanner wrench to remove the nut from the output shaft. Anyone know where I can find one of these ?

[bruadair]

Mitch,

When we had our transmission out I wanted to replace the rear seal as well but had the same issue with needing a special tool to remove that large nut. I got the part number from the Yanmar manual and was disappointed to find out that this special wrench is no longer available. I tried numerous sources only to get the same answer.

One option is to contact some local Yanmar mechanics to see if they have one in their tool box. Another option is to take the transmission to a machinist and have one made.

In the end we didn't replace the rear seal, only the forward seal. When we get to Cartagena Colombia I'll remove the transmission again (want to replace one last engine mount) where I'll take it to a machinist to make the tool. Something to note, take a look in the manual to see how many pounds of torque is recommended to put this nut on, I believe is in the 600 pounds per foot range.

Good luck. And if you do find a tool please let me know where!

Damon

[mitchk]

I just finished making one myself, wow it was a tough job! I atrted with a piece of 2" sch80 ss pipe and put in our crimping machine at work (100 ton) and sqeezed it down till the ID was 1 3/4". Then I marked where the notch's needed to be with a marksalot and ground away until I had it correct. It looks kinda rough but I will see if it works in the next day or so. If it does maybe we can run to my shop one day while you are in town and make one for you? I will have to do some research on the torque? In the parts manual it does not appear to be a tapered shaft? It may be splined? I will look tonight? And I will try to see if I can find out what torque it should be tightened to!

[bruadair]

If it works then put me down for one! Let us know how it goes and I'll see you in a few weeks.

[mitchk]

OK, My homemade tool worked! well sort of, I was able to get the nut off however when the factory assembled it they pinged the first thread to act as a lock nut. For anyone unfamiliar with this it means they used a center punch right where the inside of the nut and the shaft meet, at the first thread and put a small dent so the nut will not back off. This works great until you get ready to remove the nut. I ended up pretty much destroying the threads in the nut, I am hoping I can get a new one? The shaft threads are ok except for the first (or starting) thread. I wil have to file it a little to make it work. The hub and shaft are splined and the hub slid off very easily. This will allow me to replace both input and output seal. Just hoping I can get one of those nuts or I will have to get one made! I will take my camera to the shop and take some pics to post so anyone attemping this in the future will know what to expect!

[bruadair]

Great Job Mitch, glad you got it off okay. I'm still pretty sure I can get a tool fabricated in Cartagena fairly inexpensively but not sure about the nut. If you happen to find the need to get one made can I talk you into two? I'll be happy to reimburse you of course. Might be nice to have on hand just in case I run into the same thing.

Damon

[mitchk]

Blue Water Ships Store was able locate one in Chicago, I had it shipped UPS NDA, I am sure it has already shipped. I will get them to send another one for you, should be waiting for you when you get here. I believe they said it was about $30.00 plus freight.