Help Needed - Volvo Engine Part

[stxray]

As some of you might know, I'm in the process of rebuilding my Volvo Penta MD3B engine and I've run into a bit of a snag.

I'm looking at the exploded drawing for the "Crankshaft and Related Parts" (see below) taken from the Volvo Penta online parts store where I've circled the part in question, identified as #6.

According to the associated parts listing, #6 is identified as a "Sealing Ring" (PN 944181) which my parts supplier says is part of the gasket kit. However, in the drawing #6 points to a bearing-looking item. I've searched all the drawings and don't see that "bearing" identified. I'm confused.

Are #6, the sealing ring and the bearing-looking part the same thing? Is the drawing wrong/misleading? Is the bearing-looking part an actual part and, if so, does anyone know what it is called and it's part number?

Any help would sure be appreciated.
rs

[DesertAlbin736]

WillieC is your go-to guy. He's done a rebuild job on a MD17C & has also dealt with MD3B engines.

[tribologist]

Based on what i find in the workshop manual it seems to make sense that it is called a seal ring.

Do you have a shop manual?

Ulf

[tribologist]

Interesting... Picture of the part and the drawing is not matching...

https://www.marinepartseurope.com/en/vo ... 13759.aspx

https://www.marinexpress.se/artikel.php ... k=&id=6214

[tribologist]

This image from the md17 manual shows it nicely

You can see the radial seal behind the main shaft bearings

image.jpg

Ulf

[stxray]

Hello Tribologist,
Thank you for the information. It is most helpful. I have sent it to both my parts supplier and my mechanic.
The exploded drawing from the Volvo online parts store makes it look like a bearing whereas the drawings from the workshop manual, especially the MD17, shows it clearly as a "Bearing Shield".
I'll post the final outcome once I get everyone on the same page.

[tribologist]

I have the original printed manuals if you want them. Your dinghy, is that the LT-2?


Ulf

[stxray]

I have the original printed manuals if you want them. Your dinghy, is that the LT-2?


Ulf

Absolutely! I'd be most grateful. I'll send PM with my address.
My dinghy is the LS2-RU

[tribologist]

Will scan them and ship. I have the workshop manual for the MD11C D and MD17C, D in printed version and also the instruction book. I will scan them in high res and then mail them to you. I also have a copy of the MD1,2,3B manual that is not in as good shape that will go with it.

Im looking for a dinghy for our A25. The LT 2 and the LS3-RU are on my list.. both are for 2 people according to the sales brochure.. The LT-2 is super light and have the tubes go around so I been leaning towards that one but the one you have is interesting to since it seem to have a better bottom. Does it take three adults in good weather or is it just to small? How do you hang it on the boat? Do you have any pictures with it on the boat?

Ulf

[stxray]

Thanks for the generous offer. I sent you my address in a PM. Again, thanks.

As to the dinghy, I looked at the LT model but didn't like the stern and it's outboard bracket setup. So, I went with the LS2. Yes, it is a 2-person dinghy but I think you could do 3 in calm waters although I've yet to have the need to do that. I was trying to minimize the degree to which the dinghy extends beyond the beam of the boat. Given that the A25 stern tapers down to about 6', I felt I was limited to the smaller length. Additionally, I chose the Achilles after visiting an inflatable dinghy repair shop where the brand was highly recommended for its durability and long life. After my purchase, I returned there and had the lifting rings installed.

Prior to buying the inflatable, I had a hard, fiberglass dinghy that I towed. I found towing a dinghy to be very problematic and a constant worry and concern. Additionally, the hard dinghy had very poor stability. It was like trying to get into a canoe. I felt like I was always on the verge of tipping. I know a hard dinghy has lots of advantages but, I wanted (needed) the enhanced stability. Plus, the inflatable allows me the option of deflating it, folding it up and storing it below if need be. My original thought was I would carry it on-edge, on the swim platform. However, I was able to pick up a set of davits off of Craigslist. It was a challenge installing them given the slope of the stern deck but I got it done and that's where/how I plan to carry the dinghy. Sorry but I don't have any pictures yet as I haven't been on the water since installing the davits.

[tribologist]

Thanks! DA hangs his on davits to. Maybe i should look at that. It seems good to get it up high. Complemented with a monster fender it might be doable to take a near 8 ft dinghy through locks hanging on davits?

[stxray]

I was hopeful the previous information would have resolved the confusion but it has not.

According to the parts listings on the Volvo website http://www.volvopentastore.com/Cranksha ... _id.770522, it indicates 2 each of PN 875483 and 875484, labeled “Bearing Kits” are needed. My mechanic thinks there should be and is looking for a third bearing. He is asking how many bearing journals does the Md3B have as there should be a bearing set for each journal.

Any information or clarification anyone can provide would be greatly appreciated.

[tribologist]

Three?? The crank has 4 mains

The block and the bearing shield takes the 875483's (2 sets) and the two center bearing holders each need the 875484 sets.
If you look at the parts diagram for the two cylinder it becomes clear. I just finished and are uploading the manual. I will send you the original. Section 44A,B show how to install the mains, Section 66 is for the center bearings.

[tribologist]

Penta MD11C, D MD17C, D

https://drive.google.com/file/d/100XNNo ... p=drivesdk

MB1D MB2D MB3D
https://drive.google.com/file/d/14zoSda ... p=drivesdk

Let me know if this work. How do we get it into the archive?

Ulf

[stxray]

After reviewing your files, here's what I think I've figured out and what still has me confused.

First, as I understand it, the MD3B crankshaft has a total of 7 journals. Three of the journals are for the pistons (Big end bearing kits - 3x 875491). While 4 are for the Main Bearings 2x 875483 & 2x 875484. Do I have that correct?

Second, part of my confusion is that the parts drawing on the Volvo online parts store (see earlier post) makes it look like #8 (875483) is the top half while #9 (875484) is the bottom half of a set. If that was true, then 2 of each would mean I only have 2 main bearing sets. However, when I do a Google image search for these parts, each is shown as a complete top & bottom set. If that’s true, then #8 is a set and #9 is another set and I have 2 of each which means I have my 4 main bearings sets. Do I have that correct?

Third, I am confused by the two parts each labeled #10 (897223 - Bearing Front & 807497 - Bearing Cap Rear). Again, the drawing makes it look like one is top and one is bottom and that they are carriers for #8 & #9. Yet again, when I search for images, I find they are shown as a complete top & bottom set. Additionally, the description leads me to think that one goes on the front of the crank while the other goes at the rear. Given that the bearing are what wears out, the bearing caps do not normally need replacing. Do I have that correct?

All that said, I’m still at a loss to identify the bearing-looking part to which #6 is pointing. Yes, I know #6 is labeled as a “Seal Ring” but what is the collar in the picture? Is it a collar or bearing that is placed on the front end of the crankshaft or a bearing that is pressed into bearing sealing cover? Looking at the MD2B Engine Block (http://www.volvopentastore.com/Cylinder ... _id.770516 ). I’m wondering how closely this would match the MD3B. The MD2B drawing shows a “Bearing Cover” (#14) whereas the MD3B does not but, it does show a sealing ring (#28).
Any guidance or advice be greatly appreciated.