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yanmar rebuild?

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i have been told that rebuilding yanmar gm series diesel motors is a no go...is there any truth to this? 

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no personal experience, but saved this link in case I ever feel like trying to rebuild my 2GM20F. I think the guy who did it posts here, but I saved it off several years ago and couldn't tell you the screen name. http://j30.us/files/Rhapsody/Rhapsody_Yanmar_Rebuild_Winter_2006-2007.pdf

What reasons for not rebuilding? I would assume with a shop manual and parts from a dealer, it should all be relatively easy. Shop manuals are available online too.  

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3 minutes ago, Slick470 said:

no personal experience, but saved this link in case I ever feel like trying to rebuild my 2GM20F. I think the guy who did it posts here, but I saved it off several years ago and couldn't tell you the screen name. http://j30.us/files/Rhapsody/Rhapsody_Yanmar_Rebuild_Winter_2006-2007.pdf

What reasons for not rebuilding? I would assume with a shop manual and parts from a dealer, it should all be relatively easy. Shop manuals are available online too.  

2 shops (including MACK Boring) have said they do not rebuild yanmars anymore and that GM parts are no longer being produced. This is not for my boat but for my YC's launch. which either needs a rebuild or a new motor.

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I completed a upper end job on a 3QM series.   Had the head re-furbished, alternator and starter as well.  Was not expensive.  Just time consuming but it was winter so I had the time.  Pumps were already replaced.   Was told the lower end will last 60 years.  My understanding is the QM was the last of the heavy duty Yanmars so maybe that is a factor.

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Yanmar still sells the 1GM10 new, so some GM parts must be out there.  That said, Mack Boring a firm with a good rep and is (as you know) a Yanmar Dealer, so I would tend to take their word...

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It depends on what you mean by "re-build". They don't have cylinder liners, so there is a limit on how big oversize you can go with new pistons.

It could be that some parts are out of production by now.

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4 hours ago, Slick470 said:

no personal experience, but saved this link in case I ever feel like trying to rebuild my 2GM20F. I think the guy who did it posts here, but I saved it off several years ago and couldn't tell you the screen name. http://j30.us/files/Rhapsody/Rhapsody_Yanmar_Rebuild_Winter_2006-2007.pdf

What reasons for not rebuilding? I would assume with a shop manual and parts from a dealer, it should all be relatively easy. Shop manuals are available online too.  

That was me and still on my old blog - my rebuild was based on clogged cooling passages on a raw water cooled engine.  Didn't need to do rings and valves because compression was good and it didn't use oil.  Yes I would do it again.  I sold the boat in 2013 and now have a J/109 with a fresh water cooled 3YM30.  I don't expect to have the same cooling issues with this engine.  The manuals are available on the J/30 site for the Yanmar 2 series and J/109 site for the 3 series.

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I don't know how to say this... Think about companies like Bosch, FAG (bearings), SKF (also bearings), Lucas (shitty Brit electric), Siemens, VDO, Valeo (French company --they make some good and some Horrible Freight quality parts), etc. They all just make stuff and sell it to other people. Source the parts. There are lots of pick-em-up truck performance parts out there too. 

Rings are rings. Pistons are pistons. If OEM can't be had I'd bet someone can email someone and forged can be had for not too much money. Grind your rotating assembly (rotating assembly is everything that rotates, camshafts, cranks, oilers, etc.) down to the closest (quality) widely available tolerance and go with that. May be a little extra coin up front but if you document it (PROPERLY) I promise it'll be cheaper in the long run. 

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18 hours ago, 1215 said:

Rings are rings. Pistons are pistons. If OEM can't be had I'd bet someone can email someone and forged can be had for not too much money. Grind your rotating assembly (rotating assembly is everything that rotates, camshafts, cranks

I'd say that's bullshit. When you're dealing with the stressed rotating components (pistons, con rods, cranshafts???) you can't just pick up something that looks right and "grind them to fit". Things like these have very fine tolerances and have to deal with increase in dimensions as temperature increases. 

I have nothing against going to a bearing shop and buying generic lip seals and SKF bearings for my Yanmar raw water pump - but what you are suggesting is nuts.

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The trick is to do it within the necessary tolerances. If you're willing to do the homework, it can work out OK.

The costs might work out if you're comparing a $10K repower against a set of custom-milled slugs and connecting rods. Blocks, cams, and cranks can be really specific and tough to interchange, but pistons, rods, and bearings can be cross-referenced often by dimension, separate of application. You do have to know what you're doing.

Randii

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Hot Rodders do that sort of thing all the time - changing piston wrist pin height to accommodate longer rods, stroking crankshafts by offset grinding the journals, even using rods from other manufacturers engines to get specific qualities or dimensions etc. etc.

The thing is that anyone capable of that level of engine building ain't asking questions about it on the Interweb.

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15 minutes ago, SloopJonB said:

The thing is that anyone capable of that level of engine building ain't asking questions about it on the Interweb.

Fair enough.

The resources are out there, but this kind of roll-your-own doesn't come with a warranty, and you've gotta be fully confident in your own abilities to specify the parts and live with the results.

Randii

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Id feel better with a new engine. We're wealthy yotsmen ffs.  A B40 with an outboard? Sure thing.

And by the bye, a B40 is not a Beneteau.

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You could also treat the rebuild as a learning excercise and reserve repower as the back up plan.

 

3R

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I got a rebuilt longblock 3gm30 for my J35 from some outfit in MI about 9 years ago.. 3200 shipped to MD. local yard put it in for 750-800 bucks.. it's still going strong.. thru a rod in the old one down near Solomons and it got me home on 2.. had to keep dumping oil in it though.. went thru a case.

 

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1 hour ago, Bump-n-Grind said:

I got a rebuilt longblock 3gm30 for my J35 from some outfit in MI about 9 years ago.. 3200 shipped to MD. local yard put it in for 750-800 bucks.. it's still going strong.. thru a rod in the old one down near Solomons and it got me home on 2.. had to keep dumping oil in it though.. went thru a case.

 

That's called a getting a 2GM20 the hard way. Pretty amazing you got home with her.

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1 hour ago, Bump-n-Grind said:

I got a rebuilt longblock 3gm30 for my J35 from some outfit in MI about 9 years ago.. 3200 shipped to MD. local yard put it in for 750-800 bucks.. it's still going strong.. thru a rod in the old one down near Solomons and it got me home on 2.. had to keep dumping oil in it though.. went thru a case.

Diesels love their oil like sailors love their rum.

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1 hour ago, SloopJonB said:

Diesels love their oil like sailors love their rum.

particularly when they have a hole in the side of the block from a thrown rod!

 

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On 9/20/2018 at 8:26 PM, SomethingElse said:

I got most of my Yanmar rebuild parts online from Hoye Tractor.  

Any parts cross reference?  I looked and looked and couldn't find any.  Whats a 3GM30F in tractor speak?

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8 hours ago, Bump-n-Grind said:

I got a rebuilt longblock 3gm30 for my J35 from some outfit in MI about 9 years ago.. 3200 shipped to MD. local yard put it in for 750-800 bucks.. it's still going strong.. thru a rod in the old one down near Solomons and it got me home on 2.. had to keep dumping oil in it though.. went thru a case.

 

I have a tired original 3GM30F also in a J/35. Do you remember who you got it from?  This seems like a simpler way to go than the newer Yanmars, but a Beta is looking pretty good at the moment.

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this is old email I found... that's all I have for the engine source...

 

Date: Mon, 26 Jul 2010 12:15:08 -0700
From: holzralf@yahoo.com
Subject: Re: Yanmar engine
To:
 


I can offer a Yanmar Model : 3GM30F  Year of Manufacture - 2/21/2002  
Complies with the European  Pollution Requirements.
This Engine is Re-Manufactured with one year Warranty .
Cost :  $ 3,950.- plus core   - core charge  is $ 1,000.-
As for the New Model Engine  : 3YM30   I am restricted  to my service area.
 
Let me know !
 
Thanks AL/ Schooner Bay Imported Motors   715.779-3266
 

 

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2 hours ago, DrewR said:

Any parts cross reference?  I looked and looked and couldn't find any.  Whats a 3GM30F in tractor speak?

The Hoye Tractor site used to have you put in the Yanmar part number and it would give their part.   I just looked and now there is a marine engine page then choose your engine.  Since it's Chinese products the prices maybe affected by the tariffs going on if you are in the USA. 

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yanmar gm engine rebuilding is no drama. there are heaps out there and the parts are available albiet some might be special order from japan. 

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I had an ancient SB12 rebuilt not long ago so I can't imagine that a gm series can not be rebuilt. That said I would not do a complete rebuild a small diesel ever again. Its throwing money at something which is only going to get harder to find parts for and will never be as reliable as a new engine. Small diesels are still expensive but not much more than it cots to do a full rebuild.  For the cost of rebuilding my sb12 I could have bought a new engine and DIY'd the install.... I definitely regret that. 

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On 9/21/2018 at 3:16 PM, Zonker said:

I'd say that's bullshit. When you're dealing with the stressed rotating components (pistons, con rods, cranshafts???) you can't just pick up something that looks right and "grind them to fit". Things like these have very fine tolerances and have to deal with increase in dimensions as temperature increases. 

I have nothing against going to a bearing shop and buying generic lip seals and SKF bearings for my Yanmar raw water pump - but what you are suggesting is nuts.

I don't think you understand what I meant. 

For example, there is this company called BMW. Most people know about them because of their automobiles. Do you know that BMW has a marine division too? The BMW M20 block series was available in BMW cars, boats and Lincoln (yes, Ford, Lincoln, Mercury) cars?

Companies like Bosch, Siemens, Valeo, ZF, Getrag, Lemforder, etc....  All they do is make parts --or "stuff". VDO makes great gauges --and you can find VDO gauges on all kinds of cars. Think about Brembo brakes. How many current car manufacturers tout "brembo brakes" in their advertisements. 

Some company makes rings and Yanmar buys them --but so does John Deer or Kohler or BMW. I could also be totally wrong. Yanmar could do everything in-house... But I highly doubt it. Half the engine parts in my car can also be found in a Range Rover, Lexus, Nissan, Some Fords and Subaru. (maybe more that I don't know of) 

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1 hour ago, 1215 said:

I don't think you understand what I meant. 

For example, there is this company called BMW. Most people know about them because of their automobiles. Do you know that BMW has a marine division too? The BMW M20 block series was available in BMW cars, boats and Lincoln (yes, Ford, Lincoln, Mercury) cars?

Companies like Bosch, Siemens, Valeo, ZF, Getrag, Lemforder, etc....  All they do is make parts --or "stuff". VDO makes great gauges --and you can find VDO gauges on all kinds of cars. Think about Brembo brakes. How many current car manufacturers tout "brembo brakes" in their advertisements. 

Some company makes rings and Yanmar buys them --but so does John Deer or Kohler or BMW. I could also be totally wrong. Yanmar could do everything in-house... But I highly doubt it. Half the engine parts in my car can also be found in a Range Rover, Lexus, Nissan, Some Fords and Subaru. (maybe more that I don't know of) 

While what you're saying is true, I think the problem with old Yanmars is what DrewR said.   You won't find a cross referenced parts list anywhere.  I posted a thread on this a year or so ago and no one had any idea.  I had hoped maybe an old timey diesel mechanic would have made up a list with cross referenced Yanmar industrial/agricultural part numbers, but no such luck.

Hoye looks like they some parts listed for the "newer" GM series (i.e. 3GM30) but not the 3GM.  I don't know if most of the parts are interchangeable or not.  if you knew which agricultural engine your particular GM is based on you might have more luck because they have a long list of those engines.

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I had my 3GM30F rebuilt 2 years ago by a local mechanic/machine shop outside of Sarnia, Ontario.
No issue with parts availability at that time.  Very good experience all around.
 

I pulled the motor, delivered it to the mechanic, picked up the completed engine and reinstalled myself.
Waited longer for the machine shop to clean up the bores than searching or waiting for parts.

 

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Also had 3gm30f rebuilt within last 3yrs (CT). It was fairly extensive. Don't recall any issues with parts. Had carefully considered rebuild vs repower and it mainly came down to all the downstream effects of moving to a newer model - including having to redesign the engine cabinet and steps that are integrated. The rebuild is fine for my needs. It runs great and should be good for many years.

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On 9/22/2018 at 5:41 AM, Bump-n-Grind said:

this is old email I found... that's all I have for the engine source...

 

Date: Mon, 26 Jul 2010 12:15:08 -0700
From: holzralf@yahoo.com
Subject: Re: Yanmar engine
To:
 


I can offer a Yanmar Model : 3GM30F  Year of Manufacture - 2/21/2002  
Complies with the European  Pollution Requirements.
This Engine is Re-Manufactured with one year Warranty .
Cost :  $ 3,950.- plus core   - core charge  is $ 1,000.-
As for the New Model Engine  : 3YM30   I am restricted  to my service area.
 
Let me know !
 
Thanks AL/ Schooner Bay Imported Motors   715.779-3266
 

 

That's Alf Holzer in Bayfield, WI.  Rebuilding marine diesels is what he does, all the time. Most of the engines on this page are his remans.

Here's a 2GM20F rebuilt for $4450 + core. Might reman yours for less. Presumably he has his supply chains pretty well sorted. Also does Volvos, Universals, etc.

 

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1 minute ago, Diarmuid said:

That's Alf Holzer in Bayfield, WI.  Rebuilding marine diesels is what he does, all the time. Most of the engines on this page are his remans.

Here's a 2GM20F rebuilt for $4450 + core. Might reman yours for less. Presumably he has his supply chains pretty well sorted. Also does Volvos, Universals, etc.

 

and I will say he was a pleasure to do business with... I got everything I paid for in a timely manner. He was happy to contact my mechanics re: shipping of my nw engine and return of my core..

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11 hours ago, Bump-n-Grind said:

and I will say he was a pleasure to do business with... I got everything I paid for in a timely manner. He was happy to contact my mechanics re: shipping of my nw engine and return of my core..

Good to know!  We have a doubtful MD6a we're not sure what to do with, & a Holzer reman (Yanmar) is a serious option. My instinct at this point is: if we're gonna put money into engine work, put it into something other than a raw water Penta with a cracked block.

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Good thinking. :D

Re: some comments about rebuilt engines being something less than new - a properly rebuilt engine is better than new. If the mechanic is good then it will be built to closer tolerances than an assembly line engine (blueprinting).

A fully rebuilt engine only reuses the basic castings, crank, rods etc. Assuming you also get the injectors and pumps done then there is no reason to regard it as anything less than a brand new engine.

You're also less likely to have paint sprayed over the hoses and everything else.

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Years ago I rebuilt a raw water cooled YSM12 with new sleeve, bearings, rings and I ordered them all through Hawthorne Power Systems in San Diego. It took them forever but eventually got the  parts. <<www.hawthornecat.com>>. Don't know if they still do that kind of thing but you might give them a shout. 

BTW, that engine lasted another five years of light duty in SD and I then sold the boat to a guy who took it to SF and then did a couple of SH Transpacs, all on the same rebuild.

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