4JHE to 4JH3E Repowering

[DivinaVita]

Good Day!

From a repowering perspective, is a Yanmar 4JHE to 4JH3E swap a difficult proposition? My interest in the answer to the preceding question is predicated upon the following information...

My wife and I just purchased a Hunter 40 Legend sailboat that is in need of refit and restoration. Auxiliary power for the vessel is provided by a Yanmar 4JHE; however, the boat has laid idle for a number of years (6 - 7), without maintenance, of any kind. At my request, the marina mechanics attempted to assess the viability of the 4JHE; and, although it started easily, it immediately "ran away" and shut down about 10 seconds later.

I am told that there is a problem with the Fuel Injector Pump (FIP); and, this problem must be resolved before any additional evaluation can be undertaken. There are no FIPs available, so an injection shop rebuild is our only option. This is a $2,500 - $3,000 expense that would only allow us to begin our engine evaluation. This amount also represents a significant amount of money that could be applied toward the purchase of a remanufactured engine.

Inasmuch as the existing 4JHE has laid idle for so very long; and, inasmuch as I do not know the history of the engine, I am seriously considering repowering, rather than exposing ourselves to a protracted, "one-piece-at-a-time" rebuild project. Of the remanufactured Yanmar engines available, I am concerned about replacing the existing 4JHE with an identical engine. Parts availability seems to be quite scarce for these 30 - 40 year-old engines. There are, however, several remanufactured Yanmar 4JH3E engines available, for which parts are more readily available.

I have been told many things that "could" complicate the swap... For example, the JH3E is more compact and may require extensive engine bed modification. I am unfamiliar with these little diesel engines; and, I'm sure there are countless things that could complicate a swap. My interest lies in getting a compatible engine, in operational condition, without having to rebuild the boat around the new auxiliary power plant.

Your thoughts and ideas would be greatly appreciated!

Thank you for your time and consideration.

Rick

[LeaseOnLife]

I had thought about replacing a 4JH2-TE (same block-size as yours) with a 4JH3 or 4JH4.

Here are some of my notes:

• the width of the motor mounts is the same (470mm)
• from the rear motor mounts to the end of the transmission output flange, the new engine needed 7mm more space, probably not a big deal, maybe you can move the whole block 7mm forward. Or shorten the shaft, or move the shaft 7mm back
• the transmission output flange of the old engine is probably a 120mm diameter with a boltcircle of 100m and a pilot of 65mm. Only older Kanzaki transmission seem to use this flange. The transmission (I would have selected the ZF30) for the new engine most likely has a 102mm diameter, 82.5mm bolt circle, and a pilot of 63.5mm. You would need a fitting coupler for the shaft, plus any machining to make that couple fit the shaft.
• The shaft drop of the Kanzaki and ZF was equal at 90mm, good
• The distance between the front and rear motor mounts is 13.5mm greater on the new engines. If you had to move the engine 7mm forward already, you need 20mm extra space on the forward engine bearers.
• Exhaust size for Turbo Yanmars is critical, not sure about the non-turbos. And I do believe, you only get a Yanmar warranty if some Yanmar mechanic signs off on your installation.

Start with the installation drawings for your old engine/trans combination and compare to the new setup. There are a lot of differences, so many, to not necessarily stick with Yanmar. I could have fit a Beta 50 or 60, but Cummins, Volvo and Westerbeke would have been way to big.


Hope this helps


Dirk

[boden36]

I would get a second opinion on that.

Regards,
Richard.

[a64pilot]

If your going to re-power, I'd look to see about a Beta.
I wouldn't re-power, but I'm a decent mechanic and can readily see how if your having to pay for a mechanic to do everything how you could end up with more than new engine money, in your old engine.
You sure the injection pump is that expensive to re-build? Have you called around?

[darylat8750]

+1 on the Beta if replacement is the route you decide to go. I would take the model number and serial numbers off the injection pump and call a couple of fuel injection rebuilding shops. I would think $1 boat buck should do it. If it is around a grand to rebuild the injection pump I would do a compression check and consider general condition of the engine and especially the heat exchanger exhaust area. If that came out ok I w be inclined to fix this one. Even though I would rather have the beta.

[SailRedemption]

Originally Posted by a64pilot

If your going to re-power, I'd look to see about a Beta.
I wouldn't re-power, but I'm a decent mechanic and can readily see how if your having to pay for a mechanic to do everything how you could end up with more than new engine money, in your old engine.
You sure the injection pump is that expensive to re-build? Have you called around?

Originally Posted by darylat8750

+1 on the Beta if replacement is the route you decide to go. I would take the model number and serial numbers off the injection pump and call a couple of fuel injection rebuilding shops. I would think $1 boat buck should do it. If it is around a grand to rebuild the injection pump I would do a compression check and consider general condition of the engine and especially the heat exchanger exhaust area. If that came out ok I w be inclined to fix this one. Even though I would rather have the beta.

Although I think a beta is a solid engine, I don't think it's a good option for you with an existing Yanmar. The Yanmar sits on 18" mounts and the beta being a larger engine all around is on 22" mounts, measuring across from stringer to stringer. That would create a heck of a project when another Yanmar would be practically drop in, Mount wise.

But I second the advice about getting another quote for injector pump repair. That seems quite high.

[a64pilot]

You don't need a functioning pump to do a compression check, and a compression check will tell a lot.
I didn't know about the Beta's mount spacing, just have heard good things about them and if I understand correctly they specialize in re-powering.

I thought parts for a 4JHE were available?

[GordMay]

Greetings and welcome aboard the CF, Rick.

[darylat8750]

Originally Posted by a64pilot

You don't need a functioning pump to do a compression check, and a compression check will tell a lot.
I didn't know about the Beta's mount spacing, just have heard good things about them and if I understand correctly they specialize in re-powering.

I thought parts for a 4JHE were available?

I should have been more clear in my post. first I would check price on rebuild of injection pump at several shops that cater to the truck and industrial sectors. If price is reasonable do a compression check before spending $ .

[a64pilot]

Any idea as to hours on this engine?

[SAIL23692]

By all means check out the 4JH first. A good weeks soaking in Marvel Mystery Oil would help loosen everything up. Go slow and check everything. All the posts here are spot on. Get lots of opinions from boaters, not dealers. Since parts are either difficult or impossible to find on these engoines, carefully weigh the cost difference between repair/replace. If you do repower, post on this site as there are many of us who would welcome the chance to purchase parts from your take out

[Cheechako]

I wouldn't write off the old engine. What do you all think about the diagnosis? The injection pump causing it to run away....? I've not heard of that.... unless it's leaking into the oil pan at a fast rate..?
Can the pump be resealed? does anyone do that on those? Usually engines will rev up fast when they are running out of fuel... right?
Not sure what the "running away" means.
Anyway, by all means check out that engine before giving up on it.

[NCboatrx]

Originally Posted by BoatyardBoy

Although I think a beta is a solid engine, I don't think it's a good option for you with an existing Yanmar. The Yanmar sits on 18" mounts and the beta being a larger engine all around is on 22" mounts, measuring across from stringer to stringer. That would create a heck of a project when another Yanmar would be practically drop in, Mount wise.

But I second the advice about getting another quote for injector pump repair. That seems quite high.

BoatyardBoy, If you had bothered to check on the Beta Marine website you would have found that the Beta 43, 50 and 60 have exactly the same mount centers as the Yanmar JH series. The fact that Beta Marine also offer wider 22" mounts as an option is useful for some. Why do you keep on quoting incorrect information?

[TacomaSailor]

"At my request, the marina mechanics attempted to assess the viability of the 4JHE; and, although it started easily, it immediately "ran away" and shut down about 10 seconds later."

That does not sound like a classic diesel runaway where the engine consumes oil being scavenged from a blown turbo seal (which I assume your engine does not have) or from the crankcase/oil sump due to a bad piston rings.

Normally the "runaway" engine would run at a high speed until all the oil was consumed and it would produce gross amounts of smoke. I have seen dozens of such events and they typically last for minutes.

Some questions - did your mechanics check and verify:
- oil level in the engine before starting it?
- water level in the heat exchanger and the overflow tank?
- water discharge from the exhaust while running?
- state of diesel fuel in fuel filters
- state of fuel filters
- state of diesel fuel in the old tanks
- state of throttle linkage from on-deck lever to the fuel pump
- movement of fuel pump controls
- movement / looseness of fuel pump governor

I can think of many circumstances that would have led to the situation that you described that would be relatively inexpensive to repair/remedy.

I would have an independent diesel mechanic, who has no financial interest in finding a "bad" engine that needs replacement, inspect your suspect 4JH.

[marlinmike]

unless some wildly high hours I would do a full service on the existing Yanmar, the duty cycle on a sail diesel is not very high, so most likely a full cooling system service, valve adjust and careful checking on the quality of the current fuel supply and you should be good to go.