Yanmar 4JH2-TE complete rebuild - next steps?

[LeighWebber]

Originally Posted by briblack

Any good sources for parts, that you'd recommend?

I ordered most parts from Toad Marine Supply (which seems to go under several other names). Excellent customer service, but full Yanmar price. A couple of exceptions: I bought a new starter from Amazon, and the alternator came from ElectroMaax. Also the bolts came from an online bolt store: boltdepot.com.

[boden36]

To get back to your original plan, I would not recommend running a new engine unloaded for the time you suggest - it will need a decent load to bed the rings in.


Regards,
Richard

[LeighWebber]

Originally Posted by boden36

To get back to your original plan, I would not recommend running a new engine unloaded for the time you suggest - it will need a decent load to bed the rings in.


Regards,
Richard

That appears to be the consensus. I'll just run it until it gets up to temp, just to be sure there are no leaks. E.g., when I filled it with oil, I discovered that the hollow bolt that attaches the dipstick to the oil pan was not tight enough, and dripped a bit of oil (there are no torque recommendations for that bolt, btw -- and you can't just use the default torque for that bolt diameter, because it's hollow). I tightened it a tad, and the drip stopped. It's things like that I want to find before putting the engine in the boat.

[jhulmer]

Nice job!

I too recently rebuilt the 4JH2 that came out of my new to me boat. It had ingested saltwater in the #4 cylinder according to the previous owner. However, went I got it open there was no water and only a hint of rust on the cylinder wall. I think it was more from condensation from a year of sitting. I had rebuilt a couple gas engines and had partially rebuilt the Yanmar on my previous boat so, decided to rebuild this one.
I used all new Yanmar parts. They only had .002 over pistons, luckily we were able to clean up the bores in that .002.

Did you have to find after market pistons?

I can say it was a rewarding effort and I was able to use Yanmar paint and spray ever single exposed part before assembly. The factory spray paints after assembly on a lot the engine.

It runs like a top on the test stand I made. I was about to install it when I came across a deal on a new in the crate 4JH3 at a government auction and couldn't pass that up. I plan to keep the 4JH2 and find a boat to drive under it.
I might find another Yanmar in need of rebuild someday just for the fun of it!

Edit: I used the Yanmar service manual and better the SELOC Yanmar Inboard Manual.

Here are a few of my Pictures:

[LeighWebber]

Originally Posted by jhulmer

Nice job!

I too recently rebuilt the 4JH2 that came out of my new to me boat. It had ingested saltwater in the #4 cylinder according to the previous owner. However, went I got it open there was no water and only a hint of rust on the cylinder wall. I think it was more from condensation from a year of sitting. I had rebuilt a couple gas engines and had partially rebuilt the Yanmar on my previous boat so, decided to rebuild this one.
I used all new Yanmar parts. They only had .002 over pistons, luckily we were able to clean up the bores in that .002.

Did you have to find after market pistons?

I can say it was a rewarding effort and I was able to use Yanmar paint and spray ever single exposed part before assembly. The factory spray paints after assembly on a lot the engine.

It runs like a top on the test stand I made. I was about to install it when I came across a deal on a new in the crate 4JH3 at a government auction and couldn't pass that up. I plan to keep the 4JH2 and find a boat to drive under it.
I might find another Yanmar in need of rebuild someday just for the fun of it!

Edit: I used the Yanmar service manual and better the SELOC Yanmar Inboard Manual.

Here are a few of my Pictures:

Interesting -- your 4JH2 has a part mine lacks. On yours, attached to the gear that drives the F.I. pump, there is some sort of coupler with a visible yellow spring. What's that? Mine just has a nut that holds the gear in place.

[jhulmer]

Originally Posted by LeighWebber

Interesting -- your 4JH2 has a part mine lacks. On yours, attached to the gear that drives the F.I. pump, there is some sort of coupler with a visible yellow spring. What's that? Mine just has a nut that holds the gear in place.

That is interesting. It is a damper for the injection pump. My guess, There must have been a problem with direct drive at some point or vice-versa and they did a design change.
Edit: I just looked it up in the SELOC manual - it is a Injection pump timing advancer mechanism.



Jim

[jhulmer]

I just noticed yours is the turbo mine is not. That might explain the Timing Advancer.
I offer a hack for the dip stick handle - put a piece of yellow shrink tube over the wire handle and shrink it. It works well!
Jim

[LeighWebber]

Originally Posted by jhulmer

I just noticed yours is the turbo mine is not. That might explain the Timing Advancer.
I offer a hack for the dip stick handle - put a piece of yellow shrink tube over the wire handle and shrink it. It works well!
Jim

I like it! And the finishing touch: a can of "new engine" spray fragrance.

[Wotname]

Jhulmer & LeighWebber, thanks for posting about your Yanmar 4JH2 rebuilds. I find them enjoyable reading .

[jhulmer]

You are welcome Wotname
I enjoyed it and will probably find another Yanmar and rebuild it for the fun of it. I have bought and resold several after fixing them up to the point I would trust them in my boat. New owners are happy with them. Not trying to make any money just like doing it. I am going full time cruising in a year or so and it's nice to really know what makes them tick and how to fix them!
Cheers
Jim

[LeighWebber]

The big day finally arrived. I set the timing per the service manual -- actually much easier to do than I feared. I operated the manual fuel pump lever until fuel emerged from the final filter -- then cranked the engine (with the high-pressure lines disconnected at the FI pump) until fuel popped out of the top of the FI pump. To make the timing adjustment a bit easier, I used a red Sharpie to mark the position of the 1-4 timing mark on the aft vertical surface of the flywheel (my tranny is not attached). This made it much easier to see when the timing mark was getting close to the indexing opening. I then slowly rotated the engine with a wrench until my red Sharpie mark was about 3 inches from the indexing hole, then verrrrry sloooowly turned the engine with my eyes riveted to the #1 outlet on the FI pump. The fitting was already filled with fuel due to my earlier cranking with the starter. Just as soon as I saw the fuel start to emerge from the outlet, I stopped and looked in the indexing hole. Sure enough, I was off by several inches. I adjusted the angle of the FI pump accordingly, and tried again. It was quite satisfying how easy it was to get it spot on after only a couple of tries.

I connected the high-pressure fuel lines, filled up all fluids, connected the start battery, tested the shutoff solenoid (!), attached the exhaust elbow with a nice long wet exhaust hose leading out of my garage, filled a 5-gallon bucket with water for the sea water supply, checked everything twice, and.....

Woo hoo! The engine started after about 20 seconds of cranking! No smoke, and it purred like a kitten. Lots of water pouring out of the wet exhaust hose.

But one small problem. I thought I could get away with cleaning rather than replacing the copper crush washers that seal the oil lines connecting the lube oil cooler to the turbo and the oil filter. Bad idea. Beautiful clean golden oil flowed out of the main oil exit from the cooler and made a nice big puddle on my garage floor. Amazon to the rescue -- new washers are arriving in a couple of days.

Even with my oil leak, it was a great thrill to have the engine start so easily and run smoothly. And it's a good feeling to know every last bit of my engine in glorious detail. I'm confident in my ability to fix just about anything that could go wrong with it when I put it back in service.

[briblack]

Congratulation! Well done!!

[jhulmer]

Well Done! congrats! it is very satisfying and comforting to know you can fix it!

[Compass790]

Good job!
Satisfying aint it?

Was slightly surprised you didnt replace the crush washers when you bought new bolts.
You can re-use copper washers at least once if you heat them red hot. That softens them as they work harden. Can do it on LPG or electric stove easy

Doing it too many times they get thinner & wider as they crush down.
New is better if tolerances are an issue such as in an injection pump.
Just added this if someone else needs to rejuvenate copper crush washers.

[Toccata]

Would you be able to do a cost comparison for the forum, I have been under the impression that the sum of the parts may well be more than the cost of a new engine?
Total parts cost?
Total hours (roughly)
I put a new turbo, reconditioned fuel pump, new starter motor (all genuine Yanmar parts) on a 4JH4 TE and was perilously close to a new short engine cost.