Yanmar 4JH HTE - Remove Turbo

[ericoh88]

Hi

I have been following this site for some time and learnt so much. Thank you
CF members.

The current engine is a 1986 Yanmar 4JH HTE turbo. I am planning to do cruising/diving in Indonesia and South Pacific starting Oct 2013. After that, will decide if I have the guts to head up to Alaska/PNW or stay put around Australia/NZ.

After reading http://www.cruisersforum.com/forums/...s-85635-7.html on noelex 77 reply on the removal of turbo, I like to have a straight pipe as spare should the turbo acts up in future.

I can see a naturally aspirated engine has many advantages + some loss of power.

My question is besides the straight pipe to replace the turbo unit, do I have to replace the injectors, recalibrate injector pump and reprop?

I am not an expert in engine and my 2 cents guess is there is no need.

There is no problem with the engine now.

What are your thoughts and experience?

All ideas and suggestions are most appreciated.

-----------
Eric
Port Klang, Malaysia

[djmarchand]

Eric:

I don't specifically know that engine, but most turbocharged engines have a lower compression ratio (which is made up for in boost) than their NA brothers. This will mean lower efficiency and maybe poor combustion at higher rpms without the turbo.

But why not just pull the throttle back and not use the turbo? Turbos themselves when not impacted by water in the exhaust, etc. are very low maintenance items and should last many thousands of hours.

David

[ericoh88]

Hi David,

Thank you for the reply. I will leave the engine alone for now and enjoy
cruising in Phuket first.

Eric

[bstreep]

As noted, the turbo versions are not just the non-turbo versions, with the added turbo.

1) Your engine will work at lower RPMs, without the turbo. But, not well, and you will not be doing long-term good to your engine.

2) Keeping the turbo clean and operational is a matter of maintenance. I know, because I suck at this! Run the heck out of your turbo, on a regular basis. Yanmar recommends using their Turbo Wash to keep it clean. Their recommendation? "once a week". Seriously.

3) Removing the turbo is a 1/2 day job, as is putting it back on. I've done this twice. The turbo can be cleaned when you take it out. Do NOT pry on the vanes. The turbo spins at 70,000 to 80,000 rpms!

4) You can buy a rebuild kit for about $150. ANY turbo shop in the world can rebuild it - these IHI turbos are common on cars all over the world. YOURS has been modified to the Yanmar engine, but it is essentially the same as all of the others. Not interchangeable, but similar.

Repeat #2 as often as you can remember.

[DeepFrz]

Doesn't the HTE also have a heat exchanger (inter cooler) after the turbo to cool the air after it is compressed? I don't know how that would work without the turbo.

[ericoh88]

Bill: Yes I see your point here. Have to learn to do the regular maintenance. Thanks.

DeepFrz: That would be tough to remove. Will take a look at the engine when get to the boat next visit. Thanks.

[MoonlightSailor]

Aloha Everyone!

Just had a mechanic look and on my Yanmar 4JH-HTE and the turbo needs work or need replaced.

Anyone have sources for kits to rebuild and/or instructions removal/installation?

Mahalo!
Matt

[bstreep]

Removal instructions:


Let me see what I can do. I can take mine off in about an hour now. Put back on in about the same time, IF all goes well.



First, I hope you have decent access. I can actually sit behind my engine, to get to the turbo. Put something like beach towels or blankets under the area, so that when you drop parts (and you will), you don't have to go bilge diving for them. The Japanese, love their engines in pretty packages. Tightly fit together. It makes working on them challenging. The Germans, on the other hand, like theirs to be easy to work on.



You will need to remove the exhaust elbow. You will need to remove the intake pipes. Trust me, you will, so just get to it. Just from the turbo to the first joints. As it's intercooled, you will need to remove the coolant supply lines.



There are 2 difficult items on this process: The oil supply line, and the 4 nuts holding the turbo in place. Small hands help. Both of these are easier to take off, than they are to put back on. Be SURE and put the oils supply on before tightening nuts holding the turbo in place - they are a bear to get lined up as it is, with tiny nuts where you can't see them. While your turbo it out, buy some extra nuts for it - you are going to lose one or more.



We used these folks to rebuild ours. Just a WONDERFUL family business in Waco. And very honest. If you have to replace the turbo, the best price I've found is about $1700. Staggering, isn't it? Majestic managed to get a new exhaust half for us from Japan, and we still spent a bunch of money.



https://majesticturbo.com/


P.S. Having taken ours out a half dozen times, have a pro rebuild it. They spin at 70-80,000 rpms, and it's easy to damage them. You can probably find a shop in Hawaii - just make sure they specialize in turbos.

[MoonlightSailor]

Hi Bill...

Thanks for your kind reply with the details. Looks like I may not have to replace or rebuild the turbo just yet. But thinking of having a spare on board. There is a very very very small amount of play in the shaft. Seems like it is now spinning like it should and I'm hearing it kick in after running it a bit with higher RPM's.

Seems pretty straight forward...just replace/reinstall and go. Nothing to check after installing to measure performance or tweak?

Going to have to adjust my throttle cable as the throttle handle won't push the motor beyond 3200RPM.

Why or what has inspired you to remove your turbo 6 times? LOL...

[bstreep]

Turbo kept acting up. We are bad about using the engine hard enough. We really only use it to go in and out of the slip. Had it cleaned a couple of times, and did it myself several times. The shaft on these is lubricated with engine oil, and sometimes the shaft/bearings are the problem. Actually, most of the time. If you have the time, I'd get it rebuilt, rather than wait.

[AKA-None]

If the oil seals fail you’ll never see a cloud so dense. Don’t ask me how I know this. Get it rebuilt if there is any doubt.