DIY rebuilding of diesel engine Yanmar 6LY

[Gdavid]

Thank you so much for sharing. I am happy for your triumph and hope I never need this info but I will copy and save it all in case I do (my parents boat has this engine).

 

[DDW]

Great job. But if that is the oil filter mounted on its side on top of everything else, I'd have deep six'd that engine and found a replacement. "Engineering" like that drives me nuts.....

 

[Northern Spy]

Congratulations!

 

[Mako]

I had my stress hormones spiked after I put a mechanical pressure gauge into the sensor manifold and did not get any pressure readings... Luckily, i screwed it into the wrong port, which is for the boost sensor, not the oil pressure sensor.

I had mechanical oil pressure gauges on a previous boat (which I really prefer) but it would take quite some time after startup to finally show pressure. Pressure needed to buildup in the long copper tubing run to the pilothouse. It used to freak me out when I first bought the boat, but after awhile you get used to it and have confidence that the engine is not gunna seize one minute after startup.

 

[Waterant]

Pressure needed to buildup in the long copper tubing run to the pilothouse.

I'll keep the mechanical gauge on the engine. On the first start-ups, it registered the pressure within 3 seconds of cranking and is for troubleshooting.

 

[Mako]

I pretty much concluded the same. Great to have a mechanical gauge, down in the engine room on the engine, tee'd into the sender transmitting an electrical signal up to the bridge.

 

[Waterant]

The engine is back in the boat and running

Hey guys,
Just an update. Back in May, the rebuilt engine was installed back in the boat, all connected, and the shaft aligned

Below are more photos to show the tricky installation procedure for my own record and someone who wants to do the same to save you some time.

https://photos.app.goo.gl/Rq8ZVkqrpXeRp6yf9

So far, I had time only for a quick run out of the marina, trying the engines for a couple of hours on different RPMs.

The port (rebuilt) engine reached a max 2900 RPM on the dashboard gauge - the same as the starboard engine, which was not rebuilt. I suspect the gauge is off by 200-300 RPM; I will confirm the exact max RPM on the next run with a mech tachometer.

Temperature and oil pressure looked fine and the same on both engines.
Some light white smoke right after the start disappears after a few minutes—no smoke during the run on any RPM. It seems to be normal for those Yanmars.

Everything seems to be ok so far. I will have to put a couple of hundred hours on it to confirm if the rebuild was successful.

 

[Comodave]

I would use a photo tach, very easy to use.

 

[twistedtree]

Very impressive job. Congratulations, and I hope it gives you many house of trouble-free service.

 

[GoneDiving]

A great series!! Thanks very much.

What's your planned run in and oil change schedule for the fresh engine?

Also, I've just binge read the posts but didn't see anything regarding painting, labels, etc. Did you reapaint as you went? Any specific sequence?

Thanks again.

 

[Gdavid]

Congratulations, awesome work and thank you so much for sharing with great details.

 

[RT Firefly]

Greetings,
Mr. W. VERY well done sir! IMPRESSIVE!!!! Thanks.

 

[Sailor of Fortune]

not sure how I missed this thread... Very ambitious....and impressive job! Kudos

 

[Waterant]

What's your planned run in and oil change schedule for the fresh engine?

I plan to change the oil after 50 hours (like the first oil change per the operational manual) and send it for analysis.

Also, I've just binge read the posts but didn't see anything regarding painting, labels, etc. Did you reapaint as you went? Any specific sequence?

The parts with paint are in good condition, I cleaner with mineral spirit and left them unchanged.

Parts with some surface rust (brackets, bolts, nuts and etc), I cleaned with a stainless wire brush and mineral spirit and a 30 min spa session in Evaporust inside my 22L ultrasonic cleaner
Those parts came out as new. A few required a second 30 min treatment.

A good thing about 22L ultrasonic cleaner is that it can fit most items from this engine.

After this, on larger items (like brackets), I put a couple of layers of Yanmar spray paint ( https://shop.toadmarinesupply.com/ships_store/?p=numberresults&pn=MBP317&storetype=mdd&x=10&y=17 )
and some parts (like bolts) got painted after assembly.

I cleaned the head and block with a power washer first, then dried them with compressed air, then a stainless wire brush and mineral spirit;
Taped all machined surfaces, and put a layer of Yanmar spray paint. And another layer went on after most components were installed.

After all mechanical parts were assembled (before exchangers, electrical, and plumbing), I taped electrical contacts, machined surfaces and pipes and put a light layer of pain on the engine.

All the exchanges were painted on the back side, I put a light layer of paint there.

I taped all the labels with painter's tape and cut to size so the new paint went around the labels. It may be possible to remove the labels and put them back or order new labels but I did not feel like they were worth the trouble.

Some parts I forgot to paint because they were installed last (like the fuel filter):
https://youtu.be/vKLfBGVb1H8
I'll touch it up later.

One note is to be careful with using the brake cleaner. It's a great thing to clean bearings and other things but it eats the engine paint for breakfast and the paint will come off and that section will have to be sanded and repainted.

I hope this helps.

 

[Waterant]

Thanks, guys. I couldn't have done it without your support and encouragement