Overhaul or replace 1981 Universal diesel

[GrowleyMonster]

FPNC nailed it on the smell.

If it ain't broke, don't break it. Engine runs good. Who cares what its chronological age is? You don't use it heavily. I would pamper it a bit. A new elbow is a great pre-emptive upgrade. Injector and valve servicing would be worth the $. Zincs in the cooling system, if any, should be replaced annually. Impeller should be replaced annually. You don't want bits of broken impeller vane clogging up your cooling system. On the same topic, make sure your oldie but goodie is not raw water cooled. It's not a deal killer but a heat exchanger would be a GREAT retrofit and a big help in keeping the engine running for a few more decades of light use. Alternator upgrade is very good idea. If your present alternator runs off a vee belt and you go over 100a you might need to go with a different type belt or more of them. Otherwise it will eat belts like tater chips. Stock up on spares. Belts, impellers, filters, a starter, and don't trade the old alternator in. Keep it for a spare.You know it works. Your diesel will work great for bulk charging your batteries. For topping up, it is not so efficient and a few hundred watts of solar will do a lot to help your electrical power situation. I don't remember of the fuel pump runs on a block mounted diaphram like the A4 or not, but if it does, you might consider switching to an electric pump. Keep your prop nice and clean. An instrumentation upgrade sounds called for. In the meantime you can improvise a more accurate tach easily enough. A handheld laser gun type tach and a strip of reflective tape on the coupling can give you a baseline for checking the tach you have doubts about. A compression test would be nice but if you seem to have good power, low oil usage, and minimal smoke, and no fuel sheen behind the boat from the exhaust, I am almost certain your compression is within normal range and would really only serve as a baseline for comparing future compression tests. At this stage of its life, your engine mounts might need replacing and you might need shaft alignment.

Take care of it and I don't see any reason to replace it. The Betas are really convenient for servicing and yeah they are good little engines, but your Universal doesn't need replacing. It doesn't need a rebuild until you start burning oil or smoking heavily or overheating for no reason or making funny noise or excessive vibration, or you see metal shavings in the oil. If someone GAVE you a brand new in the crate Beta, I would say store it and keep running the M-40 for now.

[MaTao42]

Remember that modern diesel engines have a lot of 'electronic' systems that are fine in a marina but difficult if not impossible to trouble shoot in a force 5 or a remote atoll. I have a 1962 Yanmar that is very basic but very reliable.

[Shaneesprit]

1) Beta might be a good candidate if I go the repower route, due to parts availability. - will be a pain to install but. Still be available in 20 years. Especially as no one is designing new diesels.
2) Common rail injection raises concerns about remote DIY field repairs. This one is easy - Avoid & NO, ok for cars and non critical kit.
3) If you were to repair, lift it out and get it overhauled at an Engine Specialist.
4) a 1980s engine will be hard to find parts, I have replaced many engines for relatively minor issues, where the part was not available but easily overcome, but what about the next time it needs something.
As an example spent $1million because engine needed a new ring gear, it would always start but maybe not first time. Their
Options 1) heat and turn the ring gear, 2) remanufacture 3) replace the entire installation. That engine is probably still running now 10 years on. Probably Where labour is cheap and power is needed but not critical.

[Dieseldude]

Originally Posted by bensolomon

I'm ot a diesel mechanic, but.....engines of that era are simple and reliable. Replacing an engine is a big deal. I would have your injectors cleaned, put on a new mixing elbow, have the heat exchanger cleaned, change the oil and transmission fluid and see how she operates. Spend your money on upgrading the alternator and regulator for efficient battery charging, and maybe add an extra house battery for living.

For reference, I have a 1989 Yanmar 3gmhf, and I do everything I can to keep her going.

All the best,
Ben

If the lube oil consumption is low, the rings and cylinder walls are probably ok. But it would be beneficial to do some testing to an older unknown engine I would add to the list a compression test though. Unusual smoking can indicate worn or fouled valves. You can purchase a test gauge and do it yourself, or have a mechanic do it. There are details to know, so if unfamiliar, read a good guide. Even if hiring a mechanic, it is good to know how to do it properly to ensure the mechanic does it right.

The tester can connect through an injector port, or possibly through a glow plug port or decompression valve port. You will need the right adapter to connect the tester. Make sure that you get a written record of compression figures. You need to know what typical compression figures for your engine should be. Expect slightly lower for an older engine. Figures can vary with atmospheric pressure, so are not absolute. Ralationship between cylinder units is important. Variations of much more than 10% can indicate need for overhaul.

Large diesels have indicator cocks through which a tester can be connected, but small diesels generally do not. If it has indicator cocks, live performance testing can be done with a performance tester that plots a chart of pressure throughout the entire cycle. There are costly gadgets, so would need a mechanic who is so equipped.

Another useful test is to scope the cylinders with a video inspection scope. Such things as presence of carbon deposits, and condition of cylinder walls and piston crowns can be assessed. You might even get a look at valves if camera angle can be so controlled. Good to have a unit that will record the video.

Another useful source of info is to get the crank case oil lab tested. A sample should be taken at or near your oil change interval, as newer oil will not be loaded with materials that indicate wear. The lab report will have valuable clues about the condition of the engine.

Your older diesel, if kept up is a very simple and robust machine compared to newer complex electronically controlled engines. Its simplicity makes it a great asset to the boat. So could be well worth some major maintenance or overhaul.


PS:
If smoke is bluish, this can be lube oil burning due to worn valve seals. Bluish smoke upon sudden loading and starting is indicative of leaking valve seals. Not sure if this engine is turbocharged, but if so, of course smoke can be indicative of turbo wear. Lube oil can be leaking past turbo shaft seals, or incorrect air mixture could cause smoke. Air manifold could be fouled too.