Diesel Engine Diagnose

[yttrill]

Originally Posted by Steve Bean

FWIW, the manual for my Universal Model 40 (a marinized Kubota) says not to use the decompression lever to stop the engine. It uses a fuel shutoff.

Yep, i have direct evidence that is right in the form of a broken decompression control rod

[yttrill]

Ok I don't seem to be able to post photos . grr. I have retrieved, by hand, two loose and bent rods from under the non-valve side of the rockers. These appear to be seats for the rockers and nothing more. They were loose both horizontally and vertically (well i pulled the out past the non-valve side of the rockers). They're a handspan long and each go into a large hole i can't see into, and bent 80% of the way down by 15 degrees. The rods are about 3mm (1/4inch) thick. Two remain in place.

[If I try to add an attachment i get a message saying the post is too long, over 60K .. that's after using the attachment manager which allows 5 photos of 400K each .. ]

[yttrill]

[yttrill]

[yttrill]

[Jim Cate]

OK, those bent rods are the push rods. They go between the tappet, which rides on the cam, and one end of the rocker arm. The other end of the rocker arm forces the valve open, against the pressure of the valve spring. The push rods should be perfectly straight. There are various reasons why they may have bent. I'll let the real experts guess as to which reason is the cause in this case.

Jim

[shakey doug]

Are you able to post a contact number??

[Snowpetrel]

Damn fine boat you've got. If I recall correctly before the Kubota went in the 240v genset alternator was bolted above the maIn engine, and belted off it. Maybe you could replace it there while you get the Kubota sorted.

Ini's up in pitwater.

Those push rods look pretty bad. Could the broken decompressor have somehow jambed the valves causing the rods to bend? Hopefully the valves are not damaged.

Maybe a plywood cover for the petrol genset and a few more solar panels might be the cheapest solution for now. Plenty of cabin space for solar...

Sent from my HTC_0PCV2 using Cruisers Sailing Forum mobile app

[yttrill]

Originally Posted by shakey doug

Are you able to post a contact number??

Sure: 0420 466 233. Location Drummoyne, Sydney Harbour.

[yttrill]

Originally Posted by Snowpetrel

Damn fine boat you've got.

Ini's up in pitwater.

Ini did some things really well (Dutch are famous for welding steel boats!)
Some others .. not so well. Yep, Dream of Gaia is up in Pittwater. I was actually in Coffs Harbour when she went out on her maiden voyage, the two fire-engine red Gaia's together

Those push rods look pretty bad. Could the broken decompressor have somehow jambed the valves causing the rods to bend? Hopefully the valves are not damaged.

Yes. There seems to be a bit of metal filings in there, though its hard to see due the location and oil. So it looks like I will have to take the head off, right?

Maybe a plywood cover for the petrol genset and a few more solar panels might be the cheapest solution for now. Plenty of cabin space for solar...

A bit hard to organise on a pension. I have 10 solar panels, but my batteries are 7 years old, that's the real problem. I need over $7K for new batteries. Refrigeration is all switched off. Can just keep the computer running if it's a sunny day.

[Snowpetrel]

Ha, yes Ini built her on a very tight budget, but I was very impressed with her speed and sea kindliness offshore. And the simple keel cooled engines solves a lot of other potential issues, things could be lots worse, like an engine full of salt water!

Anyway, i'm very interested as I just worked out your engine is the baby brother (or is it sister?) to my engine (a kubota VH1100B, rebadged as a nanni 4.110HE), all 70mm series with common parts but mines a 4 cylinder version.

I didn't know you could use decompressors in them, wasn't sure if there is enough clearance in the top of the cylinder for the cracked valves. So I'm interested to see hows yours was set up. I have a workshop manual for the 70 series but it's a big file (about 8mb or so) , happy to email it to you if you want. PM me.

Anyway, I'd like to hear what someone with more knowledge has to say, but you might just be lucky, and have only damaged the push rods. hard to know. but it could be worth getting some new ones and give her a go. Bar it over first by hand with the rockers off and redo the valve clearances. hopefully the rocker got jammed up by the broken decompressors and caused the bent rods. if that's the case the valves might not have been damaged.

Im surprised its going to cost 7k for new batteries. I'd certainly look at testing what you have (with a hydrometer) and pulling any batteries with dead cells out of the bank. might just tide you over for a while. One dead battery in your bank will suck all the juice out of any decent ones left, so you will be left with flat batteries all the time, and even solar wont easily keep up with a internal short causing a dead cell. Any batteries with consistent cell specific gravities will be badly sulphated up but still better than nothing. Top up and charge all the batteries first, the cells with low water will likely be the problem ones.

And if you can afford it a much smaller bank of good batteries will be much better than a big bank of crap ones!

It would have been neat to see the two Gaia's together.

[yttrill]

Originally Posted by Snowpetrel

Im surprised its going to cost 7k for new batteries.

1800 Ah = 9 x 200Ah AGM @ around $700 each comes to $6300. Plus removal of old batteries and installation of new ones, 8 hours @ $100/hr = $800 plus one day on a marina to shore power charge the batteries up, $200. Over $7K .. and that's conservative. And doesn't include 2 x Calcium engine start batteries.

Yes, I need that much, I live aboard. And AGM work best if they're not discharged below 80%. So the real available power is only 360 Ah, which is able to deliver only 15 amps over 24 hours. That's fridge, freezer, and computer at 5A each (roughly) plus some microwave use and vacuum etc.

So I'm screwed by a single overcast day without a generator.

Frankly I'm considering Lithium. 200Ah is $2600 but they last longer, deliver much more current without damage, and are designed to be discharged to zero. Worried about fire though (metal fires cannot be extinguished).
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[transmitterdan]

I think you are overly pessimistic about what you can do with AGM batteries. AGM batteries can be discharged to 50% without losing much cycling ability. Even down to 40% won't hurt much. An 800AH bank should give 400AH usable without undo stress.

As you rightly point out charging back to 100% and all the way to float stage at least once a week is important. If you have a huge bank then you also need a huge charger. I think the minimum is 0.1C so for an 1800AH bank you need a 200A charging souce. If you have too small a charging source that can hurt the life of an AGM battery. For best cycle life size the bank based on a reasonable discharge usage and have the correct size charger.

[Snowpetrel]

Thats some serious draw! I got by for a few years with just 120 amp hours of lead acid and 80 watts of solar, but I didn't use the computer much, and never had a fridge or freezer. These days with LED lights and my tablet I would get by much better and still be able to use the web a fair bit, but then I enjoy being minimalist.

Does she still have the old air marine wind gen?

[yttrill]

Originally Posted by transmitterdan

I think you are overly pessimistic about what you can do with AGM batteries.

Nope, I've been told the numbers by installers. The nominal life is 4 years for the type I have (new designs claim up to 12 years, look on eBay but don't believe them). I've been careful with mine so they're still going (just) 7 years later. I am a fairly heavy user though (live aboard, nuke lots of coffee, computer, fridge, freezer, TV, industrial vacuum, electric toilet ..

If you have a huge bank then you also need a huge charger.

Nope, you're misunderstanding my setup: I'm over 90% solar. In summer I get 50 amps at noon. I only use my generator once a month in summer. In winter I just turn off the fridges or head to Far North Queensland. In bad conditions I run the genset for 20 minutes in the morning. Its intolerably noisy! Solar tops the batteries up quite well (the genset will never do that).

At sea the sails shade the panels but then the wind gen kicks in, in 30 knots it will also make 50 amps .. and it runs at night too.

I have a charger/inverter but it only charges at 70amps. Add the alternator with trick box, I get maybe 100amps if the batteries are way down but it soon drops to 50 total at which point the noise isn't worth it ;(

The system is fine in summer in Sydney and winter in the tropics, its useless in Sydney winter because of poor sun angle, low number of hours of daylight and frequency of heavy cloud cover. The real problem is once the freezer is stocked up I can't turn it off.