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Old 24-10-2014, 21:07   #1
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Bringing an Old Diesel Back to Life

So, how would you do it.
Lets say you approach a boat with a diesel that hasn't been fired up in 6-8 years but has good history and low miles on a rebuild. How do you bring this old girl out of the rust?

What steps would any of you take to determine if the engine was salvageable? Filters to clean, lines to replace, injector maintenance, glow plug business? I've def. brought gasoline engines with this much dust on them back to life, I would assume a marine diesel is just as capable, I am a mechanic, but I am no diesel mechanic.

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Old 24-10-2014, 22:17   #2
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Re: Bringing an Old Diesel Back to Life

Hi, can you turn the engine over? Diesels are fairly forgiving as long as a) there is fresh oil b) the fuel lines are in good order and no air bubbles.
The injectors may need servicing or changing but apart from that, assuming there is nothing broken inside then she should fire up.
If you can't turn her over then I'm afraid it is a complete strip down.

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Old 24-10-2014, 22:26   #3
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Re: Bringing an Old Diesel Back to Life

So stay away from seized cylinders. I've heard of using a high acidity oil such as olive oil to free up cylinders. (This assumes their seized due to a rust). Obviously a blown con rod or some other serious failure.

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Old 25-10-2014, 15:49   #4
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Re: Bringing an Old Diesel Back to Life

Charge battery(ies); check crankcase oil level; drain water separator; change fuel filter; suck out as much old fuel as possible and refresh with fresh fuel; check coolant and top off if possible(not so easy with raw water cooling.
By now battery is charged.
Crank and if it starts allow it to warm up.
Drain oil and refresh. If it doesn't start make plans after checking compression and fuel. No compression= no ignition. No fuel= no ignition. If it runs all is well.
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Old 25-10-2014, 16:20   #5
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Re: Bringing an Old Diesel Back to Life

I'm no diesel mechanic either. However, I can't help but wonder what might be "living" in the injectors, pump, & fuel line by now. Meaning the biological stuff which grows in Diesel fuel which sits. Like I said, not a mechanic, but it would seem like it'd be possible that such growth in these components may have; totally blocked them, or worse.

So, given that, might it make sense to have a pro take a look at these components first, or at least near the beginning of the above listed maint. items, prior to trying to get her ready to turn over?

That, & if they have to pull the injectors out to inspect them/clean them up, I'd imagine that it'd give you an opportunity to get a peek at the inside of the cylinders I would think (via a scope).


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Old 25-10-2014, 16:37   #6
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Re: Bringing an Old Diesel Back to Life

If you want to be really careful you can spend the time and pull the tank, rinse with acid; rinse with hot water and blow dry.
Then pull all fuel lines; replace or purge with a solvent and blow out with compressed air.
Drain water separator change gaskets and fill with fresh fuel.
Discard fuel filter refill with fresh fuel and new gasket.
Dismantle fuel lift pump, change diaphragm and gaskets.
Send injection pump out for a rebuild, and replace after timing check.
Drain and refill crankcase with new oil.
Pull injectors and have them sent out to be set up, or rebuilt. Install with new seals.
Coolant? Oil press gauge? Temp gauge? Alternator output gauge? Crank it.
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Old 25-10-2014, 16:38   #7
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Re: Bringing an Old Diesel Back to Life

If it is a diesel and it is not seized you may just be in luck. 17 years ago I sort of picked our Perkins 4-108. During our re-fit, one of the things we had to do was still see if it worked. With minimal effort we started her up and she sounded just fine. Engine Restart | Sailing Vessel Vigah There is some short videos on the page bottom. Since then we have done a little more. Engine / Power Train | Sailing Vessel Vigah

Had to remove the rocker arm and clean it up and then we flushed it with diesel and two oil changes.
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Old 25-10-2014, 16:43   #8
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Re: Bringing an Old Diesel Back to Life

Disconnect injector lines,remove injectors- see if you can turn over engine EASILY-if not,put a socket/breaker bar to try with force(turn crankshaft).If turns easy may be lucky.If turns but hard(with alot of force)pull head.Also pull head if doesn't turn at all.

You may be lucky in that after cleaning cylinders and stoning on drill all comes back easy.This typical to do.

New tips for injectors and possible seal job on injector pump will get you back running.

2-6 years long time,valves are open to let moisture into head chamber-this'll clean up well mostly.Seals go south over time without useage.

Rings break if started with oxidation within cylinders.This why if turns easy you're ok-but if not-pull head and clean/stone.

All the Best
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Old 25-10-2014, 17:11   #9
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Re: Bringing an Old Diesel Back to Life

My take on this is a little different.
Assumptions are dangerous but you make the assumption that it ran fine the last time it was running.
SO: The first thing you need to ascertain is whether it turns. That means you need to bar it over by hand. If it doesnít turn with a bar on the flywheel, you have major issues.
Verify it has oil in the crankcase and the oil is not contaminated by water or coolant. High oil level does not mean overfill but probably water in the oil pan. The water has had lots of time to go the bottom and the oil can look clean.
Verify coolant system has some coolant. If not look for where it went.
If it turns, pull the valve cover off and determine that all the valves are free. I donít like leaving an engine in one crank position for a long time and pistons are just one issue. Valve springs donít like to spend years compressed and they can break after you start it up and run it for a while or they can be very weak from being compressed for so long. Make sure they all have clearance so you know you donít have a partially sticking valve.
Now pull the injectors and spill a little marvel mystery oil in each bore. Leave the injectors out. Bar it around a couple of revolutions. Put a rag over the injector ports to keep the mess down.
Get some batteries and crank it. Bear in mind that it could need the starter serviced too.
If it cranks at fair speed with the starter, I would do a cold compression check. I know, you donít check compression on a cold engine but it is a fairly good indicator of rings and cylinder wall condition at this point.
Cranking with no injectors should spin it enough for the oil pump to start to circulate oil. Watch the gauge or pull the sending unit and see if it pumps out oil.
With the Marvel in the bores I would look for a minimum of 250 psi in each cylinder. If it is rust and crud free they could easily go over 350 with the addition of the Marvel.
The hard part is deciding what to do if the compression is marginal. I have managed to coax some rings back into life but dubious and I would never count on it.
Wet exhaust not put to bed correctly means a couple of exhaust valves open to salt water until the stuff in the muffler evaporates, if it ever does. If they drained the exhaust there is much less chance of a couple of rusty bores. Rust is far more the potential problem then varnish and carbon, unless the engine was really abused by the former owner.
If everything works so far, you have a very good chance of putting the engine back in service and now you can do the fuel system stuff, pumps and all.
You might want to send the injectors out but I would pop them back in and see what happens. Chances are they will work just as well as they did when the engine last ran.

Good luck.
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Old 25-10-2014, 20:26   #10
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Re: Bringing an Old Diesel Back to Life

Did anyone mention water pump impellors? Chunks of impellor rubber can block coolant channels in the engine block. (Why isn't there a strainer to catch that stuff?)
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Old 26-10-2014, 09:15   #11
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Re: Bringing an Old Diesel Back to Life

I didn't read all the posts. Sounds as if you are looking to buy?

I had luck with a pair of 6-71s that had sat a few years. Get a new battery stick the fuel line in a jerry can of fresh fuel and try it. You might want to purge the fuel line up past the fuel pump. It might just fire up and smoke like hell at first.

For what it may be worth or not?
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Old 26-10-2014, 09:31   #12
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Re: Bringing an Old Diesel Back to Life

Having done this before, I would pull the injectors and fill each cylinder up with Marvel Mystery Oil and let the motor sit for a week before attempting to turn it over. Rust on the cylinder walls can do a number on the rings when everything is dry from sitting for so long. I had two motors each with a siezed piston. Marvel freed both up, honed the cylinders and been running on them since 2008.

As others have recommended, I'd pull the heads and lightly hone the cylinders as step one. While honing you'll turn the engine over by hand and it should spin easily with no sticky spots. Once done, put the head(s) back on and do a compression check. If that passes, then start refurbing the fuel and cooling system.

Also check the exhaust manifold for any signs of cracks or corrosion since a bad manifold can screw up a newly rebuilt motor - ask me how I know


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Old 27-10-2014, 05:45   #13
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Re: Bringing an Old Diesel Back to Life

My neighbor bought a used boat this summer & had a mobile fuel polishing company come out. I talked to the guy & he said with old diesel all they do it pump it through a water separator & 30 micron filter. I have the dual Racor setup with the pressure gauge & an electric pump. An inline electric pump is really handy for priming when you change filters. Regarding the engine I would at a minimum change the oil & water pump impeller. Then turn it over a few times with the compression release valve pulled. Remember that it's pumping water every time you turn it over so you want to be careful that water doesn't back into the motor if you have a hard time starting it.
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Old 27-10-2014, 06:29   #14
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Re: Bringing an Old Diesel Back to Life

Diesels can sit for a while and not be hurt. Four years i bought a volvo md2001 that sat since about 1985, Guy bought it new for a boat but died and it sat in his garage till a ex volvo dealer l know got it. It was new and never run, still had clean oil in it. We put the fuel lines in a jug of fuel, hooked up a battery and after a dozen turns she bled out and fired right up. Still runs like a top, l have about 140 hours on it now. I had only one problem, after the first few hours the aluminum seals (washers)on the fuel lines corroded and started to leak.

Good luck with it.
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Old 27-10-2014, 07:35   #15
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Re: Bringing an Old Diesel Back to Life

If it has compression relief vlvs. open them and cut fuel supply off. Crank engine a couple times to get oil circulating, then go for broke.

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