Detroit Diesel. Non Starter

syd said:
.........., I had trouble shutting that engine down, which is an intermitent fault, ...........
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Thought about this one and you could have an issue with your stop solenoid .. as referred to by others ... a simpler thing with respect to stopping the engine, (as compared to replacing or cleaning up the solenoid) is the cable adjustment (yellow arrow in pic ... believe this is your SB engine). this needs to manage to pull the leaver to full "no fuel"... if it has worked loose by vibration, you will not pull this to full "no fuel" .... and if you have an ignition barrel issue (as this provide your stop), you may pull the stop solenoid to partially shut during the starting process, which will maker her un-likely or slow starting ... once governor kicks in at starting moment, solenoid may restrict WOT somewhat...
 
Excellent suggestions. Thanks. I can't wait to get stuck in and report back. With regards to ignition/stop/start switch; This works on a dual switch system per engine. Switch one is a simple on and off switch, this turns on the dials and clock, switch two is a spring loaded lever which stays centralised, you hold the switch up to crank and hold it down to stop the engine. No keys. I think we are on to something where this is concerned. There is a cable operated stop but the previous owner has put stickers on these that say "Do not use. Emergency only". I asked him about this and he said it was because if you use them you have to go into the engine bay and reset the pump every time. So I've always just used the switches to stop the engines.

Cheers for now
Syd
 
syd said:
.... There is a cable operated stop but the previous owner has put stickers on these that say "Do not use. Emergency only". I asked him about this and he said it was because if you use them you have to go into the engine bay and reset the pump every time. So I've always just used the switches to stop the engines.

Cheers for now
Syd
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The emergency stop, is probably the air shutoff to the air chamber .... lower red arrow in the picture ... and yes, that is a manual re-set in the engine room. It is not a fuel shut-off, but a air shutoff which is installed as an alternate shutoff mechanism, in case a fuel shutoff failure, or a runway engine....
 
I've just had a light bulb moment. I've always treated the engines with kid gloves. i.e. I've always pottered about at 10 knots, never really opened them up. I remember why now. After I had changed the oil and fuel filters when I first bought the boat, I let the engine warm up then gave it a good rev in nuetral. As soon as the engine in question got up to 2000rpm it revved irratically and pumped out a load of smoke. It scared the bejesus out of me so I've not done it since. Could this be a symptom of the fuel shut off solenoid or a different issue?
 
Syd,
What you describe here is not necessary a fuel shutoff issue ... As you have treated these with "kids gloves" ... two stroke DD's need to be treated a bit rough ... they enjoy best to be working hard ... not overloaded, but hard... You would not have smoke (black or white) if your fuel shut-off was restricting fuel... If you have been running her low all the time, you will have carbon buildup on pistons and valves, and that would cause black smoke and un-even combustion in chambers ... running engine properly warm should loosen the carbon buildup and burn this off.... (you can inspect the pistons through inspection hatches on block ... no danger there and easy to do ...approx 14mm spanner I seem to recall..). This will give you an indication of piston, piston ring and cylinder liner status. Bottom line is that you should not have erratic rpm at WOT .... and there should not be any smoke ... black, blue or whatever colour!!! now if you have blue smoke, and your piston rings / liners are in a bad shape, you do face a re-build or a runaway engine consuming it's own lube oil as fuel... (you definetly do not want the latter !! ... but KIS should apply, so start with basic inspections and tests as discussed above...)
 
Will be starting tomorrow, as soon as feeler gauges arrive. Alf. I've got the proceedure for adjusting exhaust clearances but what position should rockers be in to adjust injector height? Is it just a reversal i.e. Exhaust rockers be fully depressed to adjust injector?
cheers
Syd
 
Syd,

Afraid you have part of the procedure ... you need to disconnect throttle cables, stop solenoids and back off buffer screw & idle screw as wel as fuel-rack ... and remove fuel lines for each injector before you start adjusting.. Send me PM with e-mail address and I'll cut out the "Tune-up" section of the manual and e-mail it to you...

For checking valve clearances, you should have enough today, but not for full tune-up and adjustments....
 
Sorry chaps not a thread drift but I have 6V53 Detroits in my Sunseeker Travado, they run like a pair of beauties!
The port one is a bit rough at cold idle and seems to hunt; any first thoughts and also what oil should I be using 40 weight?
And any preference in brand?
Many thanks in advance !
 
Use straight 40 oil ... do not use multi-grade !!!

Chevron Delo 40W
Shell Rotella 40T (or 50)
Exxon XD-3 40W

they should not hunt ... for more than 20 - 30 seconds or so ... if they do, it indicates something is out of tune ... these engines have a buffer screw on the governor(absolutely last resort) which spot of prevents the engine dropping too low .... This should never be used to level out RPM more than 25 RPM ... is she still hunts, she is out of tune and will hunt herself upwards and upwards, until you have a runaway ... Suggest a tune-up (Idle off, buffer screw off, thrrottle & stop wires off)... Open rocker covers, do valve clearance adjustments, followed by fuel timing... then set fuel racks (you have 2 racks x 3 cylinders) in sync., adjust idle, and avoid using buffer screw if you can...
 
Alf,
thank you very much indeed. I just love these old motors. Many years ago I ran Greyhound buses for roadshows and events and they had 8V71s. We had one but with over 1.4 million miles on it. In fairness the engines were tray mounted so you could roll them out so it was probably not original but the mileage showed they were good for a very long time.
 
Phew. What a struggle that was. Engine room not big enough for a fat bloke. I checked all the exhaust gaps 16 thou and injector heights.not one of them needed adjusting. Must have been done just before i bought the boat Still a non starter. What next. Checked fuel lines and air cleaner. Smokes whilst cranking and tries to fire but wont catch. Found out why I could nt shut it down one time. The throttle cable was interfering with the stop solenoid.
 
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Right Syd.... Suspected something like this ...and would propose something like Omega said .... you need to get some pre-heated air in there, or pre-heat combustion chambers to get that initial help with the combustion of fuel being injected.... the smoke is heated fuel, but as yet not ignited...

If you could wriggle to the outside again, you could open the inspection hatches of the cylinders (oval hatches half way down the block) and have a look at the piston crowns (14 mm spanner and a torch will do) .. If you have carbon buildup, your pistons will have a black layer of build-up, and your valves will have a similar build-up, which will prevent closing and as such you'll loose compression, which of course is vital for combustion...

If you have excessive build-up of carbon (and don't worry, the air chamber will contain a fair bit of this "gunk" ... so you will get dirty) ... on the piston crowns, you need the heat (as per Omega's siggestion ... perhaps a 750W heater on the air manifold for 30 min + to get the iron lump going... get her going, but you will not get her properly heated in neutral... you need a good run under load and 1500 RPM plus with 65 - 70 degree C plus .... >150 degree F for a good while before you get rid of the excess carbon .... and she will smoke ... black...

If you have excess carbon and a exhaust valve leak, you won't get a proper readout from a compression test anyway ... So... get her started ... good run .... and if you get rid of carbon properly, you will need to take new clearance checks as with carbon burnt off. If valves then are properly seated, I'll buy you a pint if valve clearances are not excessive after the carbon buildup is removed...

Of course there is the "big bill" issue to worry about.... but keep it simple first...
 
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Due the cold weather we have been getting, our Ford Sabre's which have no preheaters were reluctant to start, they too rely on excess fuel and half open throttle to start, provided we have a good cranking speed they will oblige. However we found it much easier to them going by introducing warm air into the air inlet, via a plug on the crossover on the inlet tract, whilst one of us turned the engine over, they fired almost immediately but stopped when the warm air was removed, so we kept the air gun going for a minute or two whilst they were running and then they settled down to a regular tick over. I am sure that treatment will get yours going as well. It is not rocket science most plant on building sites get the "gun" every morning during winter.

180S.jpg


Ours are easy to get at as you can see.
 
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Syd,

Please listen to Omega .... KIS !!!!

Thise addetives won't help starting and I'd be reluctant to use them ... besides that, they will work best at operating temperatures, and those DD's will clear this them self once you get some proper load on them !!
 
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