Hi,
I have an inboard diesel but the fan belt that runs the alternator is off and getting a new one on has proved difficult.
Just wondering if a diesel engine needs a battery after it has started?
It is an electric start and the battery is full. If i turned it on and ran it for 10 hours, would it drain the battery and cut out?
Thanks
No. Diesel engines do not require an electrical system to keep running (not the one in your boat anyway) modern computer controlled ones do but you don't have one of them. You could even take the battery leads off once it's started
Somer injector pumps have a fuel shut off solenoid that needs constant battery voltage to it to keep it open
Regards Don
Post war diesels sure don't meet battery connected.
I used to star them with handle and cigarette butt in winter.
The rest need battery because all safety features would be disabled.
What about get handyman and modify alternator bracket to fit common belts.
Ok I have never tried this on a diesel but the old story is if you need an emergency belt use pantyhose .
If you do try it I would love to hear how it goes and if it seems to work take plenty of spares I can't see them being good for many hours !
Also just to clarify you do still have a good working belt going to raw water pump yeah? That is one that I wouldn't be trying pantyhose on! short of in an emergency
Good luck with the trip, sounds like you are having lots of fun. hope you are going to share an account of the trip when you are done.
I expect the alternator belt also runs the water pump, I haven't seen a small diesel with separate belts although they might exist. You will absolutely need the water pump to run the engine for more than a very short time.
The kill switch may need electric power, but if you can find the cut-off on the engine you can shut down manually.
Belts are often difficult to get on, especially if they are wide ones like on my old Triumph car. If you loosen the alternator, even take out the bottom bolt that allows you to twist the alternator pulley in to get the belt into the pulley, you will be able to put the bolt back in when the belt is on.
If you have steel pulleys you could try a clip belt. These are available from engineering firms. They are noisier and will demolish alloy pulleys. I would suggest working out whether its an A belt or V belt, measuring the circumference and just buying a replacement from an engineering firm.
Most diesels water pumps are driven off the end of the camshaft but if you have an alternator then you may as well use it. The initial charge after start up is better for a battery than a solar panel especially, if its a starter battery and not a deep cycle.
Thanks all.
I actually have 2 spare belts but cant fit them because the four allen blots that lossen the front end to raise this guard thing that lets me slip the belt under have siezed.
The steel pulleys are so thick and strong i cant file a groove.
Basically, i have 4 siezed bolts that wont budge, cant split them or drill them out as not enough room for tools.
Its just an alternator belt, i have solar for charging the battery so i guess i dont really need it.
I was wondering if there was some kind of belt that had a clip so i guess i will go find one of those.
And yes, the water pump works without the belt.
Cheers
When you get the belt problem sorted just make sure you do not run the alternator "open circuited" ie with the battery switches off.
If you do you will fry the alternator.
Engine Looks like a beast, what is it ?
Have you tried a dremel with the flexy powerhead attachment on the bolts ( assuming wd40 has had a chance
SP,
It might be quicker to drill out the grub screws and retap them.
You could also try an easyout, after soaking in WD40 or similar.
If you cannot do it a local engineer should be able to do it in around 30 minutes.
Measure across the pulley groove to determine the section size of the belt, if it measures 1/2" then it's an "A" section if it measures 5/8" then it's a "B" section. I doubt if it would be anything bigger than that. V belt lengths are sized in 1" increments, so it should be easy to get a correct fitting belt.
Thanks Ramona,
I have been searching for a clip belt but no luck.
Do they have a specific name?
Can we see a picture of the seized bolts.
There really aren't many that cant be beaten.
On another tack - does the chain not have a link piece.
A lot of old school chains have 1 U shaped link.
The vertical components of the U slide through the ends of the chain.
Once through , a plate with 2 holes to match the pins is put over the pins and a circlip locks the plates in place.
Hence turning the U into a D - imagine that D flipped on its side.
Finding that would allow to remove the chain and hence fit the belt.
It will be a subtle difference on one side of the chain - it will only be detectable on one side.
The 4 bolts are behind the chain guard thing.
I will try take a pic tomorrow.
It seems somebody painted it at one stage and put paint straight over the bolts so cant get any wd40 into the groove.
I will try pantyhose tomorrow while i'm there until i get hold of some link belt.
As for the chain, i was just going to cut it off with some bolt cutters and put a new one on as it looks quite old.
Ok, cool, I'll do that.
I was going to leave port with no alternator as i dont really need it now that i know the engine will run without a battery so the pantyhose thing was more like a test of the pantyhose idea incase i need it in the future :P
I dont smoke weed anymore nor am i a pirate so maybe i should change my name lol :P
Please just split the chain and replace the alternator belt with the correct belt. You can then simply replace the link in the chain. It is poor practice to use ad hoc repairs when not required. If you have a breakdown at sea then by all means use temporary repair techniques but it should not be necessary. ie carry a spare belt and this can be replaced by taking the link out of the chain wherever you are. The alternator is actually an essential piece of your electrical setup. Flat battery equals no radio, no navigation lights and probably no engine run as most marine diesels have an electric fuel lift pump and they wont run with a flat battery.
Thanks Frant.
Like i said, easier said than done. I have 2 spare belts and if it was as simple as removing the chain link it would be done already. I also dont see how my suggestion of cutting the old chain off with bolt cutters and replacing it with a brand new chain is makeshift.
I have 4 siezed bolts that aint budging anytime soom without specialized tools so simply cant get my spare belt on.
The diesel engine is simply a backup auxiliary at this point. My brand new yamaha outboard will do all the motoring plus it has a 6amp alternator on it.
The inboard diesel will only be used in rough seas if the outboard cavitates or if the outboard dies which i doubt since its brand new.
How many yachts have a backup engine for their engine?
Most yachts this size have a small outboard and nothing else. I have what seems to be a reliable old diesel inboard, a brand new outboard and am all set. I will use pantyhose as a test, get some powertwist when i can source some and it saves me messing around with ancient bolts that havent been removed since it was built in world war I.
No need for insults :P
Just got back from the first trip with the outboard. Was 3 not full throttle on the diesel, 4 knots at 75% throttle on the outboard.
These new outboards are light and quiet. Why have one?
Coz i am motoring 100kms with a 30 yr old diesel. Now that i know the outboard outperforms the diesel, i will probably remove it at some stage.
As for fuel economy, 1 litre of petrol per hour aint bad.
Bad thanks for the warning about petrol as the 25 litre tank was left in the locker overnight. Will leave it in the cockpit from now on.
Cheers
