Is this bad to run the engine without alternator?

[Blaster]

Hi all,

 

Just removing my crank pulley to send it to a workshop to re-manufacture one with V ribs, but still will need to run the engine on daily basis for heating the water. 

So this is the question, can this possibly damage the engine, running at some 1000-1100rpm with no load? The double alternators I actually have still create some load and and disconnecting them, does this change anything? Thanks for replies.

[IanD]

1 minute ago, Blaster said:

Hi all,

 

Just removing my crank pulley to send it to a workshop to re-manufacture one with V ribs, but still will need to run the engine on daily basis for heating the water. 

So this is the question, can this possibly damage the engine, running at some 1000-1100rpm with no load? The double alternators I actually have still create some load and and disconnecting them, does this change anything? Thanks for replies.

No load = no problem.

 

With a load, Beta Marine say that you shouldn't run the engine for long periods while charging batteries below 1200rpm...

[Blaster]

9 minutes ago, IanD said:

No load = no problem.

Thanks for your reply.

 

I just always knew you have to run any engine with ate least some load, like if you run your outboard on gear, you should never run it on a stand but in a water tank so there is some load at least.

[Tony Brooks]

If you have taken the crank pulley off, then what is driving the engine water pump and alternator. Not enough info. I fear you could be asking to boil your engine with no water pump turning.

[Tracy D'arth]

How are you running alternators and the cooling water pump with no crank pulley?

 

Tony beat me to it!

Edited July 17, 2023 by Tracy D'arth

[IanD]

1 minute ago, Blaster said:

Thanks for your reply.

 

I just always knew you have to run any engine with ate least some load, like if you run your outboard on gear, you should never run it on a stand but in a water tank so there is some load at least.

That may be for cooling purposes. Running a diesel for a few hours with no load isn't going to be a problem, but better not to do it regularly for a long time since this may cause things like bore glazing. A diesel engine in a boat has very little load on it anyway when you're pootling past moored boats, sometimes for what seems like forever... 😉

[MtB]

2 minutes ago, IanD said:

Running a diesel for a few hours with no load isn't going to be a problem,

 

As other have said, it depends which diesel. If the crank pulley drives a V belt for coolant circulation, the engine will (probably) overheat. 

 

Also if like the BMC 1.5 and 1.8, the pulley incorporates a crankshaft torsional damper, the OP 'could' possibly end up with a busted crankshaft.

 

 

We need to know which engine.

 

 

[Tony Brooks]

@Blaster Is this the BMC with the polly V belts someone asked about a week or so ago? If so, as Mike says, don't run it without the damper.

 

More info required, let's have a photo so we know what you are talking about.

Edited July 17, 2023 by Tony Brooks

[booke23]

 

 

His previous posts seem to indicate he has a Thornycroft 1.8, so a BMC.

Edited July 17, 2023 by booke23

[magnetman]

Presumably having a poly v pulley means an intention to hang a larger alternator off the end. Is this a good idea ? 

 

I would have thought not. The power unit itself must have been designed with a certain amount of crankshaft takeoff power available. 

 

Would it not be liable to cause problems to add more load ?

[booke23]

Deleted duplicate post.

Edited July 17, 2023 by booke23

[magnetman]

I think the advice not to run large capacity alternators at idle may be because they won't get adequate cooling due to low rpm. 

 

It depends what type of alternator it is. If it is a large frame like an Iskra or a Leece Neville it may be more tolerant of slow running. 

 

Beta Marine did have some serious problems with crankshaft pulleys at one stage. 

 

 

[Tony Brooks]

2 minutes ago, magnetman said:

Presumably having a poly v pulley means an intention to hang a larger alternator off the end. Is this a good idea ? 

 

I would have thought not. The power unit itself must have been designed with a certain amount of crankshaft takeoff power available. 

 

Would it not be liable to cause problems to add more load ?

 

I think Brooke23 has confirmed that this is the one long fitted with a polly-V belt and so I think that he would be very ill-advised to run the engine with no water pump or cooling. I am sure the photos we saw did not show a second V belt.

[magnetman]

Water pump and alternator both on a poly vee belt? 

[Tony Brooks]

3 minutes ago, magnetman said:

Water pump and alternator both on a poly vee belt? 

 

If it is the engine I am thinking of, then yes, and much interest in where the pulleys came from ensued but got no answer.

Sorry, this is not the engine I thought we were talking about. It was  ionayes who has the 1.5 with polly-V belts.

 

We need to know the engine, exactly what pulley has been taken off, or a photo, before I can give a sensible answer.

 

I now SUSPECT it is a twin alternate boat and the OP is talking about taking the second crankshaft pulley off that drives the second alternator, but who knows and how is he going to secure the other pulley with one missing.

 

 

[Tracy D'arth]

Could be the same so why does he need to get the crank pulley machined for a polyvee if it already is?

 

I like the idea of a polyvee pulley set on a 1.8 BMC but great care is needed with the woodruff key in the crank which half drives the sprocket and half drives the pulley. It is a weak point. I would be very careful with the build and want the parts to all be a perfect fit on the crank.

 

If the pulley is missing, the chain sprocket is not retained and all the oil will run out too!  Do Not Run It!

Edited July 17, 2023 by Tracy D'arth

[IanD]

29 minutes ago, magnetman said:

I think the advice not to run large capacity alternators at idle may be because they won't get adequate cooling due to low rpm. 

 

It depends what type of alternator it is. If it is a large frame like an Iskra or a Leece Neville it may be more tolerant of slow running. 

 

Beta Marine did have some serious problems with crankshaft pulleys at one stage.

 

 

AFAIK the serious problems were when Beta used a tapered key/groove instead of a splined shaft for attaching the pulleys, they haven't done this for a long time now.

 

But there is still a possible torsional resonance problem (crank/pulley/flywheel/torsional damper?) at low rpm, that's why they now say in the manual (and on a warning plate on/near the engine?) that 1200rpm is the minimum recommended speed for battery charging.

[magnetman]

Yes I think it was taperlock pulleys Beta had trouble with. 

 

Thornycroft is an interesting name. Back in the day they made engines and boats but more recently (90s?) it seems to be badge engineered power units. 

 

What units are they marinising these days? 

 

 

 

[Tracy D'arth]

9 minutes ago, IanD said:

 

AFAIK the serious problems were when Beta used a tapered key/groove instead of a splined shaft for attaching the pulleys, they haven't done this for a long time now.

 

But there is still a possible torsional resonance problem (crank/pulley/flywheel/torsional damper?) at low rpm, that's why they now say in the manual (and on a warning plate on/near the engine?) that 1200rpm is the minimum recommended speed for battery charging.

We have seen one splined shaft Beta total failure in the last 10 months, it is still a weak point on these engines. Made worse of course with a Travelpower as well.

[Blaster]

Hi all,

 

thanks for your input, very helpful!

 

the plan is to remove the crank pulley which is actually 120mm diameter and send it to a workshop to machine a new one to the exact same specs but with 6 V ribs for each belt and 190mm diameter. 

 

the whole thing is to have a better grip and higher speed from the alternators.

I don't see anything else driven by this belts, no water pumps, nothing. 

 

the engine is Thornicroft 1.8 but when I contacted Calcutta I have been told that this is not an ordinary BMC or Leyland but looks like a Mitsubishi engine, branded by Thornicroft.

 

So I'm with decision to make, does it make sense to take the pulley off and send it to be copied in larger version, and could this later on damage the engine cause of a higher torque? And would the fact that I take the crank pulley off will create some issues, especially if I run the engine in the meantime? Cheers

[IanD]

22 minutes ago, Blaster said:

Hi all,

 

thanks for your input, very helpful!

 

the plan is to remove the crank pulley which is actually 120mm diameter and send it to a workshop to machine a new one to the exact same specs but with 6 V ribs for each belt and 190mm diameter. 

 

the whole thing is to have a better grip and higher speed from the alternators.

I don't see anything else driven by this belts, no water pumps, nothing. 

 

the engine is Thornicroft 1.8 but when I contacted Calcutta I have been told that this is not an ordinary BMC or Leyland but looks like a Mitsubishi engine, branded by Thornicroft.

 

So I'm with decision to make, does it make sense to take the pulley off and send it to be copied in larger version, and could this later on damage the engine cause of a higher torque? And would the fact that I take the crank pulley off will create some issues, especially if I run the engine in the meantime? Cheers

 

Are you planning to use the 6-rib pulley to drive one big alternator or two?

 

If you drive one mahoosive one, bear in mind the side load on the crank will be bigger because of higher belt tension, and it would be good to check if this is OK -- if such an arrangement has commonly been used on that engine you should be fine, if not you may run into similar pulley attach problems that Beta had in the old days. It might also be a good idea to use a freewheel pulley on the alternator, I know Beta recommend this when using big crank pulleys and large alternators.

 

If you plan to use a single pulley to drive two alternators (like in the picture) then you won't have enough belt wrap angle round the crank pulley so it will be prone to slipping, the normal solution to this is an idler wheel to get close to 180deg wrap angles -- see attached photo (which is for one mahoosive alternator...).

 

I looked into this when I was considering using a diesel engine and high-power alternators, and had many interesting discussions with Beta Marine on the subject... 😉

[Mike Hurley]

That looks like a Ford to me.

[magnetman]

Yes. I think the water pump driven by the cam belt ? 

 

Ford 1.8XLD ?

Thornycroft 110 = Ford 1.8XLD

 

https://shop.chastheboat.co.uk/products/injection-pump-timing-belt-for-thornycroft-110-ford-xld-418-engines-as152088

[Mike Hurley]

6 minutes ago, magnetman said:

Yes. I think the water pump driven by the cam belt ? 

 

Ford 1.8XLD ?

Thornycroft 110 = Ford 1.8XLD

 

https://shop.chastheboat.co.uk/products/injection-pump-timing-belt-for-thornycroft-110-ford-xld-418-engines-as152088

Cam belt being the weak point on that engine.

[magnetman]

I don't like cam belts. 

 

 

Also a belt driven high pressure pump on that engine. Is it a road vehicle engine?