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Historical engine - which engine gauges and why?


dpaws
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41 minutes ago, zenataomm said:

Thank you for the kind comment, I haven't added to it in ages and I have been nagged about abandoning it.

Well they're right and it's absolutely brilliant - the whole Greggs saga had me doubled over with giggles like a child! Please, neither cease nor decease until you've published at least one volume in hardback; it would keep us both tickled pink for many a dark evening on board!!! 

Edited by dpaws
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51 minutes ago, Tonka said:

What about an hourmeter so as you know when to change the oil

Or will you wait for the oil to turn black

Oh, go on then. Not at the helm, though

A boat log is more fun

Richard

It'll turn black pretty quickly in most diesels

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Now if you had a Kelvin all you'd need would be 

A sense of touch (the cylinders should be "as hot as a man's hand can bear");

Keen eyesight (there is no oil pressure you just have to make sure the reservoirs are full and the dipstick is at the correct mark before starting out);

Good hearing (keep listening for the splashing sound to show that the Rae water pump is working);

A sense of smell (to detect anything overheating).

 

 

 

 

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I've got an oil pressure gauge on the engine and coolant temp which I can read from the wheel for my old Coventry victor. I know what's normal on the gauges. The coolant barely registers on the canal but can climb to around 75 deg on when pushing the Ouse for high tide at Goole. Not sure if it is that hot though because I can still put my hand in the skin tank if I lift the cover. I also put my hand on the cylinder barrels like Koukouvagia just said and compare to see if there is a difference between the two.

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I think the biggest problem would be not which gauge needed but where to get them from for a slow revving engine. Oil pressure gauges can be sourced but tachos with the low rev range and authentic white dial face, in my experience, are difficult if not impossible to find. 

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1 hour ago, RLWP said:

One of them says you are out of champagne

Richard

Good grief, WHICH ONE !!!!

:)

35 minutes ago, zenataomm said:

Strewth Laurie, the temperature pressure on your back pedalling mudguards is a bit fast!

Been running fast for 10 years, still waiting for a plumber to fix it !!

:)

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2 hours ago, plainsman said:

I think the biggest problem would be not which gauge needed but where to get them from for a slow revving engine. Oil pressure gauges can be sourced but tachos with the low rev range and authentic white dial face, in my experience, are difficult if not impossible to find. 

Ahhh but there are many ways to resolve the issue. I had a problem with no stopping power with a JP3 and Blackstone gearbox, finally identified by a genius on here as being worn reverse cones - apparently the gear box has two clutches, one for each direction and my reversing clutch was slipping! 

I've now got a PRM500 hydraulic box fitted so the issue will never arise again, but if I had had a propshaft tacho fitted then I'd likely have sussed the issue myself.

I'm now investigating bi-rotational propshaft tachos :) My engine's max rated RPM is 1500 but the day to day limit is 1200. The PRM's reduction ratio is 2:1 so I can fit a 600-0-600 tacho (no issue with over-speeding the gauge, physical limit is 1350). A couple of examples are below; common instruments on big ships of course, absolute unquestionable overkill on a narrowboat but don't worry, if you're not tempted by the $36000 asking price for the Pan Delta system then a little bike computer with a magnetic cadence sensor should do the same job for £20...

It means I don't need to find a cream-faced low-rev engine tacho - though they do exist with mechanical drive if you google carefully... the one below is a little 3" unit made in Japan for a Yanmar LD engine: 

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Edited by dpaws
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The tachos used on push bikes use a hall effect sensor, they count the number of times the magnet passes the sensor and then do a sum based on wheel size. They are inherently bidirectional

Richard

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Right...

Oil pressure can tell you a lot about the health of the engine but to do this needs to be monitored in the long term, and some of the signs to watch for are quite subtle. The chances of an oil pressure guage preventing a catastrophe are slim, you would need to be watching it at the exact moment the oil pressure failed but before the audible warning (bad sound from engine) kicked in. But I still think every engine should have an oil pressure guage and a vintage engine must have a nice brass one.

Water temperature is really useful. Its good to get engines up to temperature quickly, and not to overheat them when playing at full revs on a river. You might even find that your engine never gets up to temperature if you are just running to charge batteries.

Rev counters are nice to have but with a bit of practice your ears are almost as good, and listening to the sound of an engine should be practised, it will forewarn of many problems.

Volts and amps are the most useful but these are not directly engine related.

..............Dave

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10 minutes ago, RLWP said:

The tachos used on push bikes use a hall effect sensor, they count the number of times the magnet passes the sensor and then do a sum based on wheel size. They are inherently bidirectional

Richard

Yes, exactly, these are simply grown up versions using either magnets or lasers I guess. You can buy a hand-held laser tacho gun for about £20 from various places online.

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In my youth after market vacuum gauges were advertised for cars.

The adverts claimed they could diagnose almost anything that could possibly go wrong with an engine,  but I never bought one or knew anyone who had one, so no experience of them, direct or third hand. 

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6 minutes ago, cuthound said:

In my youth after market vacuum gauges were advertised for cars.

The adverts claimed they could diagnose almost anything that could possibly go wrong with an engine,  but I never bought one or knew anyone who had one, so no experience of them, direct or third hand. 

I had one on  Ford Escort. It was a handy way of improving economy if you drove watching it

No bloody use on a diesel

Richard

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2 minutes ago, RLWP said:

I had one on  Ford Escort. It was a handy way of improving economy if you drove watching it

No bloody use on a diesel

Richard

Why are they no use on a diesel?  I thought they measured the vacuum in the inlet manifold when the engine was on overrun? Doesn't thst happen on a diesel? 

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14 minutes ago, cuthound said:

Why are they no use on a diesel?  I thought they measured the vacuum in the inlet manifold when the engine was on overrun? Doesn't thst happen on a diesel? 

No.

the diesel has no throttle. Engine speed is controlled by the amount of fuel injected on each compression stroke.

 

 

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15 minutes ago, cuthound said:

Why are they no use on a diesel?  I thought they measured the vacuum in the inlet manifold when the engine was on overrun? Doesn't thst happen on a diesel? 

A really big feature of a diesel is that it has no throttle so there is minimal vacuum in the intake manifold. This is one of the main reasons that they are so efficient.

On every cycle the engine consumes a full gulp of air and the power is controlled by injecting a variable amount of fuel.

.............Dave

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5 minutes ago, dmr said:

A really big feature of a diesel is that it has no throttle so there is minimal vacuum in the intake manifold. This is one of the main reasons that they are so efficient.

On every cycle the engine consumes a full gulp of air and the power is controlled by injecting a variable amount of fuel.

.............Dave

Which leads you to think about a petrol engine, where the amount of air on part throttle is limited. Where a diesel is a constant compression engine (give or take flow losses at speed), a petrol engine is a variable compression machine. At part throttle it starts with a cylinder full of mixture below atmospheric pressure

Note: compression, not compression ratio - that's a function of geometry

Richard

Edited by RLWP
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29 minutes ago, RLWP said:

I had one on  Ford Escort. It was a handy way of improving economy if you drove watching it

No bloody use on a diesel

Richard

Anyone remember the windscreen wipers that worked on vacuum, when you put your foot down they stopped!

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