1978 SR2 Lister oil pressure, capillary gauge readings

[Karen Lea Rainey]

Hi,

 

My engine starts up 1st time everytime no problem, but I think it sounds a little to fast at idle comparing it to other boats?

 

The problem is it builds 22 - 25lbs of oil pressure from the start and falls to around 10 to 15lbs within half hour and to 5lbs in about an hour.

I have changed the oil twice with Morriss Golden Film 20 Sae but it hasn't improved much at all.

It is not making oil as I have checked the dipstick regularly and it is the same.

I took the boat 4 miles yesterday at a slow pace until the pressure dropped to 5lbs.

It has a capillary tube attached to rge engine as the inbuilt pipe is not in use.

The strainer is not choked with nits and the flow of oil between passages appears to be good.

A car mechanic of mine says that the crank case bearings are probably worn and not making a tight enough fit.

He suggested that a sLICK 50 type restorer will improve the pressure over time what does anyone think about the problem?

My sentiments are if it needs a major overhaul then what have I got to lose with tryimg an engine restorer like SLICK 50

[Karen Lea Rainey]

Sorry I meant to type in the strainer is not choked with bits although if it were " nits " I could understand why it was happening

[RLWP]

It does sound like it is worn out. I can't see how pouring stuff into the crankcase is going to put back lost metal

 

These SR engines have a reputation for being able to run for ever, which is unfortunately true. The last one I rebuilt apparently worked fine. When stripped, the bearings were worn out, two connecting rods were bent, the fuel pumps were badly corroded and a piston in the gearbox was in two parts. This means that they are not necessarily cheap to rebuild

 

Richard

Edited July 2, 2014 by RLWP

[Grace and Favour]

I suggest that if you put 80ml of Slick 50 into your engine, you'll waste about £20

 

However, if you put 160ml in, you'll be wasting about £40

 

(Slick 50 is an highly refined immiscible extract pressed from snakes)

[Karen Lea Rainey]

Apparently it works by sticking a coat of PTFE / Teflon onto the metal bit by bit, overtime it increases the oil pressure a little, but it may also stick to the non moving parts when the engine gets hot

• Save my money for a rebuild then seems the probable answer,
• Snake oils, has anyone had a good response from them?

[alan_fincher]

If it otherwise seems OK, it really might be worth trying a alternate gauge on it, to see that the 5 psi reading is true.

 

This may be clutching at straws, but sometimes it is the instrumentation that is faulty, not the engine.

 

Does it also have an oil pressure warning light? If it is really as low as 5psi, I might expect that to be illuminating by that stage.

[Karen Lea Rainey]

No warning lights on the boat, you just feel the boat is not making a smooth channel in the water and you can hear a deep rumbling beginning under your feet,

when you go a bit faster the gauge goes back up a bit by 3 or 4lbs but it doesn't last long. What pressure do listers operate at anyway, 1978 air cooled SR2

[RLWP]

The manual says 'On engines fitted with a lubricating oil pressure gauge a recorded pressure of 15/20 lbs./sq.in. is adequate'

 

How badly is it leaking oil from the top end?

 

Richard

Edited July 2, 2014 by RLWP

[Karen Lea Rainey]

There are no leaks of oil from any part of the engine, and I have put a new Delphi fuel lift pump on the engine together with a new fuel line through the pump and filter,

Ive had the boat 2 months now and it previously had a direct feed into the fuel rack (bypassing the filter and pump). Sleemans have a new best customer at the minute,

by the wat the fuel lift pump looked worn a bit on the push bar

[PhilR]

The oil pressure relief valve on the SR's is set at 50 lbs/sq inch. With an engine in good condition the reading on start-up should be 50 PSI.. This will drop to 30 or 40 PSI within ½ hour of running and after an hour or so might drop to 15PSI. That is normal.

 

If the gauge is recording 10-15 PSI after an hour or two that is also acceptable.

 

But, 22-25 PSI on start-up and 5 PSI after an hour doesn't sound good. Your engine either has worn bearings, worn oil pump or a faulty relief valve..... or maybe a faulty gauge?

 

Changing to a different oil is unlikely to make any difference. You have already tried Morris's SAE 20/20 which is probably one of the best oils for the engine.

 

Regarding the idling speed, that is very easy to adjust.

[Karen Lea Rainey]

I suppose I could couple up the oil pressure gauge which existed on the engine all of the pipes are still there,

perhaps it was changed to make the oil pressure gauge visible whilst driving the boat.

 

Q does the original oil pressure gauge play any part in opening or closing valves / passageways to maintain the pressure within the engine

[Stilllearning]

All an oil pressure gauge does is show you what the engine oil pressure is, it is an entirely passive instrument.

A rebuild does sound likely to be needed unfortunately.

[Mrs Tawny Owl]

If you'd like a calibrated ear to pop over and either confirm your worst fears or hopefully find a less serious problem I'll send Richard over.

 

We're not far away assuming the boat's in Tamworth, and he's very experienced with Lister SR's of various sizes in all sorts of states from needing a little light fettling to a complete rebuild.

 

Sue

(Also of Primrose Engineering)

[Karen Lea Rainey]

I just may be getting to the bottom of this, been to Narrowcraft this afternoon to see when they can fit me in for a service/repair.

 

THe engine started today on just 18lbs pressure and fell away after a few mins to 10lbs.

After yesterdays run of 4 hours it would appear that my oil is getting diluted from leaky injectors/ or loose nuts etc.

 

I took the top off the engine and both rocker covers are virtually swimming in a mixture of diesel and oil, just doesnt smell right.

This would also explain why after an oil change I get 25lbs pressure to begin with and it falls away as it gets diluted with fuel.

Anyway my boat is booked in for next wednesday so hopefully it will be soon sorted,

regards Keith and my little Dartline boat "Robbie"

[Mrs Tawny Owl]

That's good,

 

Sorting injectors should be a lot less than a rebuild!

The last engine Richard had that problem on, one of the injectors was "hosing" according to the overhauler which meant it was pumping diesel into the oil rather than where it should have gone.

Overhauled injectors and the problem has gone.

Of course if you just have a loose pipe / nut that will be even cheaper.

 

Good Luck.

[alan_fincher]

Stating the obvious but......

 

If you do have diesel being leaked into the oil in a big way

 

and

 

There is not stuff dripping out of the engine at the same rate

 

then

 

You would expect the level on the dipstick to be increasing rapidly.

 

My understanding is that whilst it is far from ideal, oild air-cooled Listers will run very happily even when a high percentage of the "lubricant" is Diesel, (certainly percentages well into double figures, I've been told). Before it affected things badly, I would expect it to be very obvious by an increased level on the dipstick, (but I'm happy to be corrected by those with greater knowledge if I've been misinformed!)

Edited July 3, 2014 by alan_fincher

[Karen Lea Rainey]

THe oil level on the dipstick rose about 1cm after yesterdays 4 hr Journey, tells me all I need to know (hopefully), Im told this is very common on the lister engines due to either vibration or not laying up for winter properly.

[PhilR]

 

I took the top off the engine and both rocker covers are virtually swimming in a mixture of diesel and oil, just doesnt smell right.

This would also explain why after an oil change I get 25lbs pressure to begin with and it falls away as it gets diluted with fuel.

Anyway my boat is booked in for next wednesday so hopefully it will be soon sorted,

regards Keith and my little Dartline boat "Robbie"

 

 

THe oil level on the dipstick rose about 1cm after yesterdays 4 hr Journey, tells me all I need to know (hopefully), Im told this is very common on the lister engines due to either vibration or not laying up for winter properly.

 

A 1cm rise on the dipstick after 4 hours running represents a serious leakage of fuel into the sump. But it shouldn't be an expensive repair assuming the bearings and pump are in good condition. The SR's will withstand considerable oil dilution without damage.

 

25 psi at start-up, after an oil change, does sound a bit low, my SR2 always starts up with 50 psi oil pressure, but maybe I am lucky?

 

Good luck and please report back the outcome.

[Karen Lea Rainey]

The boat is currently at Narrowcraft (Alvecote) who tell me it is running as sweet as a nut, cant find anything wrong with it except the capillary oil gauge has loads of air in it and they have bled it.

There was also a loose nut on the injector,

According to them the boat is just old and will never be a F1 boat again but it is good to go.

I'll pick it up on Thursday and see how it is,

I don't know if he was just searching or bluffing but he says he'd had 3 enquires if the boat was coming up for sale.