Moises noises.

[Moises]

Hi Keith, what do you think about this pump? Nice squirt of oil with no air bubbles.
I have assembled the cover with silicone without a paper gasket.
The valve discharges at 80/85 psi. It's too much?
Merry Christmas!

[Keith Clements]

Looks ok. 85 psi may be ok if the oil is 30 sae and not at 90 c.
The wear may me accomodating the lack of gasket. Just be careful no silicone finds it way to block the timing chain oil feed.

[Moises]

I have assembled the Javelin engine. Now I have problems with oil pressure.
I use oil Castrol GTX 15W-40 A3-B3 Ref. 14c19f
Cold start
With cold oil at 800 rpm. Oil pressure is 65 psi. After 10 minutes it drops to 28 psi. Accelerating to 4,000 rpm it goes up to 70 psi.
After a short tour
With hot oil at 1.000 rpm the oil pressure is 8 psi. At 3.500 rpm it goes up to 30 psi.
What is the reason ? Oil pump, crankshaft bearings, camshaft, ... ?

[Forumadmin]

That is good pressure. Do not worry. It is the oil grade I think. Although the 40W is better than the original 30, modern oils get that viscosity from additives so the base oil is 15W. I have the same on Amy's Javelin and it has been like that for 15 years. No wear anywhere when I took the engine apart a few months ago.
There might be an issue so keep an eye on the cold start pressure.

This is just an hypothesis but, if a 30 grade oil should give 50 psi when hot (and that is on a new engine), a 15 grade, which is half the viscosity, would give 25 psi. Since you now often get 0W oils for cold climates I am not quite sure how that theory works. Some reding to do, I guess.

Note the setting of the pressure relief valve should be done with straight 30 grade oil which is hot.

[Moises]

Thanks Keith, do you think I should have installed an oil cooler?

[Forumadmin]

An oil cooler is useful if the air temperature is high and the water cooling is struggling. It is also useful for extended high revs driving. I would not install one without a thermostatic bypass as cold oil can be damaging. On Amy's Jav I have installed the cooler under the wheel arch to get the heat out of the engine compartment. It has been fitted with its own fan, although this is not necessary, but was done when I had water cooling issues.
Madrid summer temps might well demand a cooler. I fitted a temp sensor in the banjo bolt on the oil filter housing. Oil's working temp is hotter than water and should be 110 to 125C.

For every pound of fuel burned in an engine, the combustion process also generates a pound of water! If engine sump temperatures rarely exceed 212 degrees (water's boiling point), the water will mix with sulfur (another combustion by-product) and create acids that can eventually damage bearings.

[Moises]

I have reassembled the engine. I have corrected the crankshaft end float and I have checked the gearbox. Everything seems correct. I have driven 90 kms. At 3,500/4,000rpm. the oil pressure has been maintained around 2 kg/cm2. and the water temperature has not reached 75ºC.
However, the transmission noise is still deafening. It looks like a machine gun. When I step on the clutch the noise stops. Is it the clutch friction plate or maybe the mainshaft extension bearing? I will appreciate suggestions.
All the best

[Keith Clements]

If the noise stops as soon as you step on the clutch, I would strongly suspect the clutch. Chris had a similar problem. There are two things to check. The thickness of the friction plate and the thickness of the gasket. It might also be the seating of the actuator knuckle.
What happens if you reduce the play in the clutch pedal?

[David Morris]

Hi Moises,

Very glad that you have the engine running well. Well done! I would suggest getting the rear axle up on a couple of axle stands, or similar, and running the car safely in gear. You should be able then to pin-point where the transmission noises are coming from?

All the best,

David

[Moises]

Thanks, Keith and David. I already did this test at the beginning and I was not able to locate the noise. Now, since the noise is more characteristic (machine gun) I will repeat the test. Maybe you'll be lucky. I think Keith may be right and the problem is in the clutch friction plate.

[Keith Clements]

viewtopic.php?p=20623#p20623
Has the testing and checking method for the friction plate.
Note that similar plates have different dimensions. The Borg and Beck number is a sure way to make sure you have the correct one.

[Keith Clements]

Is the noise there when in neutral ģear and clutch not depressed? If it is, then it could be the input shaft or layshaft. If it then goes away with the clutch depressed but the layshaft still spinning, then it is interference on the clutch actuator I suspect. If it does not go away then perhaps a gearbox issue.

I do not think you need to put on axle stands if the noise is there in neutral.

[Nick Webster]

i have just been reading through these posts again and noticed Keith's post about oil viscosity. Please note that oil viscosity change vs temperature is not a straight line. Furthermore the effect of viscosity modifying additives does not act on the "thin" end of the graph. The effect, for a given temperature compared with monograde oil, is to lower the high end of the line and raise the lower end.

Oil pressure as shown by the dashboard gauge is not at all the critical factor in lubrication. It is merely a crude indication of the performance of the pump - a favourite assumption being that high pressure must mean oil is flowing well through the system, but it follows that a high pressure might actually mean there is a blockage somewhere.

I realise this is not Moises Noises, but just thought I'd make the point. I do not wish to lead discussion away from the subject!

Nick

[Keith Clements]

The number before the W is the viscosity at a winter temperature (zero Fahrenheit = -18C) and the number after the W is the viscosity at the operating temperature (212 degrees Fahrenheit = 100C). Since Jowett engines and gearboxes in temperate climates required a 30 monograde there is an advantage in using a 5W30 as it will flow properly and thus get to the bearings when the engine is cold yet it will also be good when warm. If the engine is used in tropical climates say over 30C then a 5W40 would be preferable. Racing boys use a 0W40 as this is low viscosity when cool and thus improves the power of the engine and is also good at high revs when the oil gets very hot, say 120C. Oil pressure can show if the pump is not working, or the oil pipe has burst or your main bearings have gone. It can also show if some silicone has blocked the gallery to your bearings or there is something wrong with your oil pressure relief valve. The lubrication properties of modern oils are much better than they were 70 years ago and the thinning additives gets the oil where it is needed when cold. Other additives reduce emulsification which occurs when burning petrol creates water, but you still need to get the oil to 100C to vapourize that water and take it out via the breather. High oil pressure then might be bad as it means your oil is not hot enough and is turning to water!

[Nick Webster]

Although there are advantages in oils with viscosity as low as 10 or 5 or less they are genearlly not suitable for older engines. This is because another factor should be taken into account which is build clearances. Older engines are not built to such fine tolerances and even if you do a pretty good job of fitting up shell bearings there are many other places it will leak away while the engine is stopped. The prize candidate with the Javelin / Jupiter being the valve train I should think. If the gap is small enough "stiction" will keep it there. That is to say the size of the gap is relative to the tendency for the resting oil to creep away, depending on viscosity. I remember when the firm I worked for intoroduced a ground breaking 5W oil in the 1980s and were then obliged to withdraw it due to a number of Alfa Romeo cam failures. The thin film of oil remaining in the cam area was not sufficient to provide adequate lubrication while the oil circulated from the sump. I would say though that you will never catch me with a straight grade oil in my sump. I would quite like to use a 15W but I don't think there is a classic oil to that specification that also meets the zinc specification.

I see little correlation between the oils used by racing cars who don't need or expect their engines to last tens of thousands of miles. It is true that the best oils give the best protection but all are affected by dust and water pollution within the engine and hence regular oil changes are the real answer. Changing the filter on a Javelin is such an awful job (even a canister) I can quite believe that historically many engines never had their best chance.

I don't think you need to get the oil up to 100 degrees C to start the water evaporating out. Indeed, most bearings start to get unhappy about 85-90 degress. Water (especially under a slight crankcase vacuum) will start to evaporate before that. The unfortunate thing is that some of the javelin timing chest is exposed to cooling air when really it doesn't need it and condensation forms in the middle section. Then there's another problem -- the density of water is such that it gives a wonderful reading on the pressure gauge.

Nick