1936 Model 18 oil pressure advice

Well, it was going when it stopped (if you know what I mean) and I also can't see how the pipes could be put the wrong way round... they are steel pipes and would need to cross over each other. As it is, flow from the tank is the top fitting into the timing cover and return is the bottom.

I think the pump isn't full of oil and probably won't do anything until it is. I think I'll run it up and down the hill again before I pull the cover off, just in case I get lucky.

It's a hell of a way to keep fit.

Previously richard_payne wrote:

If there is oil in the tank and there is no tap or anti-drain valve in the feed line then oil has to be getting to the feed side of the pump. Normally, a couple of kicks should be enough to see some movement in the tell-tale.

If the sump is dry (drained) then it will take quite a bit of kicking before the return starts showing as there will need to be a (small) quantity of oil in the sump first.

The oil from the pump enters the gallery in the timing cover at the bottom and is fed to the crank via the oil-feed jet. There would be no harm in removing the slotted domed cover in the middle of the timing cover and checking that oil is getting up that far, or indeed in unscrewing the tell-tale for dismantling and cleaning and to check that oil is being fed into the gallery.

Personally, being the curious type, I'd probably take the cover off for a look but if you do, be careful that the cams don't fall out or you'll have to re-do the valve timing.

Well, I agree with you that the best case scenario would be to remove the cover and go through everything in a deliberate and thorough manner. However I'm not exactly overwhelmed with free time at this point in my life (work,babies), so I'm trying to be practical about doing what is necessary to get out whilst the sun shines.

I've run the thing up and down, and filled the return pipe with oil and pushed the bike backwards (in gear of course!) to bring oil into the scavenge side. I have yet to see any trace of return or indeed any movement on the telltale. I started it again (It starts so well) but I didn't want to keep it going obviously. I did manage to drain a little more oil out of the sump (1/4 cup maybe), but it was definately old oil (looking very glittery ...hmm) so no indication really that new oil was going through.

I have been looking for a decent schematic of the oil pump and circuit, but haven't found one as yet. If anyone could point me in the direction that would be great. Anyway, I've removed the dome headed cover in the timing cover and retrieved a spring and what looks like a broken oil feed jet. I can't tell if this is actually significant to the lack of pressure indicated at the telltale as it looks like it's been broken for a very long time. As for the telltale itself, I can't get the main body out of the timing cover as the case is too close to be able to get a socket on. I don't want to use an open ended becasue it's tight and I don't want to crush the fitting I could modify a socket of course, which is what I might have to do. I'm also not sure how much oil is supposed to be coming out of the oil pressure jet hole, as I can't really see that it's much if anything. This probably backs up the suggestion that the pressure jet, although not perfect, is not the cause of this.

In fact, in relation to the telltale; do I have to remove the main bronze(brass) housing from the top of the timing cover or should I be able to move or extract the telltale when only the top cover (with the split aperture) is removed. I have taken this off, but can get no movement out of the telltale with fingers. Should I be able to?

P.S and to be clear... no shut off taps for the oil...I'm guessing it's the original 1936 pump so I don't know whether that have any system to prevent drain through.Also, I'm also guessing this pump is pretty worn, so does the fact that the tank doesn't seemed to have lost oil through the pump in the last 24 hours suggest anything. Is that too short a time to tell?

Right, I just got the telltale body out... 18mm 3/8" drive worked perfectly.

It does appear that there is new oil at the bottom of the 'well' but when I turn the engine over on the kickstart there doesn't seem to be much, if anything coming into the well from anywhere.

Previously richard_payne wrote:

I hate to be the bearer of bad news but there is something pretty horrible going on in your timing chest, Richard.

The oil feed jet is usually quite dull with just a polished ring where it lightly bears on the crank nose. Yours seems to have been quite badly ground away by the crank and perhaps spun with it while the rear part remained seized in the housing. That could perhaps be due to running without oil.

I don't know if the pre-war oil pumps were, like the wartime production, cast in mazac. If so, and if stored 'dry' (not in oil), they can oxidize, expand and seize. If the pump has seized then something in the drive will have been damaged too.

I really think that it would be prudent to remove the timing cover at least and bear in mind that a full engine strip might be required.

Ok, Gin and Tonic administered. I've started the process of removing the timing cover. Mag sprocket off. What is the fitting for the drive sprocket for the mag chain... looks like it has a keyway. Is it parallel or tapered fit?

Previously richard_payne wrote:

The sprocket on the cam does indeed have a keyway. It is a taper fit as per the mag spindle. I usually find it slightly easier to get at for removal.

Good Luck !

Thank you Richard, you've been really helpful.

I'll let you know what I find.

Previously richard_moss wrote:

Previously richard_payne wrote:

The sprocket on the cam does indeed have a keyway. It is a taper fit as per the mag spindle. I usually find it slightly easier to get at for removal.

Good Luck !

Thank you Richard, you've been really helpful.

I'll let you know what I find.

Well, I've just removed the timing cover and had a look. It seems that the main drive shaft for the pump has seized and stripped either it's own teeth or the teeth on the crankshaft scroll gear. It doesn't go round when the engine does anyway.

Also, the rear cam spindle, which has the mag chain drive spocket on the end of it has obviously picked up on the bush and rotated it in the timing cover.I think it's been like that for a long time. A lot of wear. That wouldn't be the easiest to machine either, as I'm not sure where you'd pick your reference off.

I'll sleep on it!