No oil in rocker box.

[Mr. V]

I've just torqued the head down on my '73 1275 midget engine and thought that before I put the manifolds on I'd crank the engine over, with the plugs out, to check that oil is getting to the valve gear. Nothing. Not even a sign.

I'd have thought that the oil pump being positive displacement and all that it would be pumping oil to the rocker gear even at cranking speed.

Am I mistaken, and, if not, what do people recommend?

[svenedin]

Have you changed anything on the engine? E.g the rocker pedestals or the order of the pedestals? One of the pedestals with an oil way through it must be placed where the oil way goes through the head. Also if (as I assume) you have changed the head gasket, has this perhaps blocked the oil way to that directs oil through the head?

Lastly, and not intended to be facetious, has the engine got oil in it?

Stephen

[geoberni]

Also, in addition to Stephen's suggestions, have you disturbed the oil pump?
It might need priming.Try searching the forum, I think the question has come up in the past couple of years as to if the Starter Motor turns it fast enough for the oil pump to get oil up to rockers....

[svenedin]

Also, in addition to Stephen's suggestions, have you disturbed the oil pump?
It might need priming.Try searching the forum, I think the question has come up in the past couple of years as to if the Starter Motor turns it fast enough for the oil pump to get oil up to rockers....

If it doesn't turn the engine fast enough to get oil up there and the rocker gear is dry I'd be inclined to give it a good dose of oil before starting the engine and then turn the engine over on the starting handle to get it spread around.

[Mr. V]

Thanks everyone.

I've used a Payen BK450 head gasket. I left the rocker shaft assembly unmolested (25 ft lb was too much for the pedestal
nuts, so I've done them up as tight as I dare - about 17.5 ft lb). Everything seems to line up. I haven't touched the oil pump. I can hear a sort of squirting noise down below for a second when I stop cranking.

That's about it.

[svenedin]

I don't have a 1275 engine (I have a 1098) but here is some info on your gasket. Interestingly the oil way to the rockers is mentioned. It's also interesting that Minispares recommend running the engine for the first time for 2-3 minutes with no water. Phil can tell us whether the oil pump should be able to lubricate the rockers just from cranking.

Stephen

https://www.minispares.com/tam1521-head ... nal-gasket


Rocker oil way arrowed (corresponding oil way on top of block)

IMG_9342.jpeg (2.42 MiB) Viewed 6375 times

[Mr. V]

By the way, the oil light goes out after a few turns of the crank.

PS. If I have to take the head off again can I reuse the BK 450 (engine has not run with it), or, to be on the safe side, should I get another one?

[philthehill]

The oil pump should deliver oil to the rocker assembly just by cranking.
If the oil light goes out then oil is being pumped. It has quite a convoluted journey to the rockers so it will take a little while for the oil to arrive there.
I would suggest that you first take the plugs out and then crank over the engine on the starter. Oil should appear at the rocker shaft after a few moments. Keep turning the engine until the oil appears.
As regards the head gasket - if you have to remove the head I would recommend that you fit another new replacement head gasket.

[Mr. V]

Thanks Phil.
I have tried the cranking process a number of times, with a maximum of about 20-25 seconds on one occasion. I've already set the tappets to 15 thou. Could it take longer and could I damage the rocker bushes, which still have residual oil on/in them, if I do it for longer? I'm fairly confident the BK450 gasket wouldn't have blocked the oil passage and I feel pretty sure the company that skimmed the head, which has a good reputation locally, wouldn't have left debris behind to cause a blockage. It went through several operations and tests - admittedly not an oil oil passage test - and lubrication didn't seem to be a problem before I removed the head.

[philthehill]

It could take longer and you will not do any damage.
If you still do not get any oil up to the rockers then I am afraid it looks like the head will have to come off and you will need to check the head gasket is fitted right and the oil galleries are clear especially the one that runs horizontally across the head. If you do take the head off turn the engine over on the starter and see if any oil comes up to the top of the block. If it does then you will know you have a blockage through the head gallery. If you have compressed air give the horizontal a good blow through, unfortunately you cannot run a brush through that gallery as the gallery has a 90 degree bend in it and it is plugged with a brass stopper.

[Mr. V]

Thanks Phil. Fingers crossed!

[Mr. V]

I've struck oil after a minute of cranking!

I assume that a trickle is all I'll get at cranking speed. I also assume that the rocker bushes don't need much oil due to the fact that they're not working hydrodynamically like the other journals do.

Anyway, thanks for the advice and encouraging words!

Steven.

[svenedin]

Splendid! Are you going to follow the Minispares advice on the head gasket you used? Running the engine for the first time for 1-2 minutes with no water etc?

Stephen

[Mr. V]

I think so, but it does sound rather alarming!

[svenedin]

It does but engines are often tested for very short periods of time without any water coolant. I presume this ensures a better seal and avoids any risk of water interfering with the first sealing. Make sure you use a stopwatch and don't get distracted!

Stephen

[Andmurph]

I’ve installed a BK540 on the Midget. Running a few minutes with no coolant warms the plastic coating on the gasket and allows it to seal before adding coolant. I ran it for four minutes then let it fully cool for an hour or so before re torquing the head. Then add the coolant. No issues whatsoever.

Andrew

[philthehill]

For info:-
https://www.minispares.com/ajm1140-head ... ead-gasket

[les]

Well in all these years I’ve not heard of this ‘running without water’ idea.

[philthehill]

I wonder what it does to the water pump seal ??

[Mr. V]

I'm disappointed you don't know the answer to that one Phil, but it looks like I'm soon to find out!

Anyway, thanks everyone. I'll provide some sort of coda to this story in a few miles time.