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**wilf** · 22 March 2014, 09:23

Think it needs to go into the head via a drilling in the block face. That must be blocked? Sorry but I foresee the LH head coming off again, unless someone here has a better idea?

**GDPR** · 22 March 2014, 10:57

The jackshaft has to rotate to feed both heads. There is a flat machined in the shaft journal that allows oil to feed alternately which regulates pressure.

Just get on and assemble it - when it is running you will get oil in the other head.

**rushdenstag** · 22 March 2014, 12:03

Originally posted by kryten View Post

The jackshaft has to rotate to feed both heads. There is a flat machined in the shaft journal that allows oil to feed alternately which regulates pressure.

Just get on and assemble it - when it is running you will get oil in the other head.

Ok - if that is correct the LH never gets the same volume of oil as the RH - is that true ?

**wilf** · 22 March 2014, 13:55

Kryten - I thought Rushdenstag had already tried rotating the engine, but still could get no oil feed to the lh head?

**GDPR** · 22 March 2014, 14:37

If you read "rotated to" that gave me reason to believe the engine wasn't actually run. If the gallery to the jackshaft is clear, then the only thing blocking could be the head or the head gasket.

But what do I know... only been doing this 39 years...

**wilf** · 22 March 2014, 15:05

This was the line that made me think of a blockage at the head/block face:

"what i am more concerned about is the fact that regardless of where the engine was rotated to no oil flowed through to the LH cylinder head, each time i pumped oil it flowed to the RH cylinder head and also the pressure relief valve opened"

Don't wish to be at cross purposes here.

**GDPR** · 22 March 2014, 17:32

After rebuilds, it has taken up to 20 seconds for the heads to get an oil supply with the engine running at a fast idle - that's why you should flood the cams and buckets with oil as well as smearing graphogen on the cam lobes because of the low pressure pulsed supply to both cams and the chain tensioners - there is a lot to lube with quite a limited supply and it has to force the air, which is compressible out of the drillings.

Just because one head only gets oil up at cranking speed doesn't mean there is a problem as it can take a while initially....

I'll go back to the naughty corner now....

Once supply is established the first time the problem goes away....

**davidf** · 22 March 2014, 17:33

The jackshaft is quite a strange design at the point where the heads are fed. It has alternate slots which connect the head feed to supply, then open to sump, as it rotates (I can't remember how many times per revolution, but you can count the slots on the jack-shaft). So, to feed each head, it has to be in quite a precise position, and I seem to remember that the spacing of the slots means that there is not a position where it can feed both heads at once. So, you need to try quite small movements of the crank to move from 'not feed' to 'feed'. If you are seeing oil at one head every time you test, then I think you are coincidentally always in a position where it is not feeding the other head. When I first built my engine, I thought it was sensible to manually rotate the pump and 'observe' the oil weeping from the camshaft bearings. I remember having quite a difficulty getting the 'sweet spot' crank position for one of my heads.

**rushdenstag** · 22 March 2014, 17:53

Originally posted by davidf View Post

The jackshaft is quite a strange design at the point where the heads are fed. It has alternate slots which connect the head feed to supply, then open to sump, as it rotates (I can't remember how many times per revolution, but you can count the slots on the jack-shaft). So, to feed each head, it has to be in quite a precise position, and I seem to remember that the spacing of the slots means that there is not a position where it can feed both heads at once. So, you need to try quite small movements of the crank to move from 'not feed' to 'feed'. If you are seeing oil at one head every time you test, then I think you are coincidentally always in a position where it is not feeding the other head. When I first built my engine, I thought it was sensible to manually rotate the pump and 'observe' the oil weeping from the camshaft bearings. I remember having quite a difficulty getting the 'sweet spot' crank position for one of my heads.

OK - i will pull the jackshaft and check that all the slots are ok, when the engine is rebuilt (job for sunday AM) i will try again - Cheers guys thank you

**rushdenstag** · 22 March 2014, 18:00

Kryten - thank you for the advice, you could be wright first time - i was not dissing you !

**milothedog** · 22 March 2014, 18:12

Originally posted by kryten View Post

If you read "rotated to" that gave me reason to believe the engine wasn't actually run. If the gallery to the jackshaft is clear, then the only thing blocking could be the head or the head gasket.

But what do I know... only been doing this 39 years...

Ian

**davidf** · 22 March 2014, 18:17

Originally posted by rushdenstag View Post

OK - i will pull the jackshaft and check that all the slots are ok, when the engine is rebuilt (job for sunday AM) i will try again - Cheers guys thank you

To clarify, look at the diagram http://www.rimmerbros.co.uk/Item--i-GRID005157.

You can see the 2nd groove round the jackshaft boss (in the diagram, appears to be in line with GHF301) is the one that aligns with the feed from the main gallery. So, this groove is always pressurised. The slot on top intersects with this, and is closed both ends, so this is also always pressurised. The slot you can see below and to the right (mostly hidden by 147907) is open to the rear, and not connected to the pressurised groove at the front. You can just see the blind front of this slot above GHF301. You can also just see the rear end of another slot 'over the horizon' to the left.
The head feed holes in the block are roughly where the back edge of the picture of 147907 cuts across the top slot.
So, as the jackshaft rotates past each head feed hole, it aligns the pressurised slot (feeds oil), then the land (so the feed is closed off) then the open slot (so the head is relieved of residual pressure), then the land again (closed feed), and then the next pressurised slot.
So, you can see that you have quite a small opportunity to find the correct position to feed a particular head.
It is a really odd design - I would love to know the purpose of it!
I can understand an intermittent feed, which would supply less than main gallery pressure, but why the complete relief of pressure between each feed?

**jleyton** · 23 March 2014, 10:09

One other trick that may well be worth trying, which I've done every time I've had an oil pump off, or whatever, is to run up the oil pump from an external source.

With everything else in place, remove the distributor and drive the oil pump hexagonal drive with a battery powered drill. (I don't remember the size but just get a socket on the end). It's great to see the oil pressure rising and yet knowing that there are no components rotating unlubricated.

From the comprehensive descriptions above, it may well be that feed doesn't get to one, or other, head this way however if you use my suggestion to get the system up to pressure and then maybe turn the engine over slowly, that should do the trick.

Good luck.

Cheers

Julian

**rushdenstag** · 24 March 2014, 21:50

ok an update !!

pulled the jackshaft - not as good as it could be - replaced with a V good second hand unit.
rebuilt the engine and checked the oil feed again - a slight dribble to the left !
i think this will improve with the engine rotating

cheers - thanks to all that commented

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oil to right but not to the left ??????

oil to right but not to the left ??????

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