Sprint top-end oil supply ?

[MIG Wielder]

Hello All, I'm helping out with this Sprint cylinder head job and we were a bit boggled as to exactly how the oil supply gets to the rocker shaft and camshaft from the cylinder block. We can see all the rockers are drilled with an oil way that comes out of the end of the rocker and onto the exhaust valve tappets , and the rocker shaft is hollow and has drillings to let oil out to the rockers. We can also see that the camshaft support bearings have oilways underneath . But how does oil get into these drillings please. Naturally we want to clean these out. It all looks very different to the 1850. ( No surprises there ).

Thanks Tony.

[Carledo]

Camshaft and rocker oil supply comes from the front of the jackshaft via a drilling in the block and through the head gasket.

HTH, Steve

[MIG Wielder]

Hi Steve, Thanks for that. Does that mean that the oil supply to the rockers and valve gear goes through the LHS end two stud and bolt holes ? ( Coloured red in the photo ).
Now I think the 2 green circled holes are waterway holes but I don't know why they are so small. I would have thought that they would have been as large as possible.
What are the 3 yellow circled holes for please ?

Thanks very much,

Tony.

[Carledo]

IIRC the yellow circled holes are oil drain back from the cambox to the sump (along with the oval hole at top right of the pic) and the green holes are oil supply (though I thought there was only one) but it's been a long time since I paid any attention to this sort of thing - it just IS!

Shove a bit of welding wire through the holes and see where it comes out!

Steve

[tony g]

All those holes are for water.(not the bolt holes though) The oil return is into the chain area only at the front

Tony

[dursley92]

Now I think the 2 green circled holes are waterway holes but I don't know why they are so small. I would have thought that they would have been as large as possible.
Thanks very much,

Tony.

Apparently the holes are sized to optimise the water flow, it means more cooling water goes to the places where its most needed. I read about it somewhere that explained it. If those holes were bigger it would mean more flow in the centre but not enough cooling to the ends of the head.

[Carledo]

The discoloured sections adjacent to the green holes are the blanked bits opposite holes in the block. This is indeed to control water circulation within the block and is mainly to stop the front end overcooling whilst the rear end overheats, all clever stuff!

Tony G, you may well be right about the yellow holes, it's been a long time since I truly LOOKED at the underside of a Sprint head, other than to try and determine just where the blow was in the head gasket! But i'm still sure the green holes must be the oil supply, it has to get up there somehow! and i'm equally sure about the oval hole at the upper right corner being a drain, since the engine sits slightly lower at the back (only a degree or two, but it's enough) there must be a way for oil to escape the rear end of the cambox or it would build up disatrously, especially under acceleration!

Think i've seen an oil circulation diagram somewhere, maybe in the Haynes manual. If I can find it, i'll scan it and post it!

Steve

[Ron1966]

If you look on the head gasket around number 1 stud it is a sort of kidney shape with a copper edge this is how the oil gets up to all cylinder head workings and this first stud rarely gets stuck.

[tony g]

Correct

If you look on the head gasket around number 1 stud it is a sort of kidney shape with a copper edge this is how the oil gets up to all cylinder head workings and this first stud rarely gets stuck.

[tony g]

Steve the green holes are steam holes to allow water in/out. After my research on re-routing the water supply by adding a stat and top hose outlet at the rear of the head and modifying the head gasket to provide equal flow across all cylinders (as far as i can measure), Im 100% that all the holes in the pic above are for either water or studs/bolts. The oil feed from the jackshaft hole feeds up to the head via one of the the front stud/bolt holes( as mentioned above). Ive done 1000 miles on my mod (no-one cared about ) so I can fit an inlet manifold without a stat housing hence my re-route. Soon to be fuel injected with OEM parts (Nissan). I respect your knowledge on Dolly's and car stuff in general and in no way am trying to argue, but I have done 12 months of work on the cooling system and know a lot more than I did before I decided to go the hard route (genetic )


Tony

Tony G, you may well be right about the yellow holes, it's been a long time since I truly LOOKED at the underside of a Sprint head, other than to try and determine just where the blow was in the head gasket! But i'm still sure the green holes must be the oil supply, it has to get up there somehow! and i'm equally sure about the oval hole at the upper right corner being a drain, since the engine sits slightly lower at the back (only a degree or two, but it's enough) there must be a way for oil to escape the rear end of the cambox or it would build up disatrously, especially under acceleration!



Steve
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[Carledo]

Steve the green holes are steam holes to allow water in/out. After my research on re-routing the water supply by adding a stat and top hose outlet at the rear of the head and modifying the head gasket to provide equal flow across all cylinders (as far as i can measure), Im 100% that all the holes in the pic above are for either water or studs/bolts. The oil feed from the jackshaft hole feeds up to the head via one of the the front stud/bolt holes( as mentioned above). Ive done 1000 miles on my mod (no-one cared about ) so I can fit an inlet manifold without a stat housing hence my re-route. Soon to be fuel injected with OEM parts (Nissan). I respect your knowledge on Dolly's and car stuff in general and in no way am trying to argue, but I have done 12 months of work on the cooling system and know a lot more than I did before I decided to go the hard route (genetic )


Tony

Tony G, you may well be right about the yellow holes, it's been a long time since I truly LOOKED at the underside of a Sprint head, other than to try and determine just where the blow was in the head gasket! But i'm still sure the green holes must be the oil supply, it has to get up there somehow! and i'm equally sure about the oval hole at the upper right corner being a drain, since the engine sits slightly lower at the back (only a degree or two, but it's enough) there must be a way for oil to escape the rear end of the cambox or it would build up disatrously, especially under acceleration!



Steve

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Just goes to show, I don't know EVERYTHING!

Steve

PS I did follow your thread about the head mods Tony, very interesting engineering, I just prefer to get my EFI by installng the engine it's attached to!

[tony g]

It was more an exercise than anything. Fitting a complete efi engine and loom as you have would prob be easier lol. Currently working on the final bits on the manifold this week so hopefully should be on the car soon too (mapping gut dependant for running )

Tony


PS I did follow your thread about the head mods Tony, very interesting engineering, I just prefer to get my EFI by installng the engine it's attached to!
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