9 replies to this topic

[sadam_lfc]

we have changed the rockershaft on my engine, as the old one broke.

now the new one's on... there's still no oil getting to the top of the engine, before the pushrod was out of place - so we took the rear plate off and found the tappet had come out of place.

that is now fixed and when the car's running it sounds fine, there's just no oil around the top of the engine

what next?

[Dan]

Did you get all the rocker posts and shaft back in the right way around? Only one post is drilled for the oil feed, this has to be in the right place.

[sadam_lfc]

Did you get all the rocker posts and shaft back in the right way around? Only one post is drilled for the oil feed, this has to be in the right place.

yeah that's in the correct position

[Dan]

What's the oil pressure like? Have you checked whether the PRV is stuck or leaky?

[mini7boy]

sadam,

assuming that you have all the pedestals positioned correctly and the rocker shaft located correctly by the grub screw that screws into the top of one pedestal and protrudes part way into the rocker shaft to keep it from rotating and shutting off the oil flow, then you need to work backwards from the pedestal through which the oil passes, through the oilway in the head, and through the oil "jet" in the top of the block.
Somewhere the oil is getting prevented from flowing all the way through to the rocker shaft.

To minimize the amount of removal and reinstallation of parts needed, I would:

1) remove the rocker shaft assembly and all pedestals
2) remove pushrods
3) remove spark plugs, but leave coil HT lead contacting the head
4) spin the engine on the starter long enough to see oil pressure on the gauge - this is important. It may take some spinning to get oil to show on the gauge. be patient
5) look to see if oil is emerging from the oil hole underneath the pedestal that has the grub screw
6) if no oil flows when good oil pressure(as good as you can get on the starter) is present, then you have a blockage either in the head or in the block.

7) you can try to poke a fine object into the oil hole in the top of the head to see if if frees an obstruction and allows oil to flow.
8) if you get oil flowing, reassemble and check to see if the rocker shaft assembly gets oiled with the engine running. If no oil flows, the pedestal may be blocked.
9) if you have determined that you cannot get oil flowing by working the oil hole in the top of the head -- continue to next step.

10) try blowing compressed air into the oil hole in the top of the head to "backflush" the oilway.
11) try spinning engine again on the starter until you get oil pressure on the gauge to see if oil emerges from the head. If not, pull the head

12) locate the hole in the top of the block through which oil passes to the head.
13) spin the engine on the starter until you get oil pressure on the gauge
14) see if oil emerges from the hole in the block.
15) if yes, then the blockage is most likely in the head - clean out the head's oilway
16) if no, then the blockage is most likely in the block- clean out the block's oilway

just as a piece of information, some racers who are concerned about getting too much oil into the area above the head(and under the rocker cover) under sustained high RPM operation install a "jet" with a smaller opening than the stock jet into the top of the block so as to restrict the amount of oil pumped up into the rocker area. These generally do not have trouble with getting plugged up, so the larger stock sized jet should not have any plugging problems either.

[sadam_lfc]

sadam,

assuming that you have all the pedestals positioned correctly and the rocker shaft located correctly by the grub screw that screws into the top of one pedestal and protrudes part way into the rocker shaft to keep it from rotating and shutting off the oil flow, then you need to work backwards from the pedestal through which the oil passes, through the oilway in the head, and through the oil "jet" in the top of the block.
Somewhere the oil is getting prevented from flowing all the way through to the rocker shaft.

To minimize the amount of removal and reinstallation of parts needed, I would:

1) remove the rocker shaft assembly and all pedestals
2) remove pushrods
3) remove spark plugs, but leave coil HT lead contacting the head
4) spin the engine on the starter long enough to see oil pressure on the gauge - this is important. It may take some spinning to get oil to show on the gauge. be patient
5) look to see if oil is emerging from the oil hole underneath the pedestal that has the grub screw
6) if no oil flows when good oil pressure(as good as you can get on the starter) is present, then you have a blockage either in the head or in the block.

7) you can try to poke a fine object into the oil hole in the top of the head to see if if frees an obstruction and allows oil to flow.
8) if you get oil flowing, reassemble and check to see if the rocker shaft assembly gets oiled with the engine running. If no oil flows, the pedestal may be blocked.
9) if you have determined that you cannot get oil flowing by working the oil hole in the top of the head -- continue to next step.

10) try blowing compressed air into the oil hole in the top of the head to "backflush" the oilway.
11) try spinning engine again on the starter until you get oil pressure on the gauge to see if oil emerges from the head. If not, pull the head

12) locate the hole in the top of the block through which oil passes to the head.
13) spin the engine on the starter until you get oil pressure on the gauge
14) see if oil emerges from the hole in the block.
15) if yes, then the blockage is most likely in the head - clean out the head's oilway
16) if no, then the blockage is most likely in the block- clean out the block's oilway

just as a piece of information, some racers who are concerned about getting too much oil into the area above the head(and under the rocker cover) under sustained high RPM operation install a "jet" with a smaller opening than the stock jet into the top of the block so as to restrict the amount of oil pumped up into the rocker area. These generally do not have trouble with getting plugged up, so the larger stock sized jet should not have any plugging problems either.

ok great, thanks for your help ... I am going to carry out a pressure test too to check it's not the oil pump

[ANON]

have you used an engine flush on it recently ?

[sadam_lfc]

have you used an engine flush on it recently ?

no, would you recommend this?

[ANON]

have you used an engine flush on it recently ?

no, would you recommend this?

GOD NO !! have seen all sorts of problems after people have used a flush in the oil.

as long as the pressure relief valve is ok just go for taking bits off and looking for signs of oil getting through as already posted.

[mini7boy]

Some of the head gaskets, not sure which part numbers, have been known to have a problem with the small "seal" that surrounds the oil pathway between the block and head.
The story goes that this seal disintegrates and can block the oil flow.