Is this is a good idea? Adjustable pushrods and shims?
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Is this is a good idea? Adjustable pushrods and shims?
Hi guys I've been having problems with my engine since I built it and I've took it out recent to do some work on the box and thought I'd fit some adjustable pushrods as the shims were a bit all over the place, however there seems to be a large quantity of oil in the heads when it's running to the point it overflows almost when the rocker covers are off, I put this down to the aftermarket rockers and rocker shaft, so I tried angling the shims a bit to try to close the hole up a little that feeds the rocker pedestal. So I'm now thinking of leaving some thin shims in there and using them to try to reduce the oil flow and using the adjustable rods to sort the lifter tolerances? What do you guys reckon please?
Shims make the valve train geometry bad and it is not all that great to start with, if you want to restrict the oil flow to the valve gear then you could fit a restriction in the drilling in the head which takes the oil from the block, you might have to remove the heads to do this!
I don't know what size the restrictor need to be, I think in Des Hamills book he talks about this but it is the sort of thing that you need to be careful with, if you get it wrong you will ruin the rocker gear!
I don't know what size the restrictor need to be, I think in Des Hamills book he talks about this but it is the sort of thing that you need to be careful with, if you get it wrong you will ruin the rocker gear!
Yes when I built the engine up I used new rockers but aftermarket ones, and at the time I read up that this could lead to bad tolerances in the rockers. Also would excess oil cause any running problems? Reason I ask is that I'm doing all this in an attempt to solve a hunting issue and I'm clutching at straws tbh.DaveEFI wrote:Too much oil in the rocker box would suggest incorrect bearing clearances between rockers and shafts to me.
Mmmm not sure I fancy that to be honest,sidecar wrote:Shims make the valve train geometry bad and it is not all that great to start with, if you want to restrict the oil flow to the valve gear then you could fit a restriction in the drilling in the head which takes the oil from the block, you might have to remove the heads to do this!
I don't know what size the restrictor need to be, I think in Des Hamills book he talks about this but it is the sort of thing that you need to be careful with, if you get it wrong you will ruin the rocker gear!
Hi
why do you want to restrict the flow? Ok it is messy when you take the rockers off, but that isn't how you run the engine normally. Any excess oil will cool the heads and top end a bit as it runs down inside the engine. I think I would just leave and take the extra top end cooling.
best regards
Mike
why do you want to restrict the flow? Ok it is messy when you take the rockers off, but that isn't how you run the engine normally. Any excess oil will cool the heads and top end a bit as it runs down inside the engine. I think I would just leave and take the extra top end cooling.
best regards
Mike
poppet valves rule!
- topcatcustom
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- topcatcustom
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Hi
what is the car to be used for? street use, round and round circuit stuff, drag racing hill climbing?
Street use then you should be fine
Circuit stuff then maybe restrict it but you would be better off increasing the sump capacity and adding some baffles if you think it could be running short of oil whilst running.
Hill climbing again bigger sump and add more baffles, probably polish/paint the valley and inside the lower block and restrict a bit.
Drag race definitely don't restrict, if possible get more oil up there to cool the top end whilst running and again paint/ polish the valley and lower block add a bigger sump and maybe a couple of baffles.
best regards
Mike
what is the car to be used for? street use, round and round circuit stuff, drag racing hill climbing?
Street use then you should be fine
Circuit stuff then maybe restrict it but you would be better off increasing the sump capacity and adding some baffles if you think it could be running short of oil whilst running.
Hill climbing again bigger sump and add more baffles, probably polish/paint the valley and inside the lower block and restrict a bit.
Drag race definitely don't restrict, if possible get more oil up there to cool the top end whilst running and again paint/ polish the valley and lower block add a bigger sump and maybe a couple of baffles.
best regards
Mike
poppet valves rule!
If the heads are filling with oil there is too much oil getting past the rocker gear. This is one of the problems that leads to the old fault of oil seeping out of the rear corners of the rocker covers and onto the exhaust.
Best option is to rebuild the rocker gear so it does not gush oil. But if you want to fit a restrictor you can tap the oil holes in the heads and fit some small allen bungs with 1mm holes drilled through them. Some folk use roll pins and tap those in. There are many ways to fit a restrictor of some sort in those holes. This would be a short term fix for me. Although some folk I have done this for as a short term fix have still not fitted new rocker gear and have been running like this for a few years now.
The more oil thats gushing out up top means less oil lower down along with lower oil pressure ?
Best option is to rebuild the rocker gear so it does not gush oil. But if you want to fit a restrictor you can tap the oil holes in the heads and fit some small allen bungs with 1mm holes drilled through them. Some folk use roll pins and tap those in. There are many ways to fit a restrictor of some sort in those holes. This would be a short term fix for me. Although some folk I have done this for as a short term fix have still not fitted new rocker gear and have been running like this for a few years now.
The more oil thats gushing out up top means less oil lower down along with lower oil pressure ?
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
I had the same problem on my rv8,lots of oil in the head after using aftermarket rockers(the oil grooves are too deep in them)at idle I had 14 psi oil pressure, so I got some brake pipe(which happens to have the same dia as the oil hole in the head)and tapped it in thus reducing the oilway to about 3mm.oil problem cured and my oil pressure leapt uo to 45 psi at idle,which as far as im concerned is better for the mains,big-ends and cam bearings.works for me.