Top End Oiling Issue – SBC

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rebelyell
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Re: Top End Oiling Issue – SBC

Post by rebelyell »

You have a problem that's causing this ... here's a band-aid (not the cure)

old stock class racing mod for stock stamped rockers is to weld a thin somewhat triangular piece across top of rocker directly above PR hole ... helps direct more oil down to pivot ... rather than first squirting onto the valve covers ...dunno how welding works w/ CC cast steel rockers.

not a fan of grooved balls ... grooves lessen surface area ... have lapped in balls w/ rockers on bench. Ya still got a problem though.

? with 145 on seat, perhaps you need short-travel lifters rather than stockers ? dunno ?
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Re: Top End Oiling Issue – SBC

Post by gridslammer »

You can also check if the radius of the pushrod matches the radius on the rocker arm. Some of the aftermarket harden pushrod won’t match a stock style rocker and cause a oil hole alignment problem.
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Re: Top End Oiling Issue – SBC

Post by btwick »

Thanks all for the tips.. Have checked push rod to rocker alignment, and all looks good. If there was more volume coming out, might consider the Moroso oil diverter plate, or tack welding small plate (a permanent version of those valve adjustment clips), but thinking something else is the culprit. Might pull the cam to check bearing placement, but not there yet...
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Re: Top End Oiling Issue – SBC

Post by prairiehotrodder »

if you put it together dry (no oil on the pivot balls) the oil from pre-lubing may have been wiped away and the damage started instantly on start up. Then once the heat / galling starts its to late. It can only get worse. On my engine i mentioned, the pivot ball wore right through the stock rocker arms. Then when i switch to the comp magnum rockers the problem started all over again. I'm inclined to think the oil doesn't have the right additives or something. There was tons of oil coming to the top, it just didn't work. Still a mystery.
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Re: Top End Oiling Issue – SBC

Post by btwick »

prairiehotrodder wrote: Tue Aug 03, 2021 3:00 pm if you put it together dry (no oil on the pivot balls) the oil from pre-lubing may have been wiped away and the damage started instantly on start up. Then once the heat / galling starts its to late. It can only get worse. On my engine i mentioned, the pivot ball wore right through the stock rocker arms. Then when i switch to the comp magnum rockers the problem started all over again. I'm inclined to think the oil doesn't have the right additives or something. There was tons of oil coming to the top, it just didn't work. Still a mystery.
Brian
Have heard more than one person not like grooved pivot balls as they reduce contact area, but the Comp Magnum rockers come with grooved balls.

With your situation, having lots of oil but same issue, would consider the possibilities of a lack of zinc in your oil, and perhaps overly stiff valve springs...

Spoke to an engine builder who commented the Magnums are prone to heating/galling.
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Re: Top End Oiling Issue – SBC

Post by prairiehotrodder »

every one of my mild flat tappet cam motors gets a jug of Lucas cam break - in additive that is supposed to have zinc. I haven't had a any cam failures. Just the rocker failures on one engine. It was a 350 with E-street heads and the smallest comp thumper cam. It was a great motor with lots of power and the customer was real happy once we got the rocker arm problem sorted out.
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Re: Top End Oiling Issue – SBC

Post by smeg »

Just put some roller rockers on and forget about it.
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Re: Top End Oiling Issue – SBC

Post by BillK »

bt,
Was this engine definitely an original roller engine with a roller cam in it when you started ?
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Re: Top End Oiling Issue – SBC

Post by cpmotors »

High flow OP (HV?) and 25psi at idle and 65 would indicate you have internal leaks , reducing restrictions (large clearances) and pressure to force oil to the top end.
I'd start with basic oil control issues.
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Re: Top End Oiling Issue – SBC

Post by btwick »

BillK wrote: Tue Aug 03, 2021 9:06 pm bt,
Was this engine definitely an original roller engine with a roller cam in it when you started ?
Yes, this was a bare block received with the project. 1995 and up OEM roller block, with one piece rear main, and the holes drilled for the spider clamp. Purchased all the internals separately.

Thanks CP motors. Yes, that could be not be enough pressure due to a leak somewhere. Found an engine builder, different than the first one, who has offered to diagnose the issue, likely with some disassembly/reassembly. Was hoping for a smoking gun that I could fix, but not looking likely.
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Re: Top End Oiling Issue – SBC

Post by Dave Koehler »

A few years ago I put a set of those comp roller tipped rocker ball things on a BBC 454 truck engine rebuild (mine) and had no oil to the rockers.
Hyd cam, oem length pushrods. Just your everyday BB towing duallie.
After much screwing around I loosened the lash up to basically zero while running and the oil began to flow.
I didn't have time to cypher out the push rod length to fix this. Just assumed the oil hole position or socket height in the rocker was positioned wrong or something.
Put some new stock rockers on and drove on.
Probably the same deal / fix here. push rod length, valve stem height, etc
Tolerance stack up strikes again.
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Re: Top End Oiling Issue – SBC

Post by BillK »

btwick wrote: Wed Aug 04, 2021 12:04 pm
BillK wrote: Tue Aug 03, 2021 9:06 pm bt,
Was this engine definitely an original roller engine with a roller cam in it when you started ?
Yes, this was a bare block received with the project. 1995 and up OEM roller block, with one piece rear main, and the holes drilled for the spider clamp. Purchased all the internals separately.

Thanks CP motors. Yes, that could be not be enough pressure due to a leak somewhere. Found an engine builder, different than the first one, who has offered to diagnose the issue, likely with some disassembly/reassembly. Was hoping for a smoking gun that I could fix, but not looking likely.
The reason I ask this is because some of the early blocks had the tops of the lifter bores "counterbored" about 1/4" and were used in flat tappet engines only. On those blocks the oil band in the stock type hydraulic roller lifters will actually come up into the counterbore and bleed off oil. I found out the hard way when I did an engine for my own truck. Every thing else on the block looked just like any other roller block. The holes were drilled and tapped for the spider etc. The one I did would get noisy as soon as it got started and the oil pressure would also drop some when hot :(

Not saying that this is your problem but just wanted to bring it up. I thought I had some pictures of it somewhere but they might be on my other computer at home.
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Re: Top End Oiling Issue – SBC

Post by btwick »

BillK wrote: Wed Aug 04, 2021 12:36 pm
btwick wrote: Wed Aug 04, 2021 12:04 pm
BillK wrote: Tue Aug 03, 2021 9:06 pm bt,
Was this engine definitely an original roller engine with a roller cam in it when you started ?
Yes, this was a bare block received with the project. 1995 and up OEM roller block, with one piece rear main, and the holes drilled for the spider clamp. Purchased all the internals separately.

Thanks CP motors. Yes, that could be not be enough pressure due to a leak somewhere. Found an engine builder, different than the first one, who has offered to diagnose the issue, likely with some disassembly/reassembly. Was hoping for a smoking gun that I could fix, but not looking likely.
The reason I ask this is because some of the early blocks had the tops of the lifter bores "counterbored" about 1/4" and were used in flat tappet engines only. On those blocks the oil band in the stock type hydraulic roller lifters will actually come up into the counterbore and bleed off oil. I found out the hard way when I did an engine for my own truck. Every thing else on the block looked just like any other roller block. The holes were drilled and tapped for the spider etc. The one I did would get noisy as soon as it got started and the oil pressure would also drop some when hot :(

Not saying that this is your problem but just wanted to bring it up. I thought I had some pictures of it somewhere but they might be on my other computer at home.
Thanks Bill. Just looked at an old video of the lifters when originally priming them looking for the counter bore. It had a small chamfer but no counter bore.

But, when viewing the oil coming from the lifter without the pushrod, noticed most of the oil coming out the top of the lifter around the saddle, not through the pushrod hole. Anyone seen that? Oil leaking around the pushrod cup, under the clip? Saw a couple of bubbles coming out around the cup, not through it. Hmm, perhaps 8 of the 16 lifters were assembled incorrectly, or the plunger just not sitting appropriately in the hole?
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Re: Top End Oiling Issue – SBC

Post by Dave Koehler »

The pintle valve in the middle of the lifter has to be pushed down by the pushrod via spring pressure for oil to travel through the pushrod.
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Re: Top End Oiling Issue – SBC

Post by btwick »

Dave Koehler wrote: Wed Aug 04, 2021 1:13 pm The pintle valve in the middle of the lifter has to be pushed down by the pushrod via spring pressure for oil to travel through the pushrod.
Got it. Thanks.
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