What pump are you using? More importantly what oil pan? Sounds to me like an oil starvation problem.

 

What oil pan and pickup. What stroke crankshaft? What pressure are you seeing?

 

You need to be more specific in part numbers and stuff. I ran a 540 with a Moroso 20403 pan and a Melling M77H pump, though it was not optimal, I never hurt anything. I DID see on the dyno that with that pan over 6500 it started to lose oil pressure probably from windage. But nothing drastic to the point of hurting parts.

 

I fought oil return problems until I ran a -10 line from the back of the heads down to the pan on both sides. At high RPM the pan would simply pump into the valve covers and in my case with AFR heads where the drain holes simply arent big enough it would load up the top end. 6500 RPM with a foot on the throttle I'd watch that gauge hit zero. Ive seen plenty of top name engine builders swear the BBC won't fill the valve covers up and suck the pan dry . They are full of crap. Restrictors or a drain line back to the pan.

 

I am using a M77HV pump. I did have a Milodon 7qt. Oil Pan, and the corresponding Pickup. I now have a Summit Oil Pan which is the same capacity and depth. I am using Brodix BB2 heads, and I do know oil will sit in the passenger head because it runs down the side of the motor when I take off the Valve Cover. I do have Oil Galley Restrictors. I am using a remote filter due to header clearance. It has -8 lines, and I have verified they are indeed flowing the correct direction. Also, the oil filter adapter on the block has no bypass, so I do not believe pressure loss can occur there. I have used this same filter remote and lines for years on my SBC's with no issue. I feel the BBC should be no different.

 

Pull that HV pump and put a standard volume. BBC's dont oil like SBC's.

 

Hv pump is not your problem and you don’t want restrictors with a roller lifter. My last engine had 75 psi oil pressure to 7500 with a moroso 21049 pan hv pump and no restrictors. It won’t suck the pan dry. If you return the same amount of oil to the pan as it pumps you’ll be fine. If you’re not, that is not a reason to starve the engine of oil because it’s not returning fast enough.

 

finally! no restrictors.

 

What filter are you using and how loose are you on the clearances?

 

What are your rod and main clearances? Might have an issue there

 

You absolutely can suck the pan dry. Yes. It happens because the oil doesnt return fast enough and thats a whole different discussion but part of the problem is that too much oil is flowing to the top end. No BBC needs a high volume pump unless your bearing clearances are shot. Best case you are using a lot of HP blowing oil through the bypass. Worst case you evacuate your pan into the valve covers faster than it can drain back.

 

Given that oil pressure increased with thicker oil, most likely explanation is that bearing clearances are probably on the large side.

 

Another vote for drain backs from the heads, just simply because they help. BBC valvecovers can hold a LOT of oil. - I personally would not run an HV pump with only 7 qrts in the pan.

The thicker oil might be telling you something, but if the gauge you're reading it from is only an 1/8" line that most come with it won't respond well with the thicker oil; meaning there may still be pressure fluctuation there that it doesn't register. We went up to 1/4" feed line and saw a difference in what the gauge reads.

 

I must be doing it all wrong lol.
I use restrictors in my big m block, I use a hv oil pump and I have Isky bushing style lifters. I use a -4 oil pressure line, the engine has sufficient oil pressure at all rpm's and has been pretty reliable for quite some time now. I use Lucas 10w40 synthetic racing oil
Oil pressure is 70 ish @ rpm and 40 @ idle hot. I am using the Moroso 20412 pan and run 6 qts including the filter.
little afr roval port 565.

 

The -8 lines may definitely be an issue, Mercruiser uses a remote filter stock and they use -10, most dry sump and remote wet pumps use -12.

To me, .003-.0032 would be a tad loose for 10w40, would consider 15w40 or 20w50 there myself but I've always liked a bit thicker oil anyway.



Restrictors in a Dart block?? Not sure why when it's priority oiling, guessing you use the allen headed ones and put them in the front then?

 

Thanks for all the input so far. I am using a NAPA Gold filter, which is made by WIX. I looked up all of the flow rating for oil filters and it flowed with the best of them. My bearing clearances were ground to .003".0032". I also measured them before assembly.
I already have a 1/4" tube on my oil pressure gage, it's been on there since the 90's. I do realize the bearing clearance is a little tight for 50W, but I was checking to see if it changed much before pulling it out . If I take the restrictors out, will it not pump more oil to the top end through the valve train? Also I did state earlier, there is no bypass on my oil filter adapter on the block. I do know some people use -10 or -12 lines on the remote filters, that being said, would my -8's be a restriction?

 

Thanks for all the input so far. I am using a NAPA Gold filter, which is made by WIX. I looked up all of the flow rating for oil filters and it flowed with the best of them. My bearing clearances were ground to .003".0032". I also measured them before assembly.
I already have a 1/4" tube on my oil pressure gage, it's been on there since the 90's. I do realize the bearing clearance is a little tight for 50W, but I was checking to see if it changed much before pulling it out . If I take the restrictors out, will it not pump more oil to the top end through the valve train? Also I did state earlier, there is no bypass on my oil filter adapter on the block. I do know some people use -10 or -12 lines on the remote filters, that being said, would my -8's be a restriction?

How long are the lines......??

I'd say so, I'd be minimum -10 for sure and if they are reasonably long them -12.

what size restrictors you got in it....??

 

The new AFR heads are cast by Edelbrock. For some fucking reason they cast little bumps right in front of one of the drain back holes. On these little bumps they engraved AFR. On the head where the bump is to the rear of the head I have to suck out the oil with a syringe so I don't get oil all over when I pull the valve covers.

 

That and the drain back holes are much smaller than any of my other heads. A -10 drain back line completely solved my drain back problem. Funny thing is that in the AFR instructions they plainly state that you may need flow restrictors or the valve covers may fill up with oil and drain the pan.

 

I had a good thread on here about bbc oiling issues. I think that it was "620" bbc oiling problems". There was a lot of good posts to it and it is good reading.

 

Buddy you need a plumber!

If I am reading your last post correctly. You indicate you are running a remote filter with #8 line size!

EEKS I would never begin with anything less than #10AN and I always use #12AN size remote oil lines and a large HP6 type oil filter that can flow a lot of oil per minute with no bypass! Also make sure all your an fittings that change direction at 45 or 90 degree are radius bends not hard angle only fittings.

Remember oil flow is a product of volume and pressure and line size, pressure alone is not the only good measure of oil flow. This is one reason you are probably thrashing your bottom ends and such. You are not only getting pressure drop but you are restricting volume of oil in flow to necessary areas.

I would also recommend you install some windage control in the pan and under the crank to make sure you are not whipping up oil malts full of air and dropping pressure. Pumps, oil pressure springs, oil weights and restrictors do not alone make for good engine oiling!

 

A friend of mine ran -8 lines to his remote filter as well as non radialised 90* fittings and his oil pressure was a disaster. Trashed bearings.

 

Priority oiling or not it will still pump enough up through the pushrods to fill the valve covers with oil faster than it can drain back to the pan.

 

Actually it gets adequate oil for the rockers and nothing excessive up top at all. I've enlarged the vents in the middle of the afr heads which appears to be useful.

 

I have a new Dart BBC block and new AFR 357 CNC heads. No oiling issues. 65# steady oil pressure at speed hot. 35# at idle hot. 9.30s at 142 MPH.

No restrictors in the block. Melling Select +25% high volume pump, Moroso Street/Strip G body oil pan and pick up. 3/8" pick up to pan clearance .0035" main bearing clearance. .0028" rod bearing clearance. Steel rods. .018" side clearance. Just basic bracket race stuff.

Built a few like this with no problems

 

9 seconds without any problems huh. Now try tooling down the road at 80-90 MPH at 4500 RPM for a a few miles and then stomp on it for a few minutes. Watch that oil pressure gauge hit zero. Then let off and see the gauge bounce a bit then nail it again and see it drop to zero again..

Its not a good feeling.

 

As far as oil, I use 20-50 Brad Penn. Lifters are Morel solid roller. No lifter bore clearance issues with Dart block.

 

I think there is a confusion of terms here but its describing the same thing. HV pumps have been used forever and are still used today. There is the theory that HV pumps can pump a pan dry. Its not that the pump is pumping the pan dry. Oil is not returning fast enough to the pan. I will agree that an HV pump is NOT really necessary. A lot of engine builders get by with a standard volume pump and increase the pump pressure. However a pump will only pump the volume that the engine can leak out on its way to the last port. Meaning that all the restrictions and tight clearances in the engine dictate how much oil will flow. The tighter these restrictions are the more restriction to flow and the more drag the oil pump will put on the engine. This is the downside to an HV pump. When you can't return oil to the pan fast enough, it APPEARS the pump sucked the pan dry. When in reality, its the drains. You need to fix the drainback, not reduce oil flow. Now granted there is HP in windage losses so too much oil is not a good thing either, but cooling of components and long term reliability is more important to me than a few extra hp in a bracket engine.

 

One thing that HV pumps ARE good for is if you are using pressure fed trunnion oiling roller lifters or EDM flat tappets. Those things blow enough oil out to cause a significant pressure drop at idle . Figure 16 .023" diameter leaks all spraying oil at the same time.

 

The lifters are equal to 1 .093 open hole.