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@vlad - yeah that is the info i have been working off for mods.

as for the oil pickup, the ID of the pickup is ~14mm and then goes into a dash 12 i think it is, which measures about 15-16mm ID, i don't believe this is the issue, more so a lack of oil pressure or smaller orifices after the pump. and i did think of going to a thinner oil type.

pretty sure the feed from the oil pump up to the main gallery is smaller than 1/2 in.

I have always run 10w40 or 15W50 in most of my cars except the shitbox which just gets the cheap mineral oil which pretty much only comes in 20w50/60.

At least with one engine from the vacationer years ago run pretty much exclusively on 10w40 and on the tear down at 400k (bought the engine with 90k) the bearings were pretty much perfect, mains certainly were, some rods had a slight lop sided wear to one side but no lines or scores in them. That engine was constantly pushed to the limit so thinner oil is fine and probably better than thicker stuff when pushing revs.

I know my local mechanic always uses thin stuff in the ford 4L and barras because thicker oil which many people think is good for them causes the hydo lash adjusters and chain tensioner to stop work properly making the engine noisy because they aren't getting the flow even when pressure reads higher. Thicker oil has it's place in performance engines for sure but they have to be built for it just like an engine that needs thinner oil.

Bummer that hurts. Many years ago with Ford's we had a problem with the big ends running out of oil and we drilled and tapped the oil passage going up to the cam and fitted restrictors because what was happening the supply couldn't keep up with the bottom end at high RPM. The crank turned into a centrifugal pump throwing off more oil than the supply. By reducing the amount that could get to the top of the engine provided more oil for the crank. We also machined a groove on the mains on the crank. Hope some ideas might provide food for thought. My guess is you already have a high volume pump fitted.

Fitting restrictors is definitely the way to go, that way you get to decide how much goes where instead of relying on the clearance to regulate the flow.
I've read about fitting ball bearings to cams to avoid having to supply oil to them other than a bit of splash lube, but that's obviously a lot of machining and probably isn't compatible with your motor.

What about engines that have the cam fed first then mains?

What engine is that? Every engine I have worked on feeds the mains first then off to the big ends with another branch going to the can etc.

yeah my engine machinist said about tapping a thread and fitting a grub screw with a hole drilled in it for the cam feeds too ... probably something worth looking into!

and yes i have a high volume pump ... i guess the fact its maxing at 35-40psi might indicate i just need to bump it up a bit, but also all the enlarging of orifices and such should all help.

I like around 50-60 psi oil pressure. 30 is getting a bit risky. If only you could see inside the engine when it's reving it's nuts off. Considering it was failing it still went really hard.

Charlescrown wrote:What engine is that? Every engine I have worked on feeds the mains first then off to the big ends with another branch going to the can etc.

Pretty much most GM V engines.

Well I guess on those engines theres little you can do. I wonder why they did it that way. Every V8 I have ever done and it's probably a few hundred all fed the oil to the mains first.