3/8" VS 1/2" Oil Pickup

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RustyRatRod

RustyRatRod

I was born on a Monday. Not last Monday.
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How important is going to a 1/2" oil pickup in a big block? Mine will be stock stroke 383, 10.5:1, in a 65 Coronet. 727 with around a 4K stall and 4.56 gears. Street car and MIGHT race it just to see what it'll do. I plan on running the Milodon 7 qt. pan and the Jegs windage tray. I will be using the MP high pressure and high volume oil pump. Most I'll ever spin it is probably 6500 and that would only be through the traps, which probably won't be much or IF at all.
 
Are you using half or full grooved main bearings?

One of my Big Block books says the stock 3/8" pick-up with standard volume oil pump and half grooved main bearings is good for around 6000rpm.
Another book says with 1/2" pick-up and high volume oil pump, is good for 7000rpm.

Its not going to hurt anything going to the bigger pick-up. Just have the machine shop do it when the block is still there. I would start with a standard volume oil pump, and if the oil pressure isn't as high as you would like it swap in a high volume pump. Pumps on the outside and not that hard to get to. No pointing in using a high volume pump if you don't need it, your just wasting power then.
 
I have full groove main bearings. I can do it myself. That's not the issue. It's the extra cost. If it can go without it, I'll do it. If it would be better with the larger pickup, I'll have to wait. I am trying to keep SOMETHING and I think the Coronet is what I have the most parts for.
 
If you can do it, I don't think any help on the suction side hurts you. I don't like full grooved bearings with the 3/8 pickup myself. I run 3/4 groove, keep the clearances on the "tighter" side of the specs (.002), and don't use the HV pumps. That has proven fine on various street builds up to about 580hp and rpms in the 6500 max range. So I think if you're going with .003 clearance and full grooved you should get the larger pickup. You can also just use the external feed and swinging pickup - that would more than cover anything you throw at it.
 
I will probably run the 7 quart pan, 3/8 pickup with windage tray. I don't think there's any way in hell it'll get hurt. At least not by lost oil pressure or volume.
 
In my experience and in agreement with some engine manuals - the sticking point is the sharp turn in the block above the pickup on the suction side. You can use a ball shaped rotary file to round the inside of the turn off - it goes a long way to help the suction side with the smaller pickup. At least then it's the pickup that's the restriction. I'll also enlarge the feeds to the mains to 9/32. If the oil clearances are good (and not huge) it will be fine. If the oil can escape out big clearances you may have a delivery problem because that pump will pull a LOT of oil at higher rpm.
 
I can tell you my experiences We (the Mopar shop,I wrenched for),picked up a stock 60,000 mile 69 383/335 Magnum. No ridge ,in the bores. The customer, wanted a stock ,strong re-ring. The first thing ,the boss said"1/2 pick up".On a mild hyd cam re-ring,spinning 62,6300. The engine ,still alive 15 years later. My story, sticking to it.(7qt pan).
 
I don't think you would have a problem. If you were running 7k+ and had the full grooves and had a leakey top end (Harland sharps bleed a lot of oil on purpose) etc then you might have to worry about it.

But you are not going all out. Winding it up like crazy. Mud racing. Etc.
 
My 383 has a Milodon pan,and a high volume pump and the rest of the oiling system is stock.I turn it anywhere from 6500-7200 RPM with any issues.
 
pump basics, they like a big suction. i would never build any kind of big block that i would twist without atleast a 1/2" pick up.
 
Can't recall if it was Mike who recommended it to me or not, but I know someone recommended me to open up to 1/2", and I probably won't even spin my 383 that high, and won't have that much squeeze...well, when I finally get back on the mainland to build it...
 
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