I had my mechanic build a 460 for me a year ago. Just got the funds to do final install on my 1977 f250 4x4 with a c6. Motor sounds great. Idles fine. However, running the truck at 50+mph for longer than 5 minutes causes oil to pour out the dipstick tube, Pcv valve, passenger valve cover on the side, and drivers valve cover at the rear. Mechanic says oil pressure is fine and motor temperature is in the safe range.
Here's a list of what was done to the motor during build.
-Block and heads hot tanked/checked for cracks.
-Heads rebuilt/resurfaced(3 burnt valves)
-Block was not bored. Still had cross hatch marks from factory.
-New rings. Same pistons.
-New camshaft
-New timing set
-New 7 qt oil pan
-New standard oil pump
-Edelbrock performer intake
-Intake sealed with gaskets on the sides and silicon on front, rear, and around water jackets.
-Pcv valve on passenger valve cover. No fresh air intake on drivers side valve cover.

Anyone know why this is happening?

 

PCV valve is new?
What cam did you put in? What RPM's are you hitting at 50?

This sounds somewhat similar to my first attempt at my rebuild. I wasn't getting oil blowout like you, but I didn't bore it out and started getting blow by on a couple of cylinders.

Too much oil in the new pan?

 

Pcv valve new and working. Installed breather this week. No tach, so I have no idea what rpms at 50. It isn't screaming at 50. Runs smooth. No idea what cam. Mechanic built it. Compression test today. Numbers between 115 and 120. Motor run barely an hour. Rings are NOT broke in yet.

 

New 7 qt oil pan with 7 qts of fresh oil.

 

You have yourself a pickle there.

Compression seems a little low, but i could be mistaken there also. Did you do a leak down test?

Why no fresh air intake on drivers side cover? Is it blocked, or capped off?

 

I installed fresh air breather. Mechanic is determined it has something to do with the 7qt oil pan. He wants to remove 2qts and see how it runs then. This doesn't sound like a good idea to me.

 

Seems like a strange idea to me also. Did you use the stock oil sump?

I'm not very familiar with the oversized pans, but that may be part of it.

I didn't think to ask you before, what oil are you running?

You should be running a 10-30 syn, or conventional with a zinc additive.

 

Is it just a deeper oil pan? What was the original oil amount, 5 Qts.?
What does the dipstick read now, on level ground, after being shut off for at least 10 minutes or so? Original dipstick and dipstick tube, I assume.

If there IS too much oil, the crank could be beating the bejesus out of the oil, foaming it up, the foam will expand everywhere.

Another idea is that for some reason, oil isn't returning to the crankcase fast enough and is pooling up on top of the heads. Drain holes on top of heads under the valve covers restricted somehow? That could explain all the oil coming out up top, but would not explain oil coming out of the dipstick tube opening. Oil out of the top of the dipstick tube sounds more like the oil foaming issue.

 

Talked to actual Ford guy who is a machinist. He says the synthetic oil I'm running is most likely the problem. The rings will not seat with the oil I'm running. I'll try running a regular/non detergent oil with added zinc. The rings are not seating, causing massive blowby. If this doesn't work, I will be getting a book and tearing the motor down myself! -Oil pan came with its own dipstick. 7qt pan.

 

Update: Drained the oil and changed the filter. Added 7 qts of 30 wt with no detergents. Motor stopped puking oil within 2miles of running it in 2nd (automatic tranny). I ran it another 64 miles at altering rpm levels and speeds. Oil level never altered. I think it's safe to say that the rings finally seated! I can't wait to get the rest of the truck rebuilt. That motor has piles of torque. I still can't believe it. Holy.....cow!

 

Good to hear. When i rebuilt my first 460, I put the bottom half of the rear main in backwards...

Your problem was easier to fix!!!

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Don't do this!!