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my 408 & my 418 have both been very slow building oil pressure at start up. win. block, SVO- N heads,full roller system, 4340 crank, H-beam rods, 11.7 pistons,melling hi-valume oil pump, rocker girdle, & main cap girdle, I allso use the thicker fel-pro racing head gaskets. I have wounderd if its the oil pump. every one I talk to doesnt have a clue. this makes me very nerves......! anyone out there have the answer as to why these engins have both done this. P.S. tried replacing oil pumps 3or4 times & oil psi. 50 to 60 depending on oil temp. also tryed differnt filters.
 

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Can you explain when you say slow to build pressure?..My 408 only sees about 50psi when cold which seems fairly typical for these engines..
 

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50 psi at idle is FAR greater than necessary. But if you're going to spin 7K you better have upwards of 80 psi when the RPM's go up that high!
Fully agree that 50PSI at idle is not needed. 20-35psi would be considered a norm.

Now as far as the [email protected], that is pure fantasy based upon an obsolete rule of thumb. Pressure needed is based upon bearing clearances used and any excess is bypassed.

To the OP, are you sure that all 3 plugs are installed under the timing cover and especially the one found at the rear of the lifter galley under the intake manifold?
 

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Both engins wereasembled by race engin shops,but if you are refering to oil gally plugs they are in. The OP I understand as you said less friction more HP. But the slow rise in pressure drives me nuts.I question the 50W racing oil, thehigh valume oil pump, the filters, even the fact that its a full roller. I ranthese in An otlaw street stock dirt track car. Their are no real ford engin builders that I know of close to me hear in eastern OH.
 

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Your problem is not a big deal. The issue you are having is with the mechanical guage, you are probably using the supplied oil feed line and they are WAY too small. Use braided brake line to your gauge, it is way safer and the gauge will rise and fall with engine rpm as it should. I have dealt with this complaint several times over the years and the larger line ALWAYS fixes it.
 

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Both engins wereasembled by race engin shops,but if you are refering to oil gally plugs they are in. The OP I understand as you said less friction more HP. But the slow rise in pressure drives me nuts.I question the 50W racing oil, thehigh valume oil pump, the filters, even the fact that its a full roller. I ranthese in An otlaw street stock dirt track car. Their are no real ford engin builders that I know of close to me hear in eastern OH.
50 wt oil !
here's a clue to the problem ..... wheel bearing grease flowing at 35 degrees below zero ...flows great at 625 degreesabove zero
 

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If you can get your oil pressure to come up faster when cold with 10-20/40 or 10/30 then use it.
I see no reason for 50 weight unless you are maxing out every teeny tiny HP you can manage and running alcohol and turning 9000 rpm or something radical like that.

But even with 50 weight there is no reason it takes 60 to 80 seconds to get pressure.

If the lesser weight oil don't prompt an almost immediate normal oil pressure reading, then you probably need to take that motor apart and measure everything for clearance.
 

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Is the heavy oil required for your engine? e.g.--loose clearances, a pan that isn't really up to the job? Sometimes it's a necessity but usually only in circumstances where a stock pan must be used and the engine spins high RPM for a good while (where oil temp will get up there and stay there). Usually a dry sump would cure those problems but anyway...

What kind of clearance do you have on the mains & rods? Cam bearings oil clearance? How far is the pickup from the bottom of the pan? And is there a gasket on the pickup tube?

50 wt oil is going to take longer to build pressure because it's thicker. The pump has to SUCK the oil from the pan before it can move it through the passages. Then once it hits restriction, it will build pressure. If there is any leak between the pump & pickup, it'll take forever and a day for the pump to prime. Once it does, it has a tendancy to aearate a little more which is not the greatest situation for the bearings. Then since it's thick, it's not going to want to flow to the restrictions quite as well, so it'll take longer than normal to build pressure. I have always had the best luck with synthetic 20w50. Year round. Oil temps stay down and pressure is rock steady at 55 psi no matter what RPM (from 1400 idle to 7800)

Where are you taking pressure from? Front of block by the filter or?

Have also seen pressure relief valves STUCK in the Melling pumps. And a LOT more often lately! Dad's stuck SHUT and exploded the oil filter (and gauge), then oiled the tires and he went over the wall. Destroyed the car but engine & trans were ok. I had one stuck open on my meth 438" and it would build pressure slowly and then it stayed lower than normal (40-45 psi). Pulled the pan/pump and fount a stuck relief. Replaced the pump with one I had already "worked on" and all has been well.

50-60 psi is plenty with these engines unless you're running Nitro, nitrous, or boosting the heck out of it with loose clearances and in those cases, you'd better be changing bearings often anyway.
 
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