oil pressure question

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69 Valiant Kid

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what do you guys have for oil pressure? i have a mopar high volume pump. 340. only started motor a few times. seemed as oil pressure was around 70 psi the first few times i started it. now this last time i let it run for a pretty long time and got the header tubes red hot, but my oil pressure dropped to 50 at idle, then 40.....then down to 30. put it in gear it might drop a little lower than 30....but if you give it gas it shoots back up to around 70. i know about all the areas to check. but are these numbers matching anyone elses? thanks
 
For a high volume pump, that is low. Usually in a fresh engine with a stock oil system engine it will go close to 80psi cold over 3500rpm. this will drop to 70-75 hot, and somewhere between 20-35psi at idle hot. This is with 10W hot or 20W hot oil (like 10-30 or 20-50). If it's at 30psi off idle, you have a problem. Check the pickup placement in relation to the pan, and for debris. If the oil drains out with glitter, pull the rod caps on a couple rods and check the bearings. What were the oil clearances?
 
moper, I can get 100psi if I fire it up then start slamming gears while still cold at 6500rpm, but thats not the thing to do.
ALWAYS WARM THE ENGINE UP TILL THERMOSTAT OPENS, IT [YOUR ENGINE] WILL LAST A LOT LONGER.

On the HV thing, to be honest I've had the same oil pressure HV or stock in the same motor, and pretty much think the HV with a stock oil system is a waste of horsepower.
Doesn't anyone know that the more you compress the oil [HV pump] the more heat you put into the oil?
so...your eating up HP for no reason [turning the HV] and creating higher oil temps.

69 VALIANT KID, Something we all missed here that is more important is that you say you got the headers red hot, not a good thing, what kind of A/F ratio you running in that thing? did they look white at all too?
 
A high volume oil pump is designed to move higher GPM (gallons per minute) rather than higher system PSI. The oil passages within the engine didn't get larger so a little higher pressure readings are expected. That will vary with sender location too, comparing Chrysler to Ford, Chevy, any and all.
There is still a relief valve in the pumps, otherwise the oil filter would blow out.
As for the thread topic.. Change the oil and the filter then see what pressures you get.
 
Red hot headers is a bad thing. Timing is most likely retarded.

Back to your oil pressure. :) This is low for fresh engine, but it depends on how it was built too. If it was built with the intention of racing, the machinist may have set the rod and main clearances in the .0025 to .003 range. If that's the case, your pressure is ok.
 
hot is when it jumped down in pressure, everytime ive started the thing its been up there in pressure(like 60-70) but this is the 1st time ive been able to run it for awhile and actually get it up to temp. the previous times starting it, i had small problems like fuel leaks and coolant thermostat housing leaks, now that that is taken care of i was able to start this beast and keep it running. and i know for a fact that the distributor timing is off. i hope to have a older mopar small block guy come over this weekend and help me out. otherwise i might just trailer it in to our speed shop here and have them jet the carb if it needs it and do 3 pulls to really dial it in.
 
340, I'm not sure what your comment on cold revving was for... I gave cold and hot numbers.

In terms of pressures with HV vs Std pumps... Pressure reading is a measured resistance to flow. If you build for the HV pump, you'll see a drop in pressure when a std pump is put in it's place with no other changes. If you build for the std pump, you should see a higher pressure at every point right up until the pump bypasses. I know my specs are different depending on the pump and application. I also don't use HV pumps for the reasons you mention. Less heat, less parasitic loss. Same as most modern builder nowadays.

69, Did you happen to get the oil clearance specs for your engine from the builder? I'm much less concerned with red headers than low oil pressure.
 
i talked with a known good engine builder here in madison, and he said my oil pressure is just fine. i appreciate everyones concern. i might start it tonight quick just to see what kinda pressure i get at COLD start up. just to see what i get.
 
Cold means little. Drive it around hot (sanely) and see what it does. A lot in the oil system changes with heat.
 
alright, well ill prolly just have to sit in the heated garage with a lawn chair and dream about that until this comming spring. salt is down here due to the snow last night.
 
lol.. I spoke to my best friend in WI today.. He's got snow. I'll be at The Dells for New Years... Whereever they are :D. In any case, let it warm up totally in the garage... Same effect... keep a careful eye on roms, temp, and oil pressure indicated.
 
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