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Oil Pressure Relief

wh1278

wh1278

Member
I have read several older posts, but I still have this question. Both my 440's after rebuilds read higher than anticipated oil pressure. I first had them pegged at 80 psi, and discovered they rebuild guy put on single station senders on my dual station boat. I replaced the senders, but am still getting somewhere between 65 and 80 (hard to read on guage). Not pegged, but high at all RPMs. I've changed the oil, and had a manual check done to validate the gauges. Now the question. Do I pursue the replacement of a spring in the oil pressure relief value (if so where do I find one), or should I consider one of these adjustable gizmos on 440source.com: http://store.440source.com/Adjustable-Oil-Pressure-Regulator/productinfo/200%2D1093/

For any that cant pull up the site, here is what it says:
Our new adjustable oil pressure relief valve is a great accessory for your big block Mopar. This unit simply screws in and replaces the original plug which holds in the oil pressure relief plunger and spring. This plug is drilled and tapped in the center with an adjusting screw which can be screwed in or out as desired. The screw is surrounded by a special liquid tight o-ring seal to eliminate leaks, and held in place by a ny-lock nut & ARP washer. Screwing the plug in will put more pressure on the relief spring and raise the oil pressure, while screwing the plug out will release the pressure on the spring, and cause the oil pressure to drop.
 
Any warranty still in effect? This would surely void it.
The Source part sounds like a good way to go if you want control on pressure. However, I would recommend using a known good mechanical gauge to set the reliefs.
 
"Min pressure 8# at idle All models"


Interesting, Chrysler low oil pressure cutout switches were set at 15# (P4120223)
 
My 440 manual indicates 45 - 65 lbs @ 2000 rpm. No lower than 20 lbs @ idle. Pressure drop due to clogged filter 7 - 9 lbs.
 
80 or 90 PSI in a BB Chrysler is just fine. If someone rebuilt the engine, or replaced pump with a high volume / high pressure pump, that is exactly what you would see. Oil pump is externally mounted on these engines and very easy to change and oil filter spins directly onto pump, unlike GM or Ford engines which are internally mounted. Putting a Milidon or a Mopar Hemi oil pump on was 1st change you made to the Chrysler big block family, 383, 400, 426 Wedge and 440 engines to get extra oil pressure (above the stock 45-60 psi) and/or extra volume. Only problem with the high pressure, make sure you use a VERY GOOD filter, such as a K&N or something like that. I have seen cheap oil filters blow apart, such as Fram, from the high pressure, especially on the performance Ford 460's, which ran quite high pressure also.
 
Last edited:
daves69 said:
"Min pressure 8# at idle All models"


Interesting, Chrysler low oil pressure cutout switches were set at 15# (P4120223)
Click to expand...

If I ever saw 8 psi on a big block Chrysler, I would be pulling the engine to replace the bearings. Never saw one that low when everything was "right".
 
"80 or 90 PSI in a BB Chrysler is just fine."

Probably need a hi perfomance oil pump drive to keep that hex from shearing off (P3571071).

FWIW,
Mopar RB Oil pump springs Red = 45-65#
Black (Hemi) = 55-75# (P4286571)

"If I ever saw 8 psi on a big block Chrysler, I would be pulling the engine to replace the bearings. Never saw one that low when everything was "right". "

I think I'd check a few things first before pulling out an engine. Sounds like you may not have had an oil pressure relief spring fail or stick wide open.
Maybe analyze the oil and filter also. Maybe even check for a clogged oil pickup screen from all the old valve seals.
 
I believe the oil pressure is too high. I changed the oil to Delvac 1300 Super 15w40 Diesel oil (recommended by guy at autoparts for my older 440). Now I get the oil smell I didn't have before, and the gauge is pegging at 80psi, even after running it awhile. Also, I started it up today and it smoked out the exhaust for a good 10 seconds (looked white, but could have been blueish). The oil level is not above the fill mark, and i don't believe it is burning or leaking coolant. I pulled the a couple plugs and they look oily. I also put new plugs in at the oil change and set gaps at .035 (per manual). So, questions I have:
1) Do I have the right viscosity oil (didn't smoke and smell before with the old sludgy oil, but I don't know what oil the shop put in there when it was rebuilt).
2) Do I open the gaps a little more to burn a little hotter (have 160 thermostat in there now and it is running at between 140 and 160)?
3) Do I search out one of the red pump springs mentioned above (only can find the high performance 75+ springs to RAISE pressure...I want to lower it to 45-65 per manual)?
4) Do I start troubleshooting the pump for clog issues or something?
5) Do I buy one of those adjustable relief gizmos and just dial it down?
I had a mechanic test the oil pressure with a mechanical device last summer, but dont know the results. Do I do that again to validate I am really getting 80+ psi...even at idle?
 
The NASCAR boys run only 30 pounds oil pressure during qualifying, to reduce pumping loads--anything for a bit more speed. And they are turning over 9,000 rpms all around that 2 1/2 mile track!

So much for the need for "at least 20 pounds" oil pressure at idle.

Jeff
 
Fastjeff, I agree, and had read an earlier post of yours about potential damaged to bearings...if pressure too high. Just trying to figure out how to get it down. Where do I find a spring that can bring it down? Like the red spring daves69 mentions above? Googled it and couldnt find it. What about the oil, is that ok to use in SoCal on a 440, recently rebuilt?
 
The "red" spring would be a "stock" pump spring in most BB Mopars. You might try calling an older Chrysler dealer PN 1737742. Check here...........
http://www.collectorsautosupply.com/query.asp?section=ENGINE&year=0&make=Plymouth
Hit Ctrl F (at the same time) to bring up the search box. Copy the PN into the box.

Maybe even find a used one.
One note, an old trick to increase oil pressure was to add washer(s) to the spring load. A rebuilder wouldn't do that, would they?

Melling has a pump kit (doesn't say whats in it) and complete pumps (HV and HP) see page 36 in the pdf here..........
http://www.melling.com/Aftermarket/PartsLookUp.aspx

Check with NAPA also.
 
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