Trojan Boat Forum

My experience with Chrysler engines is limited to the inline 6 in my Jeep and I've done some research on my own but there is very little information out there(that I could find) regarding the whys and hows.

Apparently, there is some sort of adjustment screw or nut on the (external?) oil pump. Used in mostly in racing applications I guess, but rarely in marine applications.

If anyone has any input/info I would really like to know what I'm dealing with and how to use it properly.

Freddy, not quite sure how you would adjust oil pressure. However, why don't you tell us your concern and symptoms and we can go from there.

How many hours on engine, do you have some pressure readings from a mechanical gauge, etc..There are a few things which come to mind which will cause a loss of pressure, loss of pressure after running a while and so on...

Thanks.

I am not sure but I think that is a adjustment for the oil bypass valve if your filter clogs up but I am not certain.

You can change the pressure relief on it but thats for keeping the pressure from getting to high . It prevents high pressure from doing damage , like blowing a oil filter cold . Its not a a fix for low pressure . Low pressure can be cause by worn bearings or maybe the oil pump it self delude oil etc.


What exactly is the problem you having . you have 3 pros here responding that do this for a living .

Mike, I can't remember about the external adjustment...but that would be for pressure relief valve. The 440's pump operates somewhere between 40-65Lbs.

Tightening spring tension adjustment would allow higher psi before relief valve opened. Blown off oil filters, blown out or leaking seals, hydraulic lifters operation are some of the concerns too. Some of the racing and aftermarket applications have this adjustment for sure.

He needs to get to the root symptom and cause...

here is a link to the product on my motor(according to the PO)

http://store.440source.com/Adjustable-O ... /200-1093/
For any that can’t 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.

I haven't found much along the lines of boaters using it on their motors.

I actually did a little more research today and found the PO's profile on another forum. Unfortunately, my newest findings not only confirm my belef that he wasn't just ignorant, but actually lying to me and withholding information on the boat and it's motor's history.

Enough about that. Since I purchased the boat, I had the motor removed and rebuilt. Since the block itself was junk, that was also replaced. When the boatyard re-installed the motor it was run for just a few seconds to make sure the dist. wasn't in backwards and the plug wires were in the right places. The motor started right up and ran perfectly but the mechanic noted the oil pressure was high for idle(he didn't specify what the reading was). Based on that note, I believe that although the oil pump was rebulit, the aftermarket adjustable regulator may have been replaced or reused. Right now the boat is wrapped up and I'm not messing with running it or anything like that. When I launch in April, the same mechanic will be present to align motor/tranny/propshaft and we will obviously run it and make sure all else is good. I just want to have as much info as possible going into this.

Well then, maybe it's turned too tight. Once you commission her for spring and know more, fill us in.
Good luck.

Leave it stock or put it back stock if you can . ( non adjustable ) its just one thing more to worry about and leak .

Stay away from fram filters they can swell up under hight pressure . I like AC but K&N would be a good choice

Can you find out what he meant by high pressure
And what weight oil are you using ?

+1 on the K&N filters.

As far as the oil pressure is concerned, 10 psi for every 1000 rpm you plan on running the engine is a good rule of thumb. To high an oil pressure = excessively high oil temps = potential for oil related failure.

Good luck and keep us posted.

This is new to me. The 440 pumps I'm familiar with do not have any adjustment. There is simply a plug to cap off the boar containing relief valve componenets; spring and plunger. The pressure is preset by the spring tension. Changing the spring with that of a different tension will affect the pressure at which the valve will allow bypass of a clogged filter. I know what they're doing with that device but be carefull with it. I would not use it to remedy the issue you seem to have at this time. I think more diagnosis is in order: What was the pressure? What instrument was used to take a reading or was it a regular helm gauge rigged up to the sender or a proper tester? You said it was for a few seconds; could this be higher pressure normally associated with a new rebuild?

Spec that I have for a 440 is 45-65 psi @ 2000 rpm
7-9 lb pressure drop resulting from a clogged filter. You will change this if you mess with the relief valve.

thanks for all the responses today guys.
Not sure about the oil that's in it right now, it's whatever the guys at motortech put in it. I'm also going to read through the break in instructions that came with the motor and if it doesn't mention pressure increases at initial startup(good call Big D) then I'll go see those guys and ask them. I also agree with you guys who mentioned leaving it or putting it back to stock. it just seems like it was a band aid on a broken leg, and with 0 hours it's silly to have like prowlerfish said.
good stuff guys, thanks again.

On a fresh rebuild, don't rely on anything but a proper oil pressure tester.

Keep us posted Freddy.

Just went through a rebuild myself....Merc 350, 330hp. I had spun a main bearing on the old motor leading to a new block and crank. I have built some small block cheys in the past and had them put in a high volume melling oil pump on the rebuild.....cold at idle I run about 50-60psi.....warm at rpm I run the same, for what it's worth...........John

On a new rebuilt engine there are many factors to consider. Was a high volume oil pump used. No reputable rebuilder will rebuild a oil pump always new.. Bearing clearances would regulate the oil pressure. my " 318" runs 70 psi on start up using 15w4o rottela oil. Doesnt drop much on plane.[/u]

kallen wrote:On a new rebuilt engine there are many factors to consider. Was a high volume oil pump used. No reputable rebuilder will rebuild a oil pump always new.. Bearing clearances would regulate the oil pressure. my " 318" runs 70 psi on start up using 15w4o rottela oil. Doesnt drop much on plane.[/u]

Depending on the 318 model, oil psi spec can be from 45 up to 80 @2000 rpm