1968 Charger R/T 440HP engine with TOO high oil pressure

[stushug]

I just took my Charger out for the first time since last fall. I noticed that the oil pressure was way too high. I changed the oil and filter today, with the correct WIX oil filter and 5 qts. of Amsoil Z-Rod 10W-30. The pressure is still high, it's about 75 at idle and goes to almost 100 at about 3 grand. Nothing else has changed since I had it out last fall. I did check the pressure relief valve and spring on the pump and they both seem to be ok. I've had the car for 20 years and it always idled at about 25-40 lbs and would max out around 70 lbs on the factory Rallye gauge. I thought that maybe my sending unit was the problem so I ordered a new one. While it's out I checked the pressure with a brand new test gauge today. It seems to be giving me the same readings that the factory gauge was so the readings I'm getting now are correct. I did notice on the test gauge that the hose is pulsating, it's not a steady pressure. Is that normal? This pressure is way too high, what else can I check?

 

[RJRENTON]

I just took my Charger out for the first time since last fall. I noticed that the oil pressure was way too high. I changed the oil and filter today, with the correct WIX oil filter and 5 qts. of Amsoil Z-Rod 10W-30. The pressure is still high, it's about 75 at idle and goes to almost 100 at about 3 grand. Nothing else has changed since I had it out last fall. I did check the pressure relief valve and spring on the pump and they both seem to be ok. I've had the car for 20 years and it always idled at about 25-40 lbs and would max out around 70 lbs on the factory Rallye gauge. I thought that maybe my sending unit was the problem so I ordered a new one. While it's out I checked the pressure with a brand new test gauge today. It seems to be giving me the same readings that the factory gauge was so the readings I'm getting now are correct. I did notice on the test gauge that the hose is pulsating, it's not a steady pressure. Is that normal? This pressure is way too high, what else can I check?

With my RS23V0A****** GTX, with a HIGH VOLUME OIL PUMP, 10W-30 Mobil One oil with a pint of ZDDP added, i use full groove tri metal main bearings, Clevite 77 @ 0.0025" and Clevite 77 rod bearings at 0.0025", and non bushed lifter bores. Cold oil pressure at idle is ~ 80 psi; hot oil pressure at 2500-3000 RPM is 70-75 psi; hot oil pressure at 1200 RPM idle is ~ 55-60 psi. Its been this way for years......some people prefer more or less pressures but pressure is a volume delivered function and bearing clearances both mains and rods. .....and now begins the "my way is the best/only way" controversy.......
BOB RENTON

 

[dadsbee]

I think you missed the point of his post Bob... he's 35 psi higher than what he's normally had for years and is looking for advise as to why.

 

[Beekeeper]

I know you said you checked it but is the bypass valve sticking or sticky at any point through it’s full travel?

 

[stushug]

I know you said you checked it but is the bypass valve sticking or sticky at any point through it’s full travel?

It seems to be ok, but I've never checked one before. Being that it sits so far in, I used a magnet to draw it out to where I could get my fingers on it. There is a very slight stickiness as I pull it out of its bore. Also, there are a couple very faint scratch marks on the outside diameter of the valve itself, on the inner end.

 

[Beekeeper]

It seems to be ok, but I've never checked one before. Being that it sits so far in, I used a magnet to draw it out to where I could get my fingers on it. There is a very slight stickiness as I pull it out of its bore. Also, there are a couple very faint scratch marks on the outside diameter of the valve itself, on the inner end.

I would start by pulling that pump then disassemble it clean and inspect it and lightly polish the valve and it’s bore
with crocus cloth.

 

[stushug]

I would start by pulling that pump then disassemble it clean and inspect it and lightly polish the valve and it’s bore
with crocus cloth.

Ok, I'll start there. Looks like I'm draining the oil again. Thanks!

 

[Beekeeper]

Ok, I'll start there. Looks like I'm draining the oil again. Thanks!

No need to drain the oil to pull the pump just remove the filter and pull the pump.

 

[Geoff 2]

I would be looking for sludge formation in the bypass valve chamber, as a result of sitting for months.

 

[stushug]

I pulled the pump, opened her up and found a few things. The bypass valve seems to be moving freely inside the bore. I removed it, cleaned it and the bore itself. Both o-ring seals are pretty flat so that isn't helping. The worst thing I found were a ton of scoring on both gears. I'm posting pictures for reference. I'm going to order a new pump on Summit. I'm not sure if I should get the Melling DODGE Melling M63HV Melling High-Volume Oil Pumps | Summit Racing
or the Mahle DODGE MAHLE Original 601-1029 Mahle Original Oil Pumps | Summit Racing. The Mahle is triple the price, and the Melling has very good reviews so I'm thinking that's the way to go.

 

[RemCharger]

That pump sure ate some stuff! Wouldn't be a bad idea to clean out the pan and pickup.
I would go with the melling HV .

 

[eldubb440]

shouldn't the HV pump be paired with a deep pan?

 

[stushug]

That pump sure ate some stuff! Wouldn't be a bad idea to clean out the pan and pickup.
I would go with the melling HV .

I'm thinking it would be pretty difficult to remove the pan while the engine is in the car. Is it even possible to do without at least raising the engine somewhat?

shouldn't the HV pump be paired with a deep pan?

My engine is completely stock except for a rebuild by the previous owner. The paperwork I have says everything is stock except for a .30 overbore and a purple shaft cam that I had installed that is one step above the stock cam. That cam was installed in 2009 and nothing has changed since then. I don't know about matching the HV pump with a stock pan. That's one of the things I am looking for guidance on.

 

[eldubb440]

I'm thinking it would be pretty difficult to remove the pan while the engine is in the car. Is it even possible to do without at least raising the engine somewhat?


My engine is completely stock except for a rebuild by the previous owner. The paperwork I have says everything is stock except for a .30 overbore and a purple shaft cam that I had installed that is one step above the stock cam. That cam was installed in 2009 and nothing has changed since then. I don't know about matching the HV pump with a stock pan. That's one of the things I am looking for guidance on.

my point was a HV pump could possibly suck the level in the pan too low when romping on it

 

[Beekeeper]

You pump has ate some metal and that has probably cause your bypass valve to stick.
I would for sure be dropping the pan to inspect for contamination.

 

[stushug]

I just spoke to a local engine builder that I've known for 40 years. I sent him the pictures and he didn't like the looks of the pump internals either. He recommended replacing my pump, but said I definitely do NOT want the HV, I should get the Melling M-63 which is the standard volume pump. I just ordered it from Summit with a new gasket set. Summit usually delivers to me within 2 days at most, so I'll update when I get the new pump installed.

 

[Fran Blacker]

I'd pull apart your new pump to make sure there's no manufacturing trash inside. Add some clean grease so it will suck oil, a dry pump won't suck oil.

 

[Don Frelier]

I'd pull apart your new pump to make sure there's no manufacturing trash inside. Add some clean grease so it will suck oil, a dry pump won't suck oil.

Vaseline works well for this.

And yes I would take the pan off.
It's kind of a pain but not impossible.

 

[Beekeeper]

Drop one side of the center link and swing it out of the way then lift the engine a bit and the pan will come out

 

[4406bbl]

I'd pull apart your new pump to make sure there's no manufacturing trash inside. Add some clean grease so it will suck oil, a dry pump won't suck oil.

And lightly chamfer the gear, rotor, and cover, they are very sharp new and always dig into the cover where the relief valve sits.