High oil pressure

[David Boyd]

I refreshed a 1965 273, primed the system and visually saw oil at the rockers. Upon initial attempts to fire it up I am bursting oil filters, pinned a new pressure gauge and made a heck of a mess! The only new parts installed is the rod bearings. Heads have been milled .010 and a valve job. Added a Performer intake and 650 Holley. I am not an engine builder, but very familiar with these old Mopars. Any ideas?

 

[RattyBarracuda]

Stuck oil pressure relief in the pump, maybe.

 

[Ironmike]

Wow! That's a new one for me. I'm guessing something amuck in your oil pump. Which one are you running?

 

[PRH]

I think most would be pretty surprised at how much pressure a pump can generate when the bypass valve is stuck in the completely shut position.

I know I was when I encountered that situation.

 

[33IMP]

Stuck oil pressure relief in the pump, maybe.

Nope. PROBABLY.

 

[RustyRatRod]

I've had an oil filter blown off once. I was a kid and had built a 350 Chevy. More oil pressure is good, right? Muh huh. Since they are interchangeable, I put a high pressure, high volume big block pump on it. Bout 20 seconds into a fresh fire, it blew the filter slam off. I didn't do that again. lol But yeah, I agree. A stuck relief valve is about all it can be.

 

[33IMP]

I had a maladjusted adjustable spring in my big block pump. Did almost exactly that. 100 psi at idle, pegged a 150lb gauge at 1200. Blew the first filter open.

 

[David Boyd]

Wow! That's a new one for me. I'm guessing something amuck in your oil pump. Which one are you running?

Stock. It is coming back out and replaced!

 

[David Boyd]

I refreshed a 1965 273, primed the system and visually saw oil at the rockers. Upon initial attempts to fire it up I am bursting oil filters, pinned a new pressure gauge and made a heck of a mess! The only new parts installed is the rod bearings. Heads have been milled .010 and a valve job. Added a Performer intake and 650 Holley. I am not an engine builder, but very familiar with these old Mopars. Any ideas?

Thanks for the replies! The engine comes back out today and I'll replace the pump. I will also examine the old one, to learn from.

 

[perfacar]

what weight oil are you using?

 

[TT5.9mag]

Stock. It is coming back out and replaced!

New doesn’t mean good. Your old pump is working well and there is likely just trash in the relief valve. This is why stuff should be dis assembled and clean prior to use. So if you replace the pump, the amount of work “should” be the same as what is needed on the old pump. Just take it apart, clean it, verify the relief is free and put it back on.

 

[Ant]

rod bearings

Check the oiling holes on the crank when you have the motor out, just in case.

 

[BSB67]

In the last 15 years I’ve only purchased used OEM pumps. This is after I got three terrible Melling pumps. You take a Melling and Used OEM pump apart on the bench side by side and the worn OEM is usually still better than the new Melling.

 

[David Boyd]

what weight oil are you using?

Last attempt I used 10-30, first attempt was 15-40. It was the pump! I got it out yesterday and upon closer inspection, I was a lazy butt and now I get to do a redo!

 

[David Boyd]

New doesn’t mean good. Your old pump is working well and there is likely just trash in the relief valve. This is why stuff should be dis assembled and clean prior to use. So if you replace the pump, the amount of work “should” be the same as what is needed on the old pump. Just take it apart, clean it, verify the relief is free and put it back on.

I plead; Lazy Butt! Got the pump out and it failed the proper inspection!

 

[David Boyd]

Thanks for the replies! The engine comes back out today and I'll replace the pump. I will also examine the old one, to learn from.

I got the engine out yesterday and pulled the pump. I feel stupid, as usual, it was nasty. I put it in the ultrasound last night and will completely go over today. I have a new pump ordered, but I must learn my lesson to inspect everything! Thanks for only positive comments!

 

[RustyRatRod]

What exactly was the issue with the pump? You might could help others if you get specific.

 

[B3422w5]

What was the clearance on the rod bearings.
Very snug clearances can up the oil pressure significantly.

 

[TT5.9mag]

Last attempt I used 10-30, first attempt was 15-40. It was the pump! I got it out yesterday and upon closer inspection, I was a lazy butt and now I get to do a redo!

I plead; Lazy Butt! Got the pump out and it failed the proper inspection!

Talk to us, tell us what you found.

 

[Ironmike]

Not to be picky, but ya should have taken that pump apart to clean and inspect BEFORE installing. Every Melling I ever checked was in need of a thorough cleaning. Don't like little bits of metal.

 

[TT5.9mag]

Not to be picky, but ya should have taken that pump apart to clean and inspect BEFORE installing. Every Melling I ever checked was in need of a thorough cleaning. Don't like little bits of metal.

That’s not picky. It’s par for the course.

 

[Sterling]

This is from a brand new Melling oil pump for a engine I was building. One of the reasons I take them apart before installing.

 

[David Boyd]

Talk to us, tell us what you found.

Dirt!
Already got a brand new pump installed and engine back in the Valiant. I will finish buttoning it up later this week.

 

[David Boyd]

I plead; Lazy Butt! Got the pump out and it failed the proper inspection!

The valve was stuck tight. After A couple rounds in the ultrasound I finally got the valve cap and spring out but not the valve.

 

[David Boyd]

Not to be picky, but ya should have taken that pump apart to clean and inspect BEFORE installing. Every Melling I ever checked was in need of a thorough cleaning. Don't like little bits of metal.

I love learning the stupid way! So, I succeeded!