100-plus lbs oil pressure problem

[dsmith]

I have an ERA with a 428 that has developed an oil pressure problem.

I went out to start it the other day and after it had been running for about 20 seconds I heard a squeal, sounded like a fan belt. Looked down at the gauges and watched the oil pressure guage drop to zero. Killed the motor and got out of the car. Oil was pouring out from underneath.

Towed the car down to my buddies garage and got it up on the lift. Turns out the gasket on the filter was blown out and all of the oil drained from the motor. Bottom of the filter was domed - rounded, all the dimples around the edge had been ballooned.

We put a new filter on and filled her back up with oil and watched for leaks. there were none, so we started the car up. Oil presure went up to 95 lbs at about 1500 rpm. When goosed a little, maybe 2500 rpm, it shot up to 100 lbs of pressure. At idle it is running about 70 lbs. Once again the pressure was so great that it expanded the base of the oil filter blowing it out out to a round shape.

What would be causing this? While I never actually recorded the pressure, my recollection is that the car has always had about 30-40 lbs at idle and I know it never had more than 60 when revved up or running on the highway.

This is a new car for me (1983 with recent rebuild on motor by previous owner, 700-800 miles on rebuild) I have driven it from his house to mine when I bought it (70 miles) and on a couple midnight rides since it is not yet registered. Everything has been normal.
Have been starting it on a regular basis all winter and the pressure has been normal until this past episode.

I would greatly appreciate any help/advice. We are going to take a look at the oil pump today, but I can't understand why it would be so high all of the sudden.

Is there a spot that there could be a restriction? I have checked the filter in the line to the oil cooler and all is fine there.

thanks

smith

[mickmate]

I have had the exploding oil filter problem in the past. The engine builder with the best of intentions had "adjusted" a pressure relief spring in the oil pump. I would start there and see if your oil pump relief valve has stuck in position. The side oilers also have a secondary pressure relief of the oil into the back of the crank case from the block. I'm not sure where and if the 428 has the secondary relief but you need to find out. Good luck with it and let us know what you find.

[CJ428CJ]

I think Mickmate is right. FE pumps are easily capable of generating 100 PSI or more. The pressure is regulated by a pressure relief spring in the oil pump. For a typical high volume oil pump for a 428, that spring is set to open at about 75 PSI. If the bypass valve and/or spring stuck, the pressure could shoot way up. I'd change the oil pump for sure.

Chris

[The Dreamer]

When cold and the outside temperature is cold, I see pressures in the 85-90 psi range. During the Summer month, pressure at start up is in the 70 psi range. Once warm, pressure dips to 40 psi at idle.

[Karl Bebout]

This happened to me once on a 360 truck motor. We were making the move from Ohio to Arizona and I made a nasty puddle in a motel parking lot. Changed out the filter, screwed the new one real tight, dumped in a quart of ATF, filled it the rest of the way with oil, and drove the remaining 1500 miles without any problem. I don't recommend this for your 428, but maybe a quart of Rislone will give the added detergency needed to free up the pressure relief valve. My 2¢.

[mj_duell]

Originally Posted by CJ428CJ

I think Mickmate is right. FE pumps are easily capable of generating 100 PSI or more. The pressure is regulated by a pressure relief spring in the oil pump. For a typical high volume oil pump for a 428, that spring is set to open at about 75 PSI. If the bypass valve and/or spring stuck, the pressure could shoot way up. I'd change the oil pump for sure.

Chris

I Agree. I've had it happen to my 428 and changing the pump worked.

--Mike / Turn Ten Racing, Inc.

[dsmith]

Thanks guys

Is there a favorite pump???

Not even sure what year the motor is. I asked the previous owner, but he didn't know much about the car exept it was cool, well built, and fast as....
well, I guess you all know the rest

thanks

smith

[CJ428CJ]

Go with a Melling M57HV or call up Precision Oil Pumps. You can find them at http://www.precisionoilpumps.com/

Chris

[mickmate]

The melling mentioned is HV (high volume) vs high pressure. I think that's what I have in my collection of motor bits waiting to be put together. I would recommend that as I believe flow is more important than pressure for the oil to do its job, especially on a street car. It is a cheap and readily available item from outfits like Summit. I like and use Jegs as much as I can.

[Jerry Clayton]

You said 100 lbs--how high does your guage go?? I guess I'm saying if you have a 100# guage you really don't know how much pressure you had

Also-- some of todays filters aren't rated for the HP engines of yesteryear--in the high perf fe engines the spring in the pump was just to protect the filter on cold starts--the main presure was set by the relief assy in the rear of the galley

Jerry

[CJ428CJ]

in the high perf fe engines the spring in the pump was just to protect the filter on cold starts--the main presure was set by the relief assy in the rear of the galley

I believe only the 427 used the relief assembly in the rear of the galley. I don't believe the 428s (or any other of the FEs) used the galley pressure relief.

[auto10x]

High volume and high pressure are not two different things. The pump creates oil flow to the moving parts in the engine. The pressure you see is "whats left" of the oil as it "leaks" past the moving parts. The issue is not really high volume vs. regular volume; its how wide are bearing clearances and what is the pressure relief valve set at. Find out from the engine builder what the internal clearances are, then buy a pump.
auto10x
Bill

[Carnut427]

High volume and high pressure are two different things. When what Auto10x says happens, there has to be an opening in the system so large that the pump can't build pressure, or only partial pressure, which is another problem altogether. In a normal engine, a high volume pump will produce as much pressure as the spring in it allows, unless, as in dsmith's case, something is wrong in the pump. A high volume pump will pump more volume, as may be needed with more bearing clearance, rod side clearance, etc, but as previously mentioned, will normally only pump as much pressure as the spring allows. High pressure springs, such as those used originally in side oilers, are available, and can be added to a high volume pump if that is what you wish. As for blowing out oil filters when using a high pressure spring (not in dsmith's case, as he has another problem), use the Fram HP 1 filter or equivalent; it's built to take the extra pressure. Even the neoprene seal at the top of the filter is thicker & relieved into the filter to prevent blowout. Sadly, to my knowledge, it doesn't filter any better than a standard Fram unit.

[speed220mph]

Smith: I hope that "squeal" you heard wasn't the sound of dry bearings running against the bearing journals. That's probably what it was. I heard the same thing from my engine when flying . . . in an airplane. Problem was oil starvation at one journal due to debris in an oil passage.

Your engine problem may have been as stated, causing total oil starvation. If the pressure regulator valve stuck, a dash of Marvel Mystery oil may loosen it, but I recommend you drop the pan . . . it's easy on a Cobra . . . and remove the pump for inspection. Also, remove some rod-bearing caps and check the bearings. This can be tricky with the top bearing. Rod bearings will be the first to suffer from oil loss. If they are wiped, you've found the source of your squealing noise. Look at the bearing journals, too. If they are in good shape, you can install new bearings . . . very tricky without removing the engine. The top bearings can be rotated out of their bore by pushing on the end opposite the tab using a small screwdriver and a lot of finesse.

If the rod bearings are badly wiped, you should also check the mains. One the other hand, if the crank is damaged, you'll have to remove the engine and go from there. Except for the rear main, these won't be too bad to remove, but you won't have to if the bottom bearing inserts look OK. Otherwise, it's remove the engine time. But if the bearings look good, replace them and don't forget to torque all the bolts to the correct spec. This can be somewhat difficult . . . that's an understatement . . . if you have to check rod-bolt stretch.

I'm telling you this after I just went through my 427 S/O because of a spun rod bearing. This is a long and expensive story because of the need to buy a new crank, custom pistons and much more. I think and hope yours won't be anything like what I had to deal with.

[dsmith]

Thanks for all the input.

A new melling oil pump and we are back on the road. Motor was not damaged in any way - don't know where or when the habit developed, but I am always checking that oil pressure guage. Paid off big time!!!

thanks again to everyone

smith

[Jerry Clayton]

So---what is the pressure now?

Jerry

[Carnut427]

ALWAYS glad to hear happy endings!