I recently lost oil pressure on a new build after a couple hours of track time. The cause was the pressure relief valve was stuck open on the pump. Luckily we caught it right away and there is only one rod bearing ever-so-slightly scored.

I disassembled the pump and tried to remove the valve to see why it was stuck, but it won't move. I have another pump but that valve seems to be stuck closed. I removed the spring and I still can't get the plunger(valve) to move. I've reached out to boundary but they haven't responded.

We did run the new build pretty hot (240-245 CLT), so that might be part of the issue. The valve seemed to get stuck when it cooled down and we changed the oil.

Has anyone found a solution to this? It seems like a steel plunger in an aluminum housing is causing some of this issue. Has anyone polished the channel, or sleeved it with steel? Has anyone put a different type of relief valve in?

This is for endurance racing, and the cost of a failure is much more than the motor itself, since it takes us out of a very expensive race. Once the oil it hot, I don't think high pressure is a concern. If we just keep rev's low when cold, could we just weld the valve closed?

 

Sorry I don’t have your answer but I’m super interested in more of the details. What oil were you running? Did it go to zero or near zero oil pressure or just low? How quickly did you get it shut down after oil pressure loss? How long did you run at 240-245? What oil pressure was it showing while it was hot and before failure?

 

I don't know if this will help, but I had a similar problem with a BE pump several years ago. At that time, I had JUST finished refreshing the bottom-end on my 1.8 with new, forged pistons and rods. During re-assembly I noticed that the the plunger on the relief valve was a little sticky, but I chalked that up to the pump being new. So I finished the rebuild and went on my merry way. After a successful break-in, I started running the car harder until one day - on the way home from work - I heard some "expensive noises" coming from the engine bay. Of course I shut off the engine and got a tow home.

Disassembly revealed two spun main bearings (one to the point of utter destruction) and an oil pan full of metal bits. Further inspection showed that the oil pressure relief valve was stuck open, resulting in no oil to the bearings, and thus spun bearings. I'm surprised that there were only two that were destroyed.

So, what did I do? A few hours of heat from a propane torch, white lithium grease and brake cleaner and I was able to get the plunger free from the pump. Then, using some 600-grit sandpaper rolled into a cylinder, I carefully honed out the bore of the relief valve until the plunger would slide with a minimum amount of sticking - sliding easy, but without any discernible sloppiness. Was it perfect? No, it wasn't machine-shop perfect, but it was good enough to last for these past 4 years.

YMMV

 

OEM pumps don't stick relief valves. The stuck relief valve failure mode is 100x more common on BE pumps than OEM pumps. My solution has been to run a good harmonic damper and keep stock pump. Damper reduces the harmonics and keeps the stock gears alive, stock gears don't cause the relief valve to stick.

 

I think we were running Mobile One 5W30. The pressure went to zero on the accusump gauge and the pressure gauge. We then confirmed by pulling the oil filter and nothing would come out while cranking. I am not sure how or when it got stuck, but I think the motor is ok and just needs a new rod bearing.

We were running at 240-245 for maybe 15 minutes or so, but that pump has run at that temp for 5 hours straight before. We have an aftermarket sensor so the actual pressure is unknown but it was probably in the 40s when hot and in the revs.

 

In my searching, I am getting that impression. Do they do something goofy to the housings, or is it the gears themselves?

 

The following is my guess and just me guessing, as I have never used their pump or inspected one. My guess is their gears are very well made, very strong, and very hard, and don't bend and break like the factory gears do. And because of all those traits, they flex as the crankshaft flex's and cut into the housing, sending tiny scraps of aluminum into the relief valve causing it to stick. At high revs, the valve is open to bypass a lot of oil, and high revs high load is when the gears would flex a lot and cut the aluminum and send it to the relief valve. Revs drop, oil flow drops, valve catches an aluminum shaving, valve sticks, no oil pressure. Clearances exist for a reason, and you can't design one part and ignore how it functions in a system.

 

I believe that Boundary uses oem pumps which they install their gears. From my experience 9 X out of 10 the pressure relief sticks because of contamination from reconditioning or a bottom end failure.

 

My stock pump cost me an engine due to a sticking relief valve.

The clearances are tight in the valve and any debris will make it hang up.

Tapping the oil pan is one common way to introduce debris but there are many other ways.

 

My bone stock 1.6 had a stuck valve when I first got it. It would peg the pressure gauge at 90+ psi (I did not know this wasn't normal since I had never had a car with an oil pressure gauge before). Ran some Rotella T5 through it and it all the sudden one day unstuck and scared the tar out of me. It's been fine every since. Not sure what caused it.

 

It seems like there should really be some kind of aftermarket fix for this.

Maybe fix the OEM one closed and add a valve pre-filter?

 

I run an external oil pressure relief valve (Peterson) with a return to the sump. They flow way more oil than OEM and gives much better oil control at high rpm. I also run a stock oil pump wirh the relief valve removed and a cutdown stock damper to 9k. Its cheap, easy and better. Just don't wind out the adjustment bolt all they whilst the engine is running... it makes a big mess!

It's a common fix in Australia to prevent shattered oil pump gears in high rpm race engines.

 

That is an interesting perspective on cause of stock oil pump failures. Would like to hear others' take on that.

The Bob Bundy down under (under your name) is quite clever. You do that, or the Admins?


DNM

 

ʎpunq qoq

 

noʎ ɹoɟ ʇɐɥʇ ǝןƃooƃ ǝɯ ʇǝן 'ǝɹǝɥ

 

Curious on how that setup looks and works.

 

Aren't we all? More details please!

 

I had this issue on my bp4w.. no oil pressure on cold starts was terrible. Ended up doing a full rebuild and a new OEM pump.

I am also interested in the above setup. Deets!

 

The wit I'm complementing is not HOW to write bob bundy upside down. It is the wit to identify, or be identified as, the Australian equivalent of bob bundy, and to convey that by a somewhat coded picture.

Though the information is not unappreciated.

DNM

 

I'm not sure who or when the inverted 'bob bundy' was applied, but it's pretty funny. When I was building my car I took a lot of inspiration from bbundy's posts.

There aren't really many more details to what I posted above. The oil pump needs to have the relief valve removed and blocked up so it doesn't leak. I just use an aluminium plug. The oil pressure relief valve most commonly used is the Peterson 09-0160 which has -10AN fittings. You need to weld a -10 bung or tap a fitting into the sump, but be careful where you place it so you can clear the subframe and try not to squirt oil onto the crank. Plumbing is simple... Oil filter output (use a sandwhich plate) -> relief valve -> oil cooler -> oil filter sandwich plate input. Return from relief valve to sump. You can also put the valve in the return line from the oil cooler too if you want less pressure drop, but it means the cooler is slightly less effective as it's cooling the return oil too so the output to the engine will be slightly hotter.

The Peterson valve flows a lot more oil, and doesn't chatter.. it also has much better oil pressure control and is easily adjustable. The theory is that the stock oil pressure valve gets either overcome with too much oil and backpressures into the gears blowing them apart, or alternatively, the stock valve can chatter and send pulses back down into the gears.

Just to be clear, I'm not saying not to run a Boundary pump, or a ATI damper. This works well with both, but I'm currently running a stock pump to 9k on track with a cut down oem damper. I have a boundary pump and supermiata damper on the shelf to go onto the engine next rebuild for safety.