Other options for excessive oil pressure

[turboglenn]

So tonight i decided to hook up an oil pressure guage and see what i was really getting aside from the dash's vague readings. After fixing my down pipe flex leak and double checking the 3rd leg bolt for the oil pump, just couldn't remember if i torqued it and used loc-tite so i pulled the pan in a "better safe than sorry" approach and all was good.

Once i started it up on the fresh 5w-30 i was shocked at how much pressure i was getting... I had just put in fresh oil and it was cold and the pressure was at 60+psi at idle :WOW: it would peg past 100 and bounce the guage just by free-revving to 5500

At idle when fully warmed up, i am at about 20-25psi, then by 4k I'm steady at 60 - 70 and on up to 80 by 5k or so. Then by red-line I'm still pegging past 100 until the motor is nice and hot, but even once it's hot I'm still getting damn near 90-95psi.

I've ported the OFH to the likes of the pics I've seen on here, but I'm wondering if we can modify (shorten) or change the spring that's used in the plunger passage to change the oil pressure entirely

Here's my thought... the mirage "stub-shaft_ is what many use to do the BSE which is the main cause of this (and my cause as well) so if the mirage isn't' getting too high of pressure does it have a different spring in it's housing? or is it just a way larger hole like we get after porting?

Also, i was thinking about drilling some sort of "relief hole" in the back of the stub shaft that would just let some oil escape. My current BSE has bearings in the front side turned out of align and the oil pump side i just cut it off on the band-saw, then TIG welded the hole shut. I've got the stub shaft on the other damaged engine and wanted to see if this way wasn't as loud as the oil pump gets with the stub shaft - and it isn't

So, should i work more on the OFH, drill a relief hole, or start experimenting with the spring that's in it from Mitsubishi and trying to lower pressure...

Or is this common until you've made the hole as HUGE as you can? I wasn't sure if you needed to go "down" further to wards the piston edge, or if it needed to be wider lower so i just evenly opened it up comparable with pics from here, but it is not enough

EDIT: What about drilling a small hole i the piston of the pressure spring plunger thingy (don't knwo the real name )

Anyway, people have been drilling thermostats for years a "weep hole" it's called. I wonder if i took a TINY TINY drill bit and put a small hole on the edge that would line up with that groove if i could relieve just enough that it wasnt' so high and didn't jump up as fast.... it goes from the 20psi at idle right up to 60 with any blip of the throttle

 

[stockfornow]

Ok, so where the spring sits, you take off that plug in order to get that spring out, right... Well, there's also a cooper/some sort of sealing washer that goes in there, that you can get another one, or a couple and try to put them in there, and space out the distance, meaning it will compress easier. Hope it makes sense.

 

[Clutch GSX]

Have you removed your oil squirters?

 

[turboglenn]

Stock for now, that was my first idea, Not sure if anyone's tried it but it's the least invasive and least time consuming thing to start trying... Will do it tomorrow and report back

Clutch GSX ...No, there were not removed, i have all the oil squirters still in the block with all fresh crush washers and red loc-tited in

 

[tkelly27]

I've heard of people who cut the spring having success, but it was kind of vague as to the results. Not sure about adding crush washers, that's a nifty idea though. I ported the crap out of my OFH and nothing happened, so I'll be watching this thread.

 

[Clutch GSX]

So why dont you remove them?

 

[Defiant]

Put your gauge on the head oil port and see what numbers it's giving.

 

[turboglenn]

Put your gauge on the head oil port and see what numbers it's giving.

I will try that first since it's about the easiest solution to start with.

What would i be looking for as far as "good numbers" when taken from the head? I'm guessing you mean the port that feeds the turbo??

I must admit, when i saw you were the last to reply i was almost worried that i was going to have to link every post i searched and read due to posting about something that there's over 13 pages of results for ( i made it through 8 of them last night)

So, thank you for the suggestion!

EDIT: Currently, my guage is placed where the "dummy light" sensor use to be.

 

[knochgoon24]

I'd like to see as solution to this too, except I'm seeing low oil pressure once it's hot at idle. Along the lines of 3-7 lbs at 750 RPM . I'm running 10w-30. I have a BSE, but I just cut the balance shaft and plugged it because I couldn't get the oil pump apart. I stripped out the screw and just said f it.

3-7 psi hot idle @ 750 RPM
80 psi cold idle @ 1000 RPM
15 psi at hot 1000 RPM
40 psi at hot 2000 RPM
75 psi at hot 3000 RPM
85 psi at hot 5000 RPM and that's as high as the pressure goes.

I ported my oil relief valve pretty good. There might be room to take some more off.

What worries me is that sometimes during the hot idle, the oil pressure warning light will flicker on.

I have my pressure gauge tapped where there was a plug in the OFH before. The plug on the bottom. (In that brass fitting.)

 

[SethA]

I am sure you have read most of the threads I did before doing the BSE. I remember people reporting that making the hole wider had a more profound effect than making the hole longer. (area is exposed more quickly as the piston moves). Perhaps your porting didn't make the hole wide enough?

I also seem to remember posts about experimenting with different housings/springs and not getting different results (non turbo vs turbo?). I am not sure about this, it just rings a bell with me for some reason.

I would tread lightly trying to add weep holes to the system.

Seth

 

[pneumo]

I also like to port the hole that leads to the piston, since it's about the same size as the relief hole. More oil in, more oil out.

The stub shaft has no effect on oil pressure. The Mirage stub shaft is recomended because it lets more oil flow to the oil pump shaft, which keeps the pump shafts well lubricated. This is important since the pump shaft also carries loads from the timing belt.

 

[turboglenn]

I haven't changed anything today because i've been playing catch up on bills and such after my TX trip. BUt i did notice thattoday after getting just a few miles on the fresh oil i'm not pegging past 100psi anymore (well, when it's cold it will) But for the most part i'm topping out about 90-92psi around redline (still too much though)

I'm waitign to hear back on difiants suggestion to check pressure at the head and what numbers to look for there. Since that's where i feed my turbo from and that the high oil pressure causes lifter issues, that makes the head my real concern for it's as far as pressure goes. If the head is cool i MIGHT let the bottom end run on the higher pressure, it depends on what my machinist says about the bottom end and pressures it will behave well under.

The reason i'm looking for other means besdes porting the OFH is that people have reported it not solving their issue, so i was thinking it may be more of an issue of how much pressure it takes to open that relief valve. Plus there are more passages than just that one hole that could probably help if they were ported too, but i'm not pulling the motor's front cover and oil pan off to port EVERYTHING unless i absolutely have to. The one hole next to the oil pick up is the one i THINK is for the reliefe return and it's tiny which is why i think some people gain nothing after porting the OFH...just thoughts though, i have no scientific proof

 

[pneumo]

If you're worried about feeding your turbo and lifters with too much pressure, you can swap in the oil distribution block from an early 1990 DSM. The oil distribution block is located in the left side of the head under the valvecover, there's 3 bolts with 10mm heads holding it on. The 1990 version looks taller. It has a spring loaded piston to control pressure, just like the filter housing relief valve.

The OFH releif valve is rated to open at 80psi.

 

[turboglenn]

If you're worried about feeding your turbo and lifters with too much pressure, you can swap in the oil distribution block from an early 1990 DSM. The oil distribution block is located in the left side of the head under the valvecover, there's 3 bolts with 10mm heads holding it on. The 1990 version looks taller. It has a spring loaded piston to control pressure, just like the filter housing relief valve.

The OFH releif valve is rated to open at 80psi.

Both heads i have are from a 90 model year as far as i know (all the parts i buy only fit 89-90 years.. if i get the 91+ stuff there's always a difference.. Do you have pics of the difference?

Maybe this is why Defiant said to test at the head. Also... Do you know what the reliefe in the head from a 90 model year is supposed to let off at?

 

[pneumo]

I'll get a pic for you tomorow.

 

[turboglenn]

Thanks... I'll check back in then .

In the mean time tomorrow I'm going to go grab a few extra crush washers and do some testing ( i believe i can pull the relief valve easier than pulling the OFH and if i can get 2 or 3 crush washers in there I think i can lower pressure evenly and fairly precisely. I was playing with turning the bolt out a turn at a time and realizing how much resistance until it opens you can really free up.

I also MIGHT try and mill the bolt deeper (though it doesn't have much room left for machining) My other thought was get a new different bolt with them same threads and a taller head and machining the spring seat deeper.

My only concern is i believe that stacking crush washers pretty much always results in a leak to the best of my memory I may even build up and re-machining a factory bolt to not thread in as far, but that would be more time consuming as I'd have to build a new seat with the TIG and then machine it and test, machine it and test ....too much wrenching

EDIT: BTW...here's pics of the port job on my OFH as it stands... would you think this is enough? I did it as large as i saw in the other pics where people went a tad further to get it even better... Yet mine is still pretty high. Also..I've heard different oil filters change oil pressures... What if i were to run a Fram (known for lower pressure) would this be sufficient?

You can see the holes in the side of the piston ( i assume for oiling of it's travel passage).. There's also a small divet in the front center of the piston.. I was thinking about taking one of my tiny itty bitty drill bits and making a small releife there. It would relieve some of the pressure on the face of the valve from the get-go, but should alsoaid in relieving some additional pressure via volume when it it open and it would still return through the factory passage way since it would still come out the same hole....any thoughts? I can always tig it closed and start over if it goes wrong.

 

[Defiant]

What would i be looking for as far as "good numbers" when taken from the head?

"Good" is 10psi per 1000rpm.

I'm guessing you mean the port that feeds the turbo??

Yup. I'm not a big fan of taking the oil pressure off the side of the oil pump. Of course it's going to be high there. I'm more concerned with what's getting out to the bearings.

I must admit, when i saw you were the last to reply i was almost worried that i was going to have to link every post i searched and read due to posting about something that there's over 13 pages of results for ( i made it through 8 of them last night)

Now you see what I run into every time I have to look up an answer. Welcome to hell.

EDIT: Currently, my guage is placed where the "dummy light" sensor use to be.

Oh, crap. At least hook it up to the sender port.

 

[SethA]

EDIT: BTW...here's pics of the port job on my OFH as it stands... would you think this is enough? I did it as large as i saw in the other pics where people went a tad further to get it even better... Yet mine is still pretty high. Also..I've heard different oil filters change oil pressures... What if i were to run a Fram (known for lower pressure) would this be sufficient?

The only thing I see with that porting is you could try squaring in up more and maybe go a little closer to the top of the piston. You could go wider too while you are there.

See post 80 here:

http://www.dsmtuners.com/forums/stroker-tech/224606-porting-oil-relief-hole-no-balance-shafts-3.html

I noticed post 83 cut his spring and got good results too. Your idea of modifying the bolt would basically do the same thing.

Seth

 

[turboglenn]

Defiant... I didn't know that was a bad place, on this OFH there was only one sensor hole and it was where the dummy light sender was located on the motor i pulled out. BAsically, it's at the end of the long "tube" you can make out when looking at the OFH.... TOday if i can get caught up on things around here and not have my back crippling me, i WILL get a reading from the head.

THe OFH in the pics with the fitting where the originical sending unit was , is one of two that i modified exactly the same (save for the one on the car doesn't have that hole)

SethA... I spent a lot of time last night with a "hook scale" and playing with the piston in the one i took a pic of, and i believe that honestly before removing a damper pully nd timing cover i will just try to do some changes. GOing to find that post # 83...thanks again!

Okay, I'm back and read the pages (all of them) It looks like i may clip the spring.. i have a spare and can get more if needed i'm sure. but i will keep one stock incase the clip goes bad, but i'm going to start by only pulling one coil since i've done enough porting to be at 20psi at idle (i would like to not have less than 10-15psi at idle)

One guy said he may have wiped his bearings out with too high of oil pressure.. that doesn't make sense to me since the oil film is the bearing and it would seem that more pressure = stifer bearing not letting the surfaces touch :shrugs:

Right now i'm 20psi at idle... hitting 80 by 3500RPM, then holding and slowly creeping into the 90's by redline, but i can feel the valve float at higher RPM's because i triedd taking it to 8k twice yesterday and it really slowed nad felt like it was floating past 7200

 

[pneumo]

...and slowly creeping into the 90's by redline, but i can feel the valve float at higher RPM's because I tried taking it to 8k twice yesterday and it really slowed and felt like it was floating past 7200

Valve float is different than lifter pump-up. Valve float goes away once the rpms drop down. Lifter pump takes some time to go away because the lifters are slow to bleed down the excess oil.

There's also the possibility of ignition break up at high rpm.

Anyway, here's the pics I promised. The first pic shows the late 1990-1999 oil distribution block on the left and the early 90 oil distribution block on the R. This is what you see when you pop the valvecover off.
The second pic shows what's underneath.

 

[turboglenn]

Okay, I have the 90 style with the relief valve in it as well. Do i need to modify it at all or does having it solve the issue altogether?

Also, i've never had to deal with a high oil pressure problem, it's more often the other way around and i haven't asked my machinist but is 95psi too much for the bottom end or is that a case of the more the merrier?

I'm glad to know both my heads have that early style distribution block for the head... what should i do now?

 

[pneumo]

What to do next? Stop worrying so much. Honestly, 95 psi at the OFH at high rpm isn't too high. The pressure relief valve opens at 80psi, so a few psi above that isn't cause to worry. The pressure relief valve in the head is still doing it's job for you, even though Mitsu felt it was not needed in later years.

 

[turboglenn]

What to do next? Stop worrying so much. Honestly, 95 psi at the OFH at high rpm isn't too high. The pressure relief valve opens at 80psi, so a few psi above that isn't cause to worry. The pressure relief valve in the head is still doing it's job for you, even though Mitsu felt it was not needed in later years.

That's the easiest advice to follow that i've gotten yet! Thanks... I'll still pull the pressure from the head to see what it is, but now i've got 2 inchesnof snow to deal with so she probably won't move for a few days again

 

[ddimestalon]

Im in the same situation too. I've ported the hole larger and havent seen any affects of the port, but I will admit I did add washers after the porting and it did help relieve some of the pressure. At start it went from 100psi to 80 psi. 25 psi at idle, but it would go to 75 psi at cruise (2500 rpm). I was wondering if getting a spring from a local harware store would be better than just cutting the factory spring? I found a spring from a harware store that had the same number of coils as the factory spring, but it has some give to it when compressed.

 

[19BLACKGST98]

I know a guy that had too High oil pressure (dont know the exact # but I can find out) and he destroyed his newly built strocker motor and his brand new FP turbo. His may have been higher than 95 psi at high rpms but im not sure.