2G High Oil Pressure

[DSMStyle2G]

Iv got a 97 Eagle Talon that I just replaced the oil pump on due to it being warped and leaking oil by the water pump.So I installed a oem oil pump back in its place with the balance shaft delete.The motor was rebuilt not to long ago as a stock rebuild still has oil squirter and such just a balance shaft delete which it had before i changed the pump.The balance shaft oil holes are plugged with the balance shaft block off bearings.But while replacing the oil pump I noticed the oil filter housing is not ported for the balance shaft delete.Also I noticed the the oil filter housing plunger plug doesn't have a crush washer under it but it doesn't leak.I got it back together today and took it for a drive at cold start it was at 80psi.Fully warmed up at idle it was at 15psi, at 2k rpm it was at 35-40psi and at 3k rpm it was at 65-70psi.Is this to high of oil pressure?I know at 750 rpm at idle it supposed to be at 11.5 psi and that the rule of thumb is 10psi per every 1k rpm.But I thought if I add a crush washer like there is supposed to be or port it will lower the pressure all across the board won't it?Just wanna make sure its not to high before i cruise it around more.I'm running 10w-30 aswell.Any help is appreciated Thanks

 

[99dsmer4g63]

No, that is an oil relief valve. Once oil pressure becomes more than the spring pressure it will open and allow excess oil to dump directly to the pan.

Here is my oil pressure for reference.

Ambient temps between 60-85 degrees roughly.

Cold start = damn near pegged at 100
Idle warm = 15-20 psi
Cruising 2.5-3k = 40-50
Wot shifting at about 6-7k = 85ish

You can see I’m roughly about 10-15 psi over the “rule of thumb” here.

I have the following,
- dinosaur 10w-30 all year regardless of temperatures
- No BS
- 1.8 mirage stubby shaft
- 1.8 mirage oil pressure relief spring
- OFH is pretty much as big as it could be as well.

I’m not a fan of the whole let’s stack flat washers on there bullshit. There should only be on crush washer on the relief valve bolt.

Your 3k psi seems a little high but I’d like to know what the psi is at wot. The reason for porting is to allow more oil to flow out. You start overrunning the relief spring to pan hole quickly as rpms climb which is why you want more volume to flow through there. Also why I lowered my spring pressure to allow it to open slightly sooner and ported it to allow more volume through.

-Daniel

 

[DSMStyle2G]

Alright that makes since so porting it won't necessarily change the pressure all around.Just more around the higher rpm where the higher pressure is being made.I guess I thought if I ported it and threw a crush washer back on it would change the idle oil pressure aswell but maybe there's not enough pressure at idle to overcome the spring to do so.

 

[99dsmer4g63]

I would just start with putting the appropriate crush washer on and see how that changes the psi.

After if it is still too high I would get a 1.8 spring and see how that changes your pressure.

If it is still too high porting the OFH would be what I would do next.

You can see the steps get more involved and time consuming. So start simple and quick and see how much it changes.

Biggest thing is IF you port make sure you don’t go past the sealing lip of the plunger or the OFH is now trash.

-Daniel

 

[danl]

Iv got a 97 Eagle Talon that I just replaced the oil pump on due to it being warped and leaking oil by the water pump.So I installed a oem oil pump back in its place with the balance shaft delete.The motor was rebuilt not to long ago as a stock rebuild still has oil squirter and such just a balance shaft delete which it had before i changed the pump.The balance shaft oil holes are plugged with the balance shaft block off bearings.But while replacing the oil pump I noticed the oil filter housing is not ported for the balance shaft delete.Also I noticed the the oil filter housing plunger plug doesn't have a crush washer under it but it doesn't leak.I got it back together today and took it for a drive at cold start it was at 80psi.Fully warmed up at idle it was at 15psi, at 2k rpm it was at 35-40psi and at 3k rpm it was at 65-70psi.Is this to high of oil pressure?I know at 750 rpm at idle it supposed to be at 11.5 psi and that the rule of thumb is 10psi per every 1k rpm.But I thought if I add a crush washer like there is supposed to be or port it will lower the pressure all across the board won't it?Just wanna make sure its not to high before i cruise it around more.I'm running 10w-30 aswell.Any help is appreciated Thanks

When you remove the balance shafts on a fresh build, the stock oil pump has a lot more flow than the engine needs. When the engine is warm, I get 15psi with a 900-1000rpm idle. During a pull I get about 85psi at 7000rpm. See log below, it demonstrates how the oil pressure "ramps up" quickly until the oil pressure relief valve opens to bypass oil to the pan. The two main parameters are you want more than ~10psi at idle and try to not go over 100psi at redline. Not much can be done to change the ramp effect of the stock oil pump which flows too much when the balance shafts are removed.

You must be logged in to view this image or video.

 

[DSMStyle2G]

Thanks guys I appreciate your help and giving me ideas on how to fix the issue aswell as Idea of normal oil pressure.Im going to try a softer spring like 99dsmer4g63 recommended aswell as a crush washer.I actually looked up springs for it and found a kit from RTM Racing that comes with a spring from a 1.6L Mitsu that made for balance shaft deletes and it comes with a crush washer aswell.Heres the link for reference

RTM Racing :: MITSUBISHI / EAGLE :: DSM: 2g (1995-99) :: Engine :: Block Components :: Engine Lubrication Components :: Oil Filter Housings :: OEM Lower Oil Pressure Relief Spring: DSM/EVO

If that doesn't work I'll port it some.Thanks again guys I greatly appreciate the help!

 

[99dsmer4g63]

Do you know what your oil pressure is at wot? You didn’t specify what it was.

I’m curious to know what it is. Every motor/setup is different.

-Daniel

 

[curt-s]

I've had this kind of oil pressure for 30k km.. still yet to tear anything down. Hmm

 

[DSMStyle2G]

Do you know what your oil pressure is at wot? You didn’t specify what it was.

I’m curious to know what it is. Every motor/setup is different.

-Daniel

Sorry I hadn't replied sooner got that covid bs and was down for a bit.But by 5k rpm my aem oil pressure gauge is pegged at 100 psi. 90 psi at 4k and 100 psi at 5k on up.