OIl cooler on, oil pressure low

[Sheck]

Hey guys, dont want to search for this right now as i need to get to sleep but i just fitted my oil cooler using a relocation kit (filter now sits right near the throttle body and radiator).

Ok so first attempt i wasnt getting any pressure, whoops the lines are backwards, so i swapped them and now it works. But i went for a strap and the pressure gauge (stock on the dash) says i'm only getting 2-2.5bar max! This cant be good can it?!!

Question is has anyone with similar mods had the same problem?
Is it just a dodgy dash gauge? (also seems slow to transition, from high to low)
Or have a blown the oil pump?! noooo!!!

Thanks for any help!
Dave

Goodnight!!

[Boags]

Did you put anymore oil in? You have a larger capacity for oil now, so with the same amount you have less pressure. (?)

Just a thought.

Boags

[Fatty]

Did you put anymore oil in? You have a larger capacity for oil now, so with the same amount you have less pressure. (?)

Just a thought.

Boags

hmm, yeah that was my first thought too

[Sheck]

Yea same with my first thought, so i filled it up last night and made no difference.

My thinking at the moment is that there is reduced flow through the oil cooler lines/assembly which is reducing the pressure seen at the sensor.

One way to test this is to fill it up with thinner oil (current is 15-50, so a 10-something or 0 or 5- something would help me check)
Only problem is i dont want to spend 60 bux on new oil for it to do nothing

Dave

[Sheck]

anyone? any ideas?
I'm gonna have to pull it off at this rate, going drifting tomo so i have to get it sorted

Cheers

[Sheck]

Ok just went over everything again, had the car running and stuff.
I found there was a tiny leak (like maybe half a teaspoon worth of oil after a couple of drives), this was just a couple of nuts that needed tightening on the oil filer block - sorted.

I reved the engine up and found there was no extra valve train noise, so i disconnected and reconnected the plug for the oil pressure sender unit. No change.

Now i'm thinking that maybe when i had the lines the worng way that could of stuffed the bypass valve in the oil filter which would mean that the oil is flowing past the filter which would cause a drop in the pressure. But at the same time th efilter got hot pretty quick which would indicate that its fine.

Hrrmmm maybe i should buy another gauge and replace my sender unit with the new one. Or i could get a new filter and test out that theroy..

[JBT]

I'd try another filter first.

[Sheck]

done filter and a new gauge.
Filter did nothing and the gauge showed that my stock one was off by a bit but doesnt account for all the pressure loss.
I was getting around 40psi at 5k rpm (didnt rev it higher, i hate free revving the car when i'm standing next to the engine)
Does that pressure sound ok? I've heard 10psi per 1000rpm is like the magic number but i've also heard that if your getting plenty of flow then thats better??

Think i might risk it tomo as is.

Fingers crossed
Dave

[JBT]

40 psi at 5000RPM sounds OK to me Dave, but I can't see why fitting the oil filter relocation and cooler would have changed things . I have nothing to compare with you because mine just has the 'idiot light' oil pressure gauge.

[orx626]

Hi Sheck, is the oil cooler a new addition to the system or just that you relocated the filter?

Cheers,
Danny

[Sheck]

Yea its new, only way i could fit it was with the relocation kit.

I done some research on m.net and found that any restriction before the sender unit will be seen as a drop in pressure.
I've got 12mm internal diameter lines so i think it might be the fittings making a bit of resistance.

Got a tow truck (mates bringin it) so if anything goes wrong i'll have a way home, hopefully it'll be ok. Had no valetrain noise from the test thrashes so it should be all good.

Dave

[orx626]

Sheck, any increase in restriction is of concern I know you probably don't the have time or the equipment needed, but I really recommend that you try and find which item or items are contributing to the pressure loss. It's very possible that the oil cooler is too restrictive. Honestly, I'd rather have the oil too hot (ie. shorten the oil life and have to change it more regularly) than have the oil pressure too low when running through your bearings and valve train especially at high rpm. NB. the higher the oil flow rate (higher engine rpm), the higher the oil pressure drop.

How about you remove the oil cooler from the circuit and check the pressure then. This will give you an idea as to whether the oil lines and remote filter or the oil cooler are the bigger contributor to the oil pressure loss.

I don't know if it is possible on this engine, but it may be possible to increase the oil relief pressure to offset the increase in pumping losses. If so this then raises the question....can the oil pump cope with running a higher system pressure???

I hope I've answered more questions than I've raised.

Cheers,
Danny

[Sheck]

Yea 99.9% certain that it is the oil cooler, anyways i ran the event today with the low pressure went well. Had a leak from a water line (thremostat to mani) which stopped my day. The one time i dont bother bringing hose is the day i needed it! ehhe

Got slight noise from the top end (cant say i'm surprised) but no power loss or anything.
I'll prolly lay off the drift till i get a properly built motor. Or at least a replacement.

Need to find a way to have an oil cooler on with out loosing pressure.

Dave

[orx626]

Need to find a way to have an oil cooler on with out losing pressure.

Dave

Hi Dave, the best factory oil cooler available is the series 4/5 RX-7....has an in-built thermostat to help the oil get up to operating temperature quicker. Most importantly, it will cause minimal pressure drop. They cost about $150 for one in very good condition. The only problem will be working where and how to best fit it. A custom built cooler might be a bit expensive.

Cheers,
Danny

[CT]

Flying Miata sell (it's a Mocal brand) an excellent thermostat oil cooler adaptor. And maybe try a 5w30 - it's a good choice in synthetic for BP engines.