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My 20 cents;

Your oil temp gauge isn't working properly, refer Duncan's comments above, so fix or replace is the answer.

I have never seen the need for an oil cooler thermostat in Australia, it quite simply doesn't get cold enough in all but a couple of places.

Overfilling the sump is related to oil surge, but the real reason for it is to compensate for the oil that stays in the cam covers when high rpm is used for sustained periods.

The fluctuations you see in oil pressure could be oil starvation around the pick up as so much is trapped in the cam covers, they hold well over 2 litres.

The larger the diameter of the restrictor hole the more oil goes up to the cam covers, a higher flow oil pump just makes that situation worse.

I assume that it has the standard GTR one oil feed to the head blocked off and it has a Tomei restrictor in the other. I have seen RB26's with 2 restictors, which is not correct.

The standard poor oil returtn to the sump is a well know RB problem, that's why the serious track guys run external oil returns and enlarged oil return passages to the sump. Or dry sump with a scavenge stage for the cam covers.

The one way doors stop the oil from flowing to the dip stick, that's why you can't check the oil level immediately after shutting down the engine. So don't let it worry you.

Maybe 25 cents worth.

Cheers

Gary

Hi all,

Right I found out whats going on! It's what I thought with a slightly different twist.

Basically the oil isn't getting up to temperature, therefore it takes a huge amount of time for the oil to drain past the baffles back to the area where the dipstick goes in the sump.

This makes it looks like there is no oil after starting. I'm looking into getting a oil thermostat or maybe using something like a 5w40 instead of the 10w50 to help the oil get up to temp quicker. At present I have to sit for over 30mins at 2k to get the oil to 60 degrees! Once it's up it stays up but if you don't do this it will never get up to temp, I guess due to overcooling?

Also the oil cooler is a laminova unit, does anyone know if you can get thermostats for them?

Cheers for all your time.

M

do not sit still idling or revving the engine to get things to 60 degrees. that is the worst way to do things. your oil will get up to temp much quicker just by normal driving where the engine is under load etc. not to mention the impracticality of sitting in your garage for half an hour revving your engine! start the car and you should be driving off after no more than 30 seconds. get a new proper temp guage. you should need no more than 5 mins (10 max) of sedate driving to get things up to around 70-80 degrees C. sitting in the garage waiting for things to warm up is just wearing out your engine. you want it to get to operating temp as quick as possible and the way to do that is sensible driving (ie revs under 4500, no WOT, not big boost etc).

Thanks for the detailed replies everyone.

What I'm doing now is running 0.5l extra which helps reduce the oil pressure drop when accelerating in low gears. I'm running relocated filter, oil cooler, tomei baffles and N1 pump. I guess without running the extra oil it can't return to the sump quick enough. Even if I leave the car after a long run for 45 minutes plus it still barely registers on the dipstick. I know Sydneykid mentioned it would take a while for it to drain back to the dipstick area, but if it's showing little oil in the sump isn't it wise to add a little more?

Now that I run 0.5l more, when I turn the car off when hot and check after a short while the level is 100% to the max. I basically topped it up when warm until it went to the max. When I check when cold it's up at the start of the bend, when I check when warm it's at the max line. Oil pressure drop has also been reduced.

I will also look at replacing the Greddy gauge or at least find out what needs replacing. Will also make sure I don't warm up idling now I know that the gauge is buggered!

Cheers all this is a top forum!

M

Edited by Monky
  • 1 month later...

Hi people,

I have the same set up in my GTR, tomei baffle, restrictor etc etc

what gave me the shits the other day is when I fitted my Defi gauge kit and noted my oil pressure disappear when you give the throttle a quick dab in 1st or 2nd!!!!!! yet the factory gauge just sits there at 3.5bar and doesn't even move.

This thread has been very interesting to say the least!

I will be filling my sump with the extra half a liter tomorrow and see if this improves....

cheers,

Mike

Thanks for the detailed replies everyone.

What I'm doing now is running 0.5l extra which helps reduce the oil pressure drop when accelerating in low gears. I'm running relocated filter, oil cooler, tomei baffles and N1 pump. I guess without running the extra oil it can't return to the sump quick enough. Even if I leave the car after a long run for 45 minutes plus it still barely registers on the dipstick. I know Sydneykid mentioned it would take a while for it to drain back to the dipstick area, but if it's showing little oil in the sump isn't it wise to add a little more?

Now that I run 0.5l more, when I turn the car off when hot and check after a short while the level is 100% to the max. I basically topped it up when warm until it went to the max. When I check when cold it's up at the start of the bend, when I check when warm it's at the max line. Oil pressure drop has also been reduced.

I will also look at replacing the Greddy gauge or at least find out what needs replacing. Will also make sure I don't warm up idling now I know that the gauge is buggered!

Cheers all this is a top forum!

M

Edited by The Alchemist

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