7M-GTE Oil Pressure/Oil Recomend

[Hibba]

Ok So Heres the tale.



Me and my mate (Jin~Jah) have been slowly rebuilding his cressida in my garage for the last few months. Its a 7MGE Block/Head, with all the Turbo Gear bolted on it it. (knock sensors, oil drain, oil feed etc)

Basicly it goes as follow's,

We have 15/40 oil in the engine at the moment. When you start it, it sits on about 60psi of oil pressure at idle (cold).
Now when you bring it above idle, you start getting a slight tapping from the bottem end.
After letting it idle for awhile, the oil pressure at idle will drop to 10 or so psi which is what the TSRM(7M-GTE) recomends for the pressure.
After it as warmed up to this point you can give it all the curry you want and it wont make and tapping noise's. Bring it up to 3000~rpm and it gets about 70psi of oil pressure which is what it says should be in the TSRM(7M-GTE).

Now the question I'm asking is..

What oil should we be running in this? or is there some other problem?

[cambelt]

15/40 is to thin for a stock rebuild 7m
i have a totally stock un rebuilt 7mgt and it idles at 7psi hot summer time , its stuff all but its been the same for 6 years now and no bearing trouble at all . if you nearly stall it the oil light will come on ( 4psi) , this engine has 145000klm on it from new now and still runs perfect in every way .
Also pulls a 13.3 down the quarter in a mk2
Dave
Dave

[amichie]

Ok So Heres the tale.



Me and my mate (Jin~Jah) have been slowly rebuilding his cressida in my garage for the last few months. Its a 7MGE Block/Head, with all the Turbo Gear bolted on it it. (knock sensors, oil drain, oil feed etc)

Basicly it goes as follow's,

We have 15/40 oil in the engine at the moment. When you start it, it sits on about 60psi of oil pressure at idle (cold).
Now when you bring it above idle, you start getting a slight tapping from the bottem end.
After letting it idle for awhile, the oil pressure at idle will drop to 10 or so psi which is what the TSRM(7M-GTE) recomends for the pressure.
After it as warmed up to this point you can give it all the curry you want and it wont make and tapping noise's. Bring it up to 3000~rpm and it gets about 70psi of oil pressure which is what it says should be in the TSRM(7M-GTE).

Now the question I'm asking is..

What oil should we be running in this? or is there some other problem?

You can identify which cylinder is causing the tapping sound by removing one sparkplug lead at a time.

[Jin~Jah]

15/40 is to thin for a stock rebuild 7m
i have a totally stock un rebuilt 7mgt and it idles at 7psi hot summer time , its stuff all but its been the same for 6 years now and no bearing trouble at all . if you nearly stall it the oil light will come on ( 4psi) , this engine has 145000klm on it from new now and still runs perfect in every way .
Also pulls a 13.3 down the quarter in a mk2
Dave
Dave

What weight oil are you running in it? and how much pressure does it make at idle when cold?

-James

[abently]

Engine Oil will provide more protection (at the cost of Flow - resulting in the immediate 60Psi of Oil pressure) when Cold, then when Hot.

The cSt value is always higher at Lower temperatures.

The best advice I can give, would be to get an Amplified Microphone (the Type tuners use to listen for 'Engine Knock') and pin point exactly where the noise is coming from.

For future reference, if you set your Mains & Conrods - Bearing Clearance to Factory specifications (on the tighter side if they give you a range), then you should stick to the Factory recommendations on Oil Vicosity. Which by the information you've given, seems to be right, so just locate exactly where the noise is coming from before doing anything else.

[cambelt]

You give a 7M 1 thou big ends and 1.5 thou on the mains and run a 10/40 oil and you will have a 200000klm life of hard thrashing . but 10/40 is far to thin for a factory 7m .
Dave

[abently]

You give a 7M 1 thou big ends and 1.5 thou on the mains and run a 10/40 oil and you will have a 200000klm life of hard thrashing . but 10/40 is far to thin for a factory 7m .
Dave

That may be true, but the fact remains that his Oil Pressure numbers are perfect so in this case the Oil he has in it is also perfect.

You should also be aware that just because an Oil is 10W/40, it can actually be 25+% thicker then a competitors 10W/40. cSt is an indicator of thickness which you can use to then select a thicker or thinner Oil depending on what your Oil Pressure gauge is reading.

[Hibba]

The real big problem is the cold oil pressure, That is the only time you get a knock.

When its cold and has 60psi at Idle.

When its warm and you have 7-10psi at idle its fine
When its warm and you have 60-70psi at 3000~rpm its fine.

Its just the cold bit.


The enigne wasn't built by us.
It came out of a cressida that had been rebuilt ~9000km ago give or take.

[abently]

You should be able to find a local Tuner who is happy to lend you the use of their Amplified microphone for a couple mins after the Engine has cooled right back down.

The problem is going to be hard to find without doing the above.

[The Real Roadrunner]

i think you may find the clearances on the pistons aren't quite right but that being said ive seen heaps of "slappers" last for years so i wouldn't be greatly concerned.
does it have forgies in it by any chance? as they are renouned to be noisy when cold!!!

cheers
linden

[Jin~Jah]

nah no forgies (this time )

as far as i know they're reasonably stock pistons apart from the apparant oversizedness

[RyleyMA61]

sorry for the hijack, but what is the minimum oil pressure for the 7m? after a few laps of the track, and idling to cool down, the oil would heat up and drop to around 20psi at 3000rpm... (after being between 60-40psi around the track)

i let it cool until pressure was better again. would this have damaged the engine? the low pressure light never came on.

oil is magnatec 15/40

[abently]

sorry for the hijack, but what is the minimum oil pressure for the 7m? after a few laps of the track, and idling to cool down, the oil would heat up and drop to around 20psi at 3000rpm... (after being between 60-40psi around the track)

i let it cool until pressure was better again. would this have damaged the engine? the low pressure light never came on.

oil is magnatec 15/40

Rule of thumb is 10psi of Oil Pressure for every 1000Rpm.

But Hibba has said @ 3000 Rpm, its suppose to be reading 70Psi. I'm assuming this is at Load in 4 or 5th Gear......

Eitherway, if its still reading low, once up to temperature, then its time for an Oil change as its broken down due to Fuel or over-Heating.

If you take the car to the track often, you should really get an Oil Temp gauge. This will save your Mains and Conrod bearings along with the rest of the Engine, if you don't allow the Oil to get above 135 Degrees Celsius (When 40W Oil < 3cSt) .

[Hibba]

But Hibba has said @ 3000 Rpm, its suppose to be reading 70Psi. I'm assuming this is at Load in 4 or 5th Gear......

70psi @ 3000rpm Free Reving

[RyleyMA61]

cheers abently.

oil pressure is good as gold now, going to change it anyway. just after a few laps it got hot and low pressure, then once cooled was fine again.

might relocate the oil cooler to in front of the intercooler or in direct path of air and see if it helps...

cheers
rlyey