Head Oil feed restrictor?

[Blackmk3]

My 7mgte is at the re builders at the moment, there checking it out measurements etc and ill order pistons, head gasket etc etc from there

But i was having a chat with the re builder, autho unfamiliar with the 7mgte engine they have done alot of work with 2jzs and RB nissan motors
We were talking about the 7ms habit of filling the head with oil when at the track, I race the car just for run at our local track in dual sprint style events around 7-10 laps at a time.

The re builder was looking at the size of the oil feed hole into the head and thinking compared to RB nissan motors its huge, and a common thing for the RBs to fit oil restrictors into the block to limit the oil flow.

So before anything goes ahead i thought i would just throw this question out there to the community and see of anyone's done similar?
Searching didn't come to much.

Thanks very much
Nick

 

[IndigoMKII]

I think that design comes with the fact that these are high flow/low pressure oiling systems.

I've seen oiling system modifications like better oil cooler setups that are thermostat controlled along with oil pump shimming but nothin like what you're talking about. Im curious to learn more.

 

[Blackmk3]

I already have a relocated oil filter and oil t stat and cooler setup, so the stock bypass cooler is long gone

He did mention that issues with the block restrictors are if its to restricted, during street driving situations you could run risk of starving the valve train,
where at the track there's plenty of constant oil pressure to push it all up there
It is a full trim street car/weekend track toy

 

[super51fan]

I would not do it. This is not a "RB" or a "2j" engine. IMO good luck.

 

[Blackmk3]

I understand that, but im not the first to have this issue with the 7m, and was wondering what others do

 

[hvyman]

Ive never heard of this before. 7m or 2jz.

 

[IndigoMKII]

Ive never heard of this before. 7m or 2jz.

Same. I might look into this when I pull my engine apart.

 

[super51fan]

If this is an issue why would you do a mod that "could make engine not good for street use" Usually our cam journals look like crap but kind of normal. I would not reduce oil flow to head.

Most people who build domestic engines work on enlarging and improving the oil return flow of an engine.

This is how i would go about it.

A lot of people do add some extra oil over the full mark. As much a quart seems to cause no adverse effects. IMO

I bet a lot of racing miles have been done with the 7m platform. This is the first I have ever heard of it.

Good luck.

 

[Poodles]

No real reason to restrict oil to the head as it has many large pathways back down, so the oil isn't sticking around up there. I've never heard of any of the big power guys doing it...

 

[IJ.]

Stupid idea is stupid....

 

[Rollus]

We don't wan't to fill the head by emptying the crankase, but, if we reduce oil pump pressure by cutting the spring (the opposite of shims), and install Oil feed restrictor in the head, then flow from head to crankcase would be close to the flow from pump to head.
In both case (restrict the return flow or restrict return&sump flow) rod knock happens quicker and we can swap 2JZ or RB because 7M is not reliable. This probably makes an improvement, or not.
Another improvement would be to find another rebuilder. I have never read or listen someone who seriously think about reducing oil flow in the engine unless for building pressure.

More seriously, I don't know the answear, but I just had a good read there: http://homepages.vodafone.co.nz/~lakewood/Skyline/R33_head.htm
Lots of interesting datas there also: http://mrbizzle.wordpress.com/2010/02/24/84/


I understand that's a totaly different topic in fact, because pressure is controlled by relief valves in our engines..

Reynald

 

[Nick M]

We were talking about the 7ms habit of filling the head with oil when at the track

What?

 

[gats]

But i was having a chat with the re builder, autho unfamiliar with the 7mgte engine they have done alot of work with 2jzs and RB nissan motors

Common mod to do to CA18's but not 7M's...

 

[Blackmk3]

This was a nissan aimed post, and that was what the rebuilder was referring to, alot of the New Zealand car scene is nissan related and seemingly common to fit these restrictors. I wasn't a fan of the idea but just wanted to run it past the community for opinions. And that's great ive certainly made up my mind.

As my 7m started getting older with more blow by i started getting more and more issues with the engine chucking out oil into the vented catch can.
Oil surge is what killed the bottom end. Probably due to more oil staying in the head and oil surge within the sump
Either way the engine will be getting oil drain work done to smooth things out and hopefully get more oil back quicker, plus a oversized winged and gated sump
And less blow-by with a rebuilld!

Nick

 

[Nick M]

As my 7m started getting older with more blow by i started getting more and more issues with the engine chucking out oil into the vented catch can. Oil surge is what killed the bottom end.

This seems wrong. More like oil starvation from lack of replenishment. Or the wrong grade of oil. Something like a 40 or 50 grade that just doesn't flow good unless it is 300 degrees.

 

[Blackmk3]

Oil surge is what killed the bottom end. Probably due to more oil staying in the head and oil surge within the sump

I did say that, maybe with the wrong word, Should have been Oil "Starving" instead of "Surge"
Thanks for pointing it out