4agze rebuild - fit oil restrictor going to head?(yes or no)

[~SlideWays~]

Long story short, my 4agze is being rebuilt at the moment. It has problems with filling the head with oil (at the race track only), then it has nowhere to go but out the breathers and into the catch can. This has been a massive problem and I've gone crazy with trying to fix it with extra oil drainage but then it ran a bearing after the 6th unsuccessful track day (and about 5,000 road kms).

Since it is being rebuilt I wanted to fit a restrictor in the oil gallery before the head with a 3mm hole.

The guys rebuilding it are ready to put the head back on but are questioning whether to fit a restrictor because it may starve the head of oil. And the engine had lots of blow by so was a big factor in the drain back issue.

But all of the research I've done points at it being a problem with all 16 4age's (both fwd and rwd) even without bad blow by. Its a smallport so has the factory external oil drain so obviously Toyota knew it was a problem. I've also asked for the head to be die grinded to open up and aid the drainage so it'll hopefully be better anyway, but I'll be setting the thing on fire if I have another track day ruined by $&#$% oil everywhere...

So will a 3mm hole be sufficient to feed oil for the cams? The factory gallery/feed to the head is enough to completely fill the head with constant high rev's so surely there is room to reduce it.


Here are some links to people using a restrictor:
http://www.motoiq.com/magazine_articles ... a-4ag.aspx



http://www.streetracing.co.za/forum/vie ... f=7&t=2207

We normally fix oil problems on the 4AGE's by installing a restrictor in the block where it feeds oil to the head. the hole should be around 3mm when fitted.

I and everyone I know of use a 8mm grub screw, you simply tap the oil feed channel, it's the right size for the tap, and turn the grub screw in there with some locktite. Remember to drill the hole in it first though..hehehe Also I then peen the edges of the block around it to make sure it doesn;t come out. Others say this isn't needed, but I'm a little over cautious where loose screws are concerned...

[rollaholic]

i say do it.

since you are prepared to burn it if it fails again anyway, whats the worst that can happen

[Dell'Orto]

A little risky without some trial and error I guess. The restrictor will work sweet for sustained high RPM, but what about pottering around at low speeds? Cool down laps etc

[Shrike]

They run restricters in RB motors all the time without issue how much oil do you really need in the head?

[iOnic]

Yup RB's have the same issues. This may/may not have useful info for you.

http://run-it-hard.com/2012/01/rb-oil-control/

[touge_ae101]

Maybe a late post but this sounds like a terrible idea. the way to deal with it properly is have an external oil drain feeding back to the crankcase.

seems to be a pretty common problem with 4ages that do a lot of revs... my 16v will blow a plume of smoke after 2-3mins on the rev limit.. haha only time it smokes at all

[Adoom]

Maybe a late post but this sounds like a terrible idea. the way to deal with it properly is have an external oil drain feeding back to the crankcase.

seems to be a pretty common problem with 4ages that do a lot of revs... my 16v will blow a plume of smoke after 2-3mins on the rev limit.. haha only time it smokes at all

He has already done that.

and I've gone crazy with trying to fix it with extra oil drainage

There is no way the external oil drain he has made is not big enough. It's massive.