4AGTE 16V head oil drain question

[Dongaz]

Ok I have a 4agze bottom end from the late model with the oil drain in the side of the block near the rear.
This used to have a smallport head which had the oil drain in the back lefthand corner.
I have now opted for the bigport head and therefore doesn't have the oil drain there.
I wouldn't think it makes any difference but it is also turbocharged.

My question therefore lies, is it ok to run the oil drain out of the oil plug gallery bung at the back of the head like this turbo PRB?

Is this a viable option or is it necessary to have the rear corner drilled and taped like the smallport so the engine doesn't have oiling issues with high revs?

The last thread I saw the person drilled and tapped it and didn't have any further issues. As far as I could find noone else has done this in there 86 on this forum. But then again most are just N/A and using smallports aswell.

I am also not going to just plug the side of the block as some have suggested as I don't think this is a reasonable decision.

Cheers

[Cuzzo]

I have seen that PRB style for a breather before which is what it should be used for.

If it was me and it wasnt urgent to get going, i would drill and tap a fitting in the back of the head to line up with the block fitting. I have seen other people do this aswell.

The reason is that the 4age heads pool oil in that rear corner usually from the way they are mounted in factory applications. Not sure if you can the angle the motor to reduce this. If you see another 4age running and then pulled the cam covers off you'll see the pooled oil.

[Dongaz]

Are you saying that the PRB uses it as a breather to the catch can? and only that?

Thinking about how the motor sits makes sense now. How does this effect that side with the cams etc?

[Cuzzo]

I dont know about that one in particualr but normally they use it as a breather.

No idea how this will effect the cams

[TERRA Operative]

The PRB isn't using it as a drain. Liquid flows down hill, so you'll have to fill the head completely with oil before it came out there.

I would drill a hole and install a fitting in the same place as on the smallport head.

[oldeskewltoy]

smallport head was cast with a boss that could be drilled to fit the drain, is there such a boss, or similar area to fit a drain to that portion of a TVIS head?

[30psi 4agte]

Being turbo does make a difference if you ask me.
In my particular setup having the drain connected caused issues. In my opinion the drain was located in the wrong spot from factory.

The drain is located in the worst possible postion and cops alot of oil being slung/thrown up directly into the drain from the con rods and crank. ESP on extended high RPM use.
Now...... throw some boost into the equasion and i found myself having issues with too much oil in the head causing excess overflow out of my breather pipes. Alot of oil in the head = alot of oil being forced out.

My theory behind this was that the excessive positive crank case preasure was actually forcing the splashed/thrown oil from the crank and rods up into the head through that drain pipe and not allowing it to drain back to the sump due to the rush of crank case air flowing up through that drain and out my breathers.

I blocked that drain and havent had any issues since.
For me it was a case of less is more. I found less oil reaching or being forced into the head.

[30psi 4agte]

smallport head was cast with a boss that could be drilled to fit the drain, is there such a boss, or similar area to fit a drain to that portion of a TVIS head?

TVIS head doesnt have that provision........ but if you really wanted it im sure it could be done.
Nothing too hard to do

[TERRA Operative]

Could you put a baffle in the sump to prevent the oil being blown back up the pipe?

[PrettyCoolWagon]

Could you put a baffle in the sump to prevent the oil being blown back up the pipe?

Very old thread I know, but I've seen this issue raised a few times and you never know who's trolling the internet for that certain bit of info.

QUOTE:

"...install a restrictor in the oil gallery that runs to the head. You can tap it to 6x1.25 thread and turn a grub screw in there which has a 3mm hole drilled into it. The original hole is about 5mm, the smaller 3mm hole will prevent all the oil from being pushed to the head and also ensure that the pressure that is bled of to the turbo is made up for and the bearings are getting enough oil.

We've all done it and haven't had problem like that again..."

END QUOTE.

Taken from: http://www.streetracing.co.za/forum/...php?f=6&t=4347

Some photos can be found here on MotoIQ's N/A 4AG dry sump set up.
http://www.motoiq.com/MagazineArticl...oyota-4AG.aspx

[rolleraction]

That oil gallery restrictor is identical to the one I ran in my 3SG motor, to avoid excessive oil going to the head as mentioned above.
From memory i was a Nissan (nismo) standard item, something like 6mm tapered aluminium plug with 2mm or so opening for the oil

[PrettyCoolWagon]

For anyone wondering where to buy...?

Here's some links to various ebay sellers for oil gallery restrictors, apparently boosted 4AG engines aren't the only engine to have this issue.

Some are screw in others are press fit.

For nissans
http://www.ebay.com.au/itm/TOMEI-OIL...c676bb3&_uhb=1

Universal
http://www.ebay.com.au/itm/OIL-GALLE...309d1a4&_uhb=1

For Fords
http://www.ebay.com.au/itm/FORD-RACI...de89e64&_uhb=1

OR

http://www.e-slotcar.com/category/831.aspx