Blacktop 4AGE Oiling System Research
Posted: Wed Jul 27, 2016 5:12 am
So, I just did some blacktop oil return and coolant routing investigation, and I'm a bit
shocked. Those big drains you can see in the head gasket don't do s*** until the head
is half full! Which leaves the two small ~12mm ones rear and mid-front to do the work.
Furthermore, adding external drains to it is really tricky, difficult but possible at the back
on the intake side, but hard core/impossible at the front on the intake side.
Another thought crossed my mind, too, contrary toevery engine I've ever seen, (see next post)
the right place to take your breathers off is smack in the middle of the top of the engine
and up high, which would also require some custom fab etc but would ensure that even
in a nasty flood of overflowing, it'd stay dry.
That could be emulated by taking the breathers off the usual places, routing them
together and upward, and plucking it off the middle of that. This quite possibly would
have saved me on the ute at Hampton Downs.
I guess the equivalent is to take the LHS breather and route it upward and RIGHT and
away, and vice versa for the RHS breather, otherwise it's just a giant funnel out of the
engine and into the guard :-D You heard it all here first. Probably.
I guess the purpose of that central "drain" isn't a drain at all, what in fact is, is the
channel through which blow by can escape through the head and breathers, and for
that it'd work admirably. I'd probably leave that completely alone even though it has
big potential to get a lot of oil out of the head. I wonder what 16v shit is like?
For the 20v, the entire intake side is all ports, and the gaps between the ports align
with the head bolts, and the area below the ports is 100% cooling, which only leaves
these two tiny areas at the front and back, but the back one is ultra tiny due to the
shape of the casting and the cam belt etc. I wonder if the inter port gaps can be
used in some clever fashion - maybe, just maybe.
I think I'll have to get some sort of table setup and take this smoky blacktop apart.
Thinking about this all from a FWD perspective
The same set of states in an unmodified RWD configuration
shocked. Those big drains you can see in the head gasket don't do s*** until the head
is half full! Which leaves the two small ~12mm ones rear and mid-front to do the work.
Furthermore, adding external drains to it is really tricky, difficult but possible at the back
on the intake side, but hard core/impossible at the front on the intake side.
Another thought crossed my mind, too, contrary to
the right place to take your breathers off is smack in the middle of the top of the engine
and up high, which would also require some custom fab etc but would ensure that even
in a nasty flood of overflowing, it'd stay dry.
That could be emulated by taking the breathers off the usual places, routing them
together and upward, and plucking it off the middle of that. This quite possibly would
have saved me on the ute at Hampton Downs.
I guess the equivalent is to take the LHS breather and route it upward and RIGHT and
away, and vice versa for the RHS breather, otherwise it's just a giant funnel out of the
engine and into the guard :-D You heard it all here first. Probably.
I guess the purpose of that central "drain" isn't a drain at all, what in fact is, is the
channel through which blow by can escape through the head and breathers, and for
that it'd work admirably. I'd probably leave that completely alone even though it has
big potential to get a lot of oil out of the head. I wonder what 16v shit is like?
For the 20v, the entire intake side is all ports, and the gaps between the ports align
with the head bolts, and the area below the ports is 100% cooling, which only leaves
these two tiny areas at the front and back, but the back one is ultra tiny due to the
shape of the casting and the cam belt etc. I wonder if the inter port gaps can be
used in some clever fashion - maybe, just maybe.
I think I'll have to get some sort of table setup and take this smoky blacktop apart.
Thinking about this all from a FWD perspective
- Cruising - no big drama, RPM low, oil level approximately flat, oil able to casually drain out of both left and right side front drains (front and back of engine, exhaust/LH side)
- Braking - no big drama, regardless of RPM, oil pushed at in excess of 1g toward the drains means excellent oil return, if insufficient, the rather high centre passage will come into play much earlier due to the effective angle of the surface of the oil
- WOT Acceleration in 1st gear - no big drama, only lasts a second or two, later gears pull very low Gs, much like cruising, but RPM in the 6k to 8k+ range, both oil returns will be working hard with some minimal pooling in the head at the intake side due to mild Gs.
- Hard Turning Left - no big drama, high effective to-sump pressure driving oil out of head through RHS drain at front of engine, if feed was excessive, and corner was long, loss from breathers could occur, but most corners just aren't.
- Hard Turning Right - no big drama, exactly the same as left, except LHS drain at the rear of the engine is used.
The same set of states in an unmodified RWD configuration
- Cruising - no big drama, RPM low, oil level approximately flat, oil able to casually drain out of both front and rear LHS drains
- Braking - no big drama, high effective to-sump pressure driving oil out of head through front LHS drain, if feed was excessive, initial speed was high, and RPMs kept high, loss from breathers could occur, but would not be sustained for more than a few seconds at worst.
- WOT Acceleration in 1st gear - no big drama, only lasts a second or two, later gears pull very low Gs, much like cruising, but RPM in the 6k to 8k+ range, rear LHS oil return will be working hard with some minimal pooling at the rear of the head as supply exceeds expulsion.
- Hard Turning Left - Terrible, we have a problem! Oil will pool heavily in the RHS of the head where it has NO drains whatsoever. This will take seconds to build up, but once it does, oil will be lost from breathers which are very poorly placed for this scenario, and the head will remain full of oil. This is bad for your bottom end too, as while it's in the head, it ain't in the sump, and your pick up will be sucking air to some degree after the oil volume in the sump has been reduced sufficiently. This is the scenario that drives modification of the head.
- Hard Turning Right - Exactly like FWD braking, regardless of RPM, oil pushed at in excess of 1g toward the drains means excellent oil return, if insufficient, the rather high centre passage will come into play much earlier due to the effective angle of the surface of the oil