4agze problem no 4 conrod breaking

[legend]

i rang my engine machinist the other day and he told me
the 4agze motor was prone to breaking no4 conrod due to the oil return on
the back of the head
the oil hits the conrod wilst draining back into the sump at high rpm causing rod failure

has any body heard of this he recommeded modifying the oil return

[slide86]

never heard of it. my gze doesnt even have the oil return from the head (bigport motor)

[YLD-16L]

Back of the head when in FWD configuration I think is what he is referring to.

I have not heard of this phenomenon though.

My 4A and all the others I know of don't have the external oil drain though.

[slide86]

i think the oil drain is only on the small port engine. i have seen photos, but never actually seen one.

[mr2gze]

Here is the oil drain coming out of the rear of the head on a 101 gze.


Interesting theory your machinist has on this one. I cant say I have heard of this happening though. I'm keen to hear more details about it, rather than, "he said this happens because of this". etc

Do you mean the rod bearing or the actual conrod itself? You have only said conrod. Did he give any more specifics to as why he thinks oil dripping on the rod bearing/conrod could cause it to fail?

cheers

[kingmick]

i rang my engine machinist the other day and he told me
the 4agze motor was prone to breaking no4 conrod due to the oil return on
the back of the head
the oil hits the conrod wilst draining back into the sump at high rpm causing rod failure

has any body heard of this he recommeded modifying the oil return

lol tell you machinist he gets first prize for bullshit! If he is smart he will make you a little deflector to stop it hitting the Rod and charge you $500 for making it! lol.

[Ben Wilson]

The oil is hardly going to be pouring through the hole (remembering that earlier and later 4AGs don't have it at all). I'd imagine it might be a dribble at most. I'd be very surprised if ti had enough momentum to even lift off the wall of the block.

Like Mick said, if it worries you, just build up a baffle in case.

[EVOSTi]

never heard of the problem, but for the sake of a thin piece of metal you could make a shield that deflects oil away from the conrod and to the side of the block if youre worried.

["Z" UTE]

Riddle me this guys, is that an oil drain specifically, or is it a crankcase breather?

Your machinist, knows little about "splash lubrication" as utilized in the majority of engines and gearboxes.

cheers Chuck.

[oldcorollas]

but GZE has oil squirters to piston undersides... and the mains and big ends are pressure fed from crank.... only valve gear is splash fed?

edit: possibly equaliser/breather...

[Mr Revhead]

its definitly an oil drain. the big ports are well known for filling the heads up with oil at constant high RPM. later silvertops had improved head drain.

[kingmick]

Riddle me this guys, is that an oil drain specifically, or is it a crankcase breather?

Your machinist, knows little about "splash lubrication" as utilized in the majority of engines and gearboxes.

cheers Chuck.

its main purpose is an oil drain but yes it would also work as a breather if needed but its not really as the main return is big and the topping up comes from not having multi returns.
exellent question man!!

[30psi 4agte]

Steer clear of using this as a dedicated breather though . It is noting but trouble !! The crank throws oil straight up that pipe !plus the rushing crankcase air/pressure doesnt allow it to return.
I have NO idea why toyota put it on that side of the block. (must of been a idea thought up late one friday arvo )

It would have been far more useful on the other side...... but then again that side already houses the main return for oil to the sump.

[Billzilla]

Steer clear of using this as a dedicated breather though . It is noting but trouble !! The crank throws oil straight up that pipe !plus the rushing crankcase air/pressure doesnt allow it to return.
I have NO idea why toyota put it on that side of the block. (must of been a idea thought up late one friday arvo )

It would have been far more useful on the other side...... but then again that side already houses the main return for oil to the sump.

Heh, exactly the same thing happened to a mates engine in NZ, when I lived there. The breather is much better in the block than the head, so it'd be great if we could use that hole but the oil manages to be ejected out of it at an amazing rate.
We were going to make a little hat for it, with open sides so it'd still breath but not throw oil up there but never got around to it.

[kingmick]

a inline mesh filter works wonders on the external return!