Blow-by

[Polyarkos]

My 1HDT rocker cover vents straight out to atmo via a hose to the rear bumper. I have noticed some white smoke/vapour/steam (not sure which) coming out at idle. The hose is damp with oil to the touch but I am not seeing any oil dripping on the ground (actually there a 2 or 3 small drops, but seems ok after 6 months of use).

Over the past few months the idle has been really rough in R or D, and while stationary the exhaust was smokey. After a few diesel fuel treatments (Moreys) the smoke and idle has cleared up completely - though she does belch huge black clouds under heavy acceleration.

Regarding blow-by, I do not seem to be using oil but may be using some water - what can I do to check if there is too much blow-by? I've heard that some visible smoke is normal - how much is too much?

IP and injectors are soon to be rebuilt but don't wanna spend $4000+ to do the rings etc if everything is within normal limits

Thanks in advance,

JP

 

[roscoFJ73]

Do a compression test and if its ok go ahead with the pump and injector rebuild.

There is always some oil coming out of those pipes,thats why its normally directed back into the engine to be burnt.

Can you smell engine coolant? Thats what can be the cause of "white smoke/vapour/steam"

 

[Polyarkos]

If its coolant would that mean issues with the cylinder head or gasket?

I'm getting a leak down test done next week

 

[goldchaser]

It vents to the rear bumper????

 

[Polyarkos]

It vents to the rear bumper????

Yup, the hose runs from the rocker cover to the back bumper. In NZ all engine emissions must exit behind the rear most part of the cabin - in this case its the rear bumper

 

[roscoFJ73]

If its coolant would that mean issues with the cylinder head or gasket?

Unfortunately yes,but make sure 1st.

 

[roscoFJ73]

Yup, the hose runs from the rocker cover to the back bumper. In NZ all engine emissions must exit behind the rear most part of the cabin - in this case its the rear bumper

Dont they require it to be connected as it came from the factory?

 

[Polyarkos]

Hope not..... the engine is in an FJ60. I'll fit a catch can and plumb back into the air filter if needed, but its been this way since 1990 so probably doesn't matter

 

[lostmarbles]

...... In NZ all engine emissions must exit behind the rear most part of the cabin - in this case its the rear bumper

I haven't heard of that regulation before now Poly.

My rocker-cover/valve-cover wasn't designed with any external venting itself. Instead my engine is vented from its pushrod-cover. And this vent has always, and will continue to, exit directly over my front driveshaft within my engine bay.

In this state, my vehicle gets checked 6-monthly at VTNZ.

VTNZ, as you may know, are a vehicle testing company here who are generally very much up-with-the-play as far as the latest regulations are concerned. And they seldom hesitate to fail a vehicle that doesn't measure up. So much so, that owners who deliberately (or unavoidably ...in the case of those who are strapped for cash in these hard times) keep run-down vehicles seldom visit VTNZ if they want their vehicles to pass.

The fumes coming from such vent tubes would normally become problematic only when your engine is so worn that engine reconditioning work is overdue.

Authorities have no business insisting vent lines are routed right to the rear.

A more appropriate line-of-action for authorites would be to arrange a fail based on emissions for any vehicle that emits excessive quantities of fumes from an engine vent, thereby forcing the owner to repair/recondition the engine. (And I'm aware of existing regulations that allow this line-of-action.)

 

[Polyarkos]

I thought so too must have been confusing this with exhaust emissions - but with the amount of blow-by from a 1HDT I wouldn't want oil to be anywhere near the engine bay.

Gonna fit a catch can anyway, can't afford to fail a WoF from a smokey engine even if it does just need new injectors etc