Thread: 4BD1T - set for oil drain etc

thanks John for the info. using heater feed/return line is convenient because it is so close.

I was intending supply oil from the driver side by inserting a T where the low oil pressure switch is located on the block. However, this may cause pressure to drop at the engine. Maybe I should run a double feed line from the point that supplies the alternator/vac pump.

Edit: Just read your post again John. Is it as simple as getting a new steel oil feed line to run between the filter housing and oil cooler?

Originally Posted by rar110

thanks Justin and Dougal.

Dougal I intend using a GT2560 which is water cooled. I dont understand the problem with the coolant.

easy to explain

hot water rises yeah..

if you set up the turbo so that the flow cannot use convection currents (the effect of hot water rising) to circulate coolant after shut down there is the chance that in the event of a hot shutdown the coolant in the turbochargers coolant jacket will boil off which has the potential to do 1 of several things. So in no particular order heres the potential problems if you dont get convection cooling sorted for hot shutdowns

1. when you start up you will get a sudden rush of coolant and the vapour will be taken into the engine causing further problems there via cavitation and airlocks

2. when the "bubble" purges from the turbo housing as its gotten too big to be contained and is bleeding out of the turbo, the introduction of cooler coolant could cause the turbo housing some damage

3. depending on how you have it plumbed up if the turbo blows its coolant out it may not reprime if for some reason it did manage to stay airlocked and you get right into the loud pedal early on with the engine cold and the thermostat closed it might overheat the turbo.

4. very very hypothetically... IF it managed to get airlocked from boiling off the coolant AND you restarted then got right into the noisey pedal soon enough there might just be enough heat in the turbo to prevent the coolant from staying liquid rapidly boiling it off at that point which would overpressureise the cooling system causing damage if the wrong cap was fitted or causing all your coolant to boil off in very short order. More likely in this event all you will do is burn off the coolant chemicals.


Big OH+S warning here Dont try this without lots and lots of safety gear and a brain

#4 is a real stretch but its doable... Grab a deep mild steel pot and put a litre or 2 of water in it. heat it up in one spot with an oxy torch till the metals red hot the water will heat up some (much like the coolant in your engine) now if you keep the heat cranking on that one spot and turn the pot down so the hot spot is submuerged you should be able to see the water not touching the center of the spot but boiling off the perimeter. The rapid formation of a steam bubble prevents the water from touching the center... Same deal in the turbo, in theory....

thanks Dave.

sounds like another reason to change the flange to vertical mount so the turbo is lower than the coolant lines, or to use a non-water cooled journal bearing turbo.

I first stuck my oil drain with the vac pump drain and had the same problem as justin c (great minds think alike) The seccond one, i bored a hole in the wing of the sump directly below the turbo, and welded in a 1/2bsp fitting, only to find this was below the normal opperating oil level (a no no due to the oil from the turbo being air-rated (sp). This is also the reason your drain should be as big as possible.
The third and most simple, i bored a hole in the front side plate that covers the pushrods and welded another 1/2bsp fitting. The rear plate is where the breather comes from. The breather needed extending, i just got some oil proof hose and replaced the first segment of the breather (where it attaches to the side plate) with a hose 6 or 8 inches long to clear the turbo.

Cheers
Andy

Originally Posted by rar110

I would have preferred a low mount manifold, but there is no choice. A top mount will fit. A low mount would be more room and allow use of stock nissan dump pipe (if I used journal bearing T). Even when you ring Isuzu parts they reckon they can't tell you if the $440 manifold they sell will be top or low mount, garrett or IHI. PIA. I suppose one option is to chop the horizontal flange and tigweld a new vertical flange (90 degrees).

Dave covered the cooling pretty thoroughly. I avoid all those issues by not connecting up the water jacket.
I'd love to tell you how long the turbo lasts like this, but my last time I had the T25 fitted the oil line came apart, sealing it's fate early, only had about 1000km testing. Will be installing it again soon, watch this space.

I haven't seen any factory Isuzu low mount manifolds. My one was an IHI topmount which was cut, flipped and rewelded. Very, very ugly internally and not recommended.
I'm going for the angled side mount 4BD2 style with home made adaptors in the near future.

for those guys who have tried the return via the vac pump to sump line......


What size is your return line on your vac pumps?

I just measured up a couple of the mill ones and I cant see how you couldnt have drained out through them without hassles... Unless you used a really restrictive T piece.

Dougal,

I have not actually seen one only told by an owner his one was fitted to an NPS 4x4 truck 3.9td with garrett t25. I had thought of flipping it but saw the pipe was not the same inside top and bottom. However, chopping it parallel with the ports and welding on a flange is an option. I'd rather use it as is.

great advice with this tread, it will help a lot.

Hey Dave, hope it's not too off topic, but how do you find the turbo's on the 6be6's, which type are most common?, do they last the beating they get in some of the bases around the world?, or are the guy's continually replacing them due to the challenging environment(s)?.