Budget 4bd1t -> '94 FZJ80 Build

[Wheelingnoob]

Any more progress?

 

[lostih]

I haven't really worked on it until today. I made a pressure tester as Fromage advised. With shop air I pressurized it to about 12 psi and found a pinhole in the little flange adapter I welded up to connect the silicon boot to the intake. I am doubtful this is all of my issues, but good to find it. I welded it up and have the Rtv curing before I test it again. Hopefully I'll know more this evening.

Also looks like a turbo rebuild is definitely in my future...inside of intercooler pipes is coated with oil. How urgently do I need to do the rebuild? I'd like to put it off a bit if it won't harm anything.

 

[Wheelingnoob]

Yeah if its pumping oil into the intake better to swap it for your other one or get it rebuilt soon. Problem with a diesel is it can run on oil so if enough gets pumped in it could run away. Unlikely but I have seen it happen and its scary as hell.

Maybe the turbo is what is causing your issue. I would also try adjusting your Arinoid on the pump out a bit it seemed to make a big difference in the thread on 4btswaps.


...via IH8MUD app

 

[Wheelingnoob]

Oh one more thing, i cant remember but if you used a Dakota Digital what output to the tach did you use?


...via IH8MUD app

 

[ThreeEyedBandit]

I vote for rebuild it as soon as you can. Doubtful that it'll runaway anytime soon, but as a person that has had two isuzu's runaway from bad turbos pumping oil into the intake... Very scary and hopeless feeling as it happens.

That also could be the very reason you have low boost too! Check the wheels out and make sure they haven't contacted the housings.

 

[lostih]

So the leak is better but I can still feel a wiff of air down there. I'm wondering if the boot to pipe interface is a bit loose.

I was thinking of swapping to the 16t today but when I looked at it I can push the compressor wheel into the housing...doesn't look like it has run contacting the housing...but it can just barely touch if I push it over that way. I've been told these journal bearing turbos should have more play in them, but I assume that's too much.

So a rebuild kit will be ordered. Talk to me about this runaway. If that were to happen and I shut down the truck will it only runaway until the oil is used up or can it somehow keep the fuel coming?

 

[lostih]

Yup I'm using the dakota digital box and I just added a W signal to the alternator. Very easy to do. Just solder a wire on one of the windings. I think I have a pic of it somewhere.

 

[lostih]

Oh sorry I bet you mean on the box itself. Iirc, only the high voltage v8 would get the tach to move. I spliced in to the tach signal at the igniter on the cruiser. Hope that helps.

 

[lostih]

On the aneroid...how does it effect boost? I think I must not understand what it does. Mine isn't hooked up to boost anywhere...just atmosphere. I was thinking it just adjusted fueling levels based on altitude but maybe not? I suppose if the thing is running super lean then there may not be enough density to drive the turbo?

 

[Wheelingnoob]

So the leak is better but I can still feel a wiff of air down there. I'm wondering if the boot to pipe interface is a bit loose.

I was thinking of swapping to the 16t today but when I looked at it I can push the compressor wheel into the housing...doesn't look like it has run contacting the housing...but it can just barely touch if I push it over that way. I've been told these journal bearing turbos should have more play in them, but I assume that's too much.

So a rebuild kit will be ordered. Talk to me about this runaway. If that were to happen and I shut down the truck will it only runaway until the oil is used up or can it somehow keep the fuel coming?

It sounds like the 16t needs a rebuild too. Should not be able to move it enough to contact the housings.

Problem with a runaway is its just that the engine runs on the oil no governor no way to turn it off till the fuel (oil) is used up. You could block the air intake and choke it out (most mine trucks have flaps on the intake incase of runaway on coal dust they can be shut down.

It takes quite a quantity of oil to run away. But I would be worried about the intercooler starting to fill up. Keep an eye on your oil level if it does not change I would not worry.

You going to do a 19th upgrade while you are at it?

Thanks for tge tach info, I have a sensor on my flywheel, wish I had known how easy the "W" wire method was.

 

[lostih]

Yeah I've been watching the oil level and it hasn't been changing much so I think I'm ok. I was just surprised to find it all the way at the intake.

On the 19t upgrade...I probably should, depends on if I find a rebuild kit local or not. When I rebuild how important/costly is the balancing?

 

[ThreeEyedBandit]

Does it have an aneroid and boost compensator? I think there was a split in the 1t's where they did and didn't. If it does you'll definitely want to plumb it to the manifold, otherwise you will be running low on boost. Look in the faq's on 4btswaps, they have a link to pictures and such there.

 

[lostih]

Mine just has the aneroid and no boost compensator. IIRC there were two types of aneroids as well...one that tied into the manifold and one that just went to atmosphere. I have the later I believe.

 

[ThreeEyedBandit]

You have a pyro gauge? Id so you'll want to start turning the more power screw in as you're going to be under fueled for more boost. Also look into what it takes to add a compensator, it'll help with low boost smoke once you turn it up.

 

[lostih]

I do have a pyro gauge, but my EGT's are already as hot as if like them...on long hills with it floored on the freeway I see 1150 steady. One morning after I let it idle maybe 3 minutes but still below operating temp I pulled some long freeway hills in northern CA where it topped 1200 so I let off the fuel ever so slightly and it cooled down. I assumed this might have been cold fuel enrichment, though I thought that only worked at first start. It was just kind of odd though as that's the only time EGT's have gone over 1200. I was hoping to get more boost before turning up the fuel as I was thinking that would raise EGT's. Thoughts? Turn it up anyways?

 

[lostih]

This is what I have been working on since the truck started driving.

 

[Wheelingnoob]

Yeah sounds like your EGT'S are where you want them. My thought with arinoid is that it maybe playing with fuel delivery some how. But that would just increase fuel and you need boost to off set that first. At 1100f EGT'S you should have no problem lighting that turbo. I think your turbo maybe the issue, I can't think of anything else. Maybe valve adjustment? But can't see it making that big a diffrence.

I would get a kunagawa rebuild kit (mine was actually OEM MHI parts in OEM bags). I would also recommend getting there HD thrust bearing with dual oil feeds, I did not and plan to get it at some point. The most important part of a rebuild especially if you are putting in a larger wheel is getting it properly balenced.

 

[lostih]

So did you order the kunigawa branded kit or their 'genuine MHI' kit? Do I remember right that if I go to the 19t wheel I have to machine the compressor housing? I'm trying to decide if I should do that upgrade now and only have the whole thing balanced once...

 

[Wheelingnoob]

So did you order the kunigawa branded kit or their 'genuine MHI' kit? Do I remember right that if I go to the 19t wheel I have to machine the compressor housing? I'm trying to decide if I should do that upgrade now and only have the whole thing balanced once...

I did the genuine MHI kit. Yes you need to machine the compressor cover and the CHRA for the larger wheel size. I got a wheel and cover kit so I did not need to machine the cover I got a new one.

If you are going to do it do it all in one shot, far cheaper in the long run.

 

[lostih]

Yeah. I just don't think I want to take that on at the moment. How much difference do you think I'll see with just the 18t?

For the rebuild kit...are these flat or superback? How would one tell?