12HT blowing alot of black smoke if boost is over 15psi? (1 Viewer)

[dousty]

Reason i ask is since i put new turbo on and new piston and rings my water temps are up,it will climb up to about 97-98c on long climbs etc.

I haven't checked it but my boost gauge may not be right,those water temps and overboost light kicks in at 8-9psi on boost gauge on mine.

So if i have boost well above what i think ive got i never see egts like you have. I might have a crappy boost gauge,you could have a crappy egt gauge you know,your temps don't make sense.

That's right, it could be my egt or your boost gauge. 97-98 coolant temp is what I would expect from a 12HT that has had it's fuel increased, reguardelss of what others "think".

Or it could be that my EGT is acurate and everything else you have seen is just heresay. I am, unreluctantly, leaning towards this train of thought. Very very few on this forum have any experiece with the 12HT and even fewer again have recorded figuries for a standard 12HT.

My figuires are consistant with 2 different engines and two different gearbox's and so far I haven't read of anyone's experience that matches mine. I am more than happy to be school'd beacuse it saves me the time an money of learning the hard way. That's why I ask questions that may seem rudementry but it is because I dont want to assume knowledge I don't have....knowone it born educuated ...we all learn everything we know, apart from breathing and s***ting.]



So, Do any of you have results that can be A/B'd against mine? I am doing the research in front of you all and need real time data to bounce off you all. No "I heard" or "I read" just real experience. Hopefully with participation we can build some REAL data instead of the rehashed interweb stuff we have all grown to know.

 

[dousty]

PS...I'm not having a go at anyone here, I am just trying to get everyone focused on there experience instead of what they have read. Starting now!

 

[goldchaser]

Dousty did you sat ya pulled the egt gauge from one and put it in the other truck.

Surely you couldn't have two 12hts running them temps,too much coincidence.

Problemo is egt gauges aren't cheap,expensive trial unless a mate has one you could borrow.

My reasoning is if im sitting around 500+ for a while my water temp climbs slowly up to above 95c easy(new radiator on shopping list),egts drop for a while and im back down around 80-85c water temp,if youve got up near 700 pre turbo surely ya water temp would come up pretty high after a few minutes.

I have one of those hand held laser temp guns,only about $30,if you had one or can borrow one heat motor and pull probe or pull probe heat it and check it.

 

[dousty]

It could be the gauge but I'd really doubt it. I think the 650*C limit is but a fairy tale and far from any sort of concrete guidline. EGT is but a GUIDE to cylinder temps, which is what it's all about. Cylinder temp maximum's can't be narrowed down to a specific figure for all diesel engines as every engine has a different piston crown design, injection pattern, combustion chamber design, inlet tract design, injection timing, piston composition etc... and as a result EGT temps can't be "standard" across all engines.

I honestly think that EGT's over 700*C is to be expected for a stock 12HT and I have yet to find evidence to the contrary. EGT at torque peak will be lower than peak EGT.

EGT in any diesel is rarely refered to in any sort of context other than "max". This is clearly a result of a lack of true data and a common expectation of "standard" figure.

 

[dousty]

I'll go one better and buy another EGT gauge and probe. Then I can cofirm my measurements and move on, if need be


By the way, back flush you rad first to clear the tunes of any blockage possible. Many years of crud will make it hard for your rad to flow water (proven via a slow refilling time). I bought a Aussie Desert Cooler rad for my silver wagon due to high coolant temps through Sofala but after I replaced my rad with a standard replacement I have had no further problem.

Dousty did you sat ya pulled the egt gauge from one and put it in the other truck.

Surely you couldn't have two 12hts running them temps,too much coincidence.

Problemo is egt gauges aren't cheap,expensive trial unless a mate has one you could borrow.

My reasoning is if im sitting around 500+ for a while my water temp climbs slowly up to above 95c easy(new radiator on shopping list),egts drop for a while and im back down around 80-85c water temp,if youve got up near 700 pre turbo surely ya water temp would come up pretty high after a few minutes.

I have one of those hand held laser temp guns,only about $30,if you had one or can borrow one heat motor and pull probe or pull probe heat it and check it.

 

[dousty]

Just purchased this DIGITAL EGT THERMOMETER PYROMETER W/ WELD-IN PROBE | eBay.

Will report back as needed or requested.

 

[rove_mcanus]

Black smoke is over fueling. But only if there isn't a problem with the system such as faulty turbo injectors or pump. I think you need to have your pump rebuilt by a pro to get the fueling/boost characteristics right.

Your egts are ok as well. EGT's are higher pre turbo then post. Also the 5-600 post turbo limit is for indirect injection motors with after market turbos (2h, 1hz) The precombustion chamber in these engines causes intense localised heat in the head and results in cracking. Direct injection motors don't have this problem. However with temps reaching 700-800 you might want to look at a water cooled turbo (if it isn't already) to avoid turbo failure. I think toyota turbos have water cooled turbos, which is actually unusual. Any big truck and plant equiptment don't have it.

 

[dousty]

CT26 is water cooled

 

[dousty]

I took the time today to check inlet restriction, which maxed at 1"hg. I also ran the engine breather into a bottle in case oil carry over was an issue. It didn't make any difference with EGT still over 700*C. These checks were done at standard boost level.

I think I'll check out pump timing next while I wait for my new EGT to show up. If pump timing is ok and EGT's are consitant between two gauges then I guess I'll take a look at an exhaust back pressure reading.

 

[dousty]

I checked injection timing today and it came in at around 5* so I went to the shed to get some tools but can't find my 3/8 Snap-on ratchet. Turns out the kids have been in the shed.....grr I hate buying tools twice!

So I'll adjust pump timing in the next few days and report back.

 

[dousty]

Righto, got injection timing set to around 10*, my wife's help was a bit hit and miss but I love her.

Went out for a spin and found that under the same conditions as the tests posted earlier I had 590*C!! The difference in performance was very evident and also very pleasing. So I put the boost adjuster back in and tested at 14psi. EGT's changed very little but the engine did perform a little better.

Near home I noticed my boost gauge wasn't working anymore nor was the boost light. Once home I found the pressure hose from the inlet tract had popped off the first T piece. I also noticed that there was oil dripping from the hose . So Ipopped it back on and removed the boost controller.

I had already tested inlet restriction and it was fine. I was also running the engine breather into a catch can (aka cordial bottle) so I'm quite sure the turbo is passing oil into the intake due to condition and no other factor. So now I need to do some homework. I have the turbo off my other wagon here, it was removed for a 7MGTE hybrid on that engine. But i really want to put a new/reconditioned one on for piece of mind.

So, chinese ebay job like Goldy or 60/1 mod ebay job "from" japan or a Gbentnik Gturbo? I'm not sure to be honest but I do want piece of mind and none of those options provide that, for varying reasons.


decisions decisions

 

[goldchaser]

That mob on ebay has catridges also,not sure if they fit standard housing,if your exhaust housing is ok another option,my exhaust housing was buggered.

 

[Tim-HJ61]

How was it changing the timing?

I want to advance mine a bit to burn the veggie oil a bit longer, but each time I look at the job it gets all too hard to undo the bolts at the engine side of the IP

How did you go?

Tim

 

[dousty]

That mob on ebay has catridges also,not sure if they fit standard housing,if your exhaust housing is ok another option,my exhaust housing was buggered.

I did see those on there as well so yeah, they are another option. I wonder if they have done anything with the exhaust on that 60-1 version to flow potential exhaust gasses?

 

[dousty]

How was it changing the timing?

I want to advance mine a bit to burn the veggie oil a bit longer, but each time I look at the job it gets all too hard to undo the bolts at the engine side of the IP

How did you go?

Tim

It's not a bad job. I found my Snap-on 3/8 ratchet in the rubbish along with a 6" extension yesterday afternoon , thats kids for ya!

I used the 6" extension for the bottom inside bolt and the 6" and 12" combined for the top inside bolt. My extensions are ball drive or wobble drive, gives you alot more options on drive angles. Trickiest bit is watching the fuel rise in your sawn off pipe while you bar it over. Takes about 1.5 hours from start to finish and I also remove the air filter assm to make life alot easier.

 

[dousty]

Forgot to mention that my EGT's were also still climbing to 700* at around 3000rpm, which may indicate the oil being passed by the turbo into the inlet tract.

 

[Tim-HJ61]

Forgot to mention that my EGT's were also still climbing to 700* at around 3000rpm, which may indicate the oil being passed by the turbo into the inlet tract.

Time to contact gbentink me thinks. He's over your way at the moment but will be returning to his shed soon. If you see a Bushtracker van passing everything up the steepest hills, it's probably him!


Tim

 

[goldchaser]

Time to contact gbentink me thinks. He's over your way at the moment but will be returning to his shed soon. If you see a Bushtracker van passing everything up the steepest hills, it's probably him!


Tim

Nah plenty of feedback on Gmans turbo we need dousty to get the jap one and try it.

Only thinking of dousty of course

By the way dousty i can't get my EGTs up past 550,still haven't check boost gauge,will do,got 12psi at 3-3500,probably bump fuel back up for a touchmore boost after i confirm gauge is ok or not.

 

[dousty]

My new EGT guage showed up today. Hopefully I'll get time this weekend to fit it up and give it a whirl. It's a VERY small unit!

 

[dousty]