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TOPIC: isuzu turbo egt's

Re: isuzu turbo egt's 04 Sep 2013 07:55 #124922

  • jeffo
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Can you do checks using an optical temperature probe to rule out the VDO instrument?
With a re-power (unless it's a new engine) you could have a few issues.
Was the engine maintained, fuel filters etc.
Dirty injectors will give slow/dribbly injection with most of the fuel heading out the exhaust just adding to exhaust temps., not horsepower.
Same goes for the pump. Worn plungers and barrels won't give the sharp crisp injection pressure required for good atomisation.
What exhaust have you fitted. Turbos need a free flowing system after the dump.
15psi ???? what does the book say? Are you getting any smoke.
The temps you recorded would not damage the housing. They're made from pretty good stuff. I've got a Skyline and it gets 950 to 1000 on the dyno, housing so hot it's almost see through.
But the temps drops very quickly after the dump and in no length it's down to 400 to 500 which is desirable to stop the exhaust pipework from sagging.


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Re: isuzu turbo egt's 04 Sep 2013 09:53 #124923

  • Lang
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Dieseldog,

Jon does not seem to have a gauge problem from his post above.

For your case it certainly looks like low voltage problems. The Murphy gauges may not be as voltage sensitive as the VDO.

Putting new gauges in and have them deteriorate over a few years also points to connections corroding or losing contact. The blinker/fuel gauge (which are very voltage sensitive) relationship shows this as well.

Most older designs tried to get their auxilliary power off the back of the ammeter and when they had fuse boxes acting as bus bars everything was still sucking off relatively small wires at the ammeter instead of a direct battery connection.

I have a 1979 Fiat 124 Spider which you would think was over these problems but just wired through the switches they had lousy lights and slow wipers from new. On the advice of the FIAT Club I put relays in for the lights and wipers - doubled the brightness and speed.

Lang

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Re: isuzu turbo egt's 04 Sep 2013 18:52 #124924

  • jon_d
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With a re-power (unless it's a new engine) you could have a few issues.
Was the engine maintained, fuel filters etc.
Dirty injectors will give slow/dribbly injection with most of the fuel heading out the exhaust just adding to exhaust temps., not horsepower.
Same goes for the pump. Worn plungers and barrels won't give the sharp crisp injection pressure required for good atomisation.
What exhaust have you fitted. Turbos need a free flowing system after the dump.
15psi ???? what does the book say? Are you getting any smoke.
The temps you recorded would not damage the housing. They're made from pretty good stuff. I've got a Skyline and it gets 950 to 1000 on the dyno, housing so hot it's almost see through.
But the temps drops very quickly after the dump and in no length it's down to 400 to 500 which is desirable to stop the exhaust pipework from sagging.



The engine is a Jap import. The history is not known. However, the rocker cover and top end had a good covering of sludge. The crankcase was clean.

It has sat for 6 months + and then starts on (less than) 5 secs of cranking with no pre-glowing.

I had someone for me though the Black spur, both ways. No report of excessive smoke. However they did say at some points it looked a little grey.

It has a 3 inch exhaust to the back of the bus with a big 10x24 inch muffler.

15psi is the top end of the wastegate spec.




I'm on a motorhome forum and discussing the same thing. Yesterday, a bloke with a FSR 6BG1 turbo is reckoning his pyro mostly reads 350*C. The probe is 400 mm down from the outlet. He can get it to read 500 if he tries.

This is the first bit of collaborative information that maybe mine might be ok and reading higher due to closer to the outlet.


I'm just wondering what else I should be considering? I've even pondered if the turbo is not spooling properly at low RPM and causing a pressure differential (and therefore stored heat.) I'm not sure how to check that, or even if its possible to check.

thanks.

Jon.

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Re: isuzu turbo egt's 04 Sep 2013 22:59 #124925

  • Wilweld
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A good place to start, especially if you have the turbo off, is just to turn the impeller by hand and check there is no tight spots. Then check for too much play in the bearings- grab the end of the impeller shaft and wiggle it side to side, and see if it moves end to end as well. Any tight spots in the rotation, or more than a minute amount of movement in the bearings means it won't spool properly and it's due for a rebuild.

Grant.
'79 F100- 302c 4spd&&'81 F350- Isuzu 6BB1&&Chamberlain Industrial MK11  (6G)

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Re: isuzu turbo egt's 05 Sep 2013 14:12 #124926

  • dieseldog
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Jon,
I wouldn't be to concerned with the engine if it has plenty of power. A turbo engine with a dead turbo will be sluggish, not only must the engine draw air through a stationary turbo but the exhaust will now have a big restriction. Factory turbo engines usually have a lower compression ratio than a NA one, and the fuel delivery is raised to take advantage of the extra air, which with a dead turbo, usually results in copious amounts of black smoke from the over rich mixture. So if there's plenty of power and little smoke, I'd say all is well.

If your worried about the temperature, take it for a good hard run at night, up the biggest hill you can find, and when you get to the top, have a look at the exhaust manifold and see if it is glowing. A dull cherry red on the turbo is good, but if its bright red or the exhaust pipe itself is glowing, its too hot. Look at the exhaust manifold while is cold. Should be nice and rusty with lots of rust flakes. A manifold that is smooth, and browny white, almost orange or red is a good sign it has been overheated. I think the metal must undergo a chemical change, because it will never rust the same again. If your looking at a second hand engine, it is a good way to tell if its been abused. Also, have a look at the oil drain on the turbo, make sure its clear.

I hope this might give you some direction, Shea

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Re: isuzu turbo egt's 05 Sep 2013 19:11 #124927

  • jon_d
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Thanks again.

I took the opportunity to feel a new out of the box turbo and compared to mine, there is a marked difference. Mine, while rotates, it doesn't have the "trailing spin" that a good bearing has. There is no play in the shaft.

While it's out with this cracked housing, I'll take to the IHI guys and get their opinion.


And, I bought a diesel Air fuel ratio meter last night so I should be able to check if its overfueling.

www.ebay.com.au/itm/171109114592?ssPageN...id=p3984.m1439.l2649

I think that's going to cover all the bases. It's going to be converted into a motorhome, but before it is, I'm sorting out the mechanicals first.

jd

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Re: isuzu turbo egt's 07 Sep 2013 09:03 #124928

  • Bruce99
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You could throw a kit at it Jon but if the housing is cracked? Where is the crack?
***********&&---Bruce99---&&***********

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Re: isuzu turbo egt's 07 Sep 2013 14:14 #124929

  • jon_d
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Bruce,

the housing is has 3 structural cracks. It's a throw away. I've searched the world looking for one and they are not available from IHI.

I found a second hand turbo in Taiwan, $1000.

A IHI guy here reckons he could source a housing $1400


The Chinese make copies for the Hino H06T engine. Its very close to my turbo. All most exact I think.

I contacted a few and one was willing to supply me.

Hows this, The housing is $80. And a complete turbo is $260.
I ordered 2 housings and 1 turbo. (I'm hesitant to put the Chinese turbo on but may have to.)

That's how I did the quick comparison to the IHI tightness. The new turbo just has a slippery bearing feel.


Anyway, the Chinese housing almost fits! The heat sheild in the Chinese unit is like a cylinder shape and the cavity in the housing around the shield is narrow. The IHI is like a soup bowl. So the Chinese housing doesn't slip on core and jams on the heat shield. That's only problem.

I've spent this morning mounting the housing on a rotating table and milled a lip into the housing. It fits now. :)

Next is to drop a kit into it.

Thanks.
JD

Q: how do you post an image on this forum?

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Re: isuzu turbo egt's 07 Sep 2013 15:19 #124930

  • Bruce99
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Photobucket or some other external facility is the only way to post it here.
Sounds like you've got the turbo licked.
Might need to see if you can squeeze an after cooler in but I doubt if you'd have enough room.
From memory you spun the engine around and mounted it behind the diff rather than over the steer... right?
***********&&---Bruce99---&&***********

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Re: isuzu turbo egt's 07 Sep 2013 18:14 #124931

  • Bugly
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Jon ... 'tis easy ::)

1. Upload the photo to photobucket
2. In photobucket click on the little photo to make it bigger
3. To the right of the big photo click on the 'IMG' code
4. Paste the 'IMG' link from photobucket to your forum post.
5. Bingo ... photo in HCVC forum post!!
1964 Dennis F34 fire pump with wheeled escape
1949 Dennis F1 fire pump
1948 Fordson E83W 10/10 pickup
1935 Morris Eight Series 1 2-door sedan

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