Okay--- then have you or is it even possible to come up with the optimum reading on the glow plugs at set rpms ?
I realize there are alot of variables but with the information everyone has been "feeding" you I have to assume [there's that word again !] that's where your headed. Yes ?

Dennis

 

Kevin.......imvho......continue retarding the timing until you see a exhaust temperature rise of about 20°F or less and stop there................imvho, the next thing to do is fix the exhaust so that it is helping you and not hurting you..............this is going to cost some money and time...its up to you.............

the simplest and less expensive is to install a "balance pipe"........it goes right behind the header collector from one side to the other side of the exhaust.............make sure to make surface joints (nothing sticking inside the pipes)......next is to use exhaust wrap on the headers all the way back to the collector.....................

the "best" and most expensive and complicated is a "X" design.............this design make it a "bitch" to do any under vehicle work in the future.......................

personally, for a "street vehicle", I most likely would go with the simple balance pipe..............and exhaust wrap

Kevin, if you decide to make this this change...........I need a little more info about your exhaust system.......

For other people that have installed duels..........you "need" the balance pipe as well....................

before any one ask, I am not trying to reduce exhaust restriction.........I am trying to take "advantage" of the sonic reversion pulse that travels in reverse of exhaust flow..........

to be fair, I can not say that we can tune the sonic reversion to get optimum results on a street vehicle........but I can say that it is Impossible to do with out the balance pipe on a V6-V8 engine, gas or diesel................

crossbones

 

Dennis.............the simple answer is "yes", I already know the optimum reading "window".......the so far, information that everyone has provided is "within reason" of the mathematical program I set up on the Isuzu engines..............This Does Not mean that the so far readings posted are optimum.........it just means that with the additional information that the poster provides along with the readings, I can "guestimate" where they are "tuned at", plug this in and I am getting very close matches to their glow plug readings.......

the problem with me just "saying what is optimum" is the "what if some one has a bad reading, what needs to be corrected to get the optimum reading with out spending a ton of money and many hours of work.............I all ready know what to do to make the Big improvements...........but there are simple things that can give the same symptoms and negate the change that you make...............I will give you a example of your engine............you have stated that your timing is retarding at off idle rpms..............I would think that most are going to check the mechanical pump pressure, fuel filter.....and then to think "o well, the IP is bad.................now, if you look on the drivers side of the IP you will see some linkage......look very close and you will see a "cam".....you will also see that this linkage is adjustable................this adjustment of the cam goes hand and hand with the low pressure vane pump in maintaining low rpm timing.............have I read this.......no.......have I adjusted mine to see.....no...........logic tells me that it has to.....................

I hope people understand that we/I want to know the exact result of any change we make Before spending a "dollar or a hour's time"..........

crossbones

 

As follow up to my last posted reading, the accelleration may be minimally less than when at advanced settings, however now I cannot get the truck to smoke black when I tromp on it, so I must definately be burning all the fuel being dumped in efficiently! No smoke at start up, non while idleing so I'm not too retarded either(that sounds bad dont it!) My EGT temp readings vary all the time so getting a measured increase as adjustment are made is not practical, what I can easily get is the GP reading relationship to the EGT. So far all the GP reading have been going down in relation to a given EGT. I already have a balanced 3" exhausts dumping into a single 4" pipe, so I will not be doing anything more with that. Time to tweak the fuel screw!

 

OK CB where are you? I have pictures of my ram air intake and exhaust set up in my gallery. I think I have my timing at optimum now based on the above posts, also noted today that my engine temps are showing a slight increase (have always been cold on the OEM guages, NEVER even get uo to N in normal, but today after some extendend aroung town driving It was almost to N! GP reading at parked in the driveway tonight 7.9.

 

Kevin you seem to be getting some nice results, have you checked your mileage yet ?

Dennis

 

Well Dennis, I live in a small coastal community that is basically totally isolated fron the rest of the world, we have about 50 km of highway from one end to the other (dead end), otherwise its an hour on a ferry to get anywhere, so I don't have to fill up very often, maybe once every 3 weeks, so checking milage doesn't happen often- thank god for that with the price of fuel these day's. Lower mainland price of gasoline up to 1.27+ this morning per liter- ouch! I hope this glow plug thing works out cause I'd still like to get decient milage, even if it is a heavy old pig of a one-ton!

 

CB, you didn't electrocute yourself on some glow plugs did you???

 

Kevin, I feel like a "burned out glow plug".....been doing some 10-12 hour days......it's about to "kill an old man" like me......
Keep up the good work.....
crossbones

 

crossbones,
I've read this entire thread, I don't understand what the big deal is.

what can this 'supertuning' do that a injector pop tester, egt gauge, and a timing meter do?

your claim of getting that Izuzu up to 40mpg is really kinda strange seeing as how the motor in that truck typically gets 40mpg.
that'd be like me bragging about me getting 15mpg with my truck.....

 

well man then you certainly didnt read the whole thread where he found out his balancer "TDC" mark was actually 20 degrees off spec. So how a guy can time in the engine with innacurate timing marks is beyond me.


Something I didnt see in this thread is the compression of each cylinder. Like the injectors, if the compression isnt even then the injection timing needed on one cylinder will be different than what another would need. If the compression is higher in one cylinder than another, then the fuel could be injected a little later closer to TDC....due to the added heat in the cylinder the compression stroke makes from the higher cylinder pressures. Or am I still in gas engine mind here and thats a non issue?

Now thats something that needs to be done during a major tear down...not like pulling GP's and injectors.

 

ok pud, ya got me.....
I did actually read that. I had forgotten, tho it really doesn't matter.
Finding out that the mark was 20degrees off was something he did in inspecting the engine... it really had nothing to do with glowplug testing.

A fit running engine requires alot of different things to check out. Compression testing as you mentioned is one of them.
looking at glowplug readings is fine, but without figuring out what the real problem is in a stray cylinder all it tells you is 'this cylinder is hotter or colder than the others'
you still need to do other tests to find the problem.

 

No big deal if you already know everything. For the rest of us, why not let us have our fun? I tend to give guys like crossbones a long rope, just like they do for me here at work where I'm known as being a bit "quirky".

I was skeptical and perhaps a little bit grumpy earlier on too. A pop tester is useful for finding bad injectors, an egt gauge is too crude to tell me much except when I should back off while pulling a hill, and a timing light would be great if I only knew what to set the timing at...

I'm three states away from my truck right now. When I do get back home, I'll be re-reading parts of this thread several times and will probably put together some simple electronics that will allow me to monitor each of my glow plugs from the cab (both when starting and running). Not for everyone, for sure...no problem. Then I'll be playing with the timing/IP just a little to see if I can get a couple more MPG. If I find discrepancies in the GP readings, I'll know I'll likely have to look at the injectors, etc.

Perhaps you missed the part about everyone submit your readings so when put together, maybe we can all learn something. If together we figure out that retarding the timing 1 degree from what everyone used to think was optimal will gain 2 MPG, then you can get out your tools and do it

Also, crossbones seems to have some plans for greatness later on, and is trying to learn what he can from us. I'm cool with that since he is up front about it and does share back.

 

what I meant in the last post, without being rude...was what good will a timing light do you when you have no accurate marks to go by when trying to set the timing. With the GP's you have a more informative reading to tell you whether to back it off or bump it ahead...going one way till the readings start to rise, then moving it back a hair. Plus every engine is different, so 8.5degrees BTDC for you might be good but for the next guy it might not be enough or it might be too much. Now you can time it in somewhat with your ears...but the VOM readings will help you tune it in a little more accurate...IE supertuning a diesel engine with the GPs.

Heres my thinking, correct me if Im wrong...Im still on the turn around from gas to diesel engine and how they work.
More compression means the air in the cylinder is going to get heated up to a higher temp, which is good. The higher chamber temp will allow you to inject the fuel closer to TDC because the higher temps will bring the fuel to an explosive state quicker than lower temps. Injecting it closer to TDC would in theory reduce pumping losses.....and not to mention the more you compress an ignition source the stronger and quicker the explosion.
Take gun powder for example, a bullet will bang once, sharply with a bunch of energy releasing a shockwave. Pour the powder out on the ground and light it and it will fizzle for a fraction longer, dividing the energy released into a longer time span.

My point is....somewhere in the darkness of my mind (lol) it makes sense that higher compression will require less timing than low compression...and low compression will not release the energy as efficiently as the cylinder with higher compression.

 

Timing a diesel with the glow plugs is a lot like setting the timing on old gasoline motors with a vacuum gauge.

Yes you could use a timing light and get the timing close, but you could do a much better job with a vacuum gauge.

The timing light on both engines sets it to a standard specification.
But the manufacturing process makes parts that are slightly different.
These differences make each engine slightly different in what the optimum settings for that engine will be.

Using the glow plugs to time the engine eliminates every possible error in placement of keyways, timing marks, teeth on the gears, lobes on the cam and even rod journals on the crank.
With a little trial and error, you can get your engine to run the best it can reguardless of wear on the parts, lower or higher compression or any other variable you can think of.

However if you have it set for the best it can do, then change something like injectors or the IP, you are back at square one and have to start again.

But is that really such a bad deal?
The cost of a decent digital volt meter compared to the cost of a diesel timing meter alone is enough to make this thread worthwhile to most people.
You can buy the voltmeter and a set of new injectors for less money than I have seen timing meters go for.

As I said before in this thread, I can see that Crossbones has a bunch of experience with this process on a diesel engine, but it was not an International diesel.
What he is doing with the information people are posting is drawing parallel conclusions between the engine he was working on and applying it to the International engine which we all are driving.

This is outside the box thinking, and I for one think that is a good thing.
Just because everyone did it with timing lights for years does not make it the only way or the best way to time a diesel.