Pre-Power Stroke Diesel (7.3L IDI & 6.9L) Diesel Topics Only

The IDI Myth Thread....

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  #16  
Old 09-03-2013, 09:48 PM
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Originally Posted by tjc transport
myth: adding a turbo to an non turbo IDI will only blow it up.
The other day my dad was telling me about how a guy he works with has a N/A CC IDI, and how my dad was telling him about all the IDI stuff weve been doing, and the guy was like "These old diesels aren't supposed have a turbo on them, ill never put one on mine..."

I told him to tell the guy Ill give him a ride in mine after my engine is done, and that will change his mind real quick...

I don't get that mindset.... The IDI must be pure black magic Voodoo compared to any other diesel ever... Its simple (Air/Fuel<--->Structural integrity) There are some things our engines can have tweaked to favor a certain setup, but to say adding a turbo is going to kill the engine is BS....
 
  #17  
Old 09-03-2013, 10:01 PM
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Originally Posted by FORDF250HDXLT
myth: the more you turn the fuel screw up and more black smoke you make without adding any additional air,means massive power gains.

power doesn't come from smoke and mirrors.

myth: advance the engine timing as much as possible beyond 8 BTDC to gain lots of extra clatter because that's where the power and fuel economy is for all idi's regardless of the setup.

the more fuel you provide the engine with,the lower the timing wants to be.

myth: the idi's oil cooler was over engineered and therefore you'll never need to worry about oil temps when adding a turbo to a n/a idi.

the '93 and '94 turbo engines received an oil cooler with more cooling fins.
i had to installed an aux air oil cooler to keep oil temps below 240° (at the pan) on the grades.not only were the 260°+ oil temps no good for the engine,but it transferred the heat to my coolant,bringing down it's efficiency and putting needless stress on my cooling system.

myth: the 7.3l is so legendary that god used it to start the rotation of the earth.

this ones likely true.scientist just haven't proven it yet.
Good post.

Id like to state that I agree that advanced timing isn't the end all for more power that its spread to be... Pulse timing is just a reference point in the injection event. The Duration of the injection event is controlled by a couple factors, and that is what is going to determine the length of burn and resultant power of a certain setup... If you have more fuel being injected (Turned up pump, etc) Your going to want to adjust the injection duration back to where it was to make sure you get all that fuel combusted when it is supposed to be... So the two factors in adjusting timing are duration and the start of combustion.... I would argue that its best to have the latest start in combustion possible, without burning a bunch of fuel out the exhaust, while burning enough to get the turbo spinning....

Also I think we got a good problem free oil cooler setup, but I think it can be improved from a plumbing standpoint, and lower oil temps...
 
  #18  
Old 09-03-2013, 10:55 PM
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Myth or Fact:

I have heard that the factory valve guides in the 6.9/7.3 are not suitable for adding larger amounts of boost. I.E: 15psi+. That they will wear out quicker.

I have a later model 6.9 sitting at my house that's in great shape, I was toying with the idea of boring it (due to slight rust pitting). And before I do any head work I was wondering if the valve guides and seats need replaced. Kinda want to build up a high performance 6.9 to stick in my rear engine mudder, that way space for turbos/superchargers won't be a issue.

And because of the space I was considering doing the stacked fuel pumps to see how it would turn out. Running on as main throttle and the second one for "burst" or just run then both "equal"
 
  #19  
Old 09-03-2013, 11:00 PM
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Originally Posted by FordManMT
Myth or Fact:

I have heard that the factory valve guides in the 6.9/7.3 are not suitable for adding larger amounts of boost. I.E: 15psi+. That they will wear out quicker.

I have a later model 6.9 sitting at my house that's in great shape, I was toying with the idea of boring it (due to slight rust pitting). And before I do any head work I was wondering if the valve guides and seats need replaced. Kinda want to build up a high performance 6.9 to stick in my rear engine mudder, that way space for turbos/superchargers won't be a issue.

And because of the space I was considering doing the stacked fuel pumps to see how it would turn out. Running on as main throttle and the second one for "burst" or just run then both "equal"
Havent heard of any issue with the guides... I don't see why it would be any worse than any other engine, which is nilch...

As far as the rest goes. that's outta myth territory man.... make it real ...
 
  #20  
Old 09-03-2013, 11:46 PM
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I have read that the 7.3 valve guides were tighter than the 6.9 to reduce oil consumption, but resulted in more rocker arm valve tip damage. The only shred of evidence I can find to support this is that Sealed Power replacement valve stems for the 6.9 is part #VG804 that has an I.D. Of 0.375", and the Sealed Power replacent for the 7.3 lists the #VG804 above as well as a #VG1414 that has an I.D. of 0.3745". Either way, valve stem tolerance should not be a problem with boost over 15 psi. BTW, the 7.3 has larger valve stem oil shields than the 6.9 (to reduce emissions) but may be desireable for oil consption reasons as well...
 
  #21  
Old 09-03-2013, 11:56 PM
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Yeah, I see...

However, .0005 is chump change in respect to guide tolerance... Id be willing to bet one of those specs is rounded up... ...
 
  #22  
Old 09-04-2013, 02:38 AM
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Originally Posted by RacinNdrummin
Yeah, I see...

However, .0005 is chump change in respect to guide tolerance... Id be willing to bet one of those specs is rounded up... ...
IDK... specs for the #VG804 is actually 0.3750"

Federal-Mogul eCatalog Resource Center

vs the #VG1414 @0.3745"

Federal-Mogul eCatalog Resource Center

so why two different parts? these are REPAIR guides anyway... ?
 
  #23  
Old 09-04-2013, 01:39 PM
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Originally Posted by flainn
Myth: "IDI fuel injectors are expensive to replace."

Fact: You can replace an entire set of IDI injectors for the cost of one PowerStroke injector. Live it up!
Fact. At NAPA a single injector cost me 35.99
 
  #24  
Old 09-04-2013, 05:10 PM
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Myth: the idi diesel engine is more complicated to work on and harder to start in cold weather than a gas engine,so i should stick to the gas guzzling 460 dinosaur if i want to haul and tow instead.

the idi diesel engine is extremely easy to work on just like the old school gas engine used to be before they were computer controlled and full of sensors.just because it runs on diesel fuel instead of gasoline,shouldn't scare people away.
as far as starting in cold weather goes,the idi diesel engine is by far the easiest starting engine in cold weather that iv ever owned and i haven't even attempted to test,let along actually use the block heater.with a properly tuned engine,up to par starting and glow plug system (which are also easy to work on) iv got instant cold starts with just 1-3 second crank and running times (every time) in the dead of winter here in New England.
 
  #25  
Old 09-04-2013, 05:53 PM
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Myth: An IDI is slow going up hills.

Fact: It's slow going down the hills as well.
 
  #26  
Old 09-04-2013, 07:42 PM
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Originally Posted by Chevy_Eater
Myth: An IDI is slow going up hills.

Fact: It's slow going down the hills as well.
sig material right there!
 
  #27  
Old 09-04-2013, 11:20 PM
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Originally Posted by FORDF250HDXLT
Myth: the idi diesel engine is more complicated to work on and harder to start in cold weather than a gas engine,so i should stick to the gas guzzling 460 dinosaur if i want to haul and tow instead.

the idi diesel engine is extremely easy to work on just like the old school gas engine used to be before they were computer controlled and full of sensors.just because it runs on diesel fuel instead of gasoline,shouldn't scare people away.
as far as starting in cold weather goes,the idi diesel engine is by far the easiest starting engine in cold weather that iv ever owned and i haven't even attempted to test,let along actually use the block heater.with a properly tuned engine,up to par starting and glow plug system (which are also easy to work on) iv got instant cold starts with just 1-3 second crank and running times (every time) in the dead of winter here in New England.
This is true... Hardest times ive had were with a leaky fuel system, otherwise my truck has always fired right up, even in the teens with no block heater.
 
  #28  
Old 09-04-2013, 11:26 PM
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Originally Posted by Chevy_Eater
Myth: An IDI is slow going up hills.

Fact: It's slow going down the hills as well.
Hey Man, speed is all relative mannnnnnn..... (Does his best hippie voice)
 
  #29  
Old 09-05-2013, 12:24 AM
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Myth: most things posted on oil burners

Haha just kiddin had to say it
 
  #30  
Old 09-05-2013, 12:50 AM
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Originally Posted by Fordidipower
Myth: most things posted on oil burners

Haha just kiddin had to say it
Had too.... but probably not appropriate ...

That being said.... It still, to this very day, is funny.... if you know what I mean ...
 


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