Might sound a bit strange, but I did the opposite. I was the younger fellow and my dad pitched in when he could. Yes, we had some good times too, and I showed him some of the tricks. He was there when my 6.9 came back to life. I can think of that as a good time, now that the pressure is off.

Now that you mention your son might want an IDI, its begining to make sence why you said you are looking for a 1986 crewcab......

I can't help but wonder what other tricks you have up your sleeve for the "6.9 Sponaugle Mk2"

 

My Dad and I rebuilt a '52 *****'s p/u that I bought from my maternal Grandfather for $357.00. Then we did a piece of sh..crap Ford comuter car, twice! (all frontwheel drive domestic cars back then sucked, not just Fords) Then a Camaro I sold after I got married. All the rest of them I have pretty much done myself, BUT WITH A LOT OF HIS HELP STILL. He tought me the basics so I could learn the particulars, I still call him for help almost everyday that I work on a rig.

Now my oldest son (7) follows me around and is finally old enough to be a REAL help but I wouldn't trade all the hours he was more of a hindrence for ANYTHING! That liitle fart, my other son and two daughters are my BEST friends. I have few years to decide but I am seriously leaning towards a 2wd 6.9L for him when he gets a few years older. I can't get over how cheap you can get into one, just as easy to work on as anything else, fairly safe in a crash unless you hit someone bigger than you (really hard!) and he can go around and scrounge-up "alternative fuels" for it. Plus Grandpa has a machine/ electrical shop and that always helps. I told him to start kissing-up now while he's still young and cute and not a pimply-faced teenager! Like a wise man said: puppies and kids are cute when they're young so you'll fall in love with them and not kill them when they're older.

 

NO TV!?
What are you trying to be productive with your life or something!?

 

Since I have mine up and running, there is no pressing need to be in a hurry when I build the next one.

There are a few things that I wish I had taken a little more time with, small details that would make more power, but nothing that would make a big difference.

But then again as I have said before, enough small increases do add up to a substantial gain.

I do wish I had taken the precups over to the machine shop and had the ports enlarged slightly, but by the time I was thinking about them, it would have cost me another week before I was back on the road.

But during that week, I could have been doing a bit more work on the exhaust and intake ports, which also would have made a bit more difference.

And that other turbo I have.........

You know how it goes.

 

When I finally have to rebuild this 7.3L, I'm gonna do some serious "BRAIN PICKIN" up in here.

BTW I sure wish they had just called it a "444" like I.H. it sounds so much cooler.
6.9 sounds good but 7.3 just sounds dorky.
I'm gonna get some 444 badges somewhere for mine even if I have to get 'em off of a tow truck.

 

What are the precubs for. Thats what makes it indirect injection right. Why did they just not make it direct injection? or does anyone know. I though about why they didn't make that precup port bigger sometime back just thinking when I pulled the heads off one at work. Seems to me that it would run better. Does it require more injection pressure to make a direct injection setup?

 

In general, direct injection requires more injection pressure and more accurate timing to get the same results as the pre-cup style injection. Ford and IH went with IDI mainly because of emissions, but this type of injection also generally produces smoother operation over a wider operating range. The difference in compression can also be larger from one cylinder to the next before it starts to become a problem that affects idle quality or performance.

The Ricardo comet prechamber goes all the way back to the 1930s, where it was determined to be the best method for injecting fuel at the top of the compression stroke. Injection systems today can deliver 30 000 psi of pressure in theory, compared to the 1400-2200 that out IDIs are usually set to. But the thing is, the powerstrokes are all DI, and from day one they burned more fuel than the older IDIs that had the same gearing/transmission.

I prefer IDI because the parts are cheaper, they seem to run better with less sophistication, and my research indicates the design favors fuel economy over horsepower.

 

The cups seperate the precombustion chamber from the cylinder.
Since they are rather thin metal, once the engine has been running, they get hot to help with fuel ignition/vaporazation when the injector sprays fuel on them.

The throat has an angle that creates a swirl as the gasses enter and exit the precombustion chamber which also helps flame spread.

On a NA motor, like it was designed, I think there would be little if any improvement when you modified the precup.

What has be bothered, is with the boost pressure I am running, there is over twice as much flow through the precup throat that a NA engine would have.
I am also injecting a lot more fuel, which all has to exit through the stock sized throat.

I can't help but think that throat size is costing me some power at high boost and RPM conditions.

But I also know after talking with a couple people that going to big alters the idle quality and cold start quality.

Tradeoffs, everything you do has a tradeoff.
You just have to figure out if the gain is more than what you loose.

 

Well if anyone comes along a set of clamps let me know..

 

Here are better pictures of mine. I did a little more investigating and I think the very front line on the passenger side isn't running right is it suppose to run on top of all the other lines or in the middle of them?

 

That don't look right, but I can't really see what is wrong.

I will have to look, but I think my #1 line goes under the feed line from the fuel filter as it leaves the IP.

 

Dave ... Nice overview pic ... Just one dumb question ... I noticed you fuel lines were red ... What are the black lines running between the injectors?

 

In the red and grey engine picture, the black lines are the return lines.

They attach to plastic tee's which have two O rings under them.

Over time the hot fuel makes the O rings, rubber fuel line and tee's of the return system hard and brittle.

Air leaks and hard starts are the result, the air is leaking into the lines, which breaks the vacuum holding the fuel above tank level when the engine is not running.

When you go to start, the engine runs for a few seconds, then dies.

Called air intrusion.

Replace the tee's, return lines and O rings, you are back good to go.

Cost is about 40 dollars for a return line kit at most injection shops.

My engine is the red and silver one with a turbo.