NEED 7.3l idi and 6.9l idi info.....badly

[emmer]

Hi, I am new here....I recently bought a set of heads (rebuilt) for my 7.3l idi
motor ..i went to put them on but the head the bolts would'nt go through the holes. Turns out the machine shop I bought them from actually rebuilt 6.9l heads. The ojnly differance we can find between the 6.9l heads and the 7.3l idi heads are the head bolt size. They can bore out the head bolt holes to 1/2
inch from 7/16. That wouldn't be a problem but is that the only differance between the heads???? The bolt holes?? thanks....Joe

 

[The Warden]

Unless the heads are from an early ('83 or early '84) 6.9l, the bolt holes are the only difference.

That said, I wouldn't be too comfortable with boring the holes out...I would strongly suggest going back to the machine shop and tell them to give you the 7.3l heads you were expecting, or to give you your money back. Unless you described it wrong, this was their mistake, and their responsibility to make it right. But, be nice about it, at least at first (if they blow you off, then go ahead and get more firm)...

Hope this helps some...good luck! And welcome aboard!!

 

[EvergreenRanch]

i second Warden...you paid for 7.3 heads, you should have 7.3 heads.....id have a permanent case of paranoia if i did what you are describing, cuz i dont think i have heard about it being done here before...and theres prolly a good reason it hasnt been.


and yes, Welcome

i dont have time to check (im at work) but you may wanna look at the tech article about differences between 6.9 and 7.3 might be more info there for you

 

[emmer]

Oh yeah I agree, and the machine shop will go good for the money but, the problem is that (7.3l idi heads used) are almost impossible to come by here. Most all of them are cracked.
I'm a little nervous too, however if the only diff is the diameter of the bolt holes then maybe these heads would work fine. How do I tell if these heads are (83 or early 84) ???
Are the valves the same?? Is the combustion chamber the same??
Sorry for so many questions.

 

[EvergreenRanch]

Well made it home and had a chance to do some looking for you. I found this info in the IDI tech articles section, which can be found at the top of the forum:

Cylinder head changes
Cylinder head bolts - 6.9 = 7/16"-14 UNC 5.25" long **some big differences here**
Cylinder head bolts - 7.3 = 1/2" - 13 UNC 6" long
Cylinder head bolt washer 6.9 = .105" thick
Cylinder head bolt washer 7.3 = .134" thick

Head bolt torque -
6.9 with new bolts = 75ft. lbs.
6.9 with used bolts = 85ft. lbs.
7.3 new or used = 100ft. lbs.

Cylinder head gasket changes -
Fire ring I.D. 6.9 = 4.14"
Fire ring I.D. 7.3 = 4.22"
Gasket cutouts elimitated between cylinders on the 7.3 to eliminate cosmetic corrosion phenomenon.
Viton oil drain back sealing rings added to the 7.3 (also used in later versions of the 6.9 head gasket, then eliminated again).

Head design changes -
6.9 features "centered" glow plugs, while 7.3 are "off-center"
Injection nozzles have been retracted on the 7.3 .060" to facilitate Federal and state emission certs.

Precombustion chamber volume -
6.9 = 18.34 cm3
7.3 = 20.42 cm3 (increased only for emissions certs)

so im no expert on topic so take with grain of salt, but id say bad idea.


give us some info on you such as vehicle configuration, its year, your location etc etc (see the bottom of this post for example )

 

[tonkadoctor]

There should be casting numbers on the heads and often a manufacturer will cast in a time stamp. If you can find that info somebody here or at International might be able to decipher it.

I beleive the 6.9 heads are the same from '83 - '87 with the change happening in '88 that went to '94 then the change to the powerstroke. I'm sure I missed something here and somebody will correct me.

I personnally would return them and get the right heads. If you paid anywhere around $1000 - $1300 for the pair at the machine shop you would be better off to return them and get a rebuilt set for around the same price with a warrenty and peace of mind from Napa, International, Advance, Autozone etc.....

 

[Freight_Train]

The 83 early 84 6.9L was different than the late 84-88.Also the heads are not the same between a 7.3 and 6.9L.The Glow plugs and injectors are in slightly different locations,the 7.3L has some water passages blocked off to stop leakage,diffent valve material,etc.I would take them back and DEMAND 7.3L IDI heads.

 

[92 F-350CC]

I have not heard that the 7.3 had a cracking problem, I know that they are hard to come by because the outfit here in spokane has bought up everything on the west coast.

 

[icanfixall]

Check out Ebay for Clearwater Cylinder Heads in Clearwater Florida. They sell both new and rebuilt 7.3 heads really cheap too....

 

[Freight_Train]

Also alabama Cylinder Head Exchange sells them(I mentioned Clear Water and they said they sell sell them the heads......but that could be just Front office BS.) a little cheaper than Clear Water(I think $400 each NIB)

 

[emmer]

Her's the worse part about drilling out the holes....it's no point, because the head bolds for the 7.3l are longer and won't work on 6.9l heads (too long) and 6.9l bolts are the wrong diameter.
Right now the machine shop is looking for a set of castings off a 7.3l idi. I guess I'm just going to have to wait until we find some.
So no, they are not exchangeable even if the holes are bored out. OH well.

 

[Agnem]

The bolts are too long because they put bosses on the castings for the 7.3 heads, which elevate them slightly. Like anything, you can make the 6.9 heads work with a lot of machining, but unless you want to pioneer an easier starting 7.3, it's not worth it in my opionion.

 

[EvergreenRanch]

agnem, what would have to happen to accomodate the differences in the firering? just curious....or would that be an issue?

 

[cscmc1]

Her's the worse part about drilling out the holes....it's no point, because the head bolds for the 7.3l are longer and won't work on 6.9l heads (too long) and 6.9l bolts are the wrong diameter.
Right now the machine shop is looking for a set of castings off a 7.3l idi. I guess I'm just going to have to wait until we find some.
So no, they are not exchangeable even if the holes are bored out. OH well.

Here's one with a $25 starting bid on eBay; you might ask if they have another:

http://cgi.ebay.com/ebaymotors/88-8...ewItemQQcategoryZ33617QQitemZ8076040862QQrdZ1

 

[Agnem]

6.9's start easier than 7.3's because they moved the glow plugs over in the pre-cup on the 7.3's for emissions reasons. The 6.9 injector nozzle squirts right on the glow plug, where in the 7.3 it does not. Most 6.9's will start with a bump of the key, where as a 7.3 will take at least a full second.