7.3 IDI heads on a 6.9
 

Hello, I have been reading and It seems like the 7.3 IDI turbo heads have better valves and better rocker assemblies. Do these parts have to be swaped onto 6.9 heads or will the 7.3 IDI turbo heads fit on a 6.9.

you can use the rocker arms off a 7.3 on a 6.9 head. you can not put a 7.3 head on a 6.9 the head bolt sizes are different.

If the head bolt size is the only difference I am suprised that no one makes a 1/2" head stud with 7/16 threads on one end. Are there other differences?

This may help you........

Cylinder head difference
Cylinder head bolts - 6.9 = 7/16"-14 UNC 5.25" long
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Injection nozzles have been retracted on the 7.3 .060" to facilitate Federal and state emission certs.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)

Precombusion chamber inserts are physically interchangable, however the throat has been redesigned to distinguish them apart, and the 7.3 prechamber cub has an embossed "88" on it.

Valve Stem -
The 7.3 valve stem oil sheild is larger to reduce hydrocarbon emissions. Intake and Exhaust sheilds have been color coded, even though they are identical and interchangeable.

Coolant passages -
The lower corner coolant passages on the cylinder head on the 7.3 have been plugged. This change is introduced to eliminate lower corner gasket coolant seepage during cold start engine warm-up. Mating passages in the block are also plugged. (could be why we hear more 7.3 overheating issues).

Exhaust valves - The 7.3 exhaust valve has had its alloy composition changed, with more nickel, chrome, and silver content, and decreased manganese content. The 7.3 valves may be used in the 6.9, but not the other way around.

Are you shure you did not design the 7.3 engine? I have never seen a more complete and detailed explanation of anything in my life. You are an expert on Ford diesels without a doubt. So the valves and the rockers from the 7.3 head is all that is useable on the 6.9 heads. Thanks!

The info I post is NOT always mine, but gleaned from several very good sites just for use at a later date........

7.3 valves, valve stem seals, rockers and springs are all you want in your 6.9 head.

What about 7.3L injectors in a 6.9? I installed a new set in my 89 7.3 a couple weeks ago. Then i found a guy who upgraded to a powersmoke and is now selling his 6.9 turbo dirt cheap. Would the 7.3 injectors move any more fuel than stock 6.9s? Or do I have to get stage 1s?

G code injectors for a 93 - 94 7.3 turbo will work and do injector a bit more fuel.

To get the full effect, you need to install a 93 - 94 7.3 turbo IP with the injectors.