Well i finally found out that my 7.3L out of my '90 has a 2 splits down the #2 cylinder. Now my problem is i just got a call from the head shop letting me know my heads are done which i now have $375 in.

My big question is except for pistons what parts will interchange between the 7.3L and the ultimate 6.9L. Will my heads work on the 6.9? What about bolting a 6.9L up to my E40d (which is brand new)?

 

The E4OD will bolt up to the 6.9, but the 7.3 heads take 1/2" head bolts while the 6.9 block takes 7/16"... Everything else but the flex plate interchanges though.

 

In theory, you might be able to use the 7.3 heads if you can have custom bolts made.

I'm not sure if the ARP bolts that are intended for the 6.9 will work though.

You could try giving ARP a call to find out if they have anything that would work. It won't be cheap in all likelihood but at least you can use a known good set of heads instead of starting over.

Short of that, you might be able to get your money's worth out of the heads since it can be hard to find good 7.3 IDI heads.

 

Or you may have to get another 7.3 block to put those heads on.

 

The 351W head on a 289/302 block has the same problem and they put a hardened washer under the head of the 7/16" bolt to fix it. Why wouldn't those same hardened washers work on the 7.3 head on a 6.9 block?

 

I have a 93 ford prepower stroke 7.3 would a 83 pre power 6.9 mount up to tranny

 

First year for the 6.9 - 1983
Last year for the 6.9 - 1987
By 1988 all production 7.3

6.9 - Max H.P. 175 Torque 318 ft. lb.
7.3 - Max H.P. 185 Torque 338 ft. lb.

6.9 max torque at 1800 RPM
7.3 max torque at 1600 RPM

Both max HP at 3300 RPM.

7.3 external identification variance from 6.9 - New fuel filter/fuel heater/water sparator, larger/taller cylinder head bolt bosses with ribs. Dual mass flywheel on 5spd.

Crankcase differences
Cylinder bore - 6.9 = 4.00"
Cylinder bore - 7.3 = 4.11"
Stroke for both - 4.18"
Top deck thickness - 6.9 = .500"
Top deck thickness - 7.3 = .560"
Oil drain Back holes - 6.9 = 3/8"
Oil drain Back holes - 7.3 = 7/16"

Cylinder head changes
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 cup 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.

Piston and ring sizes increased in accordance with bore changes. The 7.3 utilizes select fit pistons at the manufacturer. The engine is produced with A,B,C and D size pistons and cylinder bores. When re-using pistons, "A" pistons should go in "A" cylinders, and "B" pistons in "B" cylinders and so on. These letters are stamped on the pistons and the cylinder bores at the bottom of the bore when viewed from the crankshaft side. Service part pistons can be utilized in any bore, and are identified with an "S".

Flywheel -
IMPORTANT. DO NOT USE 6.9 flywheel or vibration damper on 7.3 or vice versa. If components are intermixed, engine vibration and premature component wear may be encountered. For identification, compare these part numbers.
Vibration damper 6.9 1805414C1
Vibration damper 7.3 1809117C1
Flywheel Auto 6.9 1803219C1
Flywheel Auto 7.3 1809212C1
Flywheel manual 6.9 E7TA-6477-AB
Flywheel manual 7.3 E8TA-6477-AA

Injection Pump - Changes have been made to increase fuel flow and change ignition timing on the 7.3. Low and High altitute calibrations are available for both.
6.9 High - 1807568C91
6.9 Std. - 1807560C91
7.3 High - 1809045C91
7.3 Std. - 1809121C91

Injection lines - Due to the .060" retraction of the injector nozzle on the 7.3, all 7.3 injector lines have been shortened by .060" However, all lines with the exception of #1 on F series, and #4 on E series, are interchangeable between 6.9 and 7.3.

Cylinder wall honing -
Plateau cylinder wall honing has been implimented on the 7.3 to promote ring seating and engine break-in.

Front cover -
The 7.3 features an embossed front cover to improve sealing and eliminate water pump replacement due to gasket seepage.

All this stuff came out of the 1987 7.3L diesel engine technician's update, which was used to quickly bring up to speed a 6.9 diesel mechanic. Also inside, was a chart which I found interesting. It shows the amount of HP required for a given frontal area at a given speed. I don't want to type up the whole chart, but I'll give you one column, for 55 MPH

Area in Sq. Ft. - HP required
50 - 56
60 - 66
70 - 78
80 - 89
90 - 99


Timing gear has 106 teeth........

 

im taking out my 89 superduty 7.3idi and putting a 6.9 no oil pressure in 7.3 and need to work truck. the 7.3 is a manual 5 speed and the 6.9 is a auto so my qestion is will the 7.3 flywheel and clutch work on the 6.9? i lucked up and bought a whole truck for 300 dollars that was involved in a accident i cant afford to fix the 7.3 right now so im in a bad possition. can anyone help?

 

if any one has done this swap and can give me any pointers it would really be helpfull thanks!!!!!!

 

It will bolt up. It is recommended to not use a 7.3 flywheel on a 6.9 and visa versa. However I did it several years before I ever heard of this, with no ill affects. I have read a paper from ford that recommended changing both the flywheel and the harmonic balancer when changing froma 6.9 to a 7.3 or visa versa.

 

so change both front ballancer and flywheel off 7.3 to the 6.9????????????????

 

were the radiators the same aswell i havent started comparing yet

 

if anyone needs a autmatic out of 2wd f250 iv got one with 54,000 miles

 

I'm not sure on the radiators, but you got it on the flywheel and balancer.

 

Being behind a 6.9 it'll be a C6, there's not a lot of demand for them, but there are a few of us with them.