getting ready for a 7.3 swap

some of yoy know i am swapping a 6.9 out of my trailer rig
86 f350 crew cab dually 4x2it currently has a 6.9 with a ats turbo
but it is gettin tired
so i picked up a 7.3 from a 89
i am gonna use my flywheel from my 6.9 and turboand my b/t tranny with a gear vender
anything i need to look out for
and or i should know befor i swap

make sure your "new" engine has a tach sensor front cover.
not a necessity but nice to have if you dont have a tach..or want to keep the one you got.
Be careful with your antifreeze. make sure it isnt going to eat away at your cylinders.

how would anti freeze get into the cyl?
and how can i tell if it has a tach sen?

Theres a big threaded bung on the top drivers side iirc of the timing cover.
if you dont have one and you want one i think i got one in the shed i'll give it to you.
If your A/F is too acidic it eats away at the cyl walls from the outside in. It is a known problem but i wouldnt say its a huge problem. I've never seen one do it myself (not that i'm a big 7.3 mechanic) but i've heard of them doing it.

i got the 7.3 home today
it does have the bung in the t/c
i am gonna put new seals in the oil cooler just to be safe
they are a pain to change in the truck
and i am gonna swap my water pump from my 6.9 since it is only 2 months old
new filters valve cover gaskets
clutch kit
and it should be ready to drop in
but i do have a bit of a scare?
i checked the oil and it is eather very low or it was drained?
unless it ran out when they pulled it somehow?
i am gonna call them tomorro and ask them about it
they said it had good oil psi and ran great
but i have heard that befor
what is a good fair priced clutch

Diggindeeper wrote:Theres a big threaded bung on the top drivers side iirc of the timing cover.
if you dont have one and you want one i think i got one in the shed i'll give it to you.
If your A/F is too acidic it eats away at the cyl walls from the outside in. It is a known problem but i wouldnt say its a huge problem. I've never seen one do it myself (not that i'm a big 7.3 mechanic) but i've heard of them doing it.

Sounds like your talking about cavitation, the IDI's were bad about it, never seen a DI have issues but nontheless just put the Ford additive in the coolant to be safe. VC8 is the part number, 2-3 bottles usually does the trick. they make test strips to check the level, you have check it every so often and add as needed.

The IDI's have more static compression than the DI and this seems to be the issue.

I've heard about eloctrolysis, but not cavitation. Electrolysis can cause some major problems, but usually only in wet sleeve motors.

It's cavitation, The 7.3 is basicly a overbored 6.9. With the thinner cylinder walls rust and engine harmonics tend to eat away at the cylinder walls untill you start compressing water, At 20.7:1 compression things get ugly fast.


Some diesel engines suffer from cavitation due to high compression and undersized cylinder walls. Vibrations of the cylinder wall induce alternating low and high pressure in the coolant against the cylinder wall. The result is pitting of the cylinder wall, which will eventually let cooling fluid leak into the cylinder and combustion gases to leak into the coolant.

It is possible to prevent this from happening with the use of chemical additives (VC8) in the cooling fluid that form a protective layer on the cylinder wall. This layer will be exposed to the same cavitation, but rebuilds itself.