I have a 76 f250 4x4 with 410v8, 4 speed, and divorced np205. I am planning to swap for an idi either 6.9 or 7.3. But i definitely want to use a 2wd zf5 for overdrive. Will a zf5 work with the 6.9idi? I know the 7.3idi came with zf5 but am not sure about the 6.9. Also any advice on the swap would be greatly appreciated

 

never came with it, but will bolt right up.
Rob

 

Yes Thats what i meant thank you. So will i need amy adapters or anything?

 

Actually yes, the ZF5 did come from the factory as on option only on the 87 6.9


But good luck finding one.


Nothing special you need all bolt in deal. I am not sure about the flywheel though. Someone that knows for sure will chime in sooner or later.

 

Great thank you. Do you know of certain pros and cons of the 6.9 vs 7.3 idi? I know the 87 6.9 is supposed to be the best year due to thick cylinder walls, higher compression, and 7.3 rockers, but what about the 7.3idi?

 

7.3 is just as good, as long as you keep up with coolant additives (SCA's), but you have to with the 6.9 also, just alot more important with a 7.3.


Only negatives about a 7.3 is it isn't a very rebuildable block do to the thin cylinder walls. You can rebuild one, with sleeves, but it can end up costing more than just shaving the minimum in a 6.9 and it's still good for future rebuilds.


Everything interchanges between the 2, even internals, the only thing that's different is the pistons, the bore is abit bigger in the 7.3

 

Thank you for the advice. I see that you have both idi's, for my purpose of the swap into a 76 with a zf5, in your opinion, which is a better option for me?

 

If you ask me, witchever comes first really. I've always wanted to find a clean 73-79 Ford truck to swap a Diesel in, but i've got enough projects for now

Be aware though with any 6.9's, they're pretty known for blowing their factory head gaskets due to having small head bolts. Oh yea that's one thing that doesn't swap between the 2 engines is the heads, the 7.3 has bigger head bolts.



It's nothing to stay away from a 6.9 but if you get one, make sure to freshen it up before installing it, as it would be a good idea also with a 7.3


Clean it up, and re seal the whole thing, head gaskets and all.


I have 2 6.9's (ones not in my sig right now cause it's stored for winter) and i've had to do head gaskets on both of 'em. The motorhome blew 'em probably from always working hard, and my E350 cargo van didn't blow 'em, they were just leaking lots of oil (warped head).

 

Yeah thats a good idea. How extensive is that and how much would it set me back. I have a good amount of knowledge of engines, an am a very good learner, but do not have any heavy machining tools or anything. Basically could i do it myself or have a professional?

 

You can do the re-seal your self. Just a matter of unbolting, cleaning, and re-installing everything.

Front and rear main, head gasket set (head gaskets, valley pan and valve covers), and oil pan. Take the heads to a machine shop and have them check them for cracks, shave 'em down if need be, and vacuum test the valves.

I wouldn't bother doing a full rebuilt if the engine is known good runner, not so high miles, and if the inside of the engine looks clean.


Cost all depends on your area, and where you get all the parts from.



I recommend Rockauto.com

 

Great thats the exact info i needed. I appreciate the help. And as far as rockauto.com, just wow. That is a goldmine and i believe they have evrything in the world. I know these diesels will go forever if properly maintained. This is exactly what i needed. I believe i am set on the 6.9 now unless i find some great deal on a 7.3 and zf5 package. I would rather have the thicker blcok amd cylinder walls

 

If you put a ZF on a 6.9, you need to be sure you get the right clutch. You can use any manual 6.9 flywheel if you order the specific clutch for the 87 that came with the 6.9 and ZF from the factory. The input shaft for the ZF is bigger than the T19 4spd, so a regular 6.9 clutch won't work. The 7.3 clutches have a different bolt pattern and will only bolt up to a 7.3 flywheel.

Alternately, you can put a 7.3 flywheel on a 6.9, and use a 7.3 clutch, but if you do, it is recommended that you also use the 7.3 harmonic balancer to maintain correct engine balance. If you do go this route, be that both pieces come from either a NA engine or from a factory turbo engine (not mix matched) because they are balanced differently.

If you use a stock 6.9 flywheel it is a solid "single mass" flywheel, and you will have the gear roll over noise problem. Search threads on this topic to see how others minimize this issue (sound deadeners, different lubricants, and over-filling). The 7.3's came with "dual mass" flywheels, but new ones are ghastly expensive, and used ones by this age are mostly ticking time bombs. Many, many 7.3 owners have done single mass conversions with aftermarket solid flywheels. Since you are thinking 6.9 anyway, easiest and cheapest route is to use the 6.9 flywheel and get the 87 ZF clutch and call it done...

 

OK, found some links with more detailed info. for you.... you will want to read this:

https://www.ford-trucks.com/forums/6...uestion-3.html

And this:

https://www.ford-trucks.com/forums/6...body-lift.html

And maybe this:

https://www.ford-trucks.com/forums/1...el-advice.html

 

Great thank you for the information. So you think i should get the specific clutch from the 87 6.9? Are they hard to find? And if i go with the 6.9 clutch zland flywheel then is it a mechanical clucth or hydraulic? Just trying to think of the easiest and best way to install clutch onto my 76 which is mechanical clutch. Which is easier to install, hyraulic or mechanical?

 

Thank you for those links they were very helpful. Basivally it seems i should get the oem clutch from the 87 6.9 that had the zf5, and the single mass flywheel that came on a 6.9. A couple guys on there said autozone had everything and also pepboys. They mentioned that the heavy duty clutch kits (12") people had used were to big and conflicted with the pressure plate and made a terrible noise that wouldnt go away. But it seemed like the stock 11" clutch amd i believe 1.25" input shaft it was fine and workwd well.