Hey guys, I got a 86 f250 with a 6.9, 4speed, 6 inch stacks, turbo, etc. But my engine (since i bought the truck) has leaked everything from everywhere, and now both my head gaskets are leakin and and i have a lot much blow by flowing out. So I got a 7.3 IDI from a buddy, its got 150k on it and hasnt run in years so i am gonna swap them, but....i think its time for some more power. So i am just looking for some pionters on what to do to it while it is out of the truck. So far i decided to replace all the gaskets and check the bearings and such. I am gonna use the same turbo i have on the 6.9 for the 7.3, and crank up the fuel. I am also gonna put in some ARP head studs and some good head gaskets.

Is there any places that sell or make a performance cam and/or injectors?
And whats a good place to send my IP for some performance tuning?

Any help would be awsome...thanks.

 

I'd put on new head gaskets if you hadn't planned to and make sure the piston rings haven't stuck from sitting so long. I'd spray a liberal amount of Kroil penetrating oil around each piston/ring. This stuff penetrates so well it will actually penetrate through Tupperware containers, not melt it, goes right THROUGH it.
Also drain ALL of the coolant and make sure you keep the SCA levels/PH balance right.

If the 6.9L is just leaking I think I'd pull it, install gaskets etc. and use it.
As far as the blow-by: I'm pretty sure ALL of these motors have a lot of it.

 

Rebuild the 6.9.

 

Hi dave, that is my plan now after thinking about it and i want to do some unique things to the truck. Do you or anyone else know of a place that would sell a performance cam for these engines...if not I am going to see if it is possible to have one made at a shop in mid PA. But other than a cam I might oversize the pistons, and find a better turbo setup. But how about some rebuilding or part tips??

 

If you already have the 7.3L there's some better parts to rob off of it.
Exhaust valves
Rockers
Valve springs
Valve stem seals
I think there's something about the valve guides that's better too

Dave likes Fel-Pro gaskets
He says if you use liberal amounts of copper spray-on gasket maker on the intake and exhaust gaskets they won't leak. And use grade 8 bolts on the intake with a little-more-than spec. torque.
The last advice was for really high boost levels but I don't see why it wouldn't be a good thing in general.

 

When I did mine, I went with the minimum amout of bore, just enough to have fresh cylinders which turned out to be .030 bore.

I used a stock cam, the clearances are rather close in the cylinder as it is now.

If you want to run over 20 PSI boost, you have to mill the pistons down.
The 6.9 is 22.5 to 1 stock, 20 PSI boost puts that close to 53.11 to 1.

A Power Stroke starts at 18 to 1 and 30 pounds boost puts it right at 54.73 to 1.

I took .020 off my pistons which dropped me to 20.25 to 1, 25 PSI boost puts me at 54.68 to 1.

A stock 6.9 running 10 PSI is seeing 37.8 to 1 for the top compression ratio.

These numbers should show you why head gaskets fail on the IDI engines with turbo's if the boost gets to high without internal mods.
Cylinder pressures well in excess of 1000 PSI during the combustion stroke.
I am real close to 1000 PSI at 25 pounds boost on the compression stroke.

Yes, I blew the valley pan gasket racing a Dodge when the boost hit 25 PSI, the IDI was never designed for that much pressure in the intake.
In fact, the IDI was never supposed to be a turbo engine.

So I made grade 8 studs for the intake manifold.
When I had the engine out to change the valley pan, I also found I had blown the exhaust manifold gasket, so I made more studs for the exhaust manifolds as well.
I also found several leaks at the manifold to cross over pipe and the ATS Y pipe, so off to NAPA and the exhaust manifold gasket bin.
I found a steel reinforced fiber gasket that was close to fitting the exhaust connections, a little work on the drill press and I was good to go.

First I sprayed the intake to head parts of the valley pan with three coats of high temp copper spray gasket maker, also a coat on ther intake and head surfaces.
Using the grade 8 studs I made, I doubled the factory torque on the studs.

Same process for the exhaust manifolds.

I did not use grade 8 fasteners on the Y and cross over pipe connections, but I did spray the gaskets I adapted just like I did the intake and exhaust gaskets, and I did tighten them down tight.

40 K since then, no leaks so far.

When you can't buy what you want, make it yourself.