Junk Yard $250.00 6.9 is a "A" engine ?

[darkbluefoxbody2]

Anyone know if the 1983 6.9 head cc's are the same as 1984+. My $250.00 early 1984 6.9 has been rebuilt or updated at some time and the heads were changed to 855C1 castings. Block is early serial number 10305. Hoping its still a low compression engine.
I haven't taken it apart do to being SUPER CLEAN and everything checks out 100%

NO CRACKS at block heater and had been changed by previous owner to a 250Watt.
Engine has NO stickers, never been repainted, clean'ish, black silicone around intake ports and intake ends, and PC valve seals on both intake and exhuast!!! (kinda worried about that)

Any way to Id a low copression "A" engine if I take it apart. (I'm thinking this was a IH replacement engine)

 

[The Warden]

If you look at the link in the first post of this thread, there's a series of files called "6.9l Update" that details the differences between the A and B engines. Hope this helps

 

[darkbluefoxbody2]

If you look at the link in the first post of this thread, there's a series of files called "6.9l Update" that details the differences between the A and B engines. Hope this helps

NOW THATS what I'm talking about!!!!!! Thanks So much!!!! I never seen that before and thats a great resource!!!!
Looks like I have an "A" engine with good heads that lower the comp ratio even more than the 20.7:1 by having larger prechambers and recessed valve hieght, GREAT MORE BOOST!!!!!!!!!!!!!!!! guess I need to take it apart for gaskets and studs to be safe!

 

[icanfixall]

You seem to feel the "low comp" engines are something special. Ask around what the comp ratio was in those engine. I recall its something like 20 to 1 where every other idi is 21 1/2 to 1 comp ratio. Its really nothing to Try to find these days. I don't recall where the lower ratio is made up either. It might be in the heads and precups. So if you have newer heads and cups your probably running what everyone else is. Come to think about it I recall something bout the precups makeing the differance.. Not so any longer. All we can buy is the 7.3 precups. They actually are a better cup too. They have a stamp in them. Its 88.

 

[darkbluefoxbody2]

Well I messed up and my engine is just your plain old "B" engine, miss read the serial number #103059 and its a mid late 1984 so the heads are the originals, Kinda feel better now knowing she's all oem and in great shape. Still has the exhaust manifold locking tabs on both which ended early on to. Looks like heads been off but manifolds were left on.

Oh well its a $250.00 gem.

Now what to do with it?

You must be registered for see images attach

You must be registered for see images attach

 

[darkbluefoxbody2]

Well its apart and is a .020 IHC rebuild, bronze valve guides (explained PC seals on exhaust) 7.3 valves, Mahle pistons .010/.010 crank. IHC gaskets, decent but has TONS of carbon inside the ports and cylinders. Maybe someone ran without a air filter? Kinda smells like French Frys Too!!!!
Cylinders are worn I think, but very little ridge, No hone marks evident. lots of small scratches that can't be felt with a fingernail or tool. Kinda weird!

Complete teardown reseal and clean up in order. "Studs too"
Found ,020 Clevite rings for $82.00 to the door too, too cheap to let those go.

Ip been apart so was rebuilt at some point

BUT one brokem exhaust bolt! now I know why IHC changed bolt designs!!!!!

 

[icanfixall]

Sounds like the engine is salvagable. What did the rods and mains look like. Was there wear on one edge more than the other edge. Run a 4 inch stone on a drill in the bores with plenty of oil to create a better cross hatch pattern. Watch the piston oil coolers at the bottom. You really don't have to stone the bore from top to bottom. Only the piston skirts reach down to the bottom of the bores. You will see the depth the rings travel. Just go about 1 inch lower than that. Maybe 5 or 10 up & down strokes is all thats needed. Your just breaking the glave. Not opening up the bore. Please don't use a oil pan gasket either. Just a good quality rtv is needed just like the factory used.