motors out..... head cracked!!!!

[The Warden]

Due to the pistons.... not the head.

According to the documentation I have, the head was changed along with the pistons. The precombustion chambers were made smaller, and I'm guessing that the spots in the head where the precombustion chambers go into had to be altered slightly to match. The exhaust valves were also made slightly thinner, BTW, to accomodate the taller "B" model pistons, and there were also fuel system changes (notably different injectors, and the IP was changed internally to adjust the timing schedule).

If you have the 6.9 Liter Diesel Engine Update (published by Ford in October 1985) document that was posted on TDS a couple of years ago, take a look at the Appendix (the 4th file as they were originally presented), pages A1 to A4. If you don't have them for whatever reason, let me know and I'll be happy to either E-mail them to you or put them up on my server and make them available for download. It's a total of 4 .pdf files that come up to 5.15 MB in size.

I know it's a moot point for this thread, since GreenBeast looks to be dropping that 7.3l in this truck, but I thought I'd at least post the info for posterity...

 

[Agnem]

Yes I remember that document Warden. Your right of course, but I bet an A model head would work on a B model engine with no problem just the same.

 

[The Warden]

I bet an A model head would work on a B model engine with no problem just the same.

Mel, you're probably right...if you have "A" heads (with the "A" precombustion chambers; again, my guess is that "A" chambers won't fit in a "B" head and vice-versa, and that's probably the only real difference between the two) on both sides. If you have an "A" head on one side and a "B" head on the other, I would venture to guess that there would be issues with one bank running differently from the other...not sure what sort of effect that would have on the engine's operation altogether, but I imagine it wouldn't be exactly "good".

What do you think on that? My logic may be partially flawed (on the tail end of an all-nighter working on a paper for one of my classes)...

 

[Agnem]

On a freshly rebuilt engine you might notice it, with everthing being tight and all, but on a run engine with already varying compression numbers, I don't think it would matter. Just a hunch though. I might be all wet. I can't see doing it on a project motor.

 

[scamp73]

i need to know where i can find a used head and where is the best place to get a rebuild for the 6.9l possibly just a re ring with gaskets and bearings.

If Ebay doesn't work check www.car-parts.com this is the best place to find used parts for anything.