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So I just got the heads off, and found out that the rebuild that was put in there has already been bored .040 over. Reading around, this is about the absolute max that one can use before running in to overheating issues right? It looks like there's quite a bit of deposits on a few of the piston heads, what is that an indication of? Do these look healthy? The plugs are uploaded in order of cylinder #.

https://picasaweb.google.com/cavellmc/Bronco?authuser=0&feat=directlink

Trying to get a feel if this engine is in decent shape and I can go about replacing the head gasket then putting it all back together again. Also that it'll last the ~1200 mile trip I'll be taking in a few weeks..

Appreciate it greatly!
 

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The pistons dont look bad at all. I would throw some new HGs on there and put it all back together.

Having said that, the variation in carbon buildup across the pistons indicate a rich condition in those cylinders that have more build up. There are a few different ways this could happen:

1) The injectors for the cylinders that have higher carbon build up are flowing more fuel than the others. Injectors rarely flow the same amount. You can get matched sets, but I think its safe to say that most factory sets are not matched.

2) You have less airflow to the cylinders that have more carbon buildup. Ive never heard of Ford having problems with a specific cylinder, but it could happen if your gaskets are not aligned properly. Remember that motors suck air in; air is not pushed in. If your exhaust is blocked (maybe a severly bent primary tube or misaligned exhaust gasket) some of the spent air/fuel mix may remain in the cylinder. This will result in less fresh air being pulled into the cylinder.

Im not great at reading plugs, so take this with a grain of salt:

#2, #3, #5, #6, and #7 look good to me.

It looks to me like the #1, #4, and #8 have some oil on them. #4 looks like it has oil on the threads, too. Maybe this is gas, not oil? It would explain why cylinders #4 and #8 look like they have some extra carbon across the top of the pistons. If it is gas, I think the injectors are the culprit. If its oil, it could be slipping by the piston rings (coming up from the crankcase) or slipping past the valve seals (coming down through intake valve guide). An easy way to tell.... are the backs of the intake valves covered with oil?

Do you get any codes when you run a self test? Have you ran a cylinder balance test? As long as your EEC is happy I wouldnt worry about it.
 

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Having taken a look at some of the better pictures, I'd suggest that your timing may be a little advanced.

On the ground strap, you can judge the timing from where the color change happens. If the color change is near the bend, or right in it, it's pretty spot on. If it's more towards the tip, it's a little retarded, moving closer to full retard. :)

The closer it is to the threaded area, the more over advanced it is.

Keep in mind, this is a general indicator and things like mixture, engine build and use will come into play but it's something to think about.

It's really tough to read things over a picture. or...for dumb people like me it is, anyhow, but I'd suggest that it's a pretty healthy engine and that you'd be OK to swap head gaskets and go. If that is a little oil moisture that we can see there, it doesnt look significant and should more than make your 1.2K mile trip. If it's fuel, it'd have to be an injector, as mentioned. Make sure there are no leaks external to the engine so you dont get a fancy engine fire and it'll still make the trip.

That small of a leak of either fluid is not much of a deal. Personally, I'd slap it back together and, if it's fuel, worry about that injector eventually. If it were oil, I'd wait till it's rebuild time and still not worry about it.

Out of curiosity, why did you pull the heads? I have been sampling the cooking sherry a little bit, but I didnt see a reason in your post?
 

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Discussion Starter #5
Thanks for the info guys!

I pulled the heads because of what I've found when taking the engine apart to replace valve cover gaskets (so bad the engine bay would smoke after 30 seconds of turning on). Bolts were either completely seized, or they could be removed with my fingers (all 12 valve cover bolts). This was supposed to be a fresh rebuild, but apparently the person didn't know what they were really doing. I've only driven the truck 3 times since I bought it, and it leaks about every fluid you can imagine.. The last owner let it sit for pretty much 2 years here in TX, and didn't take care of it very well. I'm sure everything has run dry at least a few times, that's why I'm trying to cover all my bases.

Just trying to do as much preventative maintenance as possible, so I don't have to F with it as much later on.. Figured replacing all the gaskets was a good start.. Also all water and p/s hoses, vacuum lines with silicone.. Oil pump, p/s pump with Saginaw I got off an E150, injector o ring kit, pcv valve, etc, etc.. As long as I was taking it completely apart to get to these gaskets, I just thought it'd be easier to replace some of these things while I could get to them. After I put the engine back together and it runs (hopefully... This is my first time!) then I'll be replacing the battery cables/connectors, as well as fresh plugs/cap/rotor/coil.

scld, nope, the valves are dry but some are colored differently than others.
 
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