Can I Get Your Opinions?

Now that its becoming more of a priority, I need to figure out which F head I'm putting in the Mistress. What I'd really like to do even though I'm not building a completely stock restoration, is use the F head that was sitting in the engine bay straight from the factory. The block number appears to match up numerically with the VIN from what I've found on the CJ3B page, so I'm sure its the original. Trouble is, the jeep was sitting outside with maybe the hood up, valve cover and head pulled for who knows how long. It came filled with acorn shells, mouse droppings and an old rag someone stuffed into one of the cylinders. I've patiently tried to PB Blaster the pistons and gradually got it to crank a bit. The 2 and 3 pistons move, but not 1 and 4 (broken crankshaft, connecting rods...?), the valves are set up solid, there's a broken exhaust stud in the block and God knows what else is going on. I don't even know that the block isn't cracked somewhere... but its original.
I got a second F head with the Mistress and was told that it was running the last he knew. Its a more or less complete 12 volt set up. I don't whether to use this and just do a ring job and new gaskets, etc... or have to do a complete tear down on the original and possibly just find out that it's cracked or not salvageable.
Keep in mind that I'm trying to restore her as cheaply as I can, but I am trying to re-use as much as possible. What would you do? Advice? TIA

 

there are no guarantees when it comes to engines you don't know anything about...I'm talking shape and condition, not your mechancial abilities.
Tear down and good mechancial inspection of both is what I'd do.
Then you know what you have to work with, what's usable and what's not.
Use both to build one good engine
Do it once and do it right ! yes, it will cost some dollars $$$$$
I just can't see taking a chance on somebody elses weak word or promise about their engine.....
why it is guys will spend $1500 for tires and wheels in a heartbeat and not invest in a good engine ?
just my opinion

 

Checking the spare engine will only cost you a set of gaskets, these Jeeps will never be worth big money, if I was buying one I'd rather it have a good engine vs. a so-so original.

 

I would check the bore on the original-if it is already at +.060, I wouldn't be tearing it down-scrap. On the other hand if it is +.030 or less, the block might still be usable. Pull the pan and see what happened to the crank. If it is broke, the block is probably scrap anyway.

 

If the block is already 60 over, I'd have it sonic checked for core shift. 100-over pistons are available for these engines IIRC, so at least some of the blocks should be able to handle that.

As block casting technology has improved over the years, blocks have gotten thinner but the core shift has also decreased. I expect the 134s have a lot of iron in the cylinder walls, and are likely fine beyond 60. However, these blocks may also have a lot of core shift in some cases, so sonic testing would be worthwhile. If the core is centered and the walls are thick, there's no reason to sleeve if the pistons are available. Sleeving will be considerably more expensive than testing.

 

Cylinder wall pics from an overheated F-134:

 

Just a note, there is a complete F134 on ebay for $250 dollars right now already cleaned and needs put back together.

Al
56 Willys F134 / T90 triple stick

 

I doubt if its bored over already. I doubt if anything has been done to it in the past, hence its sad condition. I don't know, I'm still sitting on the fence, but once again, lots of good food for thought. I think in my heart I'm still wanting the original block, but it makes more sense to use the replacement and hold onto the original for when I have the time. Maybe I'll pull the oil pan and take a look at the crank and mull it over. Thanks guys!

 

If the engines are together, the most diagnostic thing you can do is to put one in the chassis (or on an engine stand) and run it. Measure the oil pressure at full operating temperature both at idle and at cruising RPM. Measure the compression ratio, wet and dry. Inspect the fluids. Listen for noises. This will tell you more in a short time than you could learn by inspecting the static engine.

Your alternative is to tear down the engines and measure the sizes and clearances. You should also have a shop check the blocks and heads for cracks (magnaflux, dye, whatever they prefer). Most people don't have the tools needed to measure everything, so you'll probably need the help of a shop.

 

Tim - another startling display of my mechanical knowledge level - what is "core shift"? Where is it likely to find the capability to perform a "sonic check"? Industrial machine shop?

 

When the block is cast, the voids within the block for the water passages are made by a "core." In old-fashioned gray iron castings, the core is made of oiled sand and is removed from the block through the core plugs (aka "freeze" plugs, a misnomer). If the core shifts with respect to the rest of the block ("core shift") the water passages won't be centered with the bores, and the bore walls will be thicker on one side and thinner on the other. Some core shift is expected, and the casting design accounts for that - there will be variations from block to block.

An automotive machine shop should be able to do a sonic test. It's a hand-held ultrasound system, AFAIK. I have not seen it done, but I know it exists and is a common practice. I think you'd be more likely to find one at a shop that does performance work.

Did a quick search and found this: http://racingarticles.com/article_racing-73.html
and this: http://www.popularhotrodding.com/tech/0404phr_sonic_testing_salvaged_blocks/index.html