According to Steve Christ's book, 390 pistons have slipper skirts, whereas 360 pistons are full skirts.

Imagine my surprise when I pulled the pan off my 360 to find slipper skirt pistons. It certainly looks like a full skirt piston would be bashed into by the crank, and since the engine is siezed, I cannot check the stroke, and I cannot see any markings on the crank.

Now, I fully expect one of our resident experts to tell me that 360's can have slipper skirts, but just on the off chance I have run across a 390 where a 360 should be, I thought I would ask.

 

What is the casting number on the rods? A rod casting number with a -A is 360 and -B is 390 usually. And yes, many 360s have been found with slipper skirts. There is always hope. The crank and rods will tell you everything.

 

don't get too excited. i also found slipper skirt pistons in my 360 when i tore it down. get the # off the crank, i think if i remember mine was something like 2A, a 360. The crank is the real deal in a 360....

 

Thanks guys, I kinda figured as much, but it never hurts to ask.

The crank is locked in position by the seized pistons, and the markings are evidently on the side of the crank that I can't see. Neither can I see the spot on the any of the rods that has the number I need. Oh well.

Now the stupid thing is upside down and soaking in PB Blaster. I'll keep it sprayed up until the weekend when hopefully I'll have more time to devote to stripping it down.

I'll have to get a puller to get the damper off the front of the crank so I can try to get the crank out (after I remove the spacer,timing setup, etc). I didn't spend a lot of time looking at the rod caps, will I be able to get them all off without being able to rotate the crank to expose the cap nuts?

Thanks for your help.

 

for the puller just invest in a three finger gear puller, i spent 10 bucks on one that works perfectly, a two finger puller won't pull it evenly.

 

Yep, three fingers - that's what I am planning on.

Thanks again.

 

Just an informative FYI...

When I tore down the 360 donor I used, it in fact had the slipper skirts. These were a .060 over version so perhaps your motor has been rebuilt somewhere down the line. There is always hope, check for the casting number on the crank. And I believe you will need to rotate the crank to get at all the rod caps.

--Mike

 

I'll not claim to be any expert, as I just recently rebuilt/stroked my tired 360 into a 390. However, the pistons I removed from the 360 were skirt pistons and had "390" on the side by the wrist pin, ane believe me, they were installed in the factory as much. The FoMoCo part number of the rod bearings was tattooed on the inside of the rod caps and rods. Sorry to not make your assessment any easier.

 

Thanks, Mike.

There must be some piece of this that I'm missing or not understanding properly because I know people have done it. Here is how I understand this to work...

In order to beat the frozen pistons down the cylinder, I need to take out the crank.

In order to remove the crank, I must remove the main caps and the rod caps (along with the timing set, etc).

In order to get at all the nuts on all of the rod caps, I must rotate the crank.

I can't rotate the crank because it's attached to the frozen pistons.

Hmmm.......

By the way, Thanks JohnnyB and welcome to the site - I appreciate your input as well. I know that most of the Ford rebuild books have inaccuracies, and I figured if the piston skirt was a definitive way to ID a 360 vs a 390, it would have already been brought up in here. So from the responses I have learned that both the 360 and 390 had skirted and non-skirted pistons.

 

The removal chain of events sounds correct to me. You can take a look at the rod caps to see if you can get a socket in there without moving the crank, but I don't think so (memory tends to fade too). One thought that I have (ouch) is you can remove the mains and try to remove all the pistons at the same time with the crank. Of course, that was theory, to see it applied would be a work of art (and probably require a hoist).
--Mike

 

i have that same steve christs book big block ford engines, i saw that article in there that said 390's non skirted, 360's skirted, but as you guess have said before anything can come out of the factory and books arnt always right.

 

Hey before you start pulling the main caps make sure you mark them so they go back to the same spots, but if your using the "bible" by Christ himself, you would have known that. I used a small 1/4" chisel and tagged them with roman numeral numbers counting from the front to the back.

as for the access to the bolts on the rod caps, 1/4" drive with a universal? Those might be tough! when the caps are off you should have some more finger room to work with.

And as long as i'm on a roll... bag and tag everything! invest in a box of ziploc freezer bags and a Sharpee pen and label everything that comes off the motor, no matter how trivial. i give this advise to everyone, it makes putting it all back togather again real eazy!!

ps look at my engine in my gallery!

 

Fortunately for me, the main caps are all already numbered and have orientation arrows on them from the factory - I can even make out some yellow paint on a couple of them. The rods and rod caps have matching numbers indicating which piston they are on. I will make sure I have the orientation on those marked as well.

I still don't see how I'm going to remove the crank to beat out frozen pistons if I have to rotate the crank to gain access to the rod cap nuts. The dang crank won't turn because the pistons are frozen! Catch-22

 

There may be hope yet...do you know for certain that every piston is frozen in there? It possibly could only be a couple of them, or that once you get a couple of them out of the way you may be able to force the rest. At the worst all you have done is removed 2 or 3, maybe even 4 rods from the crankshaft and have only lost time.

 

I have a suspicion that all of them are frozen. On one bank, 3 of them hold penetrating oil with no leakdown at all - the fourth is at TDC so it doesn't hold much oil. I didn't bother checking the other side, I just flipped it over on the stand and took off the oil pan and pump.

I may flip it back over and try a mixture of Coke and diesel fuel.

Here's another question, why am I worrying about applying downward pressure on the piston that is still attached to the crank? That's what happens to the darn thing when it's running!

Nevermind - if I remove the crank, I apply the force to just one piston at a time. If the crank is still conected to all the pistons, I am trying to loosen them all by hitting just one.

Probably not such a great idea.