Heads Are Off, How Can I Tell If The Pistons Are Stock?

[sen2two]

When I purchased the car, I was told that it had forged pistons crank and rods. There was no real way to confirm this, so I've always just assumed that everything was stock. The guy I bought it from didn't seem to know much about anything.

So, seeing this is the first 302 that I have taken the heads off of, are there any identifying marks to tell if these are the stock Pistons?

 

[Gearbanger 101]

If it's still got stock heads on it, there's a 99.999999% chance it's still got a stock rotating assembly too.

FWIW, pre-'93 cars got forged pistons and rods from the factory, with a cast crank. None of this really makes a difference though, because it's usually the block that breaks before the rotating assembly does.

 

[sen2two]

I agree with you on the stock head usually means stock rotating assembly. But there were a lot of hints that the heads have been off the car. And that the motor has been out of the car as well.

Before coming into my possession, the car was once a turbo car as well. Although, i did not get the car with any of the turbo stuff on it.

It's a possibility that the heads were removed along with the turbo stuff. If I had some good quality pictures of stock Pistons, this would be a big help.

 

[Gearbanger 101]

Stock pistons will have small valve reliefs cut into either side and a small dish in the middle. I've seen some with and some without Ford part numbers (E7ZE-6110-CA) on the dome, so if you're don't have it, don't assume that automatically means they're aftermarket. You could also measure the bore to see if they're standard or oversized....but that won't tell you if the previous owner changed them out for high end slugs, or any old piston that was on sale that week.

Heads could have been removed at some point for something as simple as a bad head gasket.

Is there a problem with the engine that you think you need to do something with the rotating assembly, or are you just curious because the heads are off?

 

[sen2two]

Thanks for the info. I'll be able to check them out in the morning when it's light. The heads are off because I'm putting on a set of gt40p heads and a systemax 2 intake.

And I'm really only doing this because I was leaking oil from head gasket, valve cover gasket, and intake manifold in the rear where it meets to the block. I figure, if I'm going to pull everything off, I'm not putting stock Parts back on. So whether or not the rotating assembly is stock. It's going to remain that way. It's really just because I'm curious.

 

[Mustang5L5]

Most I've seen have a ford e7 part number right on top


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[Gearbanger 101]

Most I've seen have a ford e7 part number right on top


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Yeah, me too.....but I've seen Ford pistons without any part number on the dome as well. Some have had them on the underside of the dome. They must altered them during certain years, or build dates?

 

[Jersey Joe]

Bone stock pistons

 

[Mustang5L5]

Yeah, me too.....but I've seen Ford pistons without any part number on the dome as well. Some have had them on the underside of the dome. They must altered them during certain years, or build dates?

I have a 5.0 piston sitting as a paperweight at work in my office. Had this post come in a couple hours earlier I could have snapped some pics.


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[sen2two]

Well, the Pistons in this block look absolutely nothing like that picture posted two posts up. There is no dish in the middle, they're completely flat across the top except for two valve reliefs on the upper side of the piston towards the intake manifold side. It is also bored .030 over. There are no identifying marks on the Pistons. So they definitely aren't stock. But I have no idea what they are now...

 

[sen2two]

Pulled the lifters out to clean them. And boom, Well.... This block is a non-roller.

So.... Now I have no idea what motor this is either. My life...

 

[sen2two]

Pics of pistons after A LOT of cleaning.

 

[General karthief]

There are/was two codes on sbf blocks, one is behind the starter area that is a casting code, the other is an assembly code that is stamped on a flat spot on the back, looking down from the top you will see a flat machined spot I think is in the area between the bell housing flange and the head/intake, these are the date the engine was assmbled for installation, most times these cannot be easily seen because of machining and/or poor stamping techniques. The date code behind the started is a raised casting alphanumeric code the block was cast, at least that will give you the general year your block was cast and I think it will tell you where it was done ie: mexico or windsor or where ever they where done, hint, if it does not have threaded holes in the lifter valley, its not a roller block.
I keep thinking eary blocks did not jave a hole for the dip stick in the block on the drivers side, although its been a while so that maybe a little fuzzy, you can guess why it's fuzzy.

 

[sen2two]

Your right about the dip stick issue. It's kind of rigged to a header bolt to be held still.

 

[General karthief]

Mustang dip sticks (and I am one) where bolted to the exhaust bolt between the middle exhaust ports on the drivers side, I think early blocks had dip stick going into oil pan versus the block on newer ones, like I said not sure about that part. I just remember see'n oil pans with dip stick tubes in them, I said it was fuzzy, really fuzzy.

 

[General karthief]

FWIW you do not have a roller block if I'm seen'n the lifter valley correct, I don't think you can 'retrofit' stock roller lifters by drilling and tapping for the spyder, I think there is an issue with oiling the roller lifters or something similar. Link bar lifters are a pricey choice, is the block toast? Not having a roller block is not the end of the world, but close.

 

[sen2two]

I understand that this is a non-roller block. Which is upsetting. But not a big deal really... As far as I know, the block itself has no issues. It always ran well even with all the leaks. Which is surprising because I have never seen this extreme amount of carbon build up. At least 3 of the pistons were over an 1/8 thick. And one even more than that...

So, from what I can see. These pistons do not look stock at all. Which is nice. And at TDC, they sit flush with the deck surface. 0 decked, flat top pistons, and P heads should give a nice bump in compression over stock. No way to know how much unfortunately though...

 

[Gearbanger 101]

No way to know how much unfortunately though...

Well of course there is. Do you think people just guess? lol All you need is a piece of Plexiglas, some silicone, a burette and some water. You can even use it to cc the heads afterwards.

This dude has a pretty good set up.....


View: https://youtu.be/1J3a3b54rqE

 

[Madlash93]

This is what my 306 ((as I was told, not 100% sure how true it is)) has in it (very sure these are aftermarket)

This is what was in my old 90 Mustang

 

[Mustang5L5]

Stock piston

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