I was just going through my chiltons manual and noticed the pictures of the stock pistons, and in the middle of the dish is a nipple with a small hole. I've seen this before with other stock pistons, but I'm not sure of its purpose, is it from the manufacturing process?

Here's a pic of a blown motor with stock pistons (not mine). No nipple on them.

http://www.worldisround.com/photos/369/161.jpg

I just looked at my stock pistons yesterday and I didn't notice a nippe. It does has 4 small dishes to clear the valves it looks like though.

Here's a picture of the stock pistons.... no "nipples"...

I like nipples.

Yep, dems the one's! They look more like two butt cheeks than nipples to me. I think he was reading a girlie magazine before he checked out the Chiltons pics. BTW, shop manuals are notorious for slipping in pics of other "similar" parts.

I haven't torn down the engine yet, but in my chiltons manual it shows some photos with a nipple in the middle, I've seen them before on my Buick 455, as well as Olds 455, so they must be common. I see the pictures you guys posted do not look like the pictures in the chilton, so maybe they took them of the V6. At any rate I still can't figure out the pupose, I would thnk it would cause more bad than good since its a good spot for detontation to occur

mad wolf, what year is that LT1, because the antifreeze in it is regular, not dexcool, just wondering, sorry if it is off topic.

shocktrp's pic has the antifreeze showing[ also they aren't stock pistons, either..]

madwolf's pic they are stock pistons [I don't see any antifreeze tho..
The 'nipple' might be from 'centrifugally cast' pistons, or from a casting sprue..

Many of us use regular antifreeze also...

That looks like a flat top piston to me. Those are not stock LT1 pistons.

now those look like stock pistons.

Yep, Madwolf posted stock pistons, the others aren't. They have 7cc valve reliefs, but no nipples, the Chiltons sometimes shows other cars, but I dont recall any nipples in my Chiltons(?)

In madwolfs pic.... you can see i think 3 holes with green antifreeze in there. 96 and up are reqired to use DEXCOOL. i think other years can just use regular.

Required why? If you switch all you have to do is get all the Dexcool out of there by flushing the system.

95's came with Dex-Cool, and it's not really "required" it's just that GM thought it to be a better deal since it supposedly lasts 5 years...


Anyone got P/N's or suggestions for replacement upgraded pistons for LT1's? Something you can use with stock setup or maybe a combo of all the stuff to change with pistons?

The engine I posted a picture of is a '95. Yes, the antifreeze is green. Like Dr.Mudge said... if you flush it all out who cares what you use afterwards? As long as you don't mix...