# Pontiac 400 Cracked Cylinder



## smoke (2 mo ago)

Actually two. Is the block scrap metal, or do folks fix these?

I searched here and didn't find a simple answer, so figured I'd post. I believe you can sleeve cylinders, but it sounds like that isn't common practice anymore, or maybe it never was for 400s. Basically, I am trying to figure out if I should sell it because they are needed by folks or if the block is just scrap metal at this point.

Thanks in advance.


----------



## 67ventwindow (Mar 3, 2020)

I am not an expert. In my experience you drill to stop cracks then repair them. I dont know how a sleeve would stop the crack. Do you have pictures for we can see what your talking about.?


----------



## Scott06 (May 6, 2020)

Its very common to sleeve cylinders, certainly adds cost but wouldn’t hesitate to do it


----------



## PontiacJim (Dec 29, 2012)

smoke said:


> Actually two. Is the block scrap metal, or do folks fix these?
> 
> I searched here and didn't find a simple answer, so figured I'd post. I believe you can sleeve cylinders, but it sounds like that isn't common practice anymore, or maybe it never was for 400s. Basically, I am trying to figure out if I should sell it because they are needed by folks or if the block is just scrap metal at this point.
> 
> Thanks in advance.


A machine shop can determine if it can be saved. They will magnaflux the block and should sonic test the cylinder walls for thickness. They would want to determine why the cracks and what present bore size is.

If it is just a common block, probably not worth the investment.


----------



## Sick467 (Oct 29, 2019)

Cracked blocks are typically scrapped. In my experience, a cracked block would mean it was frozen at some point and who knows what kind of damage is hidden where you can't see. If not frozen, it underwent some catastrophic failure, but the story is the same...cracked means "I wouldn't try to salvage it". Like @67ventwindow says...I don't think a sleeve will bring it back.

On the bright side, they make real nice ballast bases for, what I call, vice or bench grinder "horse"...










Welcome to the forums BTW! Let us know what other bits and pieces you may have for sale...and throw some photos up of your cracks (that sounded funny... ). Others with more experience my see something and have some more hopeful advice.


----------



## BearGFR (Aug 25, 2008)

smoke said:


> Actually two. Is the block scrap metal, or do folks fix these?
> 
> I searched here and didn't find a simple answer, so figured I'd post. I believe you can sleeve cylinders, but it sounds like that isn't common practice anymore, or maybe it never was for 400s. Basically, I am trying to figure out if I should sell it because they are needed by folks or if the block is just scrap metal at this point.
> 
> Thanks in advance.


There's not really a simple answer. Yes, it's generally possible to have a block sleeved as long as it's not damaged to the point where it can't be. It's expensive though, so unless it's something special, like a real RamAir IV, or maybe special for another reason (it's original to the car you have), it may not be worth doing. That decision is up to you, though. If you're wanting to sell it, then I'd say it's probably not worth doing. You'll spend money on it only to find that buyers are harder to find and/or won't be willing to pay as much for a sleeved block.

Bear


----------



## 67ventwindow (Mar 3, 2020)

Sick467 said:


> On the bright side, they make real nice ballast bases for, what I call, vice or bench grinder "horse"...
> 
> View attachment 159375


If you go three high on the blocks use the cylinders for storage.


----------



## Sick467 (Oct 29, 2019)

67ventwindow said:


> If you go three high on the blocks use the cylinders for storage.


I hope I don't mess up that many more blocks between now and the end...


----------



## smoke (2 mo ago)

Thanks everyone for the warm welcome and feedback! 

The block is a 500557, so it sounds like it is the weakest of the 400s. Here is a picture; the crack is the uneven line 1/3 down the cylinder. I can feel it when running my fingernail down the wall. The engine overheated on me. Not sure if it was the cause or effect. 

Using the block as an heavy base for a vise table sounds creative. I just didn't know if scrapping it would have been a shame. Thanks again!


----------



## PontiacJim (Dec 29, 2012)

smoke said:


> Thanks everyone for the warm welcome and feedback!
> 
> The block is a 500557, so it sounds like it is the weakest of the 400s. Here is a picture; the crack is the uneven line 1/3 down the cylinder. I can feel it when running my fingernail down the wall. The engine overheated on me. Not sure if it was the cause or effect.
> 
> ...


The "557" block is not worth the effort to toss it. You can set it up on its side and use the cylinder holes to hold bottles of wine, bottles of soda, a pair of slippers, a large can of Planter's Mixed Nuts (no peanuts), Qt cans of Rustoleum paint, economy rolls of toilet paper, and cans of Pringle chips.


----------



## 67ventwindow (Mar 3, 2020)

PontiacJim said:


> The "557" block is not worth the effort to toss it. You can set it up on its side and use the cylinder holes to hold bottles of wine, bottles of soda, a pair of slippers, a large can of Planter's Mixed Nuts (no peanuts), Qt cans of Rustoleum paint, economy rolls of toilet paper, and cans of Pringle chips.


 They hold Mason jars.


----------



## geeteeohguy (Feb 2, 2008)

X2. Toss the 557 block and get an earlier block with some structure to it. I would rather run a 326 or 350 than a 557 block.


----------

