• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Rusty cylinders in block

TexasRoadRunner68

Well-Known Member
Local time
7:51 PM
Joined
Jul 24, 2013
Messages
546
Reaction score
203
Location
Dallas,Texas
So, despite being told my block would be good 0.030 over and using a 0.035 over piston, apparently there is still a ring ridge of 6 thousandths. My rotating assembly is all balanced, so at this point it’s almost cheaper to buy another block and pay to have it checked out and bored.

There are only a couple 400s close by. This one was sired behind a shop and has some surface rust but is supposedly standard bore. Is this rust that you guys think would likely clear up with .035 overbore or would it need more? I’m almost more worried about the rust than ring ridge. It seems like it should, but I have little experience dealing with rusty cylinders.

It’s about an hour away. I can get the long block for $200.

Worth the gamble?

403D5823-9887-4C2C-A11C-5432063446C8.jpeg


1EF2F167-504E-424D-9CEC-F985950430B9.jpeg


5F9F5E82-1FD5-4C8C-A0D0-C382F2342805.jpeg


248F4469-9CC2-4A44-81FE-603964783B3A.jpeg
 
Hard to tell from a pic, but I think I would pass. Remember .030 over bore only will remove .015 from the cylinder wall at the most. First pic looks like rust pits but again can't tell for sure.

I would sell the pistons you have. Get the block you have bored as little as possible to clean it up, and get the right pistons for your bore. If you buy the same brand/type of piston it shouldn't take much if anything to balance it.
 
Hard to tell from a pic, but I think I would pass. Remember .030 over bore only will remove .015 from the cylinder wall at the most. First pic looks like rust pits but again can't tell for sure.

I would sell the pistons you have. Get the block you have bored as little as possible to clean it up, and get the right pistons for your bore. If you buy the same brand/type of piston it shouldn't take much if anything to balance it.
The part that sucks is it’s a balanced rotating assembly from 440 source. So I’d need to have it balanced again…
 
The part that sucks is it’s a balanced rotating assembly from 440 source. So I’d need to have it balanced again…
Not necessarily. Call 440 source to get your pistons. Find out what your pistons weigh, and lighten the new set of pistons and rings to the same or close to the same weight as the ones you have now. Much simpler than a complete rebalance job. If you tell 440 source what happened they may even send you a set with the proper weight already.
 
I second calling 440 source. They may have .060 pistons they can, and would, trade.
CL is my first go to if I needed a block. Flackebook next, looking for a local Mopar group. In Dallas I found one guy on CL
 
I second calling 440 source. They may have .060 pistons they can, and would, trade.
CL is my first go to if I needed a block. Flackebook next, looking for a local Mopar group. In Dallas I found one guy on CL
[/URL]
440 source said I would have to sell them personally and buy another set. I brought the block in and was told it was good for 0.030 over. They are saying after boring for a 0.035 over piston that it’s still has a ridge of 6 thousandths. The guy there said “things like this happen sometimes with machine work”. My issue is that the standard bore is not hard to look up. Had they taken a dual bore gauge to the cylinders, it should not have been hard to notice it was more than .030 over.
 
There must be a million B Blocks in the DFW area. Put an ad here on FBBO. " Wanted: B Block near Dallas"
 
As long as there aren't any deep pits, it would probably clean up at .035 if it is just surface rust. I have a 400 Pontiac block that was stored outdoors since the early 80's. It was solid rust. The block was original to one of my GTO's so I wanted to try to save the block. It was already .030 and it ended up being saved at .040.
 
Why not sleeve your block?
 
Why not sleeve your block?
I’m only $150 into machine work so far. If I can pick up a decent block for cheap ish, then it’s almost better to just do that and save my current one for a future build. Otherwise It’s another $700 on pistons and likely $200-300 on balancing to go .040.
 
Knock the thing apart and have the machine shop bore the hole they see as the worst. If it's good, keep going and see if you get lucky.
 
Knock the thing apart and have the machine shop bore the hole they see as the worst. If it's good, keep going and see if you get lucky.
I mean I might be able to talk him down a bit more. I still don’t understand how a machine shop doesn’t realize the ring ridges are already beyond 0.030 over stock bore.
 
Ok, you need to understand what you are attempting to say because your statement is incorrect. The "Ring Ridge" is the unworn portion of the cylinder at the top (yes, I know you know this). But, after the cylinder is bored to 0.030" to be honed for a 0.035" piston, there is NOT a 0.006" ring ridge. The ring ridge is the exact diameter as the rest of the bore because it has been bored to 0.030" oversize. The problem is that the 0.030" bore did not completely clean up the top of the cylinder, and has left what I call an "Eyebrow". It is a divot and quite actually won't impinge on the piston or rings. The proper thing to do is have the cylinders bored another 0.010" for a 0.045" piston, and that will clean up the bores. As far as the balance goes, take an old piston and the new pistons to the machine shop, and have the new ones "Match Weighed" to the old piston. This way, you do not need to rebalance the entire rotating assy, just the new pistons.
 
This is the worst cylinder on the second block. For those with experience in this sort of thing, does that look 0.030 over, 0.060 over?

1BC80C60-72F5-4186-9082-F94348B7C246.jpeg
 
Check the weight of both sets of pistons, may be the same, no need for re-balancing.
 
There must be a million B Blocks in the DFW area. Put an ad here on FBBO. " Wanted: B Block near Dallas"

i want to live in your world were theres a million vintage anything mopar available. truth is usable 400 blocks are getting scarce they were considered undesireable to the mopar crowd back in the day just smog motors
 
i want to live in your world were theres a million vintage anything mopar available. truth is usable 400 blocks are getting scarce they were considered undesireable to the mopar crowd back in the day just smog motors
The guy I got this one from didn’t want it because it was cast crank and it wasn’t a 440. I guess the stroker potential didn’t catch on until late. Lots of these motors were probably already junked.
 
Some disassembly required. It doesn’t look as terrible as I expected, I’m hoping it scrapes by and cleans up at 0.035

70367244-D790-4080-9535-2872F7B11D6D.jpeg


87010A1B-49DE-47C6-B850-DEF447F750F6.jpeg


75B0012F-2141-4335-80A8-86279C7467C2.jpeg


D7FF16BB-2175-4AA6-A40A-9123EA596074.jpeg


D068111A-57BA-4E3D-BBA9-2F3BCCB0D267.jpeg
 
Auto Transport Service
Back
Top