Pitted cylinder walls- should I send it?

PDHSB

Member
Jun 11, 2020
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VA
Hey all, doing my first rebuild on my 4.6. I had the block deglazed, but there seems to be pitting in the bottom of cylinder #5. Can I run it this way or will this cause major issues?

It's at the bottom of the cylinder, so I don't think it will affect compression much, but will it cause my rings to seat poorly? I'd honestly be happy to get 20-30k out of this engine, I don't plan on running it for long, just as long as it preforms OK is my concern.

20210325_204049.jpg


This is a shot for scale, and here's another zoomed in:

Screenshot_20210325-205352_Video Player.jpg
 
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7991LXnSHO

10 Year Member
Sep 1, 2010
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Kearney, NE
That’s an ugly second picture. What happened to the block. Was it sitting with water in it?
It looks like time for an overbore. I would not trust a new state of rings in a mower to run long like this.
 

PDHSB

Member
Jun 11, 2020
28
3
13
22
VA
That’s an ugly second picture. What happened to the block. Was it sitting with water in it?
It looks like time for an overbore. I would not trust a new state of rings in a mower to run long like this.
I honestly have no clue, but the whole reason I'm doing the rebuild is because of low compression in this cylinder.
 

7991LXnSHO

10 Year Member
Sep 1, 2010
4,991
1,491
184
Kearney, NE
I honestly have no clue, but the whole reason I'm doing the rebuild is because of low compression in this cylinder.
There’s your problem. Can it last 20-30k? How much time and hassle is it worth to find out when we know it is not good? I do not see new rings setting right from the start. If nothing else, you should have extra oil consumption from the start.
 
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PDHSB

Member
Jun 11, 2020
28
3
13
22
VA
4.6 blocks, including the Teksid and WAP blocks are so cheap and plentiful at junkyards that it's just not worth taking the chance.

Either get it machined and get new pistons and rings to match, or get a different block.
Alright, guess I'm going to head to the junkyard soon. Can I run a WAP block with my current rotating assembly or should I just be looking for another Romeo?
 

7991LXnSHO

10 Year Member
Sep 1, 2010
4,991
1,491
184
Kearney, NE
If a little old lady/man lost their license after an accident that totaled the car, or a lower mile pickup wiped out on ice, you could be in the road for many miles. Whoever gets the engine and transmission out of our recently bent van should be set for at least 100k.
 

Nightfire

15 Year Member
Dec 1, 2002
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TX
How can you even question this? That is some major damage! Your head is most likely cracked, causing coolant to enter and cavitation. You could try to machine the cylinder and get yourself a new head
 

PDHSB

Member
Jun 11, 2020
28
3
13
22
VA
How can you even question this? That is some major damage! Your head is most likely cracked, causing coolant to enter and cavitation. You could try to machine the cylinder and get yourself a new head
I thought this originally, but the machine shop themselves told me it would run, as long as I didn't have low tension rings. Either way I've got a set of ported head I've bought so old heads are getting thrown out.