Overboring 7.3 is asking for trouble…right?

[SkylabTech86IDI]

Was pricing out an engine wish list through Summit and I’m seeing that stock pistons for a 7.3 n/an and 7.3 turbo are hard(er) to find. Most of what I see available is .030 or even 0.040 over. Surely it isn’t that you can use oversized pistons for a sleeve job.

Seems like boring out any 7.3 is asking for trouble. So what’s the deal?

 

[hacked89]

0.030 - limit of fine
0.040 - not fine

 

[bulletpruf]

0.030 - limit of fine
0.040 - not fine

Agreed. I tore down a 7.3 IDI turbo engine recently that was .040". I junked the block.

 

[Black dawg]

I dont think I would be any less worried boring one .030 vs .040.........

 

[hacked89]

I dont think I would be any less worried boring one .030 vs .040.........

.030 was approved by international during R&D as acceptable when they designed the block. .040 is not. I had a .040 engine and it lasted 1 year before cracking a cylinder.

 

[Black dawg]

that was when they were new though, we are talking about .005 difference in cylinder wall, right?

I honestly dont know what I would be comfortable with after you factor possible cavitation damage.

 

[hacked89]

that was when they were new though, we are talking about .005 difference in cylinder wall, right?

I honestly dont know what I would be comfortable with after you factor possible cavitation damage.

I think it’s safe to assume you’re going to be checking for block quality before machining it.

The most accurate blanket statement is what I gave regarding what the “fine limit” is and not just buying 0.040 over because you can. if it’s a performance build I’m going standard bore.