Diesel Place banner
1 - 10 of 10 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #1 ·
Hey guys, i’ve been trying to find ways to lower the compression on my 6.2 diesel for a turbo. I want to lower the compression to 18 to 1 and I read on a different forum that someone unshrouded the cylinder head. Would I need to do anything more like move the valves? If anyone has a better way of lowering the compression please let me know I’ve heard shaving the Pistons is a bad idea.
thanks guys.
 

·
Registered
Joined
·
3,858 Posts
Unshroud? Might want to expound on that. That being said, you can run a turbo on the stock 6.2 with head studs no problem. I did it and head gaskets were the least of my worries. For me it was **** aftermarket pistons. I ran +0.010 6.5 head gaskets and let 'er rip.
 

·
Registered
Joined
·
2,892 Posts
The above machining to the pistons and head net a ratio of 18.6:1 with a .038" MLS head gasket... You would need to have a ceramic coating applied to protect the pistons as well...

All of this was done on a CNC milling machine..

A .010" thicker gasket doesn't amount to much at all if you do the math...
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #5 ·
The above machining to the pistons and head net a ratio of 18.6:1 with a .038" MLS head gasket... You would need to have a ceramic coating applied to protect the pistons as well...

All of this was done on a CNC milling machine..

A .010" thicker gasket doesn't amount to much at all if you do the math...
The reason I heard it wasn’t good to shave pistons or machining them is because it makes the top of the piston too thin and when there’s high boost the piston can crack.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #6 ·
The above machining to the pistons and head net a ratio of 18.6:1 with a .038" MLS head gasket... You would need to have a ceramic coating applied to protect the pistons as well...

All of this was done on a CNC milling machine..

A .010" thicker gasket doesn't amount to much at all if you do the math...
Also what has to be done to the cylinder head to make it lower compression? I’m still a little confused on that part.
 

·
Registered
Joined
·
2,892 Posts
There's not much that can be done to the heads, the unshrouding I do is about all, but that alone won't get that much.. I've machined hundreds of these pistons and not 1 cracked yet... those that say that have never seen a cracked piston... There isn't a GOOD 6.2 piston, they are made different than 6.5 pistons and aren't as strong, that will never change due to the lack of 6.2's around and the spec was never for a turbo... you could bore the block to use 6.5 pistons...
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #8 ·
There's not much that can be done to the heads, the unshrouding I do is about all, but that alone won't get that much.. I've machined hundreds of these pistons and not 1 cracked yet... those that say that have never seen a cracked piston... There isn't a GOOD 6.2 piston, they are made different than 6.5 pistons and aren't as strong, that will never change due to the lack of 6.2's around and the spec was never for a turbo... you could bore the block to use 6.5 pistons...
Do you know how much I would have to tell them to machine off the pistons? Or A combination of the cylinder heads and the pistons?
 
1 - 10 of 10 Posts
Top