[patjo]

A fellow Alfisti pointed me to a local engine guy who bored his 3.0 V6 cylinders out "a little" at moderate cost. This has got me thinking, how much is it advisable to bore the 93 mm liners? Unless my numbers are off, 96 mm would get me 3.2 liters which is a nice and even number to Alfisti everywhere.

 

[Duke58]

3mm is getting near 1/8" bigger diameter, can buy bigger pistons and rings, or make your own? Are you wanting to do this to get more HP? Is the cost of new rings and pistons a moderate cost? More questions to answer your question may not help much...but your calculations are about right, ~3.2 liters is the correct volume for the four cylinders.

 

[patjo]

As to the "why?"? So no one else have to?

I'm not saying I'm wanting to do this but the thought is entertaining. Just got back from the garagege for a check, 96 mm would cut liner sleeve thickness down to 1.5 mm, that's thin for that kind of part I think. Pistons and rings in that bore are available off shelf, other properties are in the ballpark. Custom parts can still be had for money but probably more. Will the liners be too thin or can they be secured to the block some how? If not, I'm willing to put this out of my mind for now.

 

[Duke58]

1.5mm = 0.059" way too thin, not only would it run hot, I'd be concerned that the pistons and rings would break through the liners.

I've seen that someone actually machined a solid block of aluminum to make four liners, so if you've got the money, tools, knowledge, it can be done, but I don't think you can simply bore stock liners 3mm larger without consequences.

Why not install a turbo charger if you want more HP?

 

[patjo]

Only the part of the liner going into the bottom of the block would be that thin, the rest of the liner is slightly wider, thus more material left.

I prefer normally aspirated and stock external appearance, in this case. I have seen the asking price for large bore liner kits as well as complete rebuilds and it's a turn off. I'm just curious if it can be done differently at what appears to be a different price.

 

[Greg Gordon]

I am really hesitant to answer this questions because of where it could lead. However I will say that I routinely bore liners .010" over. The increase in displacement is insignificant. The advantage is that it allows the used of shiny new forged pistons without the cost of buying new liners. I also like the idea of using seasoned liners in a performance application.

Duke58 is 100% correct. You can't bore them 1.5mm. The maximum is a lot less than that and I wont discuss the actual number over the internet because it's actually complicated and would take too long to type.

Greg,
Silicone Hose Kits
OKINJECTORS.COM

 

[FMG_V6_btb]

3mm is too much for the standard liners, the lower part would be too weak and prone to crack, forget it.

 

[patjo]

Ok, I'll forget about it then. Thanks for saving me my money