2.4 Reliability
Evolved Member
Joined: Oct 2002
Posts: 2,788
Likes: 1
I've run a LR 4G64 for 3 years now in my Evo VI. It's actually been very reliable in terms of not failing. I do add oil every month, have never been able to figure out why.
I run 2 bar every day, so it has held up to the abuse. However, when I switch to race fuel, and run 2.8 bar, I do push some coolant into the overflow after a couple of passes. I use a HKS headgasket and run stock bore. I think probably the pushing coolant has more to do with lack of orings or the surface finish of the block and head. Although, it's hard to say. To me it doesn't cause any problems because I only run race fuel once or twice a year and only for a few passes.
I think with a 2.4 since the bore is larger (less material between bores) and the headgasket choice is more complicated, it's very important you really get the deck and head machined well and you get a very good engine builder.
I run 2 bar every day, so it has held up to the abuse. However, when I switch to race fuel, and run 2.8 bar, I do push some coolant into the overflow after a couple of passes. I use a HKS headgasket and run stock bore. I think probably the pushing coolant has more to do with lack of orings or the surface finish of the block and head. Although, it's hard to say. To me it doesn't cause any problems because I only run race fuel once or twice a year and only for a few passes.
I think with a 2.4 since the bore is larger (less material between bores) and the headgasket choice is more complicated, it's very important you really get the deck and head machined well and you get a very good engine builder.
I'm always around and kind of answered my own question about the deck height issue as I was hitting submit. I have a 4G69 sitting around that I will be using for a 2.4 build. I like the idea of a 2.4 with same deck height as the 4G63 as I won't have to mess with cam gear offset with an adjustable ex gear or have to mod my mivec intake gear. In my mind the 60k services will be less complicated but I'm all about ease of maintenance. The guys over at ASAP Performace have already utilized this block in a high power application so I snagged a 5k mile block from my local mitsu dealership for $100 for giggles.
I'm a 10.3:1 static compression with 10:1 pistons, 1.2mm gasket and my head decked. My dynamic compression, the compression that maters, is still only 8.5:1 give or take a bit.
Aaron or R/TErnie would have to run the math for me again to give me the exact dynamic compression for my custom cam profile. Cams change your compression which is something a lot of people don't know. fyi
Mikey