420a 10.5:1 Pistons

[dut]

Ive looked all over and cant find a good answer to this question. I am in the process of a complete rebuild on my 96 420a. I am going to stay N/A(no spray, no boost). Im doing way to much to list on the rebuild and know that everything Im doing will still not likely produce more than 200 hp. With that being said, I want to use 10.5:1 or 11.0:1 CR pistons. With such low HP I see no need for forged pistons and rods. In my situation, are forged pistons and rods really needed? And if not where can I get a good set of 10.5 or 11.0:1 cast pistons for a good price? The build is getting pretty pricey and if forged pistons arnt needed, then I would like to save the money!

 

[dr1665]

Good luck finding inexpensive, cast pistons in any compression ratio other than stock. Can't say I've ever seen any. You don't need forged bits if you're not boosting or spraying the engine. You can stick with stock rods (especially if you haven't messed yours up) and maybe pop for some higher CR pistons if you like. Don't go higher than 10.5:1CR unless you want to run race gas all the time. Expect to pay about $500 for a set of forged pistons.

 

[bullettdsm]

Good luck finding inexpensive, cast pistons in any compression ratio other than stock. Can't say I've ever seen any. You don't need forged bits if you're not boosting or spraying the engine. You can stick with stock rods (especially if you haven't messed yours up) and maybe pop for some higher CR pistons if you like. Don't go higher than 10.5:1CR unless you want to run race gas all the time. Expect to pay about $500 for a set of forged pistons.

Um.......X2

MB

 

[rsross314]

I was doing about the same thing on my n/a build couldn't find any pistons that were not high priced other then a stock set , went with a set of 10.5 je's with rings for right at 590 bucks and i'm glad i went with them now. Try Modern Performance Racing Products There are a few other sites with the same ones for about the same price just where i got mine from.

 

[420aVenge]

if i were you i would do the 2.4 swap....you could easily get over 200whp..thats what im doing now...

 

[BK85]

if i were you i would do the 2.4 swap....you could easily get over 200whp..thats what im doing now...

Aren't there some major hoops to jump through when putting in the 420a 2.4l? Like different engine mounts that will take some fabrication to solve, the different firing order and a few other things.

BK85

 

[VelocitàPaola]

Aren't there some major hoops to jump through when putting in the 420a 2.4l? Like different engine mounts that will take some fabrication to solve, the different firing order and a few other things.

BK85

Yes there are. There are threads on 2GNT detailing most of the process, but I believe at least the following needs to be addressed:

• Passenger motor mount
• Oil pan
• Accessory mounts

The firing order is easily solved by rotating the CAS/CPS, or just be using Megasquirt,

 

[Locke]

The firing order is easily solved by rotating the CAS/CPS,

To add, for the sake of completeness; the injector sequence must be shifted, and the coil signal wires need to be transposed. Still likely the easiest part of the project.

 

[JEFFREYCASTGSX]

What if you used single cam 420a pistons and then milled your head and then look for then thinest head gasket and im pretty sure you could get over 10.1:1 compression

 

[psycho]

Firing order and coil pack wires are the easiest thing to do on a 2.4 swap. Re-pinning the plug for the ECU takes 10 minutes.

Fabbing a passenger motor mount and modifying a srt or pt oil pan is the harder part. But still pretty easy if you know someone.

Everything else goes together like any other engine.