I have been researching on rebuilding a 420A engine. It is in a friends '97 Eclipse RS. He wanted to buy a rebuild kit off ebay and call it a day. I gave him my 2 cents about buying individual parts and building the way he wants it, not how the kit tells him. So he volunteered me to do all the research and give him the run down, and he'll decide. Through searching I haven't found the details I am after. Here I am with some questions.
I saw that we can use the rockers and lifters from the PTs. Then there are rockers from a 2.7 V6 that are even better for lubricating. Are there specific years I need to look for when using the 2.7 V6 rockers and the PT lifters?
Then, the head bolts. Are the 2.4l bolts a direct interchange? Given they are longer and same thread, would they be "stronger"(more threads=strength, in that it is threaded and not left out).
Any suggestions on, or preferences on brands for the bearings, lifters, etc, etc would be helpful. There is a budget of I think $1500. That is to rebuild the engine with a port and polish and to put it back together while reaching 200hp..250hp if not unreasonable...hopefully. He does not plan on boosting until the next rebuild if he doesn't sell it before then.
It will be a daily driver with his mindset that means showing off from time to time. With that, a 6 puck clutch set and a light weight flywheel too much? I tried to convince him a light weight and just over stock clutch set (disc style, not puck).


P.S. any reviews of light weight pulleys....not underdrive, but light weight?

Thanks,
Ethan

Ok. After many views of this thread, no answers,I found some on my own. The rockers are from a stratus or "cloud car" years range starting 2001. Then the 2.4 head bolts would only require a tap to get the length correct.
Now for some more research, just updating as I go. Then when the tax return comes in my friend will be ready to tear the engine down and find out exactly what he needs.

Good luck to your friend. In order to make 200 or more HP, boosting would be the cheapest and fastest way. It takes a lot to get that kind of power naturally aspirated from a 4 banger.

2011 Kia Optima SX Turbo
(SOLD)'03 Eclipse GS
(SOLD)'96 Eclipse RS
Star Stage 1 @ 5psi w/Stock Exhaust
1/4 ET- 14.78 @ 96.35mph
60ft- 2.42
1/8- 9.71 @ 76.09mph
Best 60ft-2.21

Does anyone have advice on reaching 200hp? We are rebuilding completely. Stock horsepower is 140hp. Been toying with ideas of raising ccompression. Ideas, excluding boost and spray. It will be a daily driver with pep.

You will need a combo of bolt-ons and a megasquirt stand-alone to get there. High compression and headwork/cams are the main items. Lots of good info on this site. Change your thinking from power, to power-to-weight. Do everything to make the chassis as light as possible.

2gnt: '99 RS-T, killed by a toyota, pending rebuild...
Daily: Volt
Daily #2: '99 EVG ebike- STOLEN by PEDRO

1998 Eclipse RS-T - Totaled 4/23/09 -
1998 Eclipse GST - Stroked 2.3l, HX40 fed: Build in progress
2010 Subaru Outback Limited

I hate hipsters.

Pull the engine and bore it just a bit (not too much or you will kill the sleeve) most shops can bore and hone this block in about an hour at minimal cost.

Keep the stock crank and rods, change the pistons to match the new cylinder size (try to use alu forged if you can, if you go cheap use a heavy oil).

Rebuild the head (valves, springs retainers, seals, and guides if you can) and just polish a bit with a dremel (don't dare do more than smooth and polish), this head can't really be ported.

Put the head back on using new hardware and a decent head gasket.

Install Hahn Racing portfueler on engine and change fuel pump and regulator (Hahn can help if you are not familiar with this process).

Install a chinese turbo kit (toss the bov and get a good one if you can and get a boost controller if you can).

If you experience fuel cut get a fuel cut defender (cheap just get one anyway).

Once it is ready to rock use a laptop to adjust the port fueler map (installing a wideband o2 sensor and display very very very highly recommended).

Now go do some one wheel chirps

We have a Wiki article on rebuilding this engine. Nothing too unique, but it does give you an idea of what parts are needed:

http://www.2gnt.com/index.php?d=A_Proper_Rebuild

I had a good experience with the JE pistons, Eagle rods, and Clevite bearings. If I had to do it again, I would consider a piston that didn't require so much clearance. I would absolutely stick with name brand internals and bearings. There is way too much work involved here to risk with knock-off parts. I also recommend that you build the engine with stock or lower compression for the future addition of a turbo kit. If it is power your friend is after, NA is a long and painful road. Turbo will get good results quickly and you can keep it simple, if you have self discipline. Most of us get addicted to the quest for more power and go off the deep end, but that isn't required.

On the subject of head bolts, it is the alloy and minimum cross-sectional area that mostly determines strength. Since our head can be bolted to a 2.4l block, you'll probably find the cross-sectional area to be the same. Since they are both NA engines from the same manufacturer, you'll probably find that the alloy is similar. If I were a betting man, I'd say the strength was similar enough to not be worth the swap.

Lightened pulleys are a good concept. The improvement in acceleration of the rotating assembly is pretty minor for the money you pay. I'd put it on a secondary list. If you buy a crank pulley, make sure it has a steel sleeve that fits over the crank snout. It will have to be heated for installation, but is durable enough for repeated removal/installation. The cheap ones are solid aluminum and either won't fit tightly enough (use crank bolt head to hold in place) or won't survive repeated removal/install.

Lightened flywheels do make a difference you can feel. The engine will rev up faster. The problem is that it will rev down faster as well. The stock ECU can have trouble with stalling and maintaining a stable idle after dropping the clutch while engine braking to a stop. Getting an aluminum flywheel was one of the best and worst things I ever did.

Corbin
'97 GSX dressed like a '95 ESi