420A 420a stock rebuild 300hp

[caseyrock]

EDIT: Has anyone had experience with Sealed Power pistons in the 420a for boost? If you have, please chime in.

So Winter is on the horizon which can mean only one thing....BUILD TIME!!! This will be my first DSM build. I'm pretty excited. I came from the Honda world (single cam non-vtec ) and I miss it but it's time for something new.

Well I've done a fair amount of homework and I have just a couple questions about the 420a bottom end. If you post in my thread about selling this car and buying another one you will be reported and your comment will be removed. BTW I have decided against going the 2.4 route for this build. Maybe next time...

I hear the stock rods do pretty well to around 300hp but the pistons don't hold up well. So I was thinking about getting Sealed Power pistons and Hastings rings for the rebuild.


I hear that this combo has held about 350hp reliably. Any truth to this? This seems like the way I want to go, I'm only shooting for around 250-275 hp with a HAHN s16g. These pistons are stock compression and I am thinking about milling the head a little bit and go 9.8:1-10.0:1 C/R so I still have plenty of bottom end. I know what kind of tuning this entails, don't tell me to go lower, I don't want piss poor performance down low. Will be in an automatic daily driver.

Seem like a good route? It's not terribly expensive and I even got the fresh rebuilt turbo with 0 miles and the HAHN manifold for $150. I'm basically asking for any FIRST HAND EXPERIENCES OR A LINK TO ONE concerning these pistons or rods since I didn't find one on this site (but I didn't look that hard ). There isn't even a 420a engine building thread

Also, does anyone have anything to say about their stage 1 head job/port or their cams or their reman cranks?


EDIT (11/14): Found out that Sealed Power pistons are made out of the same material/process as the SRT4 pistons. Also that 2g Neon R/T rods (SOHC Magnum motor) are actually the strongest out of the 420a/Neon swappable bottom ends. They are made out of the same material as the SRT rods which will hold 400-500hp. This wouldn't be a bad route to go if I could find the rods.

 

[cyexmaster]

Heres my build: http://forums.2gnt.com/dcboard.php?az=show_topic&forum=8&topic_id=107768&mode=full

 

[caseyrock]

Heres my build: 2GNT.com Forums - Viewing topic - My turbo project 1 year along the build....

Nice build. I had (still have) the opportunity to get a set of Eagle H-Beams with 10:1 JE pistons for $300 shipped with 150 miles on them. But....the pistons are STD size and I'm not trying to waste my money by building a block and not boring it. I thought about just buying the rods from him for $150 but I really don't want to shell out the money for a new set of oversize forged pistons and I don't really want used pistons either. So I am thinking about this route.

 

[Black-Out]

I like that your keeping compression higher, your gonna have a lot more torque and power at much lower boost pressures if your set up right. Plus with the kind of compression your wanting to run, you'll probably hit the power numbers your after at 12-14psi boost on that S16G...... the main thing you'll need for doing that though is good ignition tuning.

The way to get it done is obviously through stand alone management or a really really good piggy back that directly controls ignition and fueling events. My recommendation is to look into a Mega squirt to allow you to pull the 10+ degrees of timing you'll shed when you start getting into positive manifold pressures. Also don't forget that you may want to run a spark plug set 2 ranges cooler to help ward off detonation!

Good luck with it and keep us posted sir-

William-

 

[phunny]

I'm not sure exactly what the stock internals will hold but that seems like an awful lot. More importantly be sure to check out whoever you buy from.

TheDSMGraveyard.com - Directory

 

[caseyrock]

I like that your keeping compression higher, your gonna have a lot more torque and power at much lower boost pressures if your set up right. Plus with the kind of compression your wanting to run, you'll probably hit the power numbers your after at 12-14psi boost on that S16G...... the main thing you'll need for doing that though is good ignition tuning.

The way to get it done is obviously through stand alone management or a really really good piggy back that directly controls ignition and fueling events. My recommendation is to look into a Mega squirt to allow you to pull the 10+ degrees of timing you'll shed when you start getting into positive manifold pressures. Also don't forget that you may want to run a spark plug set 2 ranges cooler to help ward off detonation!

Good luck with it and keep us posted sir-

William-

I have some experience tuning. I street tuned my build Honda myself with Crome Gold which does everything the MegaSquirt does (but its not a standalone). I know I will need MS, I just don't know where to start since there are so many versions and firmwares. I'm more interested in reviews of the rods and pistons right now. I can run the motor on the stock ECU for a while with out any boost.

 

[bryanwheat]

I hope that you don't plan on running pump gas in a boosted engine with 10:1 compression. That won't turn out good on cast pistons and stock rods. I would highly consider looking in the classifieds and finding a used set of forged rods and pistons.

 

[caseyrock]

I'm not sure exactly what the stock internals will hold but that seems like an awful lot. More importantly be sure to check out whoever you buy from.

TheDSMGraveyard.com - Directory

Well they do have some pretty bad reviews and complaints with the BBB. I can find them on a neon website.

I hope that you don't plan on running pump gas in a boosted engine with 10:1 compression. That won't turn out good on cast pistons and stock rods. I would highly consider looking in the classifieds and finding a used set of forged rods and pistons.

I'm not an idiot or new to engine building/tuning but thanks.

 

[kzoosho]

I searched the web and the reviews seem to be mixed. Some get what they asked for in a timely manner, others get shit on. If they try to screw me I will threaten them with the BBB or court and let them know I'll bring all of these reviews with me and I gaurentee they will get their shit together in a hurry.

But maybe that dude was mad because he got fired for something. Maybe they are super backed up and understaffed. Maybe they do cheap out on some parts. IDK



I'm not an idiot or new to engine building/tuning but thanks.

The dude that got fired was pissed but o well. I wont bad mouth anyone or i would be just like him. What folks don't realize is he is a small shop that does a lot of business at fair pricing. Some folks complain about drop shipping. Show me one company that doesn't drop ship. It happens. I personally know all parties involved and like i said, ill keep my personal comments to myself.

 

[bryanwheat]

I'm not an idiot or new to engine building/tuning but thanks.

Well shit man, you already have it all covered, why ask for advise if you don't want to hear anything that is against what you think is right. I brought up a point that you didn't address. You are trying to make pretty big power for stock rods and cast pistons on the 420a on higher compression than what they come from the factory. Higher compression will increase the cylinder pressure which will lower the knock threshold of the engine. Knock is the leading killer of stock rods and pistons in these engines when you boost them. What are you planning on running fuel wise? Are you planning on just cutting back timing. That will in turn make it sluggish and defeat the reason of having high compression.

 

[caseyrock]

Well shit man, you already have it all covered, why ask for advise if you don't want to hear anything that is against what you think is right. I brought up a point that you didn't address. You are trying to make pretty big power for stock rods and cast pistons on the 420a on higher compression than what they come from the factory. Higher compression will increase the cylinder pressure which will lower the knock threshold of the engine. Knock is the leading killer of stock rods and pistons in these engines when you boost them. What are you planning on running fuel wise? Are you planning on just cutting back timing. That will in turn make it sluggish and defeat the reason of having high compression.

I can compensate for that by not running as much boost. 250 is not a crazy goal at all. I will make more power per PSI with the higher C/R. I do appreciate the help. I really just want to hear reviews on these pistons and similar setups. I know they (FM/SP) have been around for a while, just never seen them in this application. Obviously I'm not just going to just run an msd controller and an FMU, I'll be getting a full MS setup before the turbo goes on. The s16g makes around 250hp on 9-11psi on a completely stock motor, not crazy boost levels at all. I think 9.8:1-10:1 is pretty safe. Those kids destroy their motors because they aren't properly tuned.

 

[95TalonOwner]

Here's my build.....

2GNT.com Forums - Viewing topic - 3 Years and Counting and It's Finally Coming Together

My advice would be, if you're going to be doing that much, just get a good set of forged pistons and rods to begin with so you don't have and doubts about anything in the future.

 

[caseyrock]

Ok, so HAHN and a few other companies have countless miles on old internally stock motors with 9.6:1 compression running 8-10lbs and 250-275 hp. Why would it be unsafe for me to shave the head slightly (not even a half point in compression)to 9.8:1-10:1 and run slightly less boost on a completly fresh bottom end? What kills these motors is the ring land cracking due to knock or over boost. I want to find out if these pistons are better than stock. These are supossed to be performance cast pistons and they have been run by the V8 guys for years. They have even been in the old Ford and Chrysler turbo cars.

The effective compression ratio of a 9.6:1 motor with 9lbs is 15.33:1
The effective compression ratio of a 10:1 motor with 8lbs is 15.44:1
For a 8.5:1 motor with 12psi it is only 15.38:1

I think I'm pretty safe if these pistons will hold. I know I will have to tune better. I'm just asking if someone has experience with these pistons and so far no one has answered that. Like the dude that posted right after my original post, his motor didn't go even with 15+psi racing and running down the strip.

 

[Anubis_4_99]

Here is my take on your build.

You say you only want 250-275HP, and the stock rods should hold 350. Why not put out the $150 for the eagles? Then you have 200ish HP or more wiggle room and peace of mind.

Personally i would say the same thing about the pistons. And there is nothing wrong with staying std bore on a build. It's not like you can hog it out to 2.4. As long as the cylinders are in spec there isn't any reason to bore it out. Just get a good hone so the rings seat well.

If your trying to build on the cheap i understand, but realize that if you build, and you cheap out now with nearly stock parts, later when you want more there is no more room to upgrade unless you build again.

Take what you will from it, and post some progress when you do build so we can see how it goes.

 

[caseyrock]

Here is my take on your build.

You say you only want 250-275HP, and the stock rods should hold 350. Why not put out the $150 for the eagles? Then you have 200ish HP or more wiggle room and peace of mind.

Personally i would say the same thing about the pistons. And there is nothing wrong with staying std bore on a build. It's not like you can hog it out to 2.4. As long as the cylinders are in spec there isn't any reason to bore it out. Just get a good hone so the rings seat well.

If your trying to build on the cheap i understand, but realize that if you build, and you cheap out now with nearly stock parts, later when you want more there is no more room to upgrade unless you build again.

Take what you will from it, and post some progress when you do build so we can see how it goes.

Eagles are full floating rods and require full floating pistons. It's best to bore the block slightly just to get the proper clearances back. It is very hard to find a Used block that has perfect cylinders and are not worn at all. The boring is not for displacement...it's for insurance. If the stock rods with decent pistons will hold 350 or so HP, then 250 is fine. I'm not exactly building on the cheap....there is just no need to over do it.


Sent from my iPhone using Tapatalk

 

[99RedGs]

Honestly, save up the extra $350 and go forged... I'm not sure of your financial situation, but that shouldn't be more than 1-2 pay checks worth of waiting. Even if you don't plan on going for big power, this will allow you to have a safety net as well as the option to up the boost later if you should so choose.

I just finished my rebuild with a 10.5:1 wiseco / eagle combo. I am going for ~300hp as well, but on an s20g. I opted for safety and the peace of mind that when I decide to stomp the gas I won't be bending a rod. I know its not exactly what you are looking for, but there is a reason most of the replies are telling you to go forged. When you break your plan down, it basically says you are planning on running at the extreme limits of what these components are capable of without much room for error. I feel like you will cause a premature death to this engine and will have to spend money again on a rebuild. My personal opinion is to do it once, and do it right.

These engines are not knock limited so you will be fine with the higher compression (bullet can testify to this) It will just depend on your tune as you are already aware. I'm assuming you'll be running MS since I wouldn't really consider an FMU "tuning"or even reliable.

You might consider heading over to neons.org and asking the same question since someone there may have run this combo. Also, there are almost always used forged goodies for sale on there and you could probably get a set-up for barely more than what you are looking to spend on the "slightly better than stock" components.

Good luck on your build

 

[caseyrock]

I got rid of my s20g for a s16g because I'm not looking for bug power. I have a 400ci sb mustang I'm building as my project car, I don't need speed in my fwd automatic Eclipse. I've seen several threads about 420a rods not bending until repeated 18+ or so psi on a s16g or similar, but before that it's just the ring lands on the pistons that crack from being old and from fatigue. I've contacted a couple people on neons.org already that have this setup from thedsmgraveyard and they have had great results.

I'm using these rods and pistons. I found the reviews I was looking for of these pistons, they are all good for what I want. Thanks for the help. I'll do a build write-up so 420a guys will have a much cheaper alternative to forged when they aren't looking for big power.


Sent from my iPhone using Tapatalk

 

[caseyrock]

Honestly I'd even be fine with just getting the pistons and keeping my rods and just getting arp bolts from what I've read.


Sent from my iPhone using Tapatalk

 

[blindboarder_02]

Good luck with the build. I can't wait to see the results. I have my engine and trans pulled for the winter build already, and have been trying to decide which internals to run with. My power goals are actually right around yours, 235-275hp. I will be subscribed to the write-up for sure

 

[Anubis_4_99]

Well I've done a fair amount of homework and I have just a couple questions about the 420a bottom end.


I called them and the guy said that this combo has held about 350hp reliably on a customer's motor. Any truth to this?

Seem like a good route?

I'm using these rods and pistons. I found the reviews I was looking for of these pistons, they are all good for what I want.

RedG said it right, it's not about being capable of handling it, I'm sure with the perfect tune and right circumstances, they could hold more. It's about safety and reliability, which is what you asked about. And for a daily driver i would make reliability my number 1 concern. Eagles and compatible pistons may be a few hundred more, but is cheaping out on a few hundred bucks worth redoing everything all over again?

I dont plan for 500HP either when i build mine, but it's definitely going to be able to handle it parts wise.

Regardless of what you go with, good luck with the build, and hope it works out. I'll keep an eye out to see what your results are just out of curiosity.

 

[caseyrock]

Found out that Sealed Power pistons are made out of the same material/process as the SRT4 pistons. Also that Neon R/T rods (SOHC Magnum motor) are actually the strongest out of the 420a/Neon swappable bottom ends. They are made out of the same material as the SRT rods which will hold 400-500hp. This wouldn't be a bad route to go if I could find the rods.

 

[99eclipse420]

I think you need to do some more research on the 420a. I read through your first post and it seems you are getting some things mixed up between the 420a and the 4g63. If you want power go ahead and build the bottom and top end of the motor no point in doing it twice. There is no 2.4 kit for the 420a only a 2.2 which I recommend going ahead and doing with new rods and pistons you can buy a kit that comes with the crank, rods, pistons and bearings for a little over 2k.. Bore the motor out 2 over so you have a clean platform for the build and either get the head ported and polished by a shop or diy. Then new valves with a 5 angle grind and 30 degree valve shave. Then cams and springs.

 

[caseyrock]

I think you need to do some more research on the 420a. I read through your first post and it seems you are getting some things mixed up between the 420a and the 4g63. If you want power go ahead and build the bottom and top end of the motor no point in doing it twice. There is no 2.4 kit for the 420a only a 2.2 which I recommend going ahead and doing with new rods and pistons you can buy a kit that comes with the crank, rods, pistons and bearings for a little over 2k.. Bore the motor out 2 over so you have a clean platform for the build and either get the head ported and polished by a shop or diy. Then new valves with a 5 angle grind and 30 degree valve shave. Then cams and springs.

Nothing mixed up, I was talking about the 2.4l cloud car swap with srt4 internals. Take a gander over to neons.org and see what people are running with the sealed power on stock rod setup. I have done my research, and I also know how to get power out of a motor and where the most effective places to get it from


Sent from my iPhone using Tapatalk

 

[FearlessNick]

Gotcha. Well don't know much about that stuff. Best of luck to ya.


- Nick
Email- [email protected]
Twitter- @FearlessNickCG
Vehicle- 1998 Mitsubishi Eclipse RS

 

[1g8420a]

Sorry to say but, in my opinion the stock rods barley support stock.. I am tearing down my engine and my rod in cyl number 1 in bent pretty bad and, this car has low miles, with 0 mods.