building the head

[scottypimppin]

Hey guys i was just wounding if anyone here has build just the head on a 420a i got a spear one on the side and i was just woundering if its worth it to just build the head.

 

[scottypimppin]

and i was woundering the whole parts list to do it and wheres a good place to get them from too

 

[stevestevesteve]

i have done it before. bought the parts myself and had a shop install them. this was done on my old 99 RS

 

[wvturbo2]

If you get the head ported it would def help out and I'm sure they make some N/A cams you could run along with the port job.

 

[scottypimppin]

well is it worth it just doin the head or should i do the whole thing and also if i just do the head should i turbo it and would it be reliable

 

[bmxunderground]

Head work alone may not produce huge performance gains in itself. What the headwork WILL do is set you up to maximize the potential of all the other modifications you choose to have done.

Porting, polishing and changing valve angles will increase the engines airflow characteristics, helping you get more into and out of your combustion chamber.

changing valve sizes, or valve spring stiffness (or height) will help your head stay alive under stress of new cams with significantly different lobes than OEM or any performance mods that will have you at higher RPMs for longer duration than anything experienced while daily driving.

To keep from writing a book, I'd like to know, what goal do you have in mind for the performance of your car? Do you want it to feel a certain way?(torque increase in a certain range) pull a specific track time? or is there an HP# you've been obsessed with? Beginning with that in mind can and WILL save you a lot of time and money. If you give me a rough idea of what you already considered as of this moment I'll lay out a few suggestions. After that, im sure a few of the seniors here will chime in too.

Thanks,

 

[Jdog]

It is always difficult to make a boosted N/A vehicle REALLY reliable but as long as you are smart and TUNE WELL it shouldn't be a problem.

 

[scottypimppin]

well my range im lookin for is like nothin crazy it will be an daily drivin car like u could say a 12 sec car turbo one thing too its auto so i would hate to do the swap i can if i wanted to but ehh and for the whole go out and buy a turbo car no i rather build it and know what i got and have somethin to say about it than saying i bought this u know

 

[VelocitàPaola]

Please don't bump your threads (post deleted). Also, please use punctuation. It's extremely difficult to understand you when there aren't any commas or periods in your sentences.

If you just want a quick daily driver, I would invest in the turbo kit and forget about head-work for now.

 

[bmxunderground]

So you've decided on turbo. cool. First thing. If you have the ability to go 5spd then I say start there, in my opinion it will help quell some of your mental desires for the "feel" of power from a dig. Also in my opinion, ease of maintenance and overall fun factor are bonuses, plus girls find it manly.

Now addressing your power desires. a 12 second car especially an automatic, will require much more work than just a casual part here or machine work there. It will require the marriage of ignition, fuel and specific turbo setup plus drivetrain and bottom end work. Allow me to offer you a suggestion:

Given your car most likely runs 16.xx in the 1/4 mile, just an ebay turbo kit would be likely to get you into low 15's or high 14's. and be mostly reliable plus have fun and noticeably different driving experience. Start there since you won't have to take apart the long block or transmission and see how you like it.

Help for that step can be found here in quite the abundance. Like this link for building turbo on a budget: http://images.google.com/imgres?img...ox-a&rls=org.mozilla:en-US:official&sa=N&um=1

If you are thinking you want to go all in and shoot straight for 12's then plan to purchase not only the turbo kit but also:

- ignition system (MSD DIS2 variations are widely used)
- Fuel system (Mega squirt or portfueler are popular, I use portfueler)
- built bottom end w/lower compression (cimotorsports.net, slowboy or DIY)
- headwork
- transmission mods (LSD, new clutch or torque converter if staying auto)

You will need all of these things and more to create a 12 second car AND be mostly reliable. Without one of them, you are likely to increase temperatures or pressures in places that could wear parts out prematurely and thus be unreliable.

I hope I've helped, and feel free to keep asking away.

 

[bmxunderground]

I hope i'm not breaking the rules the way i'm saying this, but if I could add one more comment, just out of kindness to the wallet.

I know there is pride in building an N/A to become a powerful forced induction car but as the owner of 4 (yes 4 right now) Eclipses, I will say its just as exhilarating to build and drive the 4g63t. It may be a little easier to do, but not enough to make you feel like you are cheating or anything. If you can get your hands on say a Talon AWD, do so and build both, then you can be a real contributor!!

I love my 420a's and I also love doing things the hard way, but if money is an issue in the build, its not a bad thought to pick up a GS-T,X or Talon AWD and play around with both. To see which serves you better.

 

[Mike431635]

Power is made in the head, reliability/durability in the block (assuming no changes in CR or bore/stroke).

So yes, it's worth it to build just the head if you're going NA with it and plan to never go turbo. An NA 420A will never need forged internals, they hold up to 8psi in turbo applications just fine and that's over 200hp. Even the highest hp 420A DSM (bullet's car) is pushing about 200whp, so I believe you're safe with a stock block. Now there ARE gains to be had by raising the CR, so that's an option as well but involves replacing pistons.

My opinion-- pull the head, freshen it up, install 2.7L rockers & PT lifters (for improved efficiency), cams of your choice, and do a street port & polish.

 

[scottypimppin]

ok thanks guys ill post after in done with everything

 

[scottypimppin]

whats the best site i can get all the parts for building the head

 

[bmxunderground]

If you haven't already done so, check out the sponsor links in the marketplace. There are more than a handful of businesses there that can supply you with what you need.

If you feel retail prices are too expensive, then browse the classifieds for personal sellers. If you turn up nothing, browse the archives for related threads, and if you get bored then browse a few forum searches with the key words:

built head, cams, valve springs, headwork, ported, or other head related words that may catch a good thread. In those threads you may find a link to a supplier for something you need, but on the cheap.

hope you find what you need!

 

[Mike431635]

Slowboyracing carries some 420A stuff. (slowboyracing.com)

Modern performance does as well (Dodge SRT4 - Dodge Caliber SRT4 - Dodge Neon - Chevrolet Cobalt SS Performance Parts and Accesories)

Things you will need or want will include:

Valves (if you're going oversized; Indy & PEP make +1mm stainless valves)
Valve springs (Crower)
Cams (Crane, Crower)
Cam gears (Fidanza, AEM, OBX)
Valve stem seals (OEM)
Lifters (PT cruiser OEM)
Rockers (2.7L Dodge/Chrysler V6)
ARP cam tower studs (seems like a waste to me, but ehh)
Valve job (3-angle, 5-angle, depends on how much $$ you wanna spend)
Port & polish (same as above) and gasket/manifold match the intake & exhaust ports
Check head for flatness & deck if necessary

That's about the extent of what you can do. I'd say the greatest gains are gonna be with the porting & polishing, so find a reputable shop to do this for you. And make sure you use a stock MLS head gasket when you put it back together. ARP head studs probably aren't necessary for an NA build but you can consider that as well.

 

[scottypimppin]

ok thanks

 

[bmxunderground]

I hope you take advantage of all the information provided here and get back to us with some pics of the work and your progress!

 

[98rsclipse]

I know this thread is a few months old but just incase the op hasen't made a decision on what to do yet i will give some advice. The 420a head flows great, so for now do not get head work done its gona hurt you. Hahn ran 11 on stock head. No cams, no port or polish, not nothing but stock head and built bottom end. Meaning just rods and pistons with boost and supporting mods will put you in your 12 sec range. Save the headwork money and get suspension, lsd, and tires which will help more than headwork for your goal. You can actually affect the horsepower on this motor by doing to much headwork at your hp level. Im not saying that headwork isn't good but until you make like 400+hp i wouldn't worry bout it, so leave head alone. If anything just change valve seats, valve seals, lifters,rocker arms, and get a machine shop to freshen up head. Meaning valve job, clean old valves, check for cracks and straightness. Just upgrade the lifters to the 2.4 pt cruiser lifters and get some 2.7 rocker arms out of a stratus. The 2.7 rockers come in plenty of chrylser products just search around.

 

[all_motor_mike]

heres my opinion................ if ## gonna have the block apart to put rods and pistons in it then go ahead and port the head too. yeah u can do 400 whp with out head work yes, but with head work u could probably obtain that same hp number with 3-4 lbs less boost and not stress the engine so much even though it would be built and all. im all about volmetric efficiancy basically thats why this is my opinion, dont be like the 4g guys and just turn ## boost up to 50 to make big power (being sarcastic of course) build ## engine to make the most power naturally aspirated and then when u turbo it u wont need as much boost as u would have needed to get ## power goals.


mike