Guys I've been researching this swap as a part of my engine rebuild and was wondering if lower compression pistons was a must or can it run off the stock Ld9 pistons. I dont know anything about compression ratios thats why I am asking. I researched it and theres a how to on NY's forum and they didnt mention pistons anywhere in the how to but then I asked around and people are saying that you should do the pistons. Thanks

If you are talking about using a 2.4 crank, rods pistons in a 2.3 block, you may want to research a bit more 2.3 has a larger bore that the 2.4 so if you use stock 2.4 pistons there will be a gap around them, as you can imagine this wont work too well From as far as i know they best bet iis a custom cut set of oversized 2.4 pistons. I have been "planning" this swap for some time as well and hope to get the pistons and rods very soon.


Dreams do come true....
<img src = "http://registry.gmenthusiast.com/images/96sunfireconvt/ModdedFireBlue.jpg">

Ok well you have to be a little bit more clearer with your question, what exactly are you trying to make the motor a hybrid with? 2.3 head and 2.4 bottom end? 2.4 head and 2.3 bottom end?

If you can explain a bit further with what you're trying to do, I can try and help you further (or someone else can).



www.kronosperformance.com / 732-742-8837

Ok well you have to be a little bit more clearer with your question, what exactly are you trying to make the motor a hybrid with? 2.3 head and 2.4 bottom end? 2.4 head and 2.3 bottom end?

If you can explain a bit further with what you're trying to do, I can try and help you further (or someone else can).



www.kronosperformance.com / 732-742-8837

Double post! Tag, you're it!

ln2johnny wrote:Double post! Tag, you're it!

lol. Sorry guys that was a very general question Im talkin bout the 2.3 head and 2.4 block with the secret cam swap. Sorry again.

Hey is a 2.4 head and 2.3 bottom end possible or would that defeat the purpose b/c the 2.3 is a better flowing head?

You use a 2.4 head on a 2.3 block when you're too cheap to buy new pistons to lower the compression for boost.

You don't need to change the piston when you put the 2.3 head on the 2.4 block. The coolant holes need to be enlarge and a few other things. Before putting the cams, I would mesure the clearance. IIRC, Mylife75 mesure the clearance with the 086 and the secret cams and it was suppose to fit.



Gilles
2.3 Ho

If youre talking about a head swap there a number of things to consider. One the valve celarnace issure, you will need pistons with valve reliefs cut in the so stock 2.4 pistons are no good. The combustion chamber on the head would also be larger than the 2.4's bore as the 2.3 has a larger bore, not sure what to do about this, but it is to be considered. Also i had heard in the past that the head on the 2.3 is shorter so this will affect compression ratio so that will need to be refigured and pistons to compensate will be needed, as from what i rememerb the compression after the head swap will be around 11.4:1 with stock compression 2.4 pistons. This has been covered MANY MANY times, quite a few such posts have been by me, search a bit man there should be all the answers you need already in here.


Dreams do come true....
<img src = "http://registry.gmenthusiast.com/images/96sunfireconvt/ModdedFireBlue.jpg">

I did search thats what i'm saying Mfk-223 said no and now your saying yes you do. I get both answers when I search. I want to do pistons but I dont have the money right now. I'm doing the rebuild soon and I want to know if i can put the head on now and get pistons later b/c I need my car. So has someone done the swap and kept the Ld9 pistons?

listen to Mfk..he know what hes talking about...to do the head swap you dont HAVE to change the pistons..BUT..it will raise your compression considerably! i heard like 12:1 before 11:5:1 could be right..either way,do you plan on using pump gas with that?
personally id save for the pistons..lower the compression a bit..and be happy you dont have to take it apart again

From all research i had done on this, being that the height of the head on the 2.3 is considerably lower. Also if you plan on using HO or probably even LO cams from the 2.3 head, they both have greater lift than the 2.4 so the increased lift on the cams, and less clearance due to the shroter head, you more than likely will cause valev and piston damage without vavle reliefs. Mfk does know what he is talking about, but so do the people i have heard the this valve clearnace issue from, im just saying look into it more before you try and use stock 2.4 pistons.


Dreams do come true....
<img src = "http://registry.gmenthusiast.com/images/96sunfireconvt/ModdedFireBlue.jpg">

OK and yes Im running pump gas and how does that affect the compression. I know about the higher compression causing detonation, so you need higher octane to stop detonation right? So what does that have to do with the vales hitting pistons?

Stock 2.3 HO pistons have valve reliefs cut in them so the valves dont hit the pistons, 2.4 pistons do not. As i said the 2.3 cams have higher lift than the 2.4, meaning it is very likely that without the valve reliefs there is a good chance that the valves may hit the pistons. I dont know for sure if they will, im sure someone does, but i do know that 2.3 pistons have reliefs and 2.4's do not, that is for certain.


Dreams do come true....
<img src = "http://registry.gmenthusiast.com/images/96sunfireconvt/ModdedFireBlue.jpg">

Yes higher octane does also keep detonation at bay bu to a certain degree. 12:1 compression as far as i know it is beleived to be the highest "safe" compression ratio that can be run on conventional 93 pump gas. This is considering the engine is properly tuned. For me thats a bit too close for comfort. Itd be in your best interests to order a set of lower compression pistons. Back when i was researching someone had calculated for me and found that i think its was about 8:1 compression pistons would produice about stock compression for the 2.4 using the 2.3 head. Im not 100% sure on that, as those are the numbers from memeory, but its somewhere around there, perhaps someone can work the formula agaion to figure it out exactly.


Dreams do come true....
<img src = "http://registry.gmenthusiast.com/images/96sunfireconvt/ModdedFireBlue.jpg">

The secret cams should fit for a simple reason. the 95 intake cam only has around what? .350" lift. So it should fit. I'll mesure the lift tomorrow on my 086 head.

The exhaust cam could have .500" of lift and you wouldn't have to worry about it. by the time the exhaust cam open the valves, the piston is already going down.

With the 96-99 pistons, the secret cams should fit and the compression will go to 11.4:1.

with the 99-02 pistons, the secret cams may fit but they will be close. Like I said, I'll check the clearancce tomorrow. The compression goes a bit higher too.



Gilles
2.3 Ho

Guys thanks I appreciate all the input. Mfk-223 thanks for checking out those cams. I'll be looking for those results. But, this is a big issue and how can there be such a big difference in facts. Some one has to have to tried this. All this theory is nice but I've seen the difference between theory and actual life. Sometimes it's way off.

There are a few here i think, but check quad4forums. Considering the compression increase putting the motor close tyo the threshold of 93 octane, itd be in your best intrests to get new pistons anyway, and since your getting them, if it were me id get valve releifs just to be sure, i guess thats just me.


Dreams do come true....
<img src = "http://registry.gmenthusiast.com/images/96sunfireconvt/ModdedFireBlue.jpg">

dude just get a port and polish on the 2.4 head and a 3 angle valve job. slap on a H.O. manifold, header and some cams, possibly a 62mm tb and be done with it. youll be much happier with it trust me. since its a daily driver id go get 2.4 head from a yard so you can work on it at your own pace and as you can afford it.then all you have to do is swap it when its ready


Dark for fear of failure
An inner gloom as wide as an eye and fermenting
Roiling hate
Death gripped my veins
Unveiling rancid petals
Flowering forth foul nectar
The space between a blink and a tear
Death blooms.-mudvayne

streetfighterz wrote:dude just get a port and polish on the 2.4 head and a 3 angle valve job. slap on a H.O. manifold, header and some cams, possibly a 62mm tb and be done with it. youll be much happier with it trust me. since its a daily driver id go get 2.4 head from a yard so you can work on it at your own pace and as you can afford it.then all you have to do is swap it when its ready

Yeah I was thinking about that. Why are people swaping on these 086 heads and not just p&ping the Ld9 head. I guess you went this route? What kind of results did you see from it?

they use the 086 because even a port 2.4 head doesn't flow as much as a 086.

Plus you get higher compression.



Gilles
2.3 Ho

I saw a post in another thread about the turbo tech head and from what I understood the turbo tech head flowed pretty good is it worth it? It does cost $1300 and what I figureed to do the 086 head is gonna cost me about 2K all together(rough number and thats buying the 086 head pre loaded, putting in the secret cams, and getting pistons done.) Thats why I was stressing do I need pistons now b/c money is my major issue and I cant afford to blow a brand new head and piston if they hit. And the 2.4 head built and p&p would be alot easier but is it worth the money? I dont mean to be a dick guys there just no where in Tallahassee for me to get this information everyone does B16 this and Gs-r that and H22 crap. No ones knows anything even the performance shops up here only do honda and some only do the big eight boys. So domestic 4 beaters our out. I gotta wait till I go home for summer to get any machine work done. So thanks for all the help guys.