I have a 2002 Z24 with the GMPP supercharger kit. I drive it pretty hard, and i drive it ALOT.

recently my 2.4L engine developed a pretty noticable tick/knock (approaching 94k)... I am told it is most likely a bad wrist pin. and will need at least a new piston/rod in that cylinder....

The way i see it, if one went, others are probably likely to go as well..... And if i am going to go thru all the work of replacing one, it wouldnt be much harder to do the other 3 too.

Well if i am going to do a whole set... why bother with OEM stock replacements... they are often overpriced, and you gain nothing for all your hard work and money. So i thought it would be worth dropping in a set of forged pistons.... which of course leads to some upgraded heavy duty rods.... and then i think "well maybe i should find a stronger crank too, and make the whole bottom end strong as hell."

I understand 02's have 9.7:1 pistons factory.... do i want to stay there? or go lower due to the Supercharger? or go higher for the performance?

But i dont know a whole lot about these engines, or what on them is weak and what is plenty strong already.....

so i thought i would see what you guys would do if you were building one up. I dont have an unlimited budget, but i am not afraid to spend some money on good parts if it will mean this car will stand up to whatever i dish out and keep running strong for years to come.

So how about a list of parts you suggest, in order of most important.... like if i only had $500 for parts... what should i spend it on? then if i had $1000 in parts... what to buy then? etc etc....

also, if anyone has any parts to sell that will help me, or if you know of a good source for such parts.... that would be great. I have no idea where to look for cavy stuff... all my places for performance parts laugh at me what i ask for cavy performance parts.





my poor baby is sick... someone help me...
(2.4L engine in my cavy is ticking bad... need to make it stop)

At the very least you will have to get a set of rods and a set of pistons. I would atleast stay at 9.7:1 because your engine has been running there for a while with the supercharger and have not had any problems until now. A good set of pistons and rods will eliminated that problem. If you had more money left, a 56mm HO throttle body, a port and polish. Then get a smaller pully for more boost. Then header and exhaust. That should be enough to make it fairly strong, and very quick.

This has been covered a couple times already. The build below is similar to what I am building

Mild port work on the cylinder head
Secret Cams
Forged 9.5:1 or 10:1 pistons ( I have a set of 9.5:1 pistons for sale )
Eagle rods
stock crank
2.3 oil pump mod
Spec Stage 2 clutch

Best places for parts are
Car Customs
Turbo Tech Racing



Jason
99 Z24 Supercharged
157hp/171tq - NA
LD9 for Life

Hey J,
I email you about the cams,

But I'm wondering if I should do the same thing, or just do a whole engine swap like everyone else.

-M


Remember....syringes go in the RED waste basket.

ken soggs wrote:and then i think "well maybe i should find a stronger crank too, and make the whole bottom end strong as hell.

you will not need this, ppl on here have made over 400whp w/ turbo setup's using the stock crank without issue. you will never make that kind of power with the 2.4 GM S/C, not even close.

no, i have no need to go that far.... This is my driver car... I just drive ALOT, and I like to drive fast.

I just hate to do alot of work and GAIN nothing... if i am swapping parts, i want to swap in BETTER parts... that way i dont have to worry about them down the road.

Good to know the stock crank is plenty strong. I hear the stock rods are pretty bad....

any other suggestions for my engine while i have it apart.... I just want to make it last. i do run her harder than most "driver" cars... but not exactly drag racing 24-7 either.


my poor baby is sick... someone help me...
(2.4L engine in my cavy is ticking bad... need to make it stop)

since your going with forged pistons and rods..which is GOOD...then i suggest bumping it up to 10:1..youll get a gain and the new forged parts will be able to handle it....unfortunetly there is no aftermarket crank for the 2.4 right now so thats not even an option...but DO look into a good header,throttle body and cams..

10:1 would be dandy on a normally aspirated motor... but i just worry that may not be such a good thing with a supercharger.... (i have this very thing posted in the boost forum)

i would love to go 10:1... but i know most boosted applications run a LOWER compression.


my poor baby is sick... someone help me...
(2.4L engine in my cavy is ticking bad... need to make it stop)

not with that charger that would make you bite a harsh loss of power bullet. think about it. your head will be flowing better less restriction probabley see a 1 psi loss becuase of airflow cams will make it rev quicker will not help you build more boost just more eficently. lowering the compression means you need more air to fill that space less psi less power bump it up to a mild 10:1 you won't regret it. lower the compression you will

ok, so you've heard that boosted cars like lower compression pistons, the reason for this is so you can still run pump gas and not detonate with HIGH boost levels.

10:1 pistons would be PERFECT for use with the LD9 s/c because the boost levels are so low. the gmsc comes with a 2.8" pulley on it from the factory, this creates roughly 4.5-5 psi of boost.

stock ecotec 2.2's run 10:1 compression and gm released a s/c kit to work with them as well and they are perfectly fine AND even provide more boost than the 2.4 sc does (stock for stock).

moral of the story-get the 10:1 pistons and you wont be sorry, it's going to get you more hp. but also you've got to remember, the 2.4 (M45) gmsc is not going to yield a butt load of horsepower, its good for a nice mild build on a street driver.

hey guys... new information that was brought to my attention... please read my last post in the thread below....

let me know what you think.... wrist pin or rod bearings....

http://www.j-body.org/forums/read.php?f=40&i=147133&t=147133


my poor baby is sick... someone help me...
(2.4L engine in my cavy is ticking bad... need to make it stop)

Quote:

10:1 would be dandy on a normally aspirated motor... but i just worry that may not be such a good thing with a supercharger.... (i have this very thing posted in the boost forum)

i would love to go 10:1... but i know most boosted applications run a LOWER compression.

actually NA engines go with higher compressions..you shouldnt worry about on your SC cus your going with FORGED internals..they cost more for a reason THEY CAN HANDLE THE ABUSE alot better than the stock ones..and 10:1 isnt alot higher than stock but it WILL give you better performance....and as Z YAA mentioned people get lower compression for HIGH boost apps so they can avoid detonation...your not running high boost so dont worry about.......so lets sum this up......


You asked for our advice.....
EVERYone here said to go with 10:1 pistons....
.....i would take the advice

yes, i agree with you...

current question is what about 10.5:1....

there is a engine kit i can get and save a few hundred, but it only comes in 9.5 and 10.5.... so will the extra 0.5 hurt me and be too much, so should i skip the kit and buy everything seperately and get the 10:1's....

and also.... PLEASE read me post about rod bearings... that is the most important to me at this time.... (i linked to it just above)


my poor baby is sick... someone help me...
(2.4L engine in my cavy is ticking bad... need to make it stop)

ok dude....you wanna know if a wrist pin is bad?? get 4 equal length spark plug wires..take your idi and coils off the top of the engine..run the sires from the coils to the plugs..run the engine..get it to where you can here the ticking plain as day..THEN start pulling one plug wire off at a time...if you pull one plug wire off and the ticking stops then its a wrist pin...if you go thru all 4 cylinders doing this and it still makes the noise then odds are it is NOT a wrist pin and (knowing the engine) is more likely the bearing..go try that and get back with us....as far as the compression..you say your looking at a kit? is this kit forged internals? or something else? if it IS forged i wouldnt think 10.5:1 would be TOO harsh but you might wanna give it a more attentive tune ..someone else might wanna give a second opinion on the compression ratio

scott (section8cav) wrote: get 4 equal length spark plug wires..take your idi and coils off the top of the engine..run the sires from the coils to the plugs..run the engine..get it to where you can here the ticking plain as day..THEN start pulling one plug wire off at a time...if you pull one plug wire off and the ticking stops then its a wrist pin..

How important is the "equal length" portion of your instructions? i have spark plug wires but none are the same length... i can get 4 that are kinda close... I guess i could go buy some... but is the 60 seconds they will be on the car important enough to warrant buying wires just for this? or is a few inches difference enough to overlook for the purpose of this test?


my poor baby is sick... someone help me...
(2.4L engine in my cavy is ticking bad... need to make it stop)

also... i am just curious as to how or why this same test wouldnt effect a bearing....

i mean a bad wrist pin, and a bad rod bearing are both connected to the same rod... so what effects one end of the rod should equally effect the other end, no?

so whether the sound is from wrist pin, or from rod bearing... removing the combustion from that cylinder should effect either weak spot the same no?

why would ONLY the wrist pin noise stop with lack of spark... and why would a rod bearing not be effected by this? it is all the same unit effected by the same forces one way or another.

if my wrist pin is good.... and it is just a bad bearing... wouldnt removing the spark make the bearing quiet too?

I guess i would just like to know the theory behind this test.


my poor baby is sick... someone help me...
(2.4L engine in my cavy is ticking bad... need to make it stop)

well heres the thing...if your gonna tear down an engine to change wrist pin ..your gonna be changing the main bearings as well( or at least you should) but from what it sounds like your wanting to know how to tell EXACTLY what it is without tearing it down, which is almost impossible..especially when i never even heard the sound my self...so try the test( and no the wires dont have to be EXACTLY the same length) and get back to me..that test is what ASE says is the proper way to test for wrist pin noise..ok ?

I would think a forged piston and new rods would handle 10.5:1 assuming you have the stock pulley or have a better tune done. The stock pulley makes what 4-6 psi? I would say it could handle it. My only concern would be heat soak from the charger on a hotter running, cause of the higher compression, engine. But, i am not too familiar with the M45...

PSN ID: Phatchance249

ok, just did the spark-removal test.....

when i cut the spark to cylinder 3 (if you count from the passenger side to the driver side) my noise goes away.

Acording to the Scott (section 8 cavy) who told me about this test.... that means it is a wristpin.

but in talking to other people about this.... someone else told me "yeah that is the old test to determine where a rod knock is located"

I for one say that it should test equally for both.... i mean it is the same rod, different ends of it... the whole rod is under the same force... shouldnt matter which end of the rod is making the noise.

I have just had alot of people tell me that a wrist pin is more of a tick or a clank, higher pitched, and sounds like it is coming from the valve area.... where a bad rod bearing would cause a rod knock, which is lower pitched and comes from lower in the block.

mine sounds like a tick from the valve area. with the IDI cover off it is even more noticable.

I would LOVE this to just be a rod bearing.... but i fear it is the wrist pin... let me know what you guys think.

but it is confirmed to definately be lower end based on this test....

Some guys tell me that a bearing would get progressively worse and louder. and very unlikely to stay as a mild tick for several months. they say a bearing would more likely be a tick for a while... then get louder, and soon turn into a grinding or a loud knock.

my noises has indeed stayed the same for several months now...

how long would a wrist pin stay the same? what would happen if you left a bad wrist pin in a car? how long would it toake for it to go bad, and what would happen once it started to get worse?


my poor baby is sick... someone help me...
(2.4L engine in my cavy is ticking bad... need to make it stop)

Ok, i gots me a question. It's been a while since i've been on here. A really long while, but wasn't the gmsc capable of producing like... 8-10 psi with, i think it was a 2.5 or 2.25 in. pulley? Personaly i wouldn't consider 8-10 psi a lot of boost, but could you still get away with running 10:1 with 8-10 psi and forged internals?

Ken, anyway you look at it, i needs to be rebuilt, a wrist pin can elongate and destroy a piston\cyl wall.

rebuilt it already.

Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

ok i have a new question if anyone wouldnt mind answering it i have a pretty much stock 97 sunfire gt with a 2.4L in it, my question well actualy 2 questions is this

a) what can i do to boost accelleration on a very limited budget?
1) i already have intake and exhaust..

b) i have a kinda ticking noise in my motor some say its my guides but i fear its something worse as today while driving it is a 5speed btw 1 2 3 gear are fine when i get to 4th and 5th gear once and a while it will raise rpms when accellarating but my speed doesnt go up hardly at all i think maybe my pistons or something is F*****, if that is the case and i want better pistons what would u recommend as a compression? on a stock motor with just intake and exhaust as far as better torque/ accel

thx for the help fellas