Piston Cracked, HELP!!

[stephenrussell]

Hi there, bought a 87 csx 1 month ago, drove it for two days but had lots of blowby in engine (Leaking oil everywhere)

compression

cylinder#1 140psi
cylinder#2 130psi
cylinder#3 130psi
cylinder#4 85psi

Now I took everything apart and found two cracks on cylinder #4 between the rings on the cyl, and when you removed the rings It was actually a chunk of the piston was broken off but being held in by the piston rings...
(Malie pistons)

OK GREAT!!!! I ordered 4 new pistons, rings and connecting rod bearings from ebay... They were clevite's...... Anyways I installed them (Did not bore out motor cause block in good shape) and the car ran good for about 3 - 4 days and then I started to get the blowby all back again (Oil stick keeps popping out)

compression

cylinder#1 130psi
cylinder#2 60psi
cylinder#3 130psi
cylinder#4 130psi

I took the motor back apart TODAY!! and removed piston # 2 ( PISTON IS ONLY BEEN IN CAR FOR 2 WEEKS) and It seems to be cracked in the SAME PLAce between the two rings and chunks of the piston feel apart in my hand, BUT NO DAMAGE TO CYLINDER WALL AT ALL!!!!!!!!

[stephenrussell]

This T2 Block had 40,000 miles on it, I rebuilt the motor myself and only drove it for say under 800 miles.... Umm, anyone give me any advice. Anyone had this problem before...

The motor is running at 20 psi boost with 40 injectors and gm map sensor... I have air fuel gauge and the car never leaned out..... Oh Ya after I put new pistons inb the car the motor was very quiet (Not noisy at all) so what do u guys think????????? Do I gotta buy forged pistons now?????? I thought those clevite pistons would have been ok, hell I never eaven got to really drive the car...

[turbovanman]

Were the pistons brand new?

You have a detonation problem. How did you set your timing? what kind of boost? fuel grade used?


I just saw your other post-

Forged are a good idea but even they will still crack if you abuse them!

[mo' parts]

check your injectors, timing, and fuel press.
sounds like some detonation, and exactly how i bought my daytona. lol
not sure on the reliability of the clevites, but im sure they would be more brittle than the mahles.
how do the plugs look?? gauge readings??

[MVaughn]

What computer are you using w/ the gm map sensor? Do you let the computer control the boost or do you use a grainer?

[stephenrussell]

Yes the pistons were all brand new and were in perfect shape when I received them.. I read up on some information and came to the conclusion that detonation could have been a factor which would have been caused by too much pressure (Boost i quess) or high temperature.... Which makes me wonder if running 20 psi on stock intercooler caused my problem (I have no idea)

I set the timing by alligning the dot on the crank to the dot on the distributer sprocket, and alligned the camshaft markings parallel to the valve cover (I put it back the way it was cause I marked it) I cant recall but think the mark on the trans was at 0.......

The car started and ran good, I was running on 91 oct gasoline, boost gauge reads 20 psi on WOT, and air fuel gauge is an autometer i believe (The one with the bars that light up) and it was in the yellow I believe at WOT..... The red bars on the gauge indicate a rich mixture and it ran one bar below it......

The spark plugs all look the same, they are kinda a sandy colour with a sandy look to them..... (Looks like a lean mixture to me) But Im not too sure.......

[stephenrussell]

I believe my computer is controlling my boost.... I know it is a modified or something computer in it...... There is a bleeder hooked up on the wastgate but when I open the bleed and drive the car the boost would go above 20 psi on my gauge......... SO I closed the bleed screw but cant get the psi to go down below 19 / 20 psi; seems to me the computer is controlling it......


Any Ideas what to do???? Im thinking I should buy stronger pistons and install them... THEN bring it to someone and have it checked out????? LIKE fuel pressure, timing etc....

[lametec]

1. You're too lean.
2. You're running too hot charge temp (stock intercooler)
3. You're running too much bost for 91 octane (especially with the stock intercooler).

20 psi is borderline with 93 octane.

Cyl 2 also probably has a slight less flowing injector on it, so it leans out a bit more than the others.

[turbovanman]

How your running 20 psi on a stock fuel system is beyond me,

But yeah, you need to install some new pistons, TURN the boost down to say 14 psi, and go from there.

Have you read up on www.thedodgegarage.com ?

You need to upgrade your fuel system, computer before running over 15 psi.

[stephenrussell]

The guy I bought the car from told me that he was running say 15 psi boost and had two extra injectors that came on at WOT controlled by a solenoid etc etc.... HE ALSO INSTALLED A air / fuel gauge to make sure everything was running ok....

BUT he didn't like the idea of running a fuel line to these extra injectors...... (Fire hazard)

SO he purchased A different computer (told me it was a reprogrammed one, if that makes any sence) and Changed the stock injectors to +40 injectors and also changed the map sensor to a gm map sensor.... He then removed these other extra injectors cause he was now running more fuel and more boost all controlled by the computer.... At least thats how i understood it.....

[turbovanman]

If you can get the numbers of the injectors, we can definatley see if they are +40's. Some cals are really aggressive on spark timing so that could be it also.
91 is way to low for 20 psi, if everything checks out, then you will have to run higher octane gas or lower boost.

I know you said CSX but is it a 2.2 or 2.5? A 2.5 could have been installed also?

[Boost_virgin]

Quote:

Originally Posted by turbovanman How your running 20 psi on a stock fuel system is beyond me, But yeah, you need to install some new pistons, TURN the boost down to say 14 psi, and go from there. Have you read up on www.thedodgegarage.com ? You need to upgrade your fuel system, computer before running over 15 psi.

Check his second post he is running +40 injectors I think. The readings on the Auotmeter guage sound strange. I have this gauge to. My gauge is red lights = lean, yellow lights = good, and green lights = rich. I am all stock, and I have the second to last green light lite at WOT

[stephenrussell]

So I believe the setup should be ok (maby need a bigger intercooler for 20psi boost im not sure)

If you run a motor too lean will that cause detonation (broken pistons) is this my problem ???? or is my problem maby too much boost and too high of a temperature?????

[stephenrussell]

LIKE WHAT I am asking is what can cause detonation???????? so I can try to fix my problem instead of spending my time replacing pistons ..

[turbovanman]

Quote:

Originally Posted by stephenrussell So I believe the setup should be ok (maby need a bigger intercooler for 20psi boost im not sure) If you run a motor too lean will that cause detonation (broken pistons) is this my problem ???? or is my problem maby too much boost and too high of a temperature?????

Sorry, missed that.

We need to make sure you have the corrrect injectors just to be sure. Lean will cause detonation that will shatter and melt pistons. Your intercooler if fine at 20 psi but doing the best job.
I would fix it, turn down the boost, get a scanner and monitor knock, then turn up the boost slowly. AGain, your octane is tooooooooo low for 20 psi. You need higher or home brew gas.