Turbo-LS

iTrader: (4)

Hey guys, well after having all four cylinder fry on me from to much timing on pump gas i had the engine rebuilt and bored. Now its been together for two months and ive put all of 100 miles on it since the rebuild

Now i took the car out on saturday. car ran great. oil temps stayed 210, coolant aroudn 203-208. Now just barely boosting around mostly just crusing. So i got up on the highway took 3rd gear to 7200 rpm with 15 psi of boost with 93 octane fuel running 14 degrees of timing. After 3rd gear dropped into 4th for another 1000 rpm of pull in boost and then popped into 5th gear and decelerated.

Once i got back on the throttle, it started smoking like a train. catch can was bellowing smoke, not coolant smell oil smell. i drove it home very very easy. coolant stayed normal temps, oil stayed normal temps. oil pressure stayed good. probably went about 2 miles. did a leak down and the collant bubbled so hey i figured i found a winner a 75 dollar head gasket.

So i just got it apart and pulled the head off, cylinder 4 was the cylinder that had leakdown all other cylinders were 100% fine. so pull the head off and the piston is jammed to the intake side and the cylinder wall is all scuffed up and black. same thing that happend when i had to much timing except the pistons werent jammed to one side. and thi sis only one piston. all other 3 are fine no issues.

My questios are.
1. Would improper assemlby cause excessive heat in that cylinder and possibly pop the HG only in that cylinder.
2. Would improper assembly cause that piston to be jammed to one side .
3. Would the headgasket going out in that one cylinder cause the piston to jamm to one side and damage the cylinder and piston ( it didnt suck in any coolant nor blow out any coolant from the system when the Hg poped)
4. Is it possible to have detonation in just one cylinder under normal conditions where all other cylinders do not show any signs of detonation?
5. What are all your professional thoughts and oppinions about the whole siuation.









Modified by Turbo-LS at 1:51 PM 11/15/2006

RTW DC2R

what do you mean the piston is jammed to one side? anyway, cyl 3 is usually the one that goes on these motors as I think its the one that gets the hottest. could it have been a bad tank of gas or maybe a spike in boost? how do the plugs look?

OBRJosh

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RTW DC2R &raquo;</TD></TR><TR><TD CLASS="quote">what do you mean the piston is jammed to one side? anyway, cyl 3 is usually the one that goes on these motors as I think its the one that gets the hottest. could it have been a bad tank of gas or maybe a spike in boost? how do the plugs look?</TD></TR></TABLE>The pistion Is jammed towards the intake side doesnt move freely towards the exhaust side and can see it from the First Pic, There was about 3gals on 93 and 1 gal of 110 in the cell at the time No spike in boost held 15-16psi at the max , Brand new Cp pistions

Turbo-LS

iTrader: (4)

Fuel was good, only ony cylinder burnt.

1,2,3 plugs look good
the dead cylinder plug was fouled black and coolant

if you look at the pic from the top of the piston its pushed to the intake side, you can see the gap o the exhaust side between the cylinder wall and the piston. and you cant move it back liek you can the other cylinders

Boost stayed 15 psi to 7300rpm no spike.

vaporboy12

my cylinder looked the same way after running dead rich

Turbo-LS

iTrader: (4)

yeah im sure a rich condition will do this, its called washing down the cylinders. but it wasnt rich enough to do that. 11.2-11.5 a/f

vaporboy12

that injector could locked open my cylinder looked the same damn way. im just saying dont rule it out

Jared

looks like something happened in that cylinder. send your injectors and have them flowed individually. also, what was your piston to wall clearance? i dont think it will matter because it looks like detonation killed that cyl, but keep us updated.

Jared

also, did you always verify that physical timing matched the software?

Turbo-LS

iTrader: (4)

i believe piston to wall was .045 which is .005 more then CP calls for. it specifically states to the builders discretion on clearence.

As far as the physical timing and in the AEM. i set it up how i was told by an aem tech at aem directly. to get the car at and idle. have your idle colums what you want which i put to 16 and then go to ecu setup and sync timing then i retarded or advanced untill the crank read 16, the map said 16 and the timing in the softwars said 16

Turbo-LS

iTrader: (4)

pistaon to wall clearence is .045 which is .005 more then CP calls for but CP specifically states up to the builders discretion. It looks like alot of clearence because the piston is jammed to the intake side which is where all the damage is. there is a few light scuffs on the exhaust side but 99% of the damage is intake side
Injectors are all new with around 250 miles on them or less. only 100 mile son them since this rebuild.

I knwo what did me wrong the first time i smoked all the pistons. that was my error in syncing the timing within the aem and on the distributor. this time around i specifcally did this with aem on the phoen to ensure it was 100% correct and the timing hasnt been an issue since.

Is is possible for an injector to **** the bed that quickly, im sure it is anythign is possible but it seems highly unlikely. also through the pulls in the gears the car ran fine, it didnt break up at all. ive tuned several cars and never had an issue. the car pulled hard through the gears and then i let off the throttle. onc ei go tback on the throttle it sounded like a damn subaru and smoked like a train.

a/f stayed solid 11.2-11.5 during the boosting. never had any boost spike nor a lean condition. and timing map is solid and conservative

It just doesnt make sense to me how one cylinder takes a **** and the piston being jammed into the intake side and not being able to move it back to center like all other 3 pistons will do

Turbo-LS

iTrader: (4)

Would it happen if the wrist pin/rod were to tight not allowing the piston to move freely, instead jamming it and causing it to rub on the cylinder walls?

vaporboy12

i would say have the injectors checked.. i am leaning toward cylinder being washed but thats just my thoughts i could be wrong..

Turbo-LS

iTrader: (4)

cylinder being washed is going to jam the piston to the intake side???? I know it can kill a motor but jamm the pisotn to where i cant move it back its just stuck in that position?

Possibly when the HG went for a split second it got hydrolocked and possibly bent the rod a little causing the piston to shift to one side or the wrist pin being tight made the piston gte stuck like that?

Evern when i fried the pistons before they were locked to the side like this one is

JDogg

probably scuffed the piston in teh first 10 mins the engine was running and then the skirt collapsed causing all the cylinder wall damage. 0.0045" piston-wall is fine, thats normally where i run em.

SpeedDreamz.com

I hope your piston to wall clearance was not .045 maybe .0045 and that is ok. Galled the piston and the ring bound up.


Modified by SpeedDreamz.com at 11:19 PM 10/23/2006

OBRJosh

First time car was started, it idled at 13.5 -14.5 AF

h22apwrd95

iTrader: (1)

What about a broken ring issue? Something could physically be holding the piston cocked to the side. What happens when you rotate the crank?

Mike

OBRJosh

Crank spins freely nothing abnormal , but in the top picture you can see how the pistion it closer to the intake side and it will not move at all

Turbo-LS

iTrader: (4)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">probably scuffed the piston in teh first 10 mins the engine was running and then the skirt collapsed causing all the cylinder wall damage. 0.0045" piston-wall is fine, thats normally where i run em.</TD></TR></TABLE>

Makes sense, but the car ran fine with 10 psi boost at mir 2 months ago. alwas ran fine, oil looked good, no flake or metalic in the oil. good a/f's always with conservative timing to make sure nothign went wrong this time around liek last time when to much timing ate up the pistons. How would the piston scuff the walls in first start up. it was started and idle for a good amoutn of time to make sure everything was kosher. broken in properly with good a/f

JDogg

no telling.. maybe that one dried up between the time it was built and when it was cranked up.

OBRJosh

At this point that seems possible, but car was started 3 days after the machine work was done

JakeSpec420

Ring End gap was incorrect!

Turbo-LS

iTrader: (4)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JakeSpec420 &raquo;</TD></TR><TR><TD CLASS="quote">Ring End gap was incorrect!</TD></TR></TABLE>

See now this Makes the most sense out of anythign so far. Ring end gap incorrect will cause the ring to not seat properly in all the way and push the piston to the side like it is right now right?

Afterwards it scored the piston and then galled the rings up and made it worse as time went on driving it. the excessive heat in that cylinder from running it like that (not knowing) probably what poped the HG in that one cylinder.

Certainly makes sense to me, what about anyone else?

JDogg

normally ring gap too tight will result in scaring and scratching all the way around the bore, not just on the thrust surfaces

take the piston out and you'll know more.