o.k here is the deal just got my car back from the dyno made like 600, benson sleeved gsr standerd bore, pauter rods ,cp pistons acl bearings,micropolished crank,gsr head,omni valvetrain,aem ems,rocket motorsports cams,t1 trigger kit(by the way that thing is f-ing genious glad i spent the money for it)any how made around 560 shifting at 9000 rpm so then we wanted to flirt with 10,000 rpm then the damn thing made almost 600whp cool right well it also picked up a knock.so further investigation led me to believe it floated a valve man i was hoping it was a valve well after pulling the head i found something i have never seen before #1 cyl.wall grooved up pretty bad as well as the piston but only on the intake side of the piston and the wall it was a conservitive tune so i dont think it was a lean condition,the rings appear ok and had 190 psi of compression in that hole,the wrist pin had no play as far as the piston wabaling so i just dont know what to do at this point so please give your hypothisis on what you think may have went wrong o yeah 70 psi at idle of oil press.i just dont understand

 

That is one long sentence! So its an 81mm bore with CP pistons, right?

 

What piston to wall clearance was it setup at, and how confident in the measurements are you?

Odds are it was detonation that killed it. Tight piston/wall clearances and a bit of detonation is a bad combo. You say the tune was conservative, but you also say you picked up some knock on the log, so it might not be quite as conservative as you think it is. If you want to email me a log and the cal. file, i'll look over it for you. tony@t1racedevelopment.com

 

damn that was a long sentence.
I dont know if a knock was picked up on the log i was not there.I just know that at some point it started to knock on the dyno.

art,yes 81mm cp's stock bore.

I would assume that in most piston/wall clerance problems you would see some scaring all the way around the wall or the piston itself,i just have never seen it do that .in one spot it's mabie an inch and a halfacross the piston and wall and top to bottom.

and im pretty confident in the measurments like 100%confident

 

do you mean knock as in detonation or an internal engine knock like a bearing?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpeedDreamz.com &raquo;</TD></TR><TR><TD CLASS="quote">do you mean knock as in detonation or an internal engine knock like a bearing?</TD></TR></TABLE>

i am thinking the same thing over here.

 

The car was tuned here at the shop. When he says it knocked.. It was an internal engine knock, not detonation.

The motor made great power, no problems what so ever. Made about 15 very clean problem free pulls, then after the last pull, the noise came about.

 

you might of spun your bearing. What were your clearance.

 

i was thinking bearing problem,as i said it was an internal knock the tune is fine and was done by a reputable shop nothing to do with them it is an internal problem i pulled all the bearings and plastigauged them the are perfect.i am just wondering what would cause it to scrape on one side of the wall the intake side and no where else.it is def. a engine build mistake but i am trying to narrow down were the mistake may have started.unless it was a untrure hone or piston failure it just seems like something was oblong for it to just rub one side.

any other ideas

 

So the knock was heard during the run, or after? What does the knock sound like? When a piston gets beat up like that, it will knock from the piston slapping the cylinder wall.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BlownHatch &raquo;</TD></TR><TR><TD CLASS="quote">i was thinking bearing problem,as i said it was an internal knock the tune is fine and was done by a reputable shop nothing to do with them it is an internal problem i pulled all the bearings and plastigauged them the are perfect.i am just wondering what would cause it to scrape on one side of the wall the intake side and no where else.it is def. a engine build mistake but i am trying to narrow down were the mistake may have started.unless it was a untrure hone or piston failure it just seems like something was oblong for it to just rub one side.

any other ideas </TD></TR></TABLE>

detonation

 

me and brad brooks had the car on the dyno. compared to my car, tommy's car has lower compression pistons, was running half the boost, and was running less timing with the afr in the high 10's. spark plugs looked great, and timing mark on the plugs showed that the car could have taken a decent amount more timing. this is on a T1 trigger kit, so timing drift isnt the case either. everything on the dyno went perfect smooth. the car did not make any noise during the pass or even after the pass.......after it sat for a while (20 min) it then made a very very faint knocking sound at idle so we shut it down and didnt go any further.


the first time the car was on the dyno last season, with out a T1 kit we made a few pulls and it did the very common stock distributor with AEM missfire. we cut the session short because it was not worth beating up the motor when we all knew ahead of time that the car wasnt going to run properly with the stock distributor unless he had one of the magical ones that just happened to work with AEM, which he didnt have. after the car left here the first time we told him not to drive it because the tune was nowhere near close since it would not make a clean pull with out miss firing.

when i spoke to tommy last night after he discovered the scored cylinder walls i did not think about his previous dyno session, but that seems to be about the only thing that would make since. when the stock distributors dont work, if you watch the timing with a timing light during a pull, its insane how much it wonders. if the car was driven or not after the first dyno session i dont know.


im more than confident in the tuner, the numbers i saw for timing, the afr's i saw, the plugs i saw, and how clean the passes/power were on the dyno.

 

Is it just 1 piston?

 

yes cylinder number one. if you pull the plug wire off while its running at idle the noise goes away, so the problem is def. in cylinder 1

 

all 4 spark plugs looked identical after pulling the plugs after each full power run also. nothing ever seemed any differnt in cylinder 1

 

it's possible that it ran leaner due to a clogged injector or something, or the piston to wall clearance could have been off on that hole.

 

I am not saying it had anything to do with anybody,it's racing this **** happens nor am i upset with anybodythe car was started up a few times and drove down the road a few times also (even though i was told not to)but not hard pulls down the road.yes it appears to b just one piston #1.i would assume if it was a cleareance issue would it just be on one side of the piston?would you be able to notice if that cylinder (injector)had a problem on the dyno im not sure about dyno tunning that is why i am asking

 

Is there a possibility the wrist pin is tight in the rod or piston? Could that cause that?

 

i checked that just now it is ok if it was a clearance do you think it would do that because the clearance was to tight or to loose?

 

First off wow Tony looking at an AEM calibration. Do my eyes deceive me. LOL just playing Tony. Tony is the man.

Most likely the bore was a little tight in Cylinder #1. The Aluminum pistons will expand at a different rate than the Iron sleeves. Creating less wall clearance at higher temperatures. It was probably just a little tight and caught the cylinder wall. Re-hone the block, get new pistons and check the piston to wall clearance before assembly again.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Turbo-charged &raquo;</TD></TR><TR><TD CLASS="quote">yes cylinder number one. if you pull the plug wire off while its running at idle the noise goes away, so the problem is def. in cylinder 1</TD></TR></TABLE>

if i remeber my schooling right that means its a piston/wrist pin problem , if it didn't go away it still could have been cyl 1 just might have been a bearing

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AllMotorMark &raquo;</TD></TR><TR><TD CLASS="quote">if i remeber my schooling right that means its a piston/wrist pin problem , if it didn't go away it still could have been cyl 1 just might have been a bearing</TD></TR></TABLE>


Hes right i beleive.

 

A buddy of mine had this problem. He used 75HP nitrous during a race while using 87 oct gas. Then all of a sudden, it sounded like he spun a rod bearing. Pulled the head and the #1 wall was scarred up and the bearings were fine. We were told that detonation was the problem.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93supercoupe &raquo;</TD></TR><TR><TD CLASS="quote">


Hes right i beleive.</TD></TR></TABLE>

Or a rod bearing.

 

either way you have to take out the rods and crank, to correct your problem, you could check your rod bearings at the same time.