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Old 09-16-2007, 01:02 PM   #1
STi_Guy04
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Default Cyl-4 Blown Yet again

So last night I was driving on the Freeway, and I started to play with a M5 and we got into a little race there on the freeway (dont condone Street Racing)
I pulled off the freeway on the exit I was going to take, and I smelt somthing a LiL funny.. kept driving down the road and now It actually smoked pretty bad.. the car still hauls ass though.

went home and Did a Compression test i got Cyl1 135 Cyl2 137 Cyl3 135 and Cyl4 110

My block is far from stock I have Cosworth rods, Mahle Coated pistions, Cosworth race bearings Car and many low 11 second passes its just wierd it would let go on the freeway. the tune is super safe.. I also have Meth and water injection on top of that for extra protection. Does anyone know out there what type of motor or one built by someone who wont blow up on the freeway?
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Old 09-16-2007, 02:08 PM   #2
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You need to do a leakdown test to pin point the issue before you go blaming the block.

You also may want to concider using a different coolant in future. I speculate that you ended up with heat spots and warped something, cylinder of head wise. Look for Evans coolant (non water based)

I would also suggest you have your injectors cleaned and flow tested. It's possible you had one lean cylinder.

Last edited by mick_the_ginge; 09-16-2007 at 08:16 PM. Reason: typos
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Old 09-16-2007, 04:39 PM   #3
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Get better pistons.
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Old 09-16-2007, 04:55 PM   #4
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Quote:
Originally Posted by STi_Guy04 View Post
...many low 11 second passes its just wierd it would let go on the freeway...
As Mick and others have seen first hand, if a ring land goes south it might not show symptoms right away, provided the piston stays together. There've been a couple on here that were apparently driven for quite a long time with a broken piston - the only symptoms were a slight increase in oil usage and some light exhaust smoking, and other than that the motors ran pretty well. It wasn't until they were talked into doing a leakdown test [which led to a teardown] that they finally discovered where the oil was going.

Last edited by flycaster; 09-16-2007 at 05:07 PM.
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Old 09-16-2007, 04:58 PM   #5
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...Then again if they were the Mahle 4032 then I expect you broke a ring land
Mick, Dustin tells me that Mahle is now offering a 2618 piston. Have you seen one, and if so, what do you think?
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Old 09-16-2007, 06:30 PM   #6
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Hey guy thanks a bunch for the information... Some other things i might add.. under just idle Its not to bad with the smoke.. Its bad once i press on the gas and rev to like 2500-3000 it smokes decent.. Also I have an element tuning catch can.. and its actually empty inside there.. one other thing, it smokes out of the main block vent and the Oil fill tube on start up, Car still runs strong Ac works good... I am doing a Cyl Leakdown tomorrow, I believe i`ll have leaking past the rings is my guess.. Its funny I had no knock.. everything seemed normal tell i pulled off the freeway and drove like 2 miles down and it started to smoke. I Run my car very rich I just moved from AZ to FL so i got better 93 oct now vs the 91 i was using in AZ.. So I guess I`ll be doing a few test tomorrow and the pulling the block based on my findings..

another thing Cyl number 1 Spark plug was Greyish white, Cyl2-3 looked blackish grey I think they are running rich, Number 4 had oil and carbon on it actually looked not so good
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Old 09-16-2007, 08:31 PM   #7
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Busted ringland....... Probably just cracked, but if you keep boosting, its going to start melting away....

Stop now, pull the motor, and your bore "should" be fine. But if you keep boosting, the rings will start to deform and cut into the cylinder wall.
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Old 09-16-2007, 09:03 PM   #8
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sounds like your "super safe" tune was off. It was just a matter of time when the motor finally let go. Its not parts that need to be replaced, its the tune.
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Old 09-16-2007, 09:56 PM   #9
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sounds like your "super safe" tune was off. It was just a matter of time when the motor finally let go. Its not parts that need to be replaced, its the tune.
No disrespect Skully, but why do people always come to the conclusion that it's the tune? Does everyone think that a daily driven 11 second car is going to last forever!!! Get a grip people. Engines fail and it would not matter how conservative a tune is if the block is putting down serious power it's not if it's going to fail it's WHEN. And lets face it, with an 11 second car their is no such thing as conservative.................

I feel for STi_Guy04 as I know too well what it's like to loose an engine but the key is to identify what actually failed and fix it for the next time.

Yes, a bad tune can break engines but it's unlikely that a car that runs multiple 11 second passes has a bad tune. Maybe the water/meth injection failed?

It's good that STi_Guy04 spotted the issue now before the whole engine lets go. This will reduce the rebuild cost.
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Old 09-16-2007, 10:41 PM   #10
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Mahle has 2618s are available.
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Old 09-17-2007, 01:00 AM   #11
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Originally Posted by mick_the_ginge View Post
No disrespect Skully, but why do people always come to the conclusion that it's the tune? Does everyone think that a daily driven 11 second car is going to last forever!!! Get a grip people. Engines fail and it would not matter how conservative a tune is if the block is putting down serious power it's not if it's going to fail it's WHEN. And lets face it, with an 11 second car their is no such thing as conservative.................

I feel for STi_Guy04 as I know too well what it's like to loose an engine but the key is to identify what actually failed and fix it for the next time.

Yes, a bad tune can break engines but it's unlikely that a car that runs multiple 11 second passes has a bad tune. Maybe the water/meth injection failed?

It's good that STi_Guy04 spotted the issue now before the whole engine lets go. This will reduce the rebuild cost.
Yeah its true you cant expect them to last forever... I some how feel that if i where just doing lower speed racing or 1/4 mile passes the motor will last alot longer.. I lost my last motor on the same cyl bombing down the freeway in the top of 5th gear. there is just something about high speed racing in our cars that just doesnt like... I`am sure the motor got quite tired of putting out 400 something whp & doing 150ish.. Was not the best decision lol

For the tune Not to much to say there the car was damn fast on pump and race. I was running 22-23psi when it happend. with methanol/h2o Funny thing is i run a really rich tune on pump gas and race anyway.. about 10.8-10.7 afr I installed my meth/h20 kit after my tune so i never tuned or leaned out my afr for the extra power.. I just squirt the stuff in to be safe? Bad Idea??

But Yeah I only drove like 15mile on the car after in failed me Well cool thing is All the labor is free. I do all the work myself so only cost is parts. I have a second car. and I`ll never do this freeway racing again haha

I`ll have the block out by then end of this week, and torn down over the weekend I`ll keep you all posted.. My Guess Is broken Ringlands on #4 cyl

Oh and what do you all mean by the number when your talking about the mahle pistions? I understand that has something to do with the type of metals used and strength and expansion rates of the pistion? but what do you look for, For building our boxer motors.. does anyone have any recommendations of Really high quality pistions.. I think i am going to step up the CR ratio to about 9.0 or 9.5 always wanted to try that out.

oh and thanks again for the info!!!
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Old 09-17-2007, 01:20 AM   #12
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The higher expansion pistons are "plasticy" meaning they can take a beating,but at warm up are small and need time to become stocke size so they quit knocking. The great news is they can take huge amounts of abuse and not shatter like the stock pistons ore stock Mahles.

I am buying Wisecos next engine faluire.
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Old 09-17-2007, 04:26 AM   #13
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What is your entire modlist?
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Old 09-17-2007, 11:30 AM   #14
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Quote:
Originally Posted by STi_Guy04 View Post
...what do you all mean by the number when your talking about the mahle pistions? ...
Unabomber has a pretty good [and short] discussion of this in the Piston FAQ. As for specific "high power" piston recommendations, there was a thread in here recently that likewise talked about this. I'm using custom JE's, but others have had great results with CP and Wiesco too - irrespective of piston choice, the bottom line is there is no subsitute for proper fit and engine assembly work.

As for your injection question, light water injection only is fine without a retune, but shooting in extra fuel (ie, water/meth mix) without a retune is not the best idea. I've heard several tuners (Azscoobie among them) mention problems including "rich detonation" here, but frankly that is not something I'm qualified to talk about. Perhaps Mick or other tuners can chime in...
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Old 09-17-2007, 06:45 PM   #15
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What is your entire modlist?
Peakboost 35r .82 Turbo kit
Pwr Radiator
Cooler thermostat
Kingpin Massive FMIC
44mm EWG
PE-850cc inj
Walbro 255lph
Perrin fuel rails
HKS bov
Element tuning catch can
Element Hydra
Hydra Mist
3.0 exhaust no cats

Cosworth Rods
Cosworth bearings I`am sure i am missing things but thats most of the important stuff
Mahle Pistions...
Stock Heads

How do you guys think about Total Seal Rings? and running like 9.5:1 compression
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Old 09-17-2007, 06:48 PM   #16
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4032 Mahle's, huh? If you broke one, I think that makes 5 so far. Let us know.
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Old 09-17-2007, 06:52 PM   #17
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Yeah I`am 98.7% sure i broke some ring lands on number 4 cylinder.. I`ll for sure let you know with some pics..
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Old 09-17-2007, 07:42 PM   #18
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Mick, Dustin tells me that Mahle is now offering a 2618 piston. Have you seen one, and if so, what do you think?







The Power Pack Plus are made from MSP25, and they have been runnning them at 35+ pounds without an issue.

Rich
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Old 09-18-2007, 10:49 PM   #19
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Hey shawn give me a call I was wondering what happend to you. sorry to hear about the engine. get rid of the Mahle and get some weiscos at 9.0:1 they seat alot better and will spool that 35r quite a bit faster.
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Old 09-19-2007, 12:16 AM   #20
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Hey shawn give me a call I was wondering what happend to you. sorry to hear about the engine. get rid of the Mahle and get some weiscos at 9.0:1 they seat alot better and will spool that 35r quite a bit faster.
spool it faster because of compression ratio?? I am pretty sure the 4032 mahles are about as light of a piston as you can get.
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Old 09-19-2007, 12:26 AM   #21
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idk if this is right at all as i am still in the learning process but have you checked to see if it could have been a head gasket? with coolant in the oil or low coolant?

also what color was the smoke?
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Old 09-19-2007, 12:46 AM   #22
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Hey shawn give me a call I was wondering what happend to you. sorry to hear about the engine. get rid of the Mahle and get some weiscos at 9.0:1 they seat alot better and will spool that 35r quite a bit faster.
Hey bro whats up... Yeah man Never got A hold of you before i left.. I Got a job down here in South Florida at Champion Audi/Porsche As a Tech... Its pretty tight So far.. We got a Black and carbon Audi R8 and 2 Carrera GT and a GT2 in for service...

But yeah for the motor its sucks.. got into a lengthy Freeway battle with an M5 Did very well for a 4-bannger turbo But I guess motor got tired of that crap lol It was the same deal we where doing on the way home from the dyno but i guess another min or 2 of WOT..

It smoked a lil more than a lil bit at idle, and when you press on the gas like very her and let go she smokes a decent amount! same deal as like last time.. smokes through the oil fill tube and Main block vent.

Yeah I`ll be changing something up for sure man... The motor had no reason to let go man!! I dunno what the deal was but for sure she`ll come back stronger than ever.. thinking of either 9.0-9.5 compression, and some head work I dunno let me know what you think or recommendations...
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Old 09-19-2007, 01:17 AM   #23
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spool it faster because of compression ratio?? I am pretty sure the 4032 mahles are about as light of a piston as you can get.
It has more to do with the amount of compression than the weight of the piston. the more air you can compress with each stroke the more power you can make down low.
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Old 09-19-2007, 03:51 AM   #24
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Quote:
there is just something about high speed racing in our cars that just doesnt like...
Yep the ecu does not listen for or care about detonation above about 5500 rpm. Long duration high load pushes a safe tune over the edge.

You had a safe tune for daily driving --- it was not a safe tune for extended time at WOT in 5th. The car is not under load long enough at the drag strip for it to be a problem.


Quote:
The motor had no reason to let go man!!
Yes it did, you broke a piston -- now figure out how to modify your tune so that does not happen. I would bet you are tuning on the dyno for max power and leaving no cushion for severe conditions. On your next tune, after you get your best power tune, pull a little timing out of the high load cells until you can see about a 1% drop in engine power. That will put you at MBT timing so you have a bit of cushion for when you beat the snot out of it.

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Old 09-19-2007, 11:21 AM   #25
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he is using the hydra and hydra mist. it will moniter detonation and pull timing throughout the rpm band and resort to another safe map if needed. he would have to have a bad knock sensor to have this problem.
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