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Old 02-04-2013, 12:26 PM   #1
kapp_badbloodz
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Default Piston Slap on fresh built motor?

This is regarding my 2008 STI. Stock fuel delivery. FP HTA Green, FIC 900s, TGV Deletes, TurboXS catless TBE, Up pipe w/38mm EWG, + most general name brand/quality supporting mods (no eBay parts).

BACKGROUND:

Had a Cosworth short block installed. Seems to have a noticeable amount of piston slap. I lost a decent amount of oil and the engine got a little hot one day. It didn't overheat and it hasn't seen boost since its been being broken in.

My question is, considering my lack of experience with built motors, is this normal? Should I be concerned? It is noticeable at idle but not under throttle nor does it get worse under throttle.

My main concern would be when it does get tuned would the slap cause any damage down the road. The short block was built new from Cosworth and professionally installed.

On a side note, do you guys notice a lot of hesitation or stumbling on built motors? I went pretty conservative with mods but replaced most performance parts. I was told I need rails/fpr but saw the 3' fuel line extension mod can remedy the situation with some tuning as well. Any thoughts/recommendations?

Thanks
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Old 02-04-2013, 12:35 PM   #2
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Is it Cosworth pistons. I had cosworth in the past and they are very quite pistons compared to the cp's i have used in the past.
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Old 02-04-2013, 12:36 PM   #3
kapp_badbloodz
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Quote:
Originally Posted by obrut View Post
Is it Cosworth pistons. I had cosworth in the past and they are very quite pistons compared to the cp's i have used in the past.
It is a fully built cosworth straight from them. All cosworth parts. The sound is minimal but noticeable.
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Old 02-04-2013, 12:57 PM   #4
Boostedbob
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Just goin off my build forged bottom end with cp pistons, I do not get any noticeable piston slap with the motor and zero oil consumption or to the point it not noticeable every 2600miles.

Do you only get the slap when the car is cold? Or also when it is warm? Keep in mind the forged material is much harder then the cast so is noiser and should quiet up as it warns up.
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Old 02-04-2013, 01:08 PM   #5
kapp_badbloodz
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Quote:
Originally Posted by Boostedbob View Post
Just goin off my build forged bottom end with cp pistons, I do not get any noticeable piston slap with the motor and zero oil consumption or to the point it not noticeable every 2600miles.

Do you only get the slap when the car is cold? Or also when it is warm? Keep in mind the forged material is much harder then the cast so is noiser and should quiet up as it warns up.
Its kind of the opposite. I don't notice it on cold start up but after a light warm up you start to hear it. I took a video of it and I'll post it up. I haven't tested it or listened to it after a decent amount of driving. You can't hear it inside the cab regardless of cold/warm.

EDIT: This was taken yesterday (Sunday). I need to replace the aftermarket BOV for stock BPV if that makes a difference :/

https://www.youtube.com/watch?v=fR8J...e_gdata_player
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Old 02-04-2013, 01:29 PM   #6
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I sent you a pm and a video link of my car on a cold startup, it sounds fine to me but I am by no means a expert.
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Old 02-04-2013, 01:30 PM   #7
kapp_badbloodz
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Quote:
Originally Posted by Boostedbob View Post
I sent you a pm and a video link of my car on a cold startup, it sounds fine to me but I am by no means a expert.
Got it and thanks you. At work so I'll reply in a few
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Old 02-04-2013, 01:48 PM   #8
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U my friend have a mild case of piston slap.. I am no expert as well but ive been dealing with the same noise for about 15k miles on my built block now..
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Old 02-04-2013, 02:16 PM   #9
kapp_badbloodz
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Quote:
Originally Posted by danger1138 View Post
U my friend have a mild case of piston slap.. I am no expert as well but ive been dealing with the same noise for about 15k miles on my built block now..
Any issues performance or mechanical wise? Short term/long term issues? Anything besides the noise complaint? Your experience and input is much appreciated

I'm glad its nothing terrible.
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Old 02-04-2013, 02:24 PM   #10
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Quote:
Originally Posted by kapp_badbloodz View Post
I lost a decent amount of oil and the engine got a little hot one day.
The wording isn't very clear...is this on the built motor, or is this the cause of the failure on your previous motor and is the reason WHY you're now running a built motor? What does being low on oil have to do with the engine getting hot?

Quote:
Originally Posted by kapp_badbloodz View Post
it hasn't seen boost since its been being broken in.
What? Who told you to stay out of boost during break-in? The engine NEEDS boost to seat the rings before the crosshatching wears down and break-in ends.


Piston slap is more or less normal on built motors, HOWEVER it should be louder when the engine is cold and go away when the engine is warm. This is because the forged pistons expand more when warm than the stock pistons. This means that in order to have the same clearance when the engine is warm, you must have more clearance when it's cold, which leads to some slap before the engine gets up to temp. I'm not sure what to think if yours is behaving the opposite.
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Old 02-04-2013, 02:32 PM   #11
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Quote:
Originally Posted by kapp_badbloodz View Post

Any issues performance or mechanical wise? Short term/long term issues? Anything besides the noise complaint? Your experience and input is much appreciated

I'm glad its nothing terrible.
So far no issues. Drove it to Arkansas n back from NY during break in. It saw 5-7 lbs of boost. No issue. So far no mechanical or performance isuues in the +15k miles its been running.

Only issue i can think of was a busted oem radiator. Besides the noise complaint, cant think of anything to worry u. I also dont get too much oil consumption to speak of. My tuner , sti mikey said the noise is pretty normal, nothing to worry about. Was tuned by him at efi, did 273 whp on low reading dyno and 330 tq.
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Old 02-04-2013, 02:33 PM   #12
danger1138
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Quote:
Originally Posted by kapp_badbloodz View Post

Any issues performance or mechanical wise? Short term/long term issues? Anything besides the noise complaint? Your experience and input is much appreciated

I'm glad its nothing terrible.
[quote="kapp_badbloodz;39065517"]

Any issues performance or mechanical wise? Short term/long term issues? Anything besides the noise complaint? Your experience and input is much appreciated


So far no issues. Drove it to Arkansas n back from NY during break in. It saw 5-7 lbs of boost. No issue. So far no mechanical or performance isuues in the +15k miles its been running.

Only issue i can think of was a busted oem radiator. Besides the noise complaint, cant think of anything to worry u. I also dont get too much oil consumption to speak of. My tuner , sti mikey said the noise is pretty normal, nothing to worry about. Was tuned by him at efi, did 273 whp on low reading dyno and 330 tq.
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Old 02-04-2013, 02:50 PM   #13
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Quote:
Originally Posted by the suicidal eggroll View Post
The wording isn't very clear...is this on the built motor, or is this the cause of the failure on your previous motor and is the reason WHY you're now running a built motor? What does being low on oil have to do with the engine getting hot?

What? Who told you to stay out of boost during break-in? The engine NEEDS boost to seat the rings before the crosshatching wears down and break-in ends.

Piston slap is more or less normal on built motors, HOWEVER it should be louder when the engine is cold and go away when the engine is warm. This is because the forged pistons expand more when warm than the stock pistons. This means that in order to have the same clearance when the engine is warm, you must have more clearance when it's cold, which leads to some slap before the engine gets up to temp. I'm not sure what to think if yours is behaving the opposite.
To clarify... yes. I lost oil in the built motor. The oil pressure sandwich plate was improperly tightened and came loose. Lost 85% of my oil, was about 4qt+ low. I caught the low pressure early and was able to park the car before overheating. But it heated up quite a bit.

Replaced the oil. No shavings/coolant in the oil. Everything is back to normal. Since I was freaking out I think I began to notice the minimal slapping sound that exists. Just asking the question as I am uneducated. This is my first built motor and although I am mechanically inclined I am absolutely not knowledgeable on the subject.

EDIT: the car has boost. I am instructed to keep boost to a minimum. But I have a base map break in tune but nothing crazy specific for my motor/build. I was told: no boost, 500 mile break in, tune for power. But I have hesitation/stumble issues and I need to swap out for my OEM BPV
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Old 02-04-2013, 02:51 PM   #14
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Quote:
Originally Posted by danger1138 View Post

So far no issues. Drove it to Arkansas n back from NY during break in. It saw 5-7 lbs of boost. No issue. So far no mechanical or performance isuues in the +15k miles its been running.

Only issue i can think of was a busted oem radiator. Besides the noise complaint, cant think of anything to worry u. I also dont get too much oil consumption to speak of. My tuner , sti mikey said the noise is pretty normal, nothing to worry about. Was tuned by him at efi, did 273 whp on low reading dyno and 330 tq.
Glad to hear. Also been told to tune with Mikey. Haven't had the time to try and schedule a tune with him.
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Old 02-04-2013, 02:52 PM   #15
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Hey kappa your in box is full just a FYI.

I'm at 10k miles on my built motor now, on break in it saw a lot of engine braking and boost, I got the motor back from my builder and he had put on 200+miles he is of the thought run her hard and check the oil. Which I pretty much did as well and followed his oil change schedule he wanted me to do.
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Old 02-04-2013, 03:11 PM   #16
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Quote:
Originally Posted by kapp_badbloodz View Post
To clarify... yes. I lost oil in the built motor. The oil pressure sandwich plate was improperly tightened and came loose. Lost 85% of my oil, was about 4qt+ low. I caught the low pressure early and was able to park the car before overheating. But it heated up quite a bit.

Replaced the oil. No shavings/coolant in the oil. Everything is back to normal. Since I was freaking out I think I began to notice the minimal slapping sound that exists. Just asking the question as I am uneducated. This is my first built motor and although I am mechanically inclined I am absolutely not knowledgeable on the subject.
Yikes....unfortunately this tends to agree with what I was already thinking. Slapping/knocking/tapping that gets louder as the car gets warmer doesn't point to piston slap, it points to an oiling/bearing problem. Since you ran the car 4+ quarts low on oil, I think there's a good chance you toasted a bearing. You might not have seen any shavings at the time, but that doesn't mean that damage wasn't done.
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Old 02-04-2013, 03:21 PM   #17
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Originally Posted by the suicidal eggroll View Post

Yikes....unfortunately this tends to agree with what I was already thinking. Slapping/knocking/tapping that gets louder as the car gets warmer doesn't point to piston slap, it points to an oiling/bearing problem. Since you ran the car 4+ quarts low on oil, I think there's a good chance you toasted a bearing. You might not have seen any shavings at the time, but that doesn't mean that damage wasn't done.
This was my thought on it. I didn't run the car very long. Maybe 5-8 minutes and under 30mph. Regardless... its an issue that I've been thinking about.

When I noticed the issue; I was at 27psi oil pressure under throttle and 15-18psi at idle. It had more than a quart left but when I stopped the rest leaked out. When I fixed the leak point I filled +/- 4 quarts to be at full. I hold oil no problem. No mechanical issues. Just noise. Its barely noticeable.

My OEM engine temp didn't rise very much but my ghetto ass EGT was running higher than normal. I caught it early. I don't foresee a long term problem but I'm just uncertain still.
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Old 02-04-2013, 03:46 PM   #18
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I hope the experts chime in, but i believe 4-8 min of running low on oil is more than enough time to mess something up..
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Old 02-04-2013, 03:47 PM   #19
kapp_badbloodz
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I hope the experts chime in, but i believe 4-8 min of running low on oil is more than enough time to mess something up..
Me too... been told its okay and normal sounding.
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Old 02-04-2013, 05:06 PM   #20
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Just an update.

I guess there is a difference between warm and warmed up. Typically I would warm the car for 20 minutes before I drive anywhere. It would make the noise in the video I posted.

Now I get home from work (12-15 minute drive) doing quite a bit more engine braking and going up to 4k RPMs than I normally do. Get out the car and pop the hood...

Nothing... no sound.

I must be high :/
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Old 02-05-2013, 04:49 AM   #21
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I have the same noise man; built motor: cosworth pistons, eagle rods, dada dada da; and from what I've heard its super normal (forged are loud, especially the cosworth pistons) just check your oil occasionally.
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Old 02-05-2013, 09:11 AM   #22
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I am on break in right now myself. My builder told me what to expect with the extra noise, the initial puff of smoke at start up, and the extra time to warm up the motor. Being in a cold weather climate, I invested in a little block heater and it helps. I dont drive it in the snow / salt but if its cold ill take it for a spin.

Apparently, I lucked out because my build is not noisy at all. I am by no means an expert but from what I have read from your posts it doesnt sound like you did any damage. What oil were you using for break in?
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Old 02-05-2013, 10:11 AM   #23
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I am on break in right now myself. My builder told me what to expect with the extra noise, the initial puff of smoke at start up, and the extra time to warm up the motor. Being in a cold weather climate, I invested in a little block heater and it helps. I dont drive it in the snow / salt but if its cold ill take it for a spin.

Apparently, I lucked out because my build is not noisy at all. I am by no means an expert but from what I have read from your posts it doesnt sound like you did any damage. What oil were you using for break in?
Non synthetic motul 10w40, did an emergency replacement with non synthetic pennsoil 10w40 for about 30 miles, towed back to the shop for reevaluation and replaced with the motul again.

The tow set me back almost 400 bucks just for them to tell me its fine better safe than sorry I guess.

Glad to hear positive feedback and similarities with y'all. I guess since it is cold out it takes a little longer to warm up. No leaks anymore which is good.

Just got to plan out how to fix the stumble issue and then its off to tune. Any other input, experience, dos or do nots?
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Old 02-05-2013, 10:29 AM   #24
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I would get it tuned for full boost and see if your bearing is toast or not. Sounds like u are fine, get tuned!
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Old 02-05-2013, 03:36 PM   #25
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Quote:
Originally Posted by kapp_badbloodz View Post
Just an update.

I guess there is a difference between warm and warmed up. Typically I would warm the car for 20 minutes before I drive anywhere. It would make the noise in the video I posted.

Now I get home from work (12-15 minute drive) doing quite a bit more engine braking and going up to 4k RPMs than I normally do. Get out the car and pop the hood...

Nothing... no sound.

I must be high :/
Just idling the car to warm it up will not quiet noisy pistons. You have to drive the car somewhat spirited to get the pistons to expand. That would explain why it is quieter after a long drive. If your tune is safe, I would run it hard for a few pulls and immediately pull over and pop the hood. If it has noisy pistons the noise should have gotten noticeably quieter, and it seems you have already witnessed this. I don't think you're high!

It's hard to tell in the video because of the high idle, but it doesn't sound that bad... If it were a bearing it would be hammering alot more.

This is what my .0035" clearanced JEs sound like after idling for ~5 minutes on a 80* day, idling around 1,050 rpm. After a couple 30 psi pulls, she's almost silent!

https://www.youtube.com/watch?v=zTvu3X2vw7s

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