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Author Topic: worn pistonrings??  (Read 4194 times)

Offline danishmkvgti

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worn pistonrings??
« on: May 06, 2010, 07:49:36 pm »
anyone having had this??

Friend of mine might have this problem  :sad1:
Is it "just" new pistonrings or??

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Offline Teutonic_Tamer

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Re: worn pistonrings??
« Reply #1 on: May 07, 2010, 11:28:23 am »
What was the specific diagnosis to confirm this?
Sean - Independant Automotive Engineering Technician (ret'd)
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Offline danishmkvgti

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Re: worn pistonrings??
« Reply #2 on: May 07, 2010, 08:04:27 pm »
Fitted the BSH pcv fix on the car and it ran like s***. when the oil cap were taken off, excess pressure came out that way. We just compression tested it today, cylinder 3 is 0,5 bar lower than the other three. The owner is being informed tomorrow as he's on vacation and had the car in for clutch and BN Autoteknik turbo outlet and discharge pipe while he was away.
I haven't read of others  with the TFSI having experienced this, car has app. 90.000 km on the clock

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Offline Teutonic_Tamer

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Re: worn pistonrings??
« Reply #3 on: May 09, 2010, 07:32:02 pm »
Fitted the BSH pcv fix on the car and it ran like s***. when the oil cap were taken off, excess pressure came out that way. We just compression tested it today, cylinder 3 is 0,5 bar lower than the other three.
A compression test where only ONE cylinder is lower, is NOT usually a sign of worn piston rings.  It is usually indicative of other issues such as a worn valve seat, a seized cam follower, a knackered spark plug.  And whilst half a bar is certainly not ideal, it isn't massive problem.

Did you re-do the compression test after introducing some heavy oil into the bores?
Sean - Independant Automotive Engineering Technician (ret'd)
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07 Golf5 GTI 5dr (BWA), DSG, colour coded, Revo, WALK, WL ARBs, 235 PS2s, seat drawers, OEM tints, custom/hybrid engine mounts, Audi-esque soundproofing

~~ free official Golf V factory workshop manuals ~~

Offline danishmkvgti

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Re: worn pistonrings??
« Reply #4 on: May 09, 2010, 07:37:43 pm »
Fitted the BSH pcv fix on the car and it ran like s***. when the oil cap were taken off, excess pressure came out that way. We just compression tested it today, cylinder 3 is 0,5 bar lower than the other three.
A compression test where only ONE cylinder is lower, is NOT usually a sign of worn piston rings.  It is usually indicative of other issues such as a worn valve seat, a seized cam follower, a knackered spark plug.  And whilst half a bar is certainly not ideal, it isn't massive problem.

Did you re-do the compression test after introducing some heavy oil into the bores?

No, i'm not the tech, i'm informationgatherer, if there's such a word  :grin:
Nope, we/they are getting more accurate comp. testing equipment and then we'll see. Thx for the replies  :drinking:

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Offline Teutonic_Tamer

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Re: worn pistonrings??
« Reply #5 on: May 09, 2010, 07:50:18 pm »
See if you can get the actual compression pressure figures - both on a 'dry' run, then after pouring about 15-20ml of oil down the plughole.

Don't quote me for specifics, but 'normal' compression pressures (for a petrol engine) can be from 180psi to 220psi.  Do any of those manuals in my sticky thread http://www.mk5golfgti.co.uk/forum/index.php/topic,1797.0.html give specific pressures - or maybe a HBOL

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Haynes Book Of Lies - aka a Haynes workshop manual!  :evilgrin:
Sean - Independant Automotive Engineering Technician (ret'd)
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~~ free official Golf V factory workshop manuals ~~

Offline bobsey

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Re: worn pistonrings??
« Reply #6 on: July 20, 2010, 12:20:03 pm »
Fitted the BSH pcv fix on the car and it ran like s***. when the oil cap were taken off, excess pressure came out that way. We just compression tested it today, cylinder 3 is 0,5 bar lower than the other three. The owner is being informed tomorrow as he's on vacation and had the car in for clutch and BN Autoteknik turbo outlet and discharge pipe while he was away.
I haven't read of others  with the TFSI having experienced this, car has app. 90.000 km on the clock


I had this same problem with my ed30 when i fitted a bsh pcv fix, can you describe how the car ran with it fitted so i can compare it too mine?
And did you manage to find out what was wrong with it?

Offline danishmkvgti

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Re: worn pistonrings??
« Reply #7 on: July 20, 2010, 01:52:10 pm »
He had 1 worn pistonring, he took the pcv fix of and will run the car until it get's worse.
Symtoms are difficult to keep rpm's in idle, running badly due to the overpressure underneath the pistons when giving it a bit of rpm's.
 :smiley:

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