The Built Motor Failure Thread

[AudiA4_20T]

Hey everyone, in the wake of just about every single built motor I have seen fail in some way... I figured we could use this group to give future 2.0 people good advice about what to do and what not to do when building the motor

What I liked about my build:

- The pistons, rods, crank bearings, AEG crank

What I didnt like/made the scoring on the walls:

- I didnt get skirt coating on the pistons (may have helped)
- Didnt get coated rod bearings (did the second time around)
- Wasted money on a new oil pump (never seen a failed one)
- Used a shitty ring filer which I believe is the cause for the first problem
- Didn't coat the cylinder walls with ATF for the first crank
- Could have used a better honing tool (got it now)

[Wizard-of-OD]

Ok Ok...am I seeing you today!?

[AudiA4_20T]

Ok Ok...am I seeing you today!?

lol are you? Feel free to stop by I live near Englishtown, if not today than tomorrow

[A4TL]

would have cost less to have a (engine machine)shop build the motor in the first place?

[absolutegtr]

How much is a new oil pump? I would think buying a new one, while the whole motor is a pump is like cheap insurance...

[Grenade]

This is one of the reasons that I do leave some of the things up to the professionals. This cant be scary.

[BARRY]

Hey everyone, in the wake of just about every single built motor I have seen fail in some way... I figured we could use this group to give future 2.0 people good advice about what to do and what not to do when building the motor

What I liked about my build:

- The pistons, rods, crank bearings, AEG crank

What I didnt like/made the scoring on the walls:

- I didnt get skirt coating on the pistons (may have helped)
- Didnt get coated rod bearings (did the second time around)
- Wasted money on a new oil pump (never seen a failed one)
- Used a shitty ring filer which I believe is the cause for the first problem
- Didn't coat the cylinder walls with ATF for the first crank
- Could have used a better honing tool (got it now)

scoring is caused by incorrect clearances, and/or bad tune.

[AudiA4_20T]

scoring is caused by incorrect clearances, and/or bad tune.

hmmm, is that so... Incorrect clearances in what? the rings?

[B6Lovin]

bad tunes can cause scoring?

i'm not questioning you, just curious how.

and i hope i don't have to post up about my motor in here....

[RLB6]

hmmm, is that so... Incorrect clearances in what? the rings?

Incorrect clearances between the cylinder bore and piston. All aluminum piston expands and contract. Forged pistons expand and contract more than cast pistons of the exact diameter do due the process in which the pistons are produced. Because of this the cylinder bore has to have enough clearance in order to take into account for this diameter change with the pistons. This is very important as the piston to wall clearance has to be pretty much within spec. The clearance will vary from cast to forged pistons. Forged pistons will require more clearance than a cast piston because as stated before, forged pistons expand and contract more than a cast piston of the same diameter. Too tight of a clearance will cause scoring and in a worst case scenario, cease the piston within the cylinder bore. Too much clearance will not only cause excessive piston slap and score the walls, this will also cause the cylinder bore to prematurely "cone".

"Cone" is when the diameter of the top of the cylinder bore is larger than the bottom of the cylinder bore, therefore, causing the bore to take on a "cone" shape.

After building so many motors over the past decade, I've seen my fair share of this.

[F16HTON]

You guys are soooo way out of your leauge here....

Of course a bad tune can cause scoring....if you are too rich or too lean, you will see excessive EGTs, spark plug electrodes melt, fall into the cylinder and fuck up the walls...

Excessive EGTs also cause the pistons to expand, ring lands to break off and rings to fail too...

The tune is the key to longevity, stronger parts do dick for you if not used properly.

[RLB6]

Of course a bad tune can cause scoring....if you are too rich or too lean, you will see excessive EGTs, spark plug electrodes melt, fall into the cylinder and fuck up the walls...

Excessive EGTs also cause the pistons to expand, ring lands to break off and rings to fail too...

This has happened to me more than once.

The tune is the key to longevity, stronger parts do dick for you if not used properly.

Amen!!

[PRY4SNO]

...if you are too rich or too lean, you will see excessive EGTs, spark plug electrodes melt, fall into the cylinder and fuck up the walls...

Okay, for the BT/BAT n00bs, can you explain how an overage of both conditions cause the same end result? I.E. Lean = seize & rich = seize... seems like you're damned if you do or you're damned if you don't!!!

[Condo]

Is it possible for the thick carbon deposits on the tops of my pistons to break off and cause scoring between the piston and cylinder wall?

[Don Supreme]

This is one of the reasons that I do leave some of the things up to the professionals. This cant be scary.

Trust me, the "Pros" fuck up too, and most times they leave you with the bill.

[B6Lovin]

You guys are soooo way out of your leauge here....

Of course a bad tune can cause scoring....if you are too rich or too lean, you will see excessive EGTs, spark plug electrodes melt, fall into the cylinder and fuck up the walls...

Excessive EGTs also cause the pistons to expand, ring lands to break off and rings to fail too...

The tune is the key to longevity, stronger parts do dick for you if not used properly.

ohhhhh ok. i guess that idea was just way off base for me to figure out on my own. makes perfect sense now though. the spark plug thing is something i never would have considered - the expanding piston thing also didn't cross my mind... but in this case i think that seems a lot more logical (for clint and john's problems anyways)

i've heard that forged pistons aren't good for daily driving before, due to wearing out the cylinder walls sooner.. i guess these things are partially to blame for that, and also human error with installation.

thanks for the lesson in internals i think that last part needs to be quoted somewhere on the main page where everyone can see it

[BARRY]

You guys are soooo way out of your leauge here....

Of course a bad tune can cause scoring....if you are too rich or too lean, you will see excessive EGTs, spark plug electrodes melt, fall into the cylinder and fuck up the walls...

Excessive EGTs also cause the pistons to expand, ring lands to break off and rings to fail too...

The tune is the key to longevity, stronger parts do dick for you if not used properly.

what does that mean? i said incorrect clearances or bad tune...

[F16HTON]

Okay, for the BT/BAT n00bs, can you explain how an overage of both conditions cause the same end result? I.E. Lean = seize & rich = seize... seems like you're damned if you do or you're damned if you don't!!!

Exactly, this is why you do not fuck around with hardware changes without having you tune in check...

All you have to is read the MKIV section of VW Vortex...the B6 Forum is beginning to look quite a bit like it lately.

I am not talking shit about AZ members, however you cannot just bolt parts onto a motor and expect good shit to happen.

It seems all to much lately that everyone is taking this approach...

1.) I am going to built my motor to 2.0L because it will never break.

2.) I am going to bolt a big giant turbo to it so I can make tons of power.

3.) I am going to drive it around and break it in.

4.) I am out of $$ right now, in a few months I am going to get a custom tune

5.) Shit, I have to take my car to the tuners???? I cannot afford to take time off of work or school, I will just drive it like this for awhile.

6.) Oh shit, I just fucked up my motor.

[A4 TSCHUSS]

lol. I didnt really understand the driving the car around doing decelerations and what not for hundreds of miles either that seems to be a trend right now for break in. A few miles will suffice.

I work on boats and new engines we just leave at the dock running in gear at idle for a little bit then go hammer on it. Have NEVER had a problem. Also when rebuilding my dirt bike and 4 wheelers I put the piston and rings in, run it easy for a few minutes then beat the shit out of it, once again, NEVER had a problem. The rings are gonna seat in the first few minutes of running the engine.

[absolutegtr]

I'm with david in this one. Every motor I have ever broke in, I have:

1) Changed the oil and FILTER after the first initial crank up (and when I have had to break in a cam). And then changed the oil and FILTER after 20 miles, 50 miles, 100 miles, 250 miles, 500 miles, 1000 miles and then every 3,000 miles.
2) Drive the car fairly easily for the first ~200 miles, but still applying load onto the engine.
3) And after about ~500 miles, drive the car like I plan on driving it, with full load on the engine.

You have to seat those rings in!

[F16HTON]

I broke my motor in for about 40 miles, then I went big turbo. I drove it around for the entire day out of boost and did logging at about 9PM (to make sure there were no leaks).

Car has not been babied since. Boost seats rings...N/A cars need to seat the rings.

[dougyfresh]

I'm with david in this one. Every motor I have ever broke in, I have:

1) Changed the oil and FILTER after the first initial crank up (and when I have had to break in a cam). And then changed the oil and FILTER after 20 miles, 50 miles, 100 miles, 250 miles, 500 miles, 1000 miles and then every 3,000 miles.
2) Drive the car fairly easily for the first ~200 miles, but still applying load onto the engine.
3) And after about ~500 miles, drive the car like I plan on driving it, with full load on the engine.

You have to seat those rings in!

Exactly what I have done. The first 30miles were critical. The first 30miles was accel/decels to break the rings in. From 30-300 I've been pretty conservative with how I'm driving the car. 300+ I'm driving it normally which includes some hard driving. The first 300miles I logged every mile to make sure everything was in check and things seemed to look good. I even pulled timing out via lemmiwinks just so the car ran safer (I didn't like a few things in the logs prior to pulling timing).

I am at 700miles and have yet to bump the boost up beyond 11psi. Why? I haven't had the time to log with an eagle eye while I fiddle with boost levels. As a result I have left it at 11psi since I know the car runs fine like this. There's no rush. It'll get done when it'll get done.

[cuco33]

I don't check in here as much as i used to but clint.. your motor's done?

I won't be at WF, my boy is getting married

[Audi Skate Snow]

I put about a whole 40 miles on my car when building new motor and then beat the shit out of it... like David and greg said, rings set really quick, and never break in a lazy motor.

also for clearence a good rule of thumb is for every inch of bore have .001 of clearence... minimum on forged piston ususaly is .0045 for expansion.

[dirtybrd]

Where's this new car you're getting?

[Grenade]

Trust me, the "Pros" fuck up too, and most times they leave you with the bill.

I dont think your dealing with the correct pro's then.

[A4TL]

you know too rich is nasty because it is unstable:
1. too rich ends up misfiring which hurts the balance of the motor
2. too rich fouls the oil with gas which is a horrible lubricant

too rich is unstable because there is a point at which too rich will light off and you will have too much fire (AKA EGT's) or too rich will lite off in the exhaust manifold and your non-race turbo will take the punishment.

so its a fine delicate balance of too lean and too rich. why don't you put 4 egt k-probes in each exhaust runner? then you can measure all 4 cylinders for inequalities.

[317ssayzarc]

Of course a bad tune can cause scoring....if you are too rich or too lean, you will see excessive EGTs, spark plug electrodes melt, fall into the cylinder and fuck up the walls... Happened to me lol

The tune is the key to longevity, stronger parts do dick for you if not used properly. That is the complete truth

..

[CO AVANT]

First 20 miles are the most critical. I floored it from 2000-5000, then decel from 5000-2000 a bunch of times with ~10psi (wastegate).

Cause of my first 2.0 failure was piston tolerances too great, and not enough clearance for the rod bearing which caused it to spin. A torque plate was not used when boring out the cylinders (AMS in Fort Collins). This last build I sent my motor to someone who knows what the hell they are doing. Bob@QEDpower. I have seen oil pumps fail up here on the B6. I do not think that is a waste of money, just an investment.

IMO people need to log and keep an eye on vag blocks for the first 2000 miles of a 2.0L build, and under the most extreme conditions. I think they say they do but most don't log 90% of the time (I do). I never leave my house without my laptop anymore. I am making sure nothing goes wrong this time around. It can still happen, but with the $$ I've spent I'm taking every precaution. Good thing to as I've had to lower and lower timing advance as I've put on the miles. Running stronger and stronger each time. Now have 2000+ miles and finally switched back to synthetic 300V 5W40.

I'm sure everyone has read this site but here it is again...
http://www.mototuneusa.com/break_in_secrets.htm

[Wizard-of-OD]

I have seen oil pumps fail up here on the B6.

Not to be a critic but show me...

[CO AVANT]

Not to be a critic but show me...

what do I have them in my hand? hahaha, I don't do this shit for a living, but two of my good friends are certified audi mechanics and have shown me. Oil sludge burns them up and they lose pressure. He said many too not just the couple he has showed me for what its worth. (*High elevation where I live*)

[Don Supreme]

I dont think your dealing with the correct pro's then.

HA! - No one is perfect buddy; people make mistakes.

[Wizard-of-OD]

what do I have them in my hand? hahaha, I don't do this shit for a living, but two of my good friends are certified audi mechanics and have shown me. Oil sludge burns them up and they lose pressure. He said many too not just the couple he has showed me for what its worth. (*High elevation where I live*)

The pickup gets clogged...the oil pump does not *fail*.

Not to sound like an ass but being certified does not mean anything to me (I am one as is my father).

In all my years of repairing VW/Audi I have yet to see a failed pump.Let it sit in diesel over night and watch it come back like new.They are faily simple to service.

[CO AVANT]

uhh, I understand the pickup tube gets clogged, I didn't start doing this shit yesterday you know....just soak em in solution to get them unclogged. I'm just relaying what these guys are saying, didn't mean to piss in your wheaties. They said nothing about soaking the pump in diesel so I'm not sure if that would fix all the ones they are talking about or not. These 2 guys I talk about know their shit trust me, best 2 audi mechs in the state. A combined 35 years experience will do that. I should not have to defend them to you, no offense...
One actually just a year ago purchased a standalone program from your company for his custom Audi I5 turbo sand rail.

[A4ringedONE8T]

I have heard of a few oil pumps failing as well from a few techs I know at the dealer. Any type of impeller driven pump can fail/lose pressure if the intake is obscured or blocked. I do believe I may have lost oil pressure for a short time causing my motor problems. I dont think Clint intended for this to be a pissing match for anyone so Issam lets keep it to the topic

[dirtybrd]

The pump will fail if starved for oil, but not likely if not lubed.