noisy all of a sudden

[zooky]

I just installed a fresh rebuilt 1.6td and fired it up for the first time (well second, first time was less then 1 minute). I let it idle for 1/2 hour, it sounded perfect and was pretty quiet. After the 1/2 hour I started playing with the throttle, it sounded good and returned to idle and was fine. Next, I floored it for about 8-10 seconds and it made a sound like it was misfiring. I got off the gas and it returned to idle, it still idles smooth but now makes a loud rattling noise. What the heck happened? I popped off the valve cover, everything is fine there. I checked the timing and everything is still the same. I am going to have to dig deeper. Any ideas what to look for?? This sucks.

EDIT:
-EGT never got over 300-350
-oil pressure was normal
-engine never got hot enough to turn on fan
-all IP settings were set where Giles set them
-rebuild got all new rings, bearings, valves

[SMOKEYDUB]

when you had it at wide open throttle was it under load or were you revving it in neutral? if you were revving it in neutral you more then likely wipped out some bearings or something.

[zooky]

when you had it at wide open throttle was it under load or were you revving it in neutral? if you were revving it in neutral you more then likely wipped out some bearings or something.

neutral. Think I overreved it?

[saurkraut]

I just did a full rebuild on a 1.6td.  I started it up and put a brick on the accelerator and let 'er rip for: one thousand, one thousand two, one thousand three, one thousand four, one thousand five, one thousand six, one thousand seven, one thousand eight, one thousand nine, one thousand ten............

Sweet chocolate Moses on a Ritz cracker, I’m in shock!

[Powjetta]

When I replaced my head gasket I had a loud noise after driving for 8 miles or so.  I stopped and opened the hood because I was sure it was major damage, but nothing showed up.  After awhile I started it back up and it was quieter and eventually went away.  I don't know if it was some kind of injector knock or God's divine intervention but it hasn't come back after 10K miles.  I say keep driving it.
Dave

[zooky]

I have a Giles pump so the govenor mod is done, those revs were waaay up there, if that makes a difference.
I will be dropping the oil pan this weekend to look at the bearings then go from there...

[AdAm84]

might sound dumb, but check your motor mounts. mine started making crazy vibrations last week. we popped the hood, pulled the e-brake, put it in gear, slowly let out the clutch and watched the motor mount. it moved like a 1/2 inch or more!

[zooky]

OK, dropped the pan and checked the bearings. Main bearings are fine. The only thing I found is an indication that the #2 rod bearing spun. The bearing is still in new looking condition but the little tab that sits in that slot is flattened. I am happy I found something but the bearing is still "good" so would losing oil pressure to that bearing cause that noise before the bearing got wiped out? I have to get some new bearings before I can reassemble the bottom end and try it out, its going to drive me nuts in the meantime

[Powjetta]

it shouldn't make noise if there's no room to wiggle.  Check with plastiguage before putting it back together.

[jtanguay]

mmmm rattling noise you say... mine has some weird noise from 1000-1800 rpm.  sounds like something is bouncing around in my valve cover... i dont really care though because it runs good enough for me!  :lol:

[anarchyx34]

Next, I floored it for about 8-10 seconds...

Why would you do that?

[jtanguay]

Next, I floored it for about 8-10 seconds...

Why would you do that?

try and help seat the rings... best bet though is to get that compound that hillfolk'r was talking about from totalseal.  ring land lube or something.  supposedly it does a superb job!  :wink:

i don't really know if i would 'floor' a freshly rebuilt motor though... but i would definitely give it a few good blips on the throttle and let her idle at around 3000rpm.  Does the bentley say to hold wot @ 8-10 seconds???

[Doug]

The faster you load a new engine the better the rings will seat. Racing engines get frequent top end jobs. Do they spend two or three thousand miles breaking them in easy? I don't think so! It is WFO throttle as soon as the wheels hit the track. What better way to prove the work as well as get those rings seated so the compression is maxed and the blowby is minimal. Don't believe the nonsense that gets repeated since day one about break in procedure. It was written by the lawyers that wanted no liability on warranty not the engineers that built the damn engine!

[zooky]

it wasnt 8-10 seconds, maybe more like 4-5.
 I got it all back together, its about 80% better. I only ran it in the garage, it might get 20% better once I get it outside where the sound is not bouncing off the walls. It sounds 'dieslier' now than before. I havent brought it up to temp yet, its blowing a little white smoke. I havent made any adjustments yet either, not quite sure where to begin. I am going to play with it more tomorrow if I dont have to work...

[jtanguay]

it wasnt 8-10 seconds, maybe more like 4-5.
 I got it all back together, its about 80% better. I only ran it in the garage, it might get 20% better once I get it outside where the sound is not bouncing off the walls. It sounds 'dieslier' now than before. I havent brought it up to temp yet, its blowing a little white smoke. I havent made any adjustments yet either, not quite sure where to begin. I am going to play with it more tomorrow if I dont have to work...

did you have the injectors rebuilt? maybe that is causing the white smoke...  or maybe did you overfill the oil? i know my stupid dipstick isnt the proper one... because i've put in 5L of oil before and it didnt even reach the full mark  :shock:  didn't take too long to burn off the excess oil though... too much oil is bad!!!