Hello. 96, Z24, LD9, 170.000 miles when disaster hits!
I blew one connecting rod one month ago, so I decided to rebuilt the engine and change clutch. My CrankShaft was bent so I replaced it with an "Used but new" one changing all bearings.
During the initial "Break down" I started hearing the "typical" bearing noise, so I went ahead and removed it again from the car. And found 2 connecting rods bearings worn out. Also I discovered that the balance shaft was 90 degrees out of place.
I installed the same crankshaft with new bearings assuming that the problem was the balanshaft or maybe an overtorque bolt. Arter that, I checked all the oil clearence and endplay having all messurements in the upper middle of the range (according to Chiltons manual).
One week later, the very same noise appears again.
All other clearence were right at the first time I opened the engine. I have new oil pump, new balance shaft sprockets and chain, new timing kit, new balance shaft bearings, new rings, new lifters. All piston and cylinder messurments are OK, as per Chiltons manual.
I,ll take the crankshaft to the shop so they can check "again" de journals diameter.
Any advice?
Thanks.
"My CrankShaft was bent so I replaced it" ....
Please have the block checled for "crankshaft bore trueness" ...
The block could be bent but not cracked, outwardly appearing undamaged ...
did you replace the bearings in the balance shaft assembly? if they are toast, they can take out the rest of the bearings too.
Yeap! I replaced them also and after that checked the oil clearance . Was the same number than the connecting rods bearings clearance.
I really think that the crankshaft is the problem, because both times the worn out bearings came from cil 3 and 4.
I checked "on the fly" the crankshaft bore trueness, turning the cranckshaft with the main bearings installed. It turns perfectly smooth and the main bearings looked like new.
Anyway tomorrow IŽll take the block, caps, crankshaft and the rods to the shop again.
Other question: The sound coming from the engine appear only when cruising between 2500 to 3000 rpm, WITHOUT load. Is that normal with worn bearings?. It is possible that I ALSO have a piston pin problem or something else?. I didnt change pistons because they had the right dimensions and the cylinder didnt show any "ridge". I replaced the rings and checked dimensions.
I mean, the noise started as soon I was brave enough to accelerate the new engine to 3000 rpm, but got stronger with the first 100 miles. So I can assume that it was an abnormal situation from the very beginning, right when the bearing were new and the Plasticgauge said that the clearance was ok. Thats why maybe I have something causing the noise that is also destroying the bearings.
get the block checked to make sure its true......as long as its a bearing noise. can you describe the noise? sometimes a stretched timing chain makes a similar noise when its rattling on the TC cover ata certain rpm. ours did it at 1800rpm only.
Well, I had a stretched timing chain 2 years ago, the noise now is not the same. Also the chain, sprockets and water pump are brand new.
The noise comes from lower part of the engine (because I hear it louder when driving with a wall on the side) and is something like rotating metal parts. A continius metalic wisthle that apperas and-or get louder at 2500-3000 rpm without load. You can make it appear or increase the intensity just relaxing the throtle a litlle while the rpm are at this range. Also, doing static runs, increasing slowly the rpm you start hearing it at 2000 rpm, increasing until 3000 when dissapears, but when you descelerate, between the rpm range, the noise gets worst. Looks like a resonance noise.
Thanks for the help!
