Connecting Rod Bearings

[biodieselrabbit]

I have been reading posts on this site about performing connecting rod bearing replacement and am trying to undertake this work for my Vibe. As background, I am getting a metallic knocking sound on acceleration. It started out only when the engine/transmission were cold but can now be heard almost all of the time. I took it to a mechanic and they diagnosed it as either lower-end engine noise or the timing chain (and possibly timing chain tensioner). From reading on this site it appears that the connecting rod bearings are the most likely culprits and the symptoms do seem to match mine. viewtopic.php?f=20&t=30525&p=472276&hil ... gs#p472276" onclick="window.open(this.href);return false; by silverbullet. I will probably replace the timing chain tensioner too.

Now to the question. When I called the Toyota dealer about ordering connecting rod bearings they said they need a "mark number" which can only be found on the existing bearings. This would involve opening up the engine, finding the number, ordering the part, waiting several days for it to arrive and then closing the engine back up. I unfortunately don't have the luxury of letting my Vibe sit partially torn down for that long. It would seem to me that the VIN # would uniquely identify everything in the engine (although it is a Pontiac/GM VIN so that may have been the problem) but the Toyota parts guy didn't seem to think so. I would have guessed that all 1ZZ-FE engines of the same model year (i.e. 2003 Vibe/Matrix) would use the same rod bearings. Does anyone have experience with this kind of thing?

[Chiadog]

I am not an expert on crankshaft bearings, but from my understanding, bearing knock means damage to the crank journals as well as the bearings! therefore you MUST at the least inspect and measure the crank before ordering the correct size bearings. And likely the crank itself will need to be machined at an engine shop BEFORE measuring for bearings. You are looking at a lot of down time if you do this yourself.
You mention possibly the cam adjuster making the noise? $30.00 from Toyota, 20 minutes to replace it yourself - So replace this first to rule it out! Good luck.

[biodieselrabbit]

Thanks Chiadog. I agree that damage to the bearings definitely means the journals need to be inspected. From what I have been reading online it seems that these 1ZZ-FE engines use a much softer metal for the bearing (e.g. aluminum, etc.) than the crankshaft or connecting rod journals (i.e. steel) so it is possible for the bearing to be mangled without significant damage to the surrounding components. I am looking for a fix that will get me another 20,000-30,000 miles so I am hoping if it is the bearings, just replacing them with new ones will hold me over for a while. I know this is what joatmon on this site has done at some point.

Yes - I should try the timing chain tensioner first. Just to clarify this is not the same as the serpentine belt tensioner (I already replaced this about a year ago). I just can't believe that this would create the noise I am experiencing under the specific conditions when I hear it. Like you say though, the only way to know for sure is to replace it.

[biodieselrabbit]

Thought I would answer my own question for future genvibers. According to the guy at the Toyota Dealership (different guy than the one I spoke with the first time) there are 3 different mark numbers for a 2003 vibe base. This reflects the fact that the factory sometimes needed to use slightly thicker/thinner connecting rod bearings for each engine to allow for machine tolerance.

Rather than needing to take each old bearing out and measure it individually you can find the mark number for the connecting rod bearings stamped into the connecting rod end cap. These would be visible once you dropped the oil pan.

[455SD]

The 1ZZ-FE uses a "select fit" bearing for the Mains, and a specfic bearing rank for the Connecting Rods. When viewing the Rods, looking at the cap @ large end hole, there will be a number. This is the bearing size that fits the LEH of the CRod (a 1, 2, or 3). There is a letter engraved just above, and this is the machining match mark for the cap and rod. Top number above the letter is for piston pin diameter. The rank that the factory used is stamped on the back of the bearing insert for both the CRod and Main Journals, but as has been stated, if the insert has been damaged, especially if it has spun, you will need to verify actual Pin/Journal diameter, and most likely have to have the crank turned, as surface finish will most likely be compromised. Just installing new inserts on a crankshaft with NG roughness, will lead to early failure of new bearings. If this is the case, a crank kit might be the cheaper method of repair. BE sure to inspect the SEH of the CRod, as wear to the Pin Bushing can causde a similar sound, just a bit lighter in 'knock".
Just out of curiosity, have you tried disconnecting each of the fuel injectors while running? This will tell you whether it is a CRod bearing/piston pin issue, and what cylinder/s are affected. If the knock goes away when a specific cylinder is disabled, you'll know which one to check when you get into the engine. Also, it will help to eliminate the Timing Chain/Tensioner.
Good luck!

[biodieselrabbit]

I have not tried the method of disconnecting the fuel injectors while running. Makes sense though. Someone told me you could also diagnose connecting or wrist pin bearings by turning the crankshaft by hand just past when the piston is at the top of its stroke and pushing down on it using a screwdiver for each cylinder individually. If you hear a "click" or metallic sound that is the piston moving to make up the gap between the connecting rod/crankshaft or at the wrist pin. Unfortunately, I still have not had time to investigate further. Hope to get to it before the holidays.