Will an Oil Analysis Identify a Rod Bearing Issue?

[Rockledge]

Hi all,

I've been reading the recent posts about SHO rod bearings and realize it's kind of difficult to figure out when they might be going bad.

I was wondering if it would be worth it as a preventive measure to send a couple of oil samples to a lab to have them analyzed?

If someone posted the results of a couple of oil analyses from Blackstone Labs (for example), would that help identify a potential problem with their SHO's rod bearings?

My SHO is running fine but it does have 138K on it now, so I have to think about these things.

Any comments or opinions would be welcome.

<small>[ October 06, 2003, 06:50 PM: Message edited by: Rockledge ]</small>

 

[shojuan]

Just my $.01. Almost worthless because I have never had an oil analysis performed...but here goes. Oil analysis is expensive. For the $20 you spend on an analysis you would be well on your way towards the parts to do a rod bearing replacement. Rod bearing replacement on the SHO is so well documented that as long as time isn't money to you 7 days a week and you can spend a day with some basic hand tools on a free Saturday or Sunday afternoon then you might consider just going ahead an doing it if you're that worried about it. If time really IS money to you on those days than surely you can afford to just pay some SHO enthusiast in your area to replace the rod bearings for you. It just seems a shame to use the indirect means of oil analysis to guess at bearing where when you can take a looksee directly by dropping the easily accessible oil pan. And once you're in there you might as well replace the damn things...only an extra $50 in parts at that point.

 

[haydenm315]

Oil analysis can determine if there's engine wear due to high metal content in the oil. I don't know how it can determine which bearing it's coming from. You can take a stethoscope and place it against the oil pan while running. If you dont' hear a whole lot, you should be ok. 138k is a good time to do it. Some can go longer and get away with it. I'm in the process of doing mine on a car that's tach reads 98.5k. Copper is showing on all of the top bearings and one set is showing copper and oil burn marks. Everything is still within spec and I don't need more than the standard size clevite bearings that I purchased from NAPA.

I say go ahead and do it yourself. Parts and materials shouldn't run you over $100. I wonder how much it costs for a shop to do?

 

[Rockledge]

shojuan,

I appreciate your prompt and straightforward reply. I agree with your reasoning regarding the time involved and the benefit that can be derived from simply pulling the pan and doing the bearing job.

FWIW, I bought my SHO knowing and intending that I would be spending some of my time on it, so I'm not really asking the question from that perspective. What inspired my question was reading BobL's post about pulling his pan and finding metal particles at the bottom, and then going on to find the bad bearings that he described. Reading that leads me to believe that at least some of that metalic stuff had to be floating around in Bob's oil, wouldn't you agree?

 

[haydenm315]

Rockledge
What inspired my question was reading BobL's post about pulling his pan and finding metal particles at the bottom, and then going on to find the bad bearings that he described. Reading that leads me to believe that at least some of that metalic stuff had to be floating around in Bob's oil, wouldn't you agree? [/QB]

I dont' think the metal would float around in the engine for a long time. Soon as it hits the oil pan, it will never be circulated again because of the oil pickup tube and the strainer is sucks oil through. That's why you can get away with things on the bottom of your oil pan. Maybe the metallic stuff got stuck in between the bearing and journal for a little while. Maybe that material is from the bearing?

Both bob and I have "wiped" 6th cylinder bearings. I think his are worse than mine, because of the texture. Mine are smooth while his is rough. Is the condition of the bearings directdly related to their location. Cylinder 6 is furthest away from the oil pump. When lugging occurs and the pump is pumping enough oil through the engine will they all suffer the same amount or does it get progressively worse as you go down the line. I messed up the order of my other 5 bearings, but I think wear got more pronounced as I continued onward down the line.

 

[yamahaSHO]

Yes, an oil analysis could tell you what kind of bearings can/are going bad. Yes, residue of what every metal thats being worn away WILL circulate through your oil(very small particles).

This is how they test to see what bearings are going bad on F-16's and other airplanes as well(much harder to pull the engine on these)... They take oil samples, burn them and then analyze them.

I see no reason why you could not get the analysis done... It would not be a waste of money... you would be able to find out more information than just your rod bearings.

 

[Mr Anonymous]

The real benefit of oil analysis comes in trending -- taking periodic samples and comparing them for trends in normal/abnormal engine wear.

Certainly if the wear is bad enough it should show up in a one-time analysis, but I also wouldn't take great comfort in a single good analysis report; I'd want to see how it looks over time.

Considering your mileage, I don't know that I'd want to wait for 3-4 reports (~10000-15000 more miles) at $20 a pop to determine if damage is being done. Another thing to consider is how many of those miles you've put on, and the overall maintenance history of the car. If you do the work yourself, you can replace the rod bearings in an afternoon or so and for under $100 in parts. Or, you could take it to Fred H. at NESS and have it done for you professionally for $450.

IIWM, at 138K I'd skip the analysis and replace the bearings. It's an ounce of prevention pound of cure thing to me.

 

[haydenm315]

yamahaSHO
Yes, an oil analysis could tell you what kind of bearings can/are going bad. Yes, residue of what every metal thats being worn away WILL circulate through your oil(very small particles).

But what if all of the bearings are made of the same metal? So, if there's a large amount of copper moving around in your oil, you're in bad shape?

This is how they test to see what bearings are going bad on F-16's and other airplanes as well(much harder to pull the engine on these)... They take oil samples, burn them and then analyze them.

Sounds like a pretty good way of determining if metal is wearing away inside the motor.

 

[gosho89]

SHOooo:
The real benefit of oil analysis comes in trending -- taking periodic samples and comparing them for trends in normal/abnormal engine wear.

Certainly if the wear is bad enough it should show up in a one-time analysis, but I also wouldn't take great comfort in a single good analysis report; I'd want to see how it looks over time.

Considering your mileage, I don't know that I'd want to wait for 3-4 reports (~10000-15000 more miles) at $20 a pop to determine if damage is being done. Another thing to consider is how many of those miles you've put on, and the overall maintenance history of the car. If you do the work yourself, you can replace the rod bearings in an afternoon or so and for under $100 in parts. Or, you could take it to Fred H. at NESS and have it done for you professionally for $450.

IIWM, at 138K I'd skip the analysis and replace the bearings. It's an ounce of prevention pound of cure thing to me.

SHOooo,
I agree with your answers both on the oil sampling and bearing replacement at 138k. I work at a Caterpillar Dealership were we sell the importance of Schedule Oil Sampling (SOS) for million dollar machines. Trend oil analysis is most beneficial, it can spot a problem well before a failure accures. Even though none of my cars are worth a million dollars I still run SOS samples on all my personal vehicles at every other oil change. I recently replaced my rod bearings in my SHO at about 136k, the analysis never showed a problem but since I was resealing the oil pan I thought I would take a look. Once I observed the bearing wear I decided it was time, especialy the top bearings.

I vote for change the Bearings X

<small>[ October 08, 2003, 09:48 PM: Message edited by: gosho89 ]</small>

 

[billyshoe]

An oil survey will tell you whats wearing out by giving you readings of the metallic content of the oil sample. If you own a 89'year model with 161,000 rounds on it, it is safe to say it is down hill to the end. The cost of oil analysis will cover the cost of bearings if your crafty enough to install them properly. Piston rings is the problem that we old sho owners will dred. The heads are good if they are quiet.