Oil analysis on rebuilt engine

[Sheepdog]

Hello. I hope this is the correct place for this post. Please advise if it is not.

How long after rebuilding an engine should you wait before doing an oil sample? Are there any guidelines? I would expect that new cam, pistons, rings bored cylinders, etc would cause abnormally high readings.

Does anyone have experience with this?

Thanks, Eric

 

[427Z06]

How about a few more details like, did you rebuild it, or did you buy a rebuilt engine and swapped the accessories? What make/model?

 

[Quest]

at least past 6000miles with at least 1 more more oil changes before everything starting to settle down and seats in comfortably.

You may still get elevated silicon or iron readings (silicon coming from RTV silicone sealant and iron from ring, cylinder wall and cam wear).

 

[Sheepdog]

Sorry. Yes, I did rebuild it. It is a 454 Chevy in a boat.

I know it has to break in and I was planning on changing the oil at 20 hours.

I was just wondering if anyone had done an oil analysis this early and what the results were. It would not make sense to me to do it right now, because wear metals would be higher than normal I think.

I have always heard that engines wear in and you should not do an oil sample early, but had no documentation stating this. I searhed but could not find any either. That is how I found this site so figured I would ask the question here.

I work on boats and some people hold oil samples up as the holy grail. I tend to believe that they are just a tool to monitor your engine and are only worthwhile if done at each oil change so that you can monitor changes in an engine. An abnormally high reading on a new engine that runs well is not of much concern. I would think it should be rechecked, but not until the oil is changed after the first 20 hours it is run and then about 5 hours after this. Does that make sense?

Has anyone done an analysis on a new or rebuilt engine on it's first dose of oil? Were readings higher than subsequent oil samples?

Thanks. Eric

 

[Gary Allan]

Eric, a few have done used oil analysis on new or rebuilt engines. As you figured, the metals are way high due to machining/manufacturing left overs.

The main thing that you can figure out ..is if you screwed up and are shedding stuff way out of proportion with what you would expect ..or if you're leaking coolant into the oil and stuff.

It allows you to see how the metals decline with time. It's not essential ..but when are you going to start, when the thing is 1/3 toward your next refresh? If you've never done a used oil analysis before the rebuild ..you don't even know what to expect as "normal"

I'd go a few oil changes to remove any leftovers. From there on out it should just be stuff getting intimate with each other.

 

[427Z06]

There should be quite a few used oil analysis of major manfacturer's new engines in new cars if you think your rebuilding procedures are comparable.

 

[Oil Changer]

I favor doing one right away. Assuming it is carburated, it'll tell you if you're too rich plus what the others said about antifreeze and such. You are already aware that the numbers will be skewed a bit so use this first sample as a baseline and a little piece of mind knowing there is no coolant leaks and such. It's only $20.

 

[Sheepdog]

Thanks for the input. We actually did do one right away, I should have the paperwork today. I rebuilt both engines, they were bored oversize, one new crank, new oil cooler, all new pistons rings, bearings, cams, lifters, timing chains, oil pumps and screens.

All I know as of now is that the some readings are high, but both engines are nearly identical. The guy was freaking out a little.

The advise I gave him first of all was to put twenty hours on the engines at which point I would change the oil again, normal procedure I would think. I would wait about 5 more hours with the new oil in and then do a used oil analysis on each engine to have as a baseline.

These engines run fine. I think the owner's "expert friend" talked him into doing the used oil analysis as a baseline, which is fine, just a little too early.

These engines have less than four hours on them and are loaded with engine assembly lube and white lithium grease, lus I am sure there is outgasing of the RTV used as long as residual traces of cleaners used to clean parts for assembly. I am quite sure that the rings may not even be fully seated yet. I am also not sure how long it takes for a hydraulic cam and lifter to wear in. I am sure there will be an increase of metals just from these parts breaking in and then other higher solids from the chemicals mentioned above.

I am not that concerned about the samples as I was on the boat for the first two hours and then went back and went over the engines to be sure everything was fine. I did these engines with a two year warranty, so I am concerned if there is a problem. I don't think there is, but the oil samples are causing some concern for the owner. I was just looking for some guidelines on when used oil analysis should be started. I want the customer to feel at ease also.

The boat is now stored for the winter and will not be run again until next spring. I searched a lot of oil analysis sites for their oil testing guidelines, but could not find anything mentioning when not to do an oil anlysis or how long to wait to start doing them.

I am just trying to educate myself on how to deal with these type of things in the future.

Thanks again,

Eric