Friday, Aug 16, 2019 at 19:32
The clearance between the piston pin and bearing is very small, generally less than a thousandth of an inch (0.0254mm).
When this clearance increases to more than that, you start to get "gudgeon knock".
You can get oil sampling done to show if there's an increase in the level of the various metals that make up the engine components.
Doing oil sampling means you can get some warning of engine components that might be failing steadily - and this shows up as elevated levels of the metals comprising those components.
For example, gudgeon/wrist pin/small end bearings, are usually primarily a heavy coating of bronze onto a steel
shell.
The bronze in these bearings is comprised of about 80%-85% copper, 6%-8% lead, and 6%-7.5% tin, along with small amounts of zinc and nickel.
When the bronze starts to wear appreciably, you get increased levels of copper, lead and tin in your engine oil.
You start off with regular engine oil sampling to determine a baseline level for the above metals contamination.
Once that baseline is established, regular oil sampling determines whether the metals contamination is steady or becoming elevated.
An elevated level of the metals indicates that bearing failure is likely in the near future.
Accordingly, the oil is also checked for other bearing and component metals contamination, such as aluminium, chrome, and even silver.
Oil sampling is not cheap, but it is an effective method of monitoring engine wear, and picking up the likelihood of an important component failing, and doing highly destructive damage to your engine.
If the potential component failure is picked up early, it can save you a very substantial amount of money.
The 1HZ engine is a pretty robust, long-lived engine, and I have seen many with 500,000kms on the clock, and still performing O.K.
Cheers, Ron.
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