Piston Ring Question

[Themadmob]

Hi

How do I know if the cylinder heads have been rebored and if the rings are standard size or oversized ?

Thanks

Craig


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[SafeAirOne]

How do I know if the cylinder heads have been rebored and if the rings are standard size or oversized ?

Hmm...The cylinder HEADS don't have a bore, per-se. The cylinder heads may have been re-surfaced though, which will change their overall thickness, combustion chamber volume and therefore compression ratio of the engine. This page on TeriAnn's site tells you how to measure how much your cylinder heads have been machined: http://www.expeditionlandrover.info/...Q/FAQ_head.htm

If you're asking how to tell if the cylinders have been bored oversize in the engine BLOCK, then it's a simple matter of measuring the diameter of the bores with a bore gauge or with telescoping gauges and a 3-4" range micrometer, then comparing the readings to the factory values found in the Workshop Manual.

The first video just shows a guy using the telescoping gauge so you have an idea of what we're talking about. He's really not using them correctly though, nor is he taking the measurement with a (more accurate) micrometer, but it shows the general process:

[SafeAirOne]

Looks like we can only post ONE video per post so...





The second video shows the use of a dedicated bore gauge:

Note that engines that have had their cylinders bored oversize need matching oversize pistons. In other words, if the cylinders have been bored .020" oversize, they will use matching pistons that are also .020" oversize, along with the corresponding oversize rings. So, if your pistons measure (or are marked) oversized from the measurements given in the Workshop Manual, you can presume that the rings that are on those pistons are similarly matched oversized rings.

[Themadmob]

Thanks guys ... a great help

[Themadmob]

Thanks guys ... A great help

[SafeAirOne]

Thanks guys ... A great help

Thanks guys ... A great help

Huh. I guess there's two of you and two of me.