Piston Ring Gap Positions - 1985 LR90 2.25 Petrol

PK68 · Oct 2, 2023

Afternoon all
I have an early LR90 with a 2.25 petrol 5MB engine. It's RHD. I've had the engine out and stripped down to try and solve a couple of issues and I'm now putting it back together but I've read conflicting things regarding piston ring gap orientation? Can anyone help?
Taking it that the fan is at 6 o'clock and the bulkhead is at 12 o'clock, how should I orientate the ring gaps?
Many thanks.

lynall · Oct 2, 2023

Three rings all gaps 120 deg to each other, four rings 90 deg to each other, they will of course move in service,
In a nutshell dont line them all up!

PK68 · Oct 2, 2023

Cheers for that. I'd read stuff about all on thrust side, all not on thrust side, not inline with Conrod, not inline with gudgeon pin!!!!! I thought it couldn't be that difficult or technical!
Mine have 3 rings - top, middle and oil ring.

lynall · Oct 3, 2023

PK68 said:
Cheers for that. I'd read stuff about all on thrust side, all not on thrust side, not inline with Conrod, not inline with gudgeon pin!!!!! I thought it couldn't be that difficult or technical!
Mine have 3 rings - top, middle and oil ring.

I am sure for certain applications the gap positions are critical, like drag racing etc, but as said the rings will move in use, the only time rings do not move is if they are pegged, like some old 2 stroke engines, and that is purely to stop the ring ends lining up with the ports and getting smashed to bits.
If the oil ring is 3 piece then don't line the gaps up on that either.

Piston Ring Gap Positions - 1985 LR90 2.25 Petrol

PK68

Member

lynall

Well-Known Member

PK68

Member

lynall

Well-Known Member

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