Lex van Opstal wrote:
>Standard rocker ratio = 1.6. (22,5 : 36)
I guess my approximate measurements were too approx. I saw the 1.6 ratio
later when I looked thru RPI's site.
>Lift of the standard cam is 6.5 mm. (27.5 : 34)
By thos figures, my cam doesn't seem too worn. I hope to be able to
accurately measure it tomorrow. Have you ever tried to stick a magnetic
base dial indicator thingie to a Rover engine 8-). What's odd is that the
cam exhibits the same wear patterns as the worn cam on RPI's site.
>Bent pushrods may be a result of not having the
>preload set as it should be.
As this engine was built by a Rover specialist (John Davis MotorWorks - JDM)
in
about 1989-90 (but see below), I wonder if there could be another cause.
>From the worksheets I have for the car, on 10 Aug 95, "removed heavy Chev
springs and replaced with standard. Supplied and fitted 1 H camshaft with
new genuine lifters". I must admit that I had missed this when I mentioned
the engine had done about 180,000. That means the cam and lifters have done
considerably less. Unfortunately, the printout from JDM only shows the work
done and the date - not the odometer reading. Curses!
On 23 August, "Replaced valve springs" Odd that it was redone two weeks
later.
I thought about valve seat recession (as my engine was converted to runs on
LPG in May 99) but all the Inlet valve stems appear about the same height
(fractionally lower than the exhaust valves).
>Preload is measured with heads and rockers installed.
>The pushrodseat of the lifter should be 1 - 1,5 mm
>beneath the spring of the lifter.
I'll check these tomorrow. I bought new pushrods today.
>When valveseats are recut the valves sit deaper in the
>head and so stick out higher towards the rocker.
One would have expected any pre-load to have been adjusted then.
I'm just not sure what to do next. Do I do the minimum on the engine for
the moment or do I rebuild or do I trade-in the Rangie.
I'm considering a full rebuild of the engine. That would cost about A$5,000
(US$2850) drive in - drive out.
Thanks for the very useful information. Lex. It's much appreciated.
Best regards,
Ron
|