old design was oilheads-digest V1 #47

["Clive Liddell" <cliddell@xxxxxxxxxx>]

Robert,
For simplicity and reliability the oilhead engine fits my requirements
perfectly.  There is a reason that "bucket and shim" are only checked
infrequently, if at all and that IMO is the hassel factor.  They also give
quite wide "tolerances" (which I doubt many DIY Beemer'ists would be happy
to live with) for the same reason, I suspect.   I am looking at the specs
for my son's Yamaha R6 (on page 2 of 6 just for adjusting valve clerance)
and I note: Intake valve 0.11~0.20 and Exhaust valve 0.21~0.30  Wow! we
argue here for weeks about whether the guage should be knife through butter
or tighter or looser or whatever!

I know the word "pushrod" conjures up at least a 10" long thin, hollow weak
looking component of yesteryear...  In our oilheads these rods are barely 1"
long and serve to transmit a thrust and change of direction very efficiently
and allows the cams to run in small pools of oil under them = instant lube
as engine turns over.   Not to mention easy clearance adjustment (I have had
to adjust a couple of exhaust valves a fraction of a turn in 40000km)

The bucket and shim and similar designs end up putting side thrust on the
valve stem itself, with obvious ill effect.   Also, once having measured all
the clearances, and referred to the tables for the correction shim in each
position then you have to dismantle and remove the camshaft to actually
change them.   I do not like to disturb torqued components like cam bearings
etc - Oh don't forget to check all clearances after replacing and
re-torquing camshaft and so on....

The only thing I've had to change on my present water cooled car is the
water pump (not a low cost item on Mercedes) and since you have a K you are
well aware of the water/oil problems in the pump area there...

If BMW are eventually obliged to drop air cooling then so be it but I do not
intend to ever change from my present oilheads (never and ever are not too
remote since I'm well on the way to three score and ten years :)

Regards
Clive Liddell
Pietermaritzburg, South Africa.
'96 R850R   70k.km
'01 R1100RT 40k.km

- ----- Original Message -----
From: <rennsport@xxxxxxxxx>
To: <oilheads@xxxxxxxxx>
Sent: Monday, January 05, 2004 4:37 AM
Subject: Re: oilheads-digest V1 #47


> On Sunday, Jan 4, 2004, at 16:40 US/Eastern, BAnder6125@xxxxxxx wrote:
> >
> snip.
>
> > My Toyota MR 2 Spyder uses iridium plugs with coil on plug ignition,
> > DOHC
> > with bucket and shim valve adjustment and the 1st check  of valve
> > clearance is
> > at
> > 60K mi. Don't understand why BMW can't be a little more up to date.
> >
>
> Your MR 2 is water cooled. Your R11RS is air/oilcooled and wider temp
> swings than the MR 2. Because of this it will simply need more frequent
> valve adjustments. Also the  oilhead uses pushrods not overhead cams as
> the MR 2 does.
>
> For BMW to get with he times they would have to use an overhead cam
> design on the oilhead and for optimum performance and reliability they
> would have to use a water-cooled engine.
>
>
> Robert
>
> 95 R11RS
> 88 KRS Special

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