R26S ???

[Garnet Grylls]

Hello!

I am getting ready to do some work on my 1957 R26 engine. I have a 59 crankshaft to replace the one that is in there now. Hopefully that will help most of the bad vibrations.

I am thinking of useing a R50S piston and advancing the camshaft to R27 specifacation.  Will this be OK for dailey driving or will it give more vibration again?  Is there any other way to get more performance safely?

I will use the MZ-B ignition system. I have it on my R60/2 and like it a lot.

[Garnet Grylls]

[Rütz]

Hi,

i have this (R26 Crankshaft and R50S Piston) in my R27. Therefore i can't say much about the vibrations, which don't bother on R27.

You may use the search funktion of this forum with "tuning kolben".
There are several threads about this S-pistons.

At least the NoName/ Aftermarket (?) R50S Pistons are under the very suspicion to produce piston-seizure and vibration.

I recommend to afford this piston from an original manufaturer (KolbenSchmidt, Nüral,...).
Today you can get new KS-Pistons again through BMW itself (at least in germany...), though not cheap.

Greetings
Anselm

[Garnet Grylls]

Thank you for the info. My German translation is not so good. Did anyone dicover the cause of the seizing problems? Is there enough power increase to make the touble OK? I can go 80-90 kph easy and max just over 100.
Thanks
Garnet

[Rütz]

R27-Valve Timing means more torque at 6.000 rev's, but less at 5.000:
You can (must) rev the engine higher in the lower gears,
i.e. 60-70 km/h in 2nd or 90-100 in 3rd gear. That will improve acceleration.
It has no effect in the 4th, unless you have the shorter rear drive gear of the later R27 (6:27).

Together with the S-piston you will get the normal perfomance of the early R27, i think:
100 km/h very easy and max. 110 (115)
But acceleration above 100 is quite "small" and inconstant, 'couse 4th gear now is too "long". To improve that, they developed the shorter rear drive gear for the later R27.

Did anyone dicover the cause of the seizing problems?

No.., maybe wrong alloy, which grows to much becomming hot.

So long
Anselm

[Garnet Grylls]

Hi!
Thank you for thr reply. Very goof information. I did not know about the later R27 gearing.

I did some more translation of the "tuning kolben" threads and learned more there as well. I am also going to look at modifying my cylinder for better oiling.

Greetings
Garnet

[sjeuf12]

Hi Garnet,
on cylinder oil modifications you could perhaps do something like Richard Scheckeler described a year or so ago on the yahoo-mono-listserver

On the R26 cylinder-foot he added a small groove and a he drilled a second hole in the cylinderfoot, 180 deg apart from the original one.
This doubles the lubing of the piston, thus reducing heat and seizing problems.
The second picture is showing the original crank casing with the original oil channel.
This was first applied on the R26, with only one oil channel in the cylinder
The R25 and earlier do not have this oil channel
I believe the R27 has the dual channel (standard in the cylinder) as described as modification for the R26

I think you can do that (and I did also) provided your oil pump is in splendid working order.
By doing this you risk that the upper section of the cylinder (valves and tumblers) don't get enough oil if your pump is weak.

Have added Richard's pictures and will add a picture of what I did in a follow-up mail
In another follow-up mail I will add some pictures on what I did on a R25 in that section

@Karl: how is the upgrade coming along? Can we already add more then two pictures as attachements?

Ser

[sjeuf12]

Hi,
as prommissed, the second follow up.
This time a picture on what I did on my R26 cylinder.
I did not have to modify the crank case oil channel; that's already in there on a R26.

I believe someone has mentioned a high(?) power oil pump (Heiko??) used on governement (Behörden) and army bikes.
Can't remember the thread that was in...must be old age 

Does anyone know if this can be bought and installed as an option?

Ser

[sjeuf12]

Hi again,
finally two pictures on what I did on a R25 on the same subject.
The R25 and earlierdoes not have an extra oil channel in the cylinder-foot or cranck case.
So I made one.
I only added one oil-channel in the cylinder, so no groove (yet)

Rember, only do this if you are pretty sure that your pump delivers enough pressure and throughput.

@Kreumel
perhaps this is something that could help you in fixing the piston problem on your R24

The improved piston oiling does help a lot in reducing cylinder and piston temperature.
These over-temps are in my humble opinion caused by the rather wide front fender. 

Hope this helps,
Ser

[sjeuf12]

Garnet,
in the original thread message you complained about vibrations and about a crank as a replacement.

What type of crank do you have in there now? Is it the original one (with aluminum push-rod) perhaps modified to steel push-rod without changing the rest of the parts?
That can cause a lot of vibration.

I believe Mark Hugget has some nice info on that on his site.

Ser

[Garnet Grylls]

Hi!
Thank you for the great info on cylinder oiling. I have seen the pictures on my Mono Screensaver. Your explanation is great. I have been following Jom's thread on oil presure and will test mine first.

My crank originaly had an aluminium rod and someone put in a steel one.  It really is bad. I have a spare 59 bottom end with crank, cam, oil pump and flywheel.

I am also thinking of lightening the flywheel for better acceleration. I do like the feel of a heavy flywheel but with the heavier crank maybe I can take off a kilo. 

I also think I will leave the cam timming the way it is.  I like the torque at lower rpms. Do you think I should still consider the high compresion R50S kolben with the R26 cam?

Thanks
Garnet

[Rütz]

From 1964 on all R27 came with the greater oil pump.
See doc #207 on beemergarage.com.


But most of the older goverment/army-bikes were "upgraded" with this pump, contrary to the private ones.

Nevertheless this pumps are rare. At the dealers about three times the price of the normal ones.

[rolf]

Hey garnet,
you can also make a "new" oilpump which is like the later R27 pumps. Odeon 8 makes this from 2 normal pumps.
You an see it somewhere in older threads (but I don't know where)
The newer pumps are better but not truly necessary.
Markus, dein Einsatz, wo war noch der tret von Thomas wo er 2 Pumpen zusammnegebaut hat?
Greetings
Rolf

[emm]

Markus, dein Einsatz, wo war noch der tret von Thomas wo er 2 Pumpen zusammnegebaut hat?
Greetings
Rolf

Hang on ....

.... ah, here we are: http://www.bmw-einzylinder.de/forum/index.php?topic=1079.0 Have a look at answer #5.

Your servant,

Markus

[rolf]

Dzeng juh
Rolf M(aster)

[emm]

u ahr wellkome, mai pläschör!

[Garnet Grylls]

Hi!
Thanks again for all the good information. I have 2 oil pumps, maybe I will make one high output. Did Odeon8's new pump require a deep oil pan to fit it into? Where the 2 gears loctite (glued) together on the threades inserts?

Garnet

[Garnet Grylls]

Hey Markus
Thank you for the link to Thomas's 20mm oil pump.  I translate again and understand better. It does need the deep oil pan and he did use Loctite on the threads to hold the gears in line.

I will show the pictures to my machinest friend and see if we can make one from two. If not I see Mark Hugget has used R27 pump for 130SWF.

I think more oil is the first step to makeing more PS (heat) work safetly.

Garnet

[Garnet Grylls]

Hello Rutz

I see from an old posting that you have a 15mm R27 oil pump. Did your bike come with that pump? Do you know if I can just shorten my R26 drive to fit a late R27 pump?

Thanks
Garnet

[Rütz]

Hi Garnet,

1.
yes, it is Bj. '66.

2.
The oil pump drive shaft is just 5mm shorter.
If you are able to, you can shorten it. Don't know how easy that is.
Maybe it's hardened and you have to preserve/restore the four-cornered end.

Anselm

PS:
Did you also look here (http://www.bmw-einzylinder.de/forum/index.php?topic=1097.0)?

[Garnet Grylls]

Hello Anselm,

Thanks again for another good link. I am going to have to put down the computor and pick up some tools soon!

Garnet