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Old 12-05-2012, 06:45 AM   #1
chasbmw OP
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Cam shaft choice small seal R90/6

My R90/6 runs very well, it has been modified a bit, including a fully balanced engine, dual plugged, high compression pistons, light porting,lightened flywheel and I have run the bike for just under 2 years in this configuration, it's very smooth and fuel efficient, but I would a little more top end rush.

To that end, my mid winter therapy project could include a slightly more exciting camshaft. Looking at the Motoren Israel website the camshafts suitable for my June 1975 small seal R90/6 includes a 320 degree, a 332 degree and a 336degree camshafts all described as 'sports', but no further description as too what the characteristics of these various cams might be.
http://www.motoren-israel.com/produc...als-front.html

I'm not really looking at a full sports cam, just something that will give me a bit more mid and top end, without losing the existing bottom end smoothness. The assymetrical cam on my 1070 bike, seems to work well At all speeds, but it is not made in a small seal version.

Advice and some real world advice welcome
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chasbmw screwed with this post 12-09-2012 at 01:08 PM
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Old 12-05-2012, 09:25 AM   #2
RGregor
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Hello Charles!

The 336 cam seems to be the BMW profile, as Schleicher doesn't offer a 336 cam for the old bikes (the 336 they offer for the later bikes is a more aggressive profile than the BMW 336).
The 320 and 332 cams are Schleicher cams.
You probably remember the cam thread, there the specs were listed.
The asymmetrical cam is known to be a combination of the 320 profile for the exhaust and the 324 profile for intake.

The 320 cam is well known, in the original setup or a 3 advance (then known as HPN 320/3) and regarded as a good profile for a tourer or mild sports engine.
I know two engines that had the 320 cam installed. Both were very much fun to drive, with a fat torque curve at low and medium revs but still the engines would like to rev high.

On one of these engines a Siebenrock BBK with the asymmetrical cam was installed. The asymmetrical cam provided more torque at medium revs but above 6k5 rpm, unlike with the 320, fun was over.
The owner changed back to the 320 and is happy again.

As to the 332: no personal experience and no hearsay about that. Looking at the specs I would say it's a profile that will pronounce the top more (more lift, more lift at overlap).

If I wanted to build a smooth touring engine the 320 would be my first choice.

Rudi
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Old 12-05-2012, 09:54 AM   #3
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I thought a good majority of us came to the conclusion in that cam thread that those specs without a lift check point are not very much help as far as comparing specs or setting up the cams? Even someone's cam doctor graphs were too small to read as far as getting a lift check point out of them?
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Old 12-05-2012, 12:42 PM   #4
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Quote:
Originally Posted by supershaft View Post
I thought a good majority of us came to the conclusion in that cam thread that those specs without a lift check point are not very much help as far as comparing specs or setting up the cams? Even someone's cam doctor graphs were too small to read as far as getting a lift check point out of them?
The conclusion was that it is not possible to check the grind of the cam without check point.
The interesting thing is that quality problems had been unknown as long as Schleicher produced the 336 for BMW ...
And they still are unknown regarding Schleicher cams. And believe me, they are used a lot.

In the meantime I had a closer look onto the documentation Schleicher provide and these are equal to those in the BMW documentation:
Preload the valves 1mm and measure duration after 1mm additional lift.
The BMW doc says:
Preload 1/4 turn (no valve play) and measure after 2mm lift.
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Old 12-05-2012, 10:50 AM   #5
chasbmw OP
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Rudi, many thanks for your helpful reply, I'll wait and see if anyone has any experiance of the 332, but it sounds to me if the 320 would work well on my bike.
Charles
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Old 12-05-2012, 11:12 AM   #6
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Quote:
Originally Posted by chasbmw View Post
Rudi, many thanks for your helpful reply, I'll wait and see if anyone has any experiance of the 332, but it sounds to me if the 320 would work well on my bike.
Charles
Hello Charles!
I do have the email address of someone having the 332 in his engine (it's a 94mm*61.5mm short stroke 850cc engine).
Never talked to him about the cam.
And I remember that moorespeed has mentioned the 332 in the cam thread here.

Greetings, Rudi
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Old 12-05-2012, 11:16 AM   #7
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Thanks I will check the thread,
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Old 12-05-2012, 12:27 PM   #8
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If the early 336 aftermarket cam is ground like a BMW 336, I would recommend that. I have installed one in a customer's /6 (a BMW 336) and he loves it. A friend of mine had one in his /6 and he loved his. I love mine in my later model as do others I know. They are great midrange cams! The problem is we really have no way of knowing if they are the same or even if they are what they are suppose to be (the reason tuners time cams to start with!). Someone could time both makes themselves and compare and report. It is a touchy job and just a few degrees do make a difference but . . . .
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Old 12-05-2012, 07:33 PM   #9
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Where is the documentation? In English?

Grind? What else is there?

Any good cam manufacturer knows that cams can be ground wrong. That is why most all good cam manufacturers give their specs with a check point so you can check their timing.

Timing a cam at a rocker arm? I would get real familiar with it at the lifter myself. It makes the job a lot easier and less prone to mistakes IMO.

supershaft screwed with this post 12-05-2012 at 07:43 PM
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Old 12-05-2012, 11:38 PM   #10
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Quote:
Originally Posted by supershaft View Post
Where is the documentation? In English?

Grind? What else is there?

Any good cam manufacturer knows that cams can be ground wrong. That is why most all good cam manufacturers give their specs with a check point so you can check their timing.

Timing a cam at a rocker arm? I would get real familiar with it at the lifter myself. It makes the job a lot easier and less prone to mistakes IMO.
The documentation I have is in german.
But anyone interested can contact Schleicher prior to buying and ask for all information wanted.
http://www.schleicher-fahrzeugteile....hp?en_kontakte
I would regard this as very simple.
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Old 12-06-2012, 05:38 AM   #11
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The plan is to take the bike off to my local dyno jet operator and get a base level run done before Christmas, I can then do the works sometime in January, but a few miles on and then do a second run and see what the difference is.

This might give some comparative numbers that could be of interest
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Old 12-07-2012, 01:43 AM   #12
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Here are the specs for all of the aftermarket cams that I know of.



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Old 12-07-2012, 10:36 AM   #13
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Originally Posted by bmweuro View Post
Here are the specs for all of the aftermarket cams that I know of.



Those specs where pulled up for the previous cam thread. They have no check point. The specs given pretty much have to have no check point if I remember right. Specs with no check point are just about useless. That's why Crane to Megacycle lists a check point with their specs. Unfortunately, there is no standardized check point that the cam industry uses. Since the check point itself drastically changes the specs, there is software out there that will compare specs with difference lift check points. Check points are crucial for comparing grinds, timing grinds, and checking grinds in order to make sure that your cam is indeed timed as it is suppose to be.
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Old 12-07-2012, 08:50 PM   #14
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Quote:
Originally Posted by supershaft View Post
Those specs where pulled up for the previous cam thread. They have no check point. The specs given pretty much have to have no check point if I remember right. Specs with no check point are just about useless. That's why Crane to Megacycle lists a check point with their specs. Unfortunately, there is no standardized check point that the cam industry uses. Since the check point itself drastically changes the specs, there is software out there that will compare specs with difference lift check points. Check points are crucial for comparing grinds, timing grinds, and checking grinds in order to make sure that your cam is indeed timed as it is suppose to be.
Correct. I posted this in a previous thread and they came from Motoren Isreal.
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Old 12-08-2012, 04:14 AM   #15
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I'm wondering what the goal of this fruitless discussion is.
You are discussing incomplete data a reseller provides and are complaining they are incomplete and thus useless.
And blame the manufacturer and the product for that.

Does that make sense?

The only way to find out if the information the manufacturer provides come up to your standards would be to get the information directly from there, study them and judge then.
This way everyone here would benefit.
And the effort for that would really be minimal.

Everything else has the bad taste as if motivation for this discussion is something completely different.
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