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Old 07-03-2011, 10:56 AM   #1
Bluffskier OP
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336 cam??

I have read about the 336 cam and was wondering if it's something I should look into. I'm going to have my engine tore down somewhat and was wondering if this is something I should look into or simply skip it.

I have... well the motor is an R100/7
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Old 07-03-2011, 11:54 AM   #2
bmweuro
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Sore subject. Do a search before a bunch of folks start slamming you.
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Old 07-03-2011, 12:01 PM   #3
Bluffskier OP
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Alright, So I understand it's like asking "what type of oil" or "what is the proper service interval" is/that is the best, LoL
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Old 07-03-2011, 12:26 PM   #4
disston
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336 camshaft

I'm sure this subject has come up before, too many times? But the search engine bounces any combination of terms 336, cam, camshaft...Can someone point us in the right direction or give the link?
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Old 07-03-2011, 12:45 PM   #5
supershaft
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For the most part, it's a sore subject for googlers and the like. But then the owner of a well known and well respected BMW dealership that I was working at at the time warned me not to install one in my bike. He said that I had to run steel pushrods and raise my 8.5 compression and even then the bike would have no low rpm power and wouldn't idle below 2000rpm. After all, two of his top mechanics were just working on an airhead that has all those problems with a 336 and they couldn't fix it either. ALL of it was BS!

I installed mine without changing anything else and rushed late to a rally with my girlfriend on the back. We were amazed at all the new power everywhere in the rev range. Loaded for camping two up on the interstate through mountain passes and traffic no longer required raking the gearbox. I just kept it in fifth and motored through! Got to the rally and, of course, my girlfriend and I were very excited about it. Some people wanted to hear it run so I started it up. Guru Duane told everybody there that I had in fact installed a 308 because 336's didn't idle that smoothly. True story! My girlfriend and I were cracking up! I later got it idling even better than that by changing the needle jets!

Then shortly thereafter I put Dell's on. Now 65,000 miles later, my bike is apart at 101,000 miles for the exhaust guides going to crap. Now I am raising the compression (dual plugging it too!) and putting custom made steel pushrods in it!
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Old 07-03-2011, 02:47 PM   #6
fishkens
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Quote:
Originally Posted by disston View Post
I'm sure this subject has come up before, too many times? But the search engine bounces any combination of terms 336, cam, camshaft...Can someone point us in the right direction or give the link?
Maybe not too many times but things have gone south when discussing premature failures, country of origin, etc.

As for searching this site, use the google. Enter site:advrider.com 336 cam in google and you'll get a few dozen ADV threads on the topic.


Here are the first three results of several pages...
  1. BMW 336 cam - ADVrider
    www.advrider.comADVriderBikesOld's Cool - CachedSimilar
    15 posts - 8 authors - Last post: Mar 22, 2009
    With an otherwise stock engine, the major benefits of a 336 cam addition will be poor idling and decreased gas mileage. ...
    Get more discussion results

  2. 336 cam made in china - ADVrider
    www.advrider.comADVriderBikesOld's Cool - Cached
    15 posts - 10 authors - Last post: May 17
    Some mention made in a unrelated thread about how the 336 cams made in china were crap and had been recalled by BMW so how can I tell if a ...
    Get more discussion results

  3. 336 cam ? - ADVrider
    www.advrider.comADVriderBikesOld's Cool - Cached
    12 posts - 9 authors - Last post: Sep 14, 2010
    My 336 cam is a late model for simplex chain and is stamped on its nose at the timing sprocket. Not sure how the earlier ones are marked. ...
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Old 07-03-2011, 03:05 PM   #7
marksbonneville
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Google search: 336 cam thick yellow opaque plastic bag
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Old 07-03-2011, 03:43 PM   #8
Bluffskier OP
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I didn't know the search this site with Google trick.

No I will stick with my stock cam since I'm not rebuilding the motor now and I would rather keep my low end torque. I'm not an aggressive rider, but I do travel open straight roads at high speed, it's south, south Texas. I am keeping the 32mm carbs on it though, so it's gonna be stock.
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Old 07-03-2011, 03:48 PM   #9
marksbonneville
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Quote:
Originally Posted by Bluffskier View Post
I didn't know the search this site with Google trick.

No I will stick with my stock cam since I'm not rebuilding the motor now and I would rather keep my low end torque. I'm not an aggressive rider, but I do travel open straight roads at high speed, it's south, south Texas. I am keeping the 32mm carbs on it though, so it's gonna be stock.
No doubt you will have a great time with your bike in its stock form, especially on the long straight roads in Texas.
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Old 07-03-2011, 03:49 PM   #10
supershaft
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A 336 will cost you no low end torque below what you can load the engine at without it rattling and shuddering like a paint mixer. That is as hard on the engine with a 308 as it is a 336. Probably more so for the earlier closing intake.
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Old 07-03-2011, 07:16 PM   #11
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Have a 336 in a newly rebuilt R80 G/S ...(bumped to 100) with 40mm Bings and Staintune exhaust...this thing really moves and no problems with idle, gas mileage, or pushrods turning into pretzels.

Same experience as SuperShaft..it just works.
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Old 07-03-2011, 10:58 PM   #12
disston
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Thanks for all of the info. It's more than just dropping in one part. I understood most of that stuff but for sure not all of it. I am also rebuilding a spare motor, '77 R100S, and I think I should keep it simple at this point.

Horse Power cost big bucks.
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Old 07-03-2011, 11:10 PM   #13
supershaft
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I just want to reiterate that the stock pushrods work fine. I ran mine with the stock aluminum pushrods for many miles and more than a couple of missed shifts at 8000rpm plus with no problems. (I do run titanium retainers!) It's just that I recently did some experimenting with a spare engine in order to find out what it is exactly that rubs on almost all aluminum pushrods 308 or 336. I always assumed that it was the head gasket. It isn't. The pushrods are flexing all the way over and rubbing on the pushrod tube right where the tubes stop and start in the cylinders and heads. I thought that maybe the radius of the rocker arm was swinging the pushrod real close to the pushrod tube so I assembled an engine leaving the pushrod tube seals out and stuck a small light there and watched how centered the rods stayed going through their motions. I was surprised at just how centered they stay and just how far those pushrods must be flexing in order to be getting into the sides of the pushrod tubes like they almost always do. All that flexing has got to effect valve timing! It seems like Nascar and drag racers have been figuring out the exact same thing in just the last twenty years and have gone to way stiffer pushrods for quite a bit more power. Guess what? I am going to do the same thing although I am sure it will be for just a tad more power but, like I always say, it all adds up!

I was debating running BMW steel pushrods. They are 40% lighter than my custom rods and I have a set of them. All four of them show no sign of getting into the pushrod tubes. Then I was at a friend's house and he had some laying around and they had rub marks in the same place as most all aluminum tubes. Not nearly as prominent but they were there. I told my friend that seeing that made up my mind. I am running my .058 wall 4130 pushrods so my valves will open faster and further like that good cam intended! 40% heavier than BMW steel rods and right at twice as heavy as aluminum flexers? It turns out that the car guys are running rods up to three times as heavy for more power. Twice as heavy as they were just twenty years ago ALL the time.

I just thought that maybe those rods are just flexing during missed shifts? I kind of doubt it because I see them marked up heavily all the time on engines that could barely get to red line in neutral if you held the throttle open for ten seconds plus the owners liked to pretend that they were driving a VW Microbus while they were riding their BMW motorcycle. I can't think of a way to be any slower and easier on an engine?

Hp cost big bucks? Not if you do it right!

supershaft screwed with this post 07-04-2011 at 12:00 AM
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Old 07-04-2011, 08:27 AM   #14
Bluffskier OP
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I will get one here one day, Maybe on this bike if everything falls into place. Maybe do this last since they can be had for $157 or $127 or whatever.

Is it customary just to replace the cam on an old engine? Mine is an original R100/7 engine only pushing around 123 PSI in each hole so if I ever get a hone and rings (still got to look into that) I will def be looking up this cam, but for the time being I just hope it stays together.

The Book, says 123 PSI is about the lower service limit on compression too.
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Old 07-04-2011, 09:11 AM   #15
lkchris
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Quote:
Originally Posted by supershaft View Post
I just want to reiterate that the stock pushrods work fine.
And if they didn't the BMW parts catalog would show a version for use with this cam. It doesn't.
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