Lifter and rocker wear

[Airbear]

G'day all
Patient is a '74 R90/6, with over 200,000kms. I have been getting a bit concerned that the valve clearances for the left jug consistently increase by 1 to 2 thou each maintenance cycle. Clearances for the right jug have been consistently good - zero or very little adjustment required. I was worried that a stud or two might be stripping, but all seem ok (I tried torquing them before removal - nothing unusual happened - just a satisfying immediate 'click' from the torque wrench at standard torque setting).

Here is what I found for the left jug -

The rockers:



The lifters:



The same components for the right jug are a bit ragged too, but not quite so bad. The camshaft appears to be just fine. The rockers and lifters showed some damage last time I was in there but shortage of dollars dictated leaving them at the time - now they are somewhat worse and I might be able to find some dollars.

My question is, can these be resurfaced or is replacement the best option? If they must be replaced, can anyone suggest a good source? Thanks in advance.

[ME 109]

Gidday Charlie, I don't recall much discussion regarding resurfacing the rocker arms. Maybe they have a shallow hardening like the crank......
I wonder if the lifters are the same as a /7?
As for a sauce, I quite like a pesto with pan roasted pine nuts. Some Parmesan really tops it off.

[SteveD]

Howdy Charlie.
If those parts are replaceable with similar from the later 1977+ bikes give Jeff a call and ask him about our Deutsche friend!

[Airbear]

Gidday Steve. I understand that the rocker gear can only be upgraded one version at a time, so the 74 can only be replaced by the later /6 (1975/76), but not the /7. (Just got your email, Steve - that is a wonderful price, but won't fit, as far as I know).

Motobins price for rocker arms and needle bearings comes to $352 plus shipping. Munichs wants $337 for just the bearings.

I'm hoping there is some way to re-use what I've got, if some engineering mob can apply a new surface. Really dunno what's possible. It's new ground for me.

ps: Jeff, totally agree about the quality of that sauce.

[Duane Ausherman]

You can buy a whole good used engine for $1000, so you should be able to find good used rocker arms cheaper than new.

[Rob Frankham]

Hi,

I've just checked with the BMW parts list. This specifies the same followers for every model from the R50/5 in 1969 to the R100 Mystic in 1995. This, of course, doesn't mean that they're the same as those fitted in 1974, just that they'll fit.

As far as the rockers go, I believe the later rockers can be fitted but it requires the heads to be machined to take the spigots on the later rocker posts... depends if you have a competent machinist on tap and on how far you want to go.

If you're going to look for second hand replacements, keep an eye on Ebay... especially Ebay Germany. A lot more boxer parts seem to some up there than in the US or UK.

I wouldn't bother to try to reclaim the existing parts although it's not impossible. A good machinist should be able to build up the surface, re-profile and harden it but it's likely to cost more than new. I would only go down that line if the parts were unobtainable.

Lastly, to put in a discouraging note... with followers like that, have you looked at the cam lobes. It seems quite likely to me that you are going to have matching issues there.

Best of luck

Rob

[SteveD]

Charlie, how about the fella that did the spline? He might know?

[Major Softie]

Well, you definitely need to do something. When rockers lose their hardfacing like that, they sometimes wear frighteningly fast. Not as fast as cams, but still it can go pretty fast.

Airhead lifters seem to get damage like that more frequently, so, while I would want to replace them, the wear isn't as unusual as the rockers.

A large city would certainly have someone who could reface those rocker arms.

[ontic]

Gday Charlie,
(and wow, this thread is moving quick- I've typed slowly and previewed a few times and the posts keep on rolling in_

I've been looking into camshafts and lifters/followers lately as I am going to swap the camshaft in the G/S (to a 296 degree shaft... don't ask.. )
Being about to put in a new camshaft I asked on adv about whether to replace followers as a rule as well- there was a bit of disagreement- some say yes, Supershaft (aka Funholiday) says no- that if they are still good then keep them... as new ones can go bad...
anyway, I'm following the advice of the yes-sayers and Motoren-Israel and have bought new followers as well- for them, new cam equals new followers. (also, for many around the internet it seems, new followers should mean new cam as well, like rob says- especially if your lifters are that worn... but maybe we shouldn't go there!)

As you have seen Motobins have what you need. I ordered mine from Motoren-Israel as that is where my camshaft is coming from, and we are getting more bang for our buck with the Euro rather than the Pound at the moment.
here they are (remember to take off 19% VAT).
http://www.motoren-israel.com/product_i ... Boxer.html&
You can email them any questions you might have, Silvia Israel speaks good english and responds pretty quickly.

Motoren Israel don't seem to have rockers though... you could ask them, I've missed stuff on their catalogue before, or just buy from everything from motobins who have them.

You could of course have the old followers out of my G/S if you want (you could even have the camshaft if there was a way to make it work??), but I am not sure when I will actually have them out and what condition they will be in.
I just checked the spare heads I have in the garage but the rockers show almost the same wear as yours do.

german ebay maybe? (click for a search for bmw rockers) might be what you need.
http://www.ebay.de/sch/i.html?_nkw=BMW+ ... acat=14780

[chasbmw]

If you were feeling very flush with cash then MI have these lightweight followers

http://www.motoren-israel.com/product_i ... m-4pc.html

Charles