Rocker Shaft Problems

[tech71]

They probably assembled it that way, ( after way too many bong hits)

The welds may have been an attempt to fix the mess they made.

Classic “Wit Brothers”

Wonder if that fat ass washer on the oil transfer tube is responsible for apparent lack of top end oil

[TobyB]

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Customer states...

 

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Saving that head will be a challenge.

 

DISASSEMBLING that head will be a bit sparky.

 

I would agree that, if it has good leakdown and compression, you don't want to 

tackle that right now.  Maybe sometime in the future.

 

If there's no oil flow to the head, however, (which I doubt, if the cam hasn't seized in the head)

then there's no time like the present.  You're looking for oil pressure at the rear port, where the 

switch is.  Then run it with the valve cover off, and it should make a slow, hazy mess.

 

Somewhere around here there's a picture of Bill and me cutting the rocker shafts out of

a potential donor head-  an abrasive wheel will fit down in there and slice the things,

then the parts can be driven out.  It makes a mess, but in our case, the head casting was

OK- the rocker shafts had rusted up from decades of storage.

But you have to take the head off to do this.

 

I would also worry a little bit about what you'll find in other places- but maybe not too much,

as things like that are often 'a friend helped me once' or 'the shop fixed it cheap' rather than

'I bought a welder and a car, and the welder is the only tool I need!'

 

t

welds diffs for fun and traction

 

[jgerock]

Sort of related to this topic…

One of the rocker shafts on a 71 2002 engine I purchased had a hole with split pin. Anyone seen this before?? Cylinder head and block numbers in the pics.

[Son of Marty]

A aftermarket fix to keep the plug in the shaft from slipping out.

Edited December 29, 2022 by Son of Marty

[TobyB]

That's kinda elegant- 

when those plugs were just swedged in there, and then came loose,

it was almost impossible to re- secure them, even if you bought new 

ones and drove them in.

They almost always came loose again*

 

t

 

*unless you cleaned everything really well and used sleeve retainer

[tech71]

58 minutes ago, TobyB said:

That's kinda elegant- 

 

Good idea, going to do my next rocker shaft on the drill press.

Then again, probably not, my new OE shafts are not really compatible with that, would have to drive the plug inward unseating it in the process.

Think I will just leave them alone.

But not a bad hack on an installed engine with a loose plug.

Edited December 30, 2022 by tech71

[Lord Bastenchury]

Looks like someone wanted rocker locks, then saw the mig in the corner, and said "Hold my beer"...

[Markster]

ok so I have to ask - because I have a mig welder... Just kidding I would not do that. 

 

But I do have to ask - when properly assembled the rockers are spring loaded against a stop?  Why is it that they slide?  I noticed it one day while adjusting the valves and could literally slide the rocker over a quarter inch or so.  Why do they "float" on the shaft?

[Markster]

On 1/1/2023 at 8:08 AM, Markster said:

ok so I have to ask - because I have a mig welder... Just kidding I would not do that. 

 

But I do have to ask - when properly assembled the rockers are spring loaded against a stop?  Why is it that they slide?  I noticed it one day while adjusting the valves and could literally slide the rocker over a quarter inch or so.  Why do they "float" on the shaft?

OK so I got that it is normal the rockers slide and are spring loaded but why did BMW do this?  Was it to reduce wear in one spot?  Would this allow the valves tops to not dome out?  Was it for simplified assembly?  

 

From the IE site :

On factory M10/M30 cylinder heads, the rockers are held in position by a spring – and at high rpm, that spring may allow the rocker to move in relation to the valve stem (sometimes enough to walk off the valve stem which quickly results in a broken rocker arm). With rocker arm locks, you eliminate the spring and positively locate the rocker arm. Locks also make head assembly simpler than with thrust springs. We use these on all our performance engines.

Installation Note: These locks are meant to replace the existing retention springs, use in conjunction with the OEM shim washer. When installing; use a feeler gauge to space the lock .011″-.015″ from the rocker. This will allow for natural heat expansion of the rocker and lock while under normal use."

[Tommy]

7 hours ago, Markster said:

 Was it for simplified assembly?  

I think that's it. It's perfectly good for designed rpm range. Easy to asseble, you just put it together, no feeler gauge needed. And the parts are cheap when produced in mass.

[TobyB]

It also keeps them quiet, but allows oil flow.  Rocker locks need to be set up with just

a little clearance (end float) so that there's enough room for oil to flow out of the holes,

lubricate the rocker, and then carry away any wear particles.  Too much clearance, things move,

the pad and cam don't mate very well.  Too little, no oil flow, and things can gum up. 

But.

Put springs in there, and 

you have a perfect damper- it's oil filled, it can move slightly, and it's quiet.

Oil pressure builds up?  Spring slides back just a little, oil is released.

 

Most rocker systems that use a rod have some version of this- although, with heavier springs

and less travel.

 

t

 

[John76]

On 12/29/2022 at 9:44 AM, tech71 said:

Wonder if that fat ass washer on the oil transfer tube is responsible for apparent lack of top end oil

That would be my guess.

Notice there is no crush washer under the spray bar. Looks like the thick upper washer was used to take up the play in the banjo bolt, thus blocking the oil hole.

But... as @DoubleA posted earlier, not everyone has/needs a stinkin' oil spray bar!