7 replies to this topic

[jpsulisz]

Hello,

I did a valve adjustment on my new to me mini and found that rocker #8 is very loose - here is a video with it prior to adjustment:

Appears to me that the rocker arm is in need of replacement, from what I assume of years of usage and possibly oil starvation(?) - now I assume I can order a set of 12G1221's from MS but I also read there is a bushing, 2A21, on the older stamped rocker arms I have. Is there any risk to using entirely new rockers - or are the bushings easy enough to replace? Also, should anything else of the rocker assembly be replaced since I am going into it or can it all be re-used without risk?

I've also read some replace the head gasket if doing this - and that may lead into wanting to replace the valve guides - then maybe the valve seats and just new valves (so basically reconditioning the entire head). Is it really worth it? Or just needed for extreme circumstances?

Here is a video of the car running yesterday:

Model: 1968 Austin Mini MK2 998

Edited by jpsulisz, 12 April 2023 - 04:56 AM.

[sonscar]

It is possible the shaft could also be worn,in another life I have turned the shaft 180 degrees and redrilled the oil hole to squeeze a little more life out of tired motors.If you have the budget then replace the whole assembly.Steve..

[DeadSquare]

Listening to that, the good news is that it is running,

 

If the bushes are warn, the shaft will be worn.

 

If you slacken off all the tappet adjusters, it is possible to extract the shaft without removing the rocker pedestals, so no worry about the head gasket.

[Ethel]

I can't see that much wrong there - doesn't mean there isn't.

 

Of course they can move sideways, against the locating springs. It's more whether they can move backwards & forwards across the shaft or twist - i.e. rock in any direction other than around the shaft as intended.  Pushing them sideways does allow you to inspect the shaft, where they run, for wear. That'd likely be most evident on the bottom. The pads that contact the valves will be more indicative & critical to wear.

 

You don't have to back off all the rockers (as long as you don't turn the engine), just the ones that are pushing on the valves. But do keep track of them, so they can go back where they came from.

[jpsulisz]

It is possible the shaft could also be worn,in another life I have turned the shaft 180 degrees and redrilled the oil hole to squeeze a little more life out of tired motors.If you have the budget then replace the whole assembly.Steve..

Does anyone sell the entire assembly? I was thinking of just ordering the rocker arms and a new shaft while reusing the rest of the assembly. Do the towers wear down too?

 

I can't see that much wrong there - doesn't mean there isn't.

 

Of course they can move sideways, against the locating springs. It's more whether they can move backwards & forwards across the shaft or twist - i.e. rock in any direction other than around the shaft as intended.  Pushing them sideways does allow you to inspect the shaft, where they run, for wear. That'd likely be most evident on the bottom. The pads that contact the valves will be more indicative & critical to wear.

 

You don't have to back off all the rockers (as long as you don't turn the engine), just the ones that are pushing on the valves. But do keep track of them, so they can go back where they came from.

It may not show in the video, but it can indeed move in any direction. I think #4 is similar, but nowhere near as bad.

 

Listening to that, the good news is that it is running,

 

If the bushes are warn, the shaft will be worn.

 

If you slacken off all the tappet adjusters, it is possible to extract the shaft without removing the rocker pedestals, so no worry about the head gasket.

 

Would this just be pulling a cotter pin the on radiator side and slowly taking it apart as I pull it out and doing the reverse when installing the new shaft/rocker arms?

I ask if it's needed to go down to a head gasket since I will be working on the manifold gasket for a new muffler install. I feel like there isn't much past that apart from draining the coolant, right?
 

[Ethel]

Removing the head off an A Series is as easy as any & easier than most, but there's still an element of if it ain't broke don't fix it.

 

I wouldn't, just to service the rockers, but I might well if I also took the opportunity to decoke, inspect, & lap the valves.

[DeadSquare]

"Would this just be pulling a cotter pin the on radiator side and slowly taking it apart as I pull it out and doing the reverse when installing the new shaft/rocker arms? "

 

A qualified  "Yes". -----  When the uncompressing tappet adjusters are slackened off, it is usually possible to separate the pushrods from at least four of the rockers by compressing the thin wire spring that holds them against the pedestals, but not number one and eight  ( you might have to put a screwdriver under the rocker shaft and lever the valve spring down).

Two valves will be compressed open, so the camshaft must be rotated until those rockers can be slackened and separated.

By removing the screw in the pedestal that holds the shaft in place, and the cotter pins either end, the shaft can be moved back and forth to remove rockers one and eight, and with the other rockers all floppy, the shaft can be withdrawn.

 

The tips of the rockers will be worn where they contact the valve stem, so I'd replace them and the shaft.
 

 

 

1968 is quite a long time ago, how many miles has it done?

 

If the rocker is that wobbly, everything may be worn..................and then, where do you stop ?

[jpsulisz]

1968 is quite a long time ago, how many miles has it done?

The odometer has stopped at just under 35k, but who knows how many rotations it's done on the odometer.
 

 

If the rocker is that wobbly, everything may be worn..................and then, where do you stop ?

This is my biggest concern - because I want it to be fun and reliable to some degree, but I'll be damned if I can't enjoy it this summer because I was too anal to make everything perfect.

I was going to replace the water pump, all the water hoses, cables, wearable suspension bits, do a brake disc conversion along with new rear hardware and potentially a new rear subframe for this summer. I am planning a move to hopefully a new house with 240v support so I can weld up some of the rusty panels, my plan was to then do a rebuild then.

I think I will plan for a rocker arm replacement along with a new shaft - but have all the head gasket stuff on standby if I change my mind or see the need. Hopefully this will lead to a less 'tappety' sounding engine.


 

May I just say though, the Mini is the first car I can chill on a bucket and work on most things on the engine bay without any issue - I was enjoying myself working on the engine bay. 
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Edited by jpsulisz, 13 April 2023 - 03:38 AM.