Jump to content

Rocker shaft


Recommended Posts

Hi guys I have my head away with Peter Burgess at the moment who is going to be doing a nice clean up on it.

meanwhile I decided to give a cleanup of The Rocker and can see some of the rocker arms are quite sticky whilst others actually spin all the way around ie 360 degrees

one of them was really quite stuck and I have been able to get it to move again but my question is should I strip this down because I'm not a great believer in taking things apart unecessarily and I'm concerned about putting it back together again.   I think what confuses me is why do some rocker arms move just a bit and another ones I can rotate it fully thanks in anticipation

 

 

 

 

 

IMG_20201228_184551.jpg

Link to post
Share on other sites

You’ve gone as far a sending the head for rework. Personally I would strip the rocker shaft assembly too.

Lay it down on a nice piece of board and pull it apart keeping all the parts in order of removal.

Link to post
Share on other sites

Take it apart and replace the shaft. The 'sticky' ones are probably where they have worn the shaft. It's almost worth considering the shaft as a consumable.

If you get the reassembly wrong it will be obvious as the rockers won't touch the valve stem.

Jerry

Link to post
Share on other sites

These will last indefinitely ( 100K+ miles ) bushed with bronze. Both my '250s have these which were done by Rocker Arms Unlimited in the 'States and my spare engine is getting them done by the engine builder. With this upgrade and hardened timing chain wheels these engines should be good for 150,000+ miles between rebuilds with regular oil changes and good control of A/F ratio.

 

Tom

Link to post
Share on other sites

Thanks for feedback

I am not up to the budget of sending away, the cyl' head is costing enough!   I dont understand though one thing, Jerry said re - assemble as it came or push rods dont fit?   if I put a new shaft on what does it matter?

Thanks

Richard

Link to post
Share on other sites

When I rebuilt my engine a while back the rocker shaft was very worn. Ridges very noticeable. I replaced it and shafts as well, but when comparing new & old rockers there wasn't much difference. As Jerry said, treat the rocker shaft as a consumable. They're not expensive. As far as assembly, I think Jerry just means that if you put the rockers in the wrong order they may not be over the relevant pushrod. They are angled in plan view.

John

Link to post
Share on other sites
17 minutes ago, JohnC said:

As far as assembly, I think Jerry just means that if you put the rockers in the wrong order they may not be over the relevant pushrod. They are angled in plan view.

Yes, that is what I meant. Thanks.

Jerry

Link to post
Share on other sites

Regarding rocker shafts

Original Triumph ones are supplied without end plugs, which must be fitted or the oil just dribbles out the shaft ends rather than oiling the rockers. 
Peter W

Link to post
Share on other sites

Thanks, if I replace the shaft only, is this being silly or show I also replace the arms too?

Peter, I think I understand you - - are these like grub screws on the end of the shaft?

Richard

Link to post
Share on other sites
31 minutes ago, AarhusTr6 said:

Thanks, if I replace the shaft only, is this being silly or show I also replace the arms too?

Peter, I think I understand you - - are these like grub screws on the end of the shaft?

Richard

The plugs for the original shaft are very small bucket shaped core plugs 

 

Latterly, screwed plugs are fitted to repro rocker shafts which serve the same purpose to seal the shaft each end.

Peter W

image.jpeg.4318154f0190fb116323cfbf5cade0b5.jpeg

 

Edited by BlueTR3A-5EKT
Link to post
Share on other sites

If you replace the shaft be sure to give the insides a good clean as they are often full of swarf.  I also found that some of the drilling that feed oil to the rockers needed deburring. Without doing this the rockers jammed. In my opinion this should have been done by the producer. 

Tim

Link to post
Share on other sites
14 hours ago, Tim D. said:

If you replace the shaft be sure to give the insides a good clean as they are often full of swarf.  I also found that some of the drilling that feed oil to the rockers needed deburring. Without doing this the rockers jammed. In my opinion this should have been done by the producer. 

Tim

+1'In my opinion this should have been done by the producer.'  But it did not come from a quality supplier? That of course makes you think what else is wrong! Deburring and blowing out the swarf is normal engineering practice, at least it was in may day as an apprentice?

Bruce,

Link to post
Share on other sites

Hi all

Sorry if this is too rookie, I guess I could go down the garage and check .  . but is the rocker shaft hollow and with pin holes in it to allow free oil flow..??

Richard

Link to post
Share on other sites

Yes, it is, Richard.    

The internal diameter of the inside bore, and the metered flow from the cam shaft rear bearing, means that flow through the shaft is very slow, especially towards the front, furthest from the supply.  With age, that encourages deposits of gunge that can further inhibit flow.     A rebuild that re-uses and old shaft should always include the use of a bottle brush up and down the bore!

Link to post
Share on other sites
3 hours ago, astontr6 said:

+1'In my opinion this should have been done by the producer.'  But it did not come from a quality supplier? That of course makes you think what else is wrong! Deburring and blowing out the swarf is normal engineering practice, at least it was in may day as an apprentice?

Bruce,

The shaft in question came from one of the big two suppliers of triumph parts. 

Link to post
Share on other sites
3 hours ago, john.r.davies said:

Yes, it is, Richard.    

The internal diameter of the inside bore, and the metered flow from the cam shaft rear bearing, means that flow through the shaft is very slow, especially towards the front, furthest from the supply.  With age, that encourages deposits of gunge that can further inhibit flow.     A rebuild that re-uses and old shaft should always include the use of a bottle brush up and down the bore!

Thanks for the education John!

Link to post
Share on other sites
8 hours ago, john.r.davies said:

Yes, it is, Richard.    

The internal diameter of the inside bore, and the metered flow from the cam shaft rear bearing, means that flow through the shaft is very slow, especially towards the front, furthest from the supply.  With age, that encourages deposits of gunge that can further inhibit flow.     A rebuild that re-uses and old shaft should always include the use of a bottle brush up and down the bore!

Hi John

Given this seems to be a long term problem of reduced oil to the front rockers is there anything that can be done to maintain the flow? Reason I ask is that I'm in the process of rebuilding my engine and have purchased a hardened shaft and bushed rockers from Chris Whittor so anything I can do while its in bits would seem sensible.

I'm aware of the extra oil feed kit but it seems to receive mixed opinion as to its benefits is there a better way or is it just a case of regular oil changes?

Cheers

Andy

Link to post
Share on other sites

Please don't mention the "extra oil feed kit" if that means the external oil line, because that triggers my Witchfinder General haunting, and .... YEaAgh, Brothers and Sisters!!! Verily it is said that the Eternalle Oile Linne is YE SPAWNE of YE BEELZEBUBBe!!!!  Downe I sayy, downe on your knees and REPENT!!!

Oh, dear, Vincent Price is back.   Look, the OD diameter and slow flow isn't the issue.  They just allow eventual gunge up, but that takes many years and neglect.    Triumph carefully arranged a metered flow, and that is sufficient, unless you have needle roller rockers.   

John

Edited by john.r.davies
Link to post
Share on other sites

 

13 minutes ago, john.r.davies said:

Please don't mention the "extra oil feed kit" if that means the external oil line, because that triggers my Witchfinder General haunting, and .... YEaAgh, Brothers and Sisters!!! Verily it is said that the Eternalle Oile Linne is YE SPAWNE of YE BEELZEBUBBe!!!!  Downe I sayy, downe on your knees and REPENT!!!

Oh, dear, Vincent Price is back.   Look, the OD diameter and slow flow isn't the issue.  They just allow eventual gunge up, but that takes many years and neglect.    Triumph carefully arranged a metered flow, and that is sufficient, unless you have needle roller rockers.   

John

Fair enough John ! I'll stick to regular oil changes before you come round and burn me at the stake for my herisy!

Andy

Link to post
Share on other sites

Hi all

Well I was brave enough to dismantle the rocker today...

So some of the rockers were very hard to get off, so needed quite a lot of spray.  When I got it all apart i soaked the rockers in petrol and scrubbed them, then cleaned gently inside and on the sides with emery paper and a narrow wire brush.  The are now overnighting in petrol and I will clean again and oil them - but overall they look okay but one had a sharp edge and I filed it down.

The shaft is not bad, but some rough areas on it.  I tried rubbing with emery paper also but the grooves on some are quite deep so I think I replace.  Overall, it looked like it suffered dryness.

I have 2 curiosity questions though:

What material are the rockers and the rocker pillar/holder made from - is it aluminium?

The rocker shaft, what do the grooves cut on it do, is it to help oil get around?

 

Thanks for help so far,

Link to post
Share on other sites

Hi Richard,

the pedestals are an aluminium alloy.

The shaft is a rather soft steel. You can buy tuftrided shafts from Moss and others, I have one, but not installed it yet. The flat area’s are to aid lubrication. Make sure the bore is clean too because debris may plug the oil holes easily and check for alignment of the bore in head, pedestal and rocker shaft.

The rockers are made from cast iron I think. Avoid new repro ones, think Roger had a failure (fracture) a couple of years ago, do not know what caused it. The tips are insert-hardened, check for wear. I dressed a couple, but if you have to remove too much material replace them, because the hardened layer is not thick.

Cheers,

Waldi

Link to post
Share on other sites
1 hour ago, Waldi said:

Hi Richard,

the pedestals are an aluminium alloy.

The shaft is a rather soft steel. You can buy tuftrided shafts from Moss and others, I have one, but not installed it yet. The flat area’s are to aid lubrication. Make sure the bore is clean too because debris may plug the oil holes easily and check for alignment of the bore in head, pedestal and rocker shaft.

The rockers are made from cast iron I think. Avoid new repro ones, think Roger had a failure (fracture) a couple of years ago, do not know what caused it. The tips are insert-hardened, check for wear. I dressed a couple, but if you have to remove too much material replace them, because the hardened layer is not thick.

Cheers,

Waldi

Dank Je Waldi

I hope to keep the rockers, and buy a new shaft but will give the shaft a good scrub and clean.

Richard

Link to post
Share on other sites

I think Waldi is right about the rockers being cast iron--You get that characteristic powdery swarf when you drill them.  I didn't notice evidence of an insert on the tip, though . The tips are hard, maybe case hardened.  Removing 8 to 10 thousandths from the face didnt seem to expose soft material, just judging from a crude file test.

Ed

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.