Jump to content

Recommended Posts

I’ve just fitted a new rocker shaft from Moss which included phosphor bronze bushed rockers. A nice piece of kit. However I thought it prudent to report the difference between old and new rockers and seek comment from those of you with experience on this subject. 

After a 50 mile or so trip the engine developed a severe tappet rattle and uneven running. Removed rocker cover and found the rocker shaft oil gallery sealing plug lying on top of the cylinder head. Being starved of lubricant the exhaust rocker on no 2 cylinder had worn oval and the shaft was quite badly scored at the rocker positions for cylinders one and two. The small oil gallery in the shaft feeding the rockers at these positions were also blocked. So problem identified and new upgraded parts ordered and now fitted.

The new rockers each had a small oil gallery drilled a) on top and b) adjacent to the push rod clearly to lubricate moving parts - rocker on valve stem, and adjuster screw to push rod socket. The old rockers were different. They all had the gallery feeding the push rod but only three rockers had the gallery on top for rocker to valve stem lubrication. Is this a known issue? How on earth can there be rockers out there without that top oil gallery? Was there a modification by Triumph during production or is it just an error in parts supply? (PO had completely rebuilt the engine). Certainly lack of those galleries on the rockers must inevitably lead to premature wear of the assembly and give rise to a noisy / tappet rattle which has been an issue for me over the recent past. Alternatively missing oil galleries will result in higher oil pressure perhaps so is there a deliberate trade off for one at the expense of the other?

Slightly baffled and would appreciate opinion.

Cheers,

TonyC

 

 

Link to post
Share on other sites

Hi Tony

You have just described what I cannot get my head round why this has not happened to 2.5Pi's?  The rockers fitted to the TR5 and TR6 are part numbered 109023 and 109024 and have the very small drilled hole in the top of each rocker to aid lubrication. However the 2.5pi rockers which should have be identical are numbered 139896 and 139897 and certainly do not have the small lubrication drilled hole. Outwith this drilled hole they are identical so how come the 2.5pi didn't need this vital drilled hole then?

Alan G

Link to post
Share on other sites

Here's my rocker shaft and rockers purchased from Chris Witor complicit with holes in the rockers and split pin.

This post has me thinking should there be a spring washer (Part 40) I forgotten beneath the split pin. The new shaft has no plug either at the front (No1 Cylinder) and is solid at the back. The plugs NCA. Do these new aftermarket shafts not need a plug or spring washer?

She's not run yet so it would be good to know before hand.

Thanks

Andy

IMG_1114.jpeg

IMG_1119.jpeg

IMG_1118.jpeg

Link to post
Share on other sites

Roger, the Brown book calls out the split pin keeping everything in place and the springs compressed on the shaft. Haynes manual shows ‘end caps’. The split pin is not quite Heath Robinson but perhaps a little under engineered. Anyway my shaft seems to be as intended in that respect.

Alan, this variation in rocker oil galleries has to be under the banner ‘continuous improvement’ during production. My only dilemma now is to understand which came first and why. It may be sensible to assume the rocker with two oil galleries came as a mod to improve lubrication, or did the rocker with the single gallery come later to increase oil pressure? Neither gives me a warm fuzzy feeling as there may be a down side whichever type you use. Ouch! Once I get everything back and the sun comes out I’ll getting nice and warm and see what happens to the oil pressure. Watch this space.

A Chris Wittor chat might be interesting John. I’ll wait until after my test drive.

Thanks for all your input gentlemen.

TonyC

Link to post
Share on other sites

Andy,

Thanks for your pics. 

I’ve seen the spring washer on the exploded diagrams. Mine had neither a spring washer nor a plain washer when I took it off, but I did fit a plain washer on reassembly. Can’t grasp the benefit of a spring washer in that application as springs on the shaft keep it all in tension.

The rear pillar oil gallery plug has I believe two main functions, a) to prevent the shaft rotating in the pillars, and b) to align the oil gallery opposite the gallery plug with the oil feed from the cylinder head. I’m not familiar with Chris Wittors solution but as long as the shaft is fixed and head Vs shaft galleries are aligned it’ll be fine. Liberal coating of the rocker shaft assembly in oil just prior to start up and then check to make sure the oil is bleeding from all of those rocker holes. It all looks very nice. Something about a clean, shiny I.C.E. I’m guessing that rocker shaft isn’t torqued down yet - length of engagement of nuts on studs etc. Good luck with the project.

cheers,

TonyC

 

Link to post
Share on other sites
35 minutes ago, PodOne said:

Here's my rocker shaft and rockers purchased from Chris Witor complicit with holes in the rockers and split pin.

This post has me thinking should there be a spring washer (Part 40) I forgotten beneath the split pin. The new shaft has no plug either at the front (No1 Cylinder) and is solid at the back. The plugs NCA. Do these new aftermarket shafts not need a plug or spring washer?

She's not run yet so it would be good to know before hand.

Thanks

Andy

IMG_1114.jpeg

IMG_1119.jpeg

IMG_1118.jpeg

Hi Andy,

the nuts on the pedestals appear to be not in full contact, are the studs the correct length?

Edit:
And yes, both ends need to be closed, so the (limited amount of oil in this area) can flow where it is needed.

Edited by Waldi
Plug comment
Link to post
Share on other sites

Thanks for the replies chaps.

Long time since I rebuilt the engine now but everything was well coated in assembly lube Chris which will be repeated prior to firing her up. 

Waldi I found some other pics of the new rocker assembly which is torqued down fully and I think there is a plug in the rear end, front I cant tell so will check when I take the rocker cover off. Sticky label applied or I'm bound to forget:rolleyes: !!  

Some other pics of the old and new rocker assembly had the two Spring Washers (Part No 40 on the inside of the pedestals back and front so hopefully assembled correctly. Thinking about it there would be no sense the washer being on the outside at the front.

Checked the old shaft and it had knock in plugs back and front.

Andy 

Link to post
Share on other sites

Andy,

those spring washers are to hold the rocker against the inner face closest to the mounting hole of the front and back pedestal. Your pics look correct.

Just completed a test drive after the refurb. Sounds infinitely quieter and running sweet again. Just a bit gutted that I didn’t pick up on this a bit sooner. Anyway could all have been a lot worse.

Thanks again.

TonyC

Link to post
Share on other sites
On 5/23/2022 at 8:58 PM, cp25616 said:

Hi Tony

You have just described what I cannot get my head round why this has not happened to 2.5Pi's?  The rockers fitted to the TR5 and TR6 are part numbered 109023 and 109024 and have the very small drilled hole in the top of each rocker to aid lubrication. However the 2.5pi rockers which should have be identical are numbered 139896 and 139897 and certainly do not have the small lubrication drilled hole. Outwith this drilled hole they are identical so how come the 2.5pi didn't need this vital drilled hole then?

Alan G

Yes an interesting thing

The 'sportscar' range Spitfire ,GT6, mk2/3, TR250/5/6 all list 109023 & 109024  whereas Big Saloon/Estate & GT6 Mk 1 listed the 139896 & 139897.  I do not have a Vitesse, Herald , Vanguard Dolomite etc IPC to check.

As one who sold both types I confirm that the deilled hole in the top was the only obvious difference (and the price of about &2.00 each rocker in the 1980's)

Have you also spotted the engine valve part number change by one digit between saloon and sports car?  Price wise the 6 cyl TR valve was almost double the quivelent positioned saloon valve.  My guess is there was a material difference.  Certainly sold a lot to the trade and never had any moans.

Peter W

Edited by BlueTR3A-5EKT
Link to post
Share on other sites
2 hours ago, FatJon said:

I’m about to start building an engine so this caught my eye. Surely a rocker shaft which is open at either or both ends is just going to pee out any oil fed into it and not do much at all towards lubricating the valve gear. 

Agreed.

Hold it up to the light.  If light shines through, it will ruin your rockers in very quick order.

Original Triumph shafts did not have the end plugs fitted, you had to fit your own before fitting the rocker shaft.   On our stock bin for rocker shafts there was a sign saying !!! Sell with end PLUGS.  137811 !!!

Peter W

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.