Rocker Oil Feed

[68spitfire]

Hi all,

 

Checked my tappets through yesterday, only one needed adjustment by a couple of thou'

 

Decided to run the engine with the rocker cover off to check the oil delivery to the rockers.

 

So I blocked off the engine breather to make the engine run smooth first.

 

On running the engine not a lot happened at the top end, only a small amount of oil was visible starting to bubble through the small hole on the top of the rockers.

 

I did notice that valve 5 (from the front) did not have any oil at all coming from its hole.

 

The question is firstly, how much oil should flow from the holes on top of the rockers?

 

Just a drip or a constant flow? Obviously not squirting into the air!

[Pete Lewis]

its possible over the years some of the shaft , rocker scroll and the splash hole get clogged up but

the feed is taken from the rear cam journal which has a slot/flat on it this allows pressure from the back  journal/oil gallery to feed up the head to the rear pedestal and gives a short squirt once in every revolution of the cam , so the flow is interrupted not constant

 

fitting the dreaded external feed gives far too much oil in the rocker /valve chest and oil down the valve guides gives you Smoke.

 

even if its restricted with a 1mm plug its still excessive in most cases 

 

john has a term for it ???

 

Pete

[68spitfire]

Hi Pete,

 

I do have oil getting up there, its very little just a drop eventually oozing out of most of the holes though I would have thought it would be more to be enough to run down onto the space between rocker and valve top.

 

As one appears to have no oil exiting the hole I think I should maybe strip down the rocker assembly and check for any blockage, especially on that rocker.

[Pete Lewis]

thats sounds a plan , there is not much from this interrupted supply , if you remove the rocker shaft and  pedestals you will see the small hole in the head which aligns with a hole up the rearmost pedestal

 

if you crank the engine over   you will see oil lift up the hole in the head , its not a magnificent amount  when running at full pressure its obviously a good bit more than on the starter.

 

but its lasted all these years  ,  do make sure the pozi/phillips   screw s fitted in the rear pedestal to secure the shaft ,if this falls out you dont feed the  rockers.

 

Pete

[68spitfire]

Well, what a productive evening.

 

Out in the garage, rocker gear off.

 

Wiped off all of the oil on the top of the head and spun the engine over with no plugs in.

 

Oil came bubbling up out of the hole so I know its not something lower down.

 

Stripped the rocker assembly down and cleaned everything.

 

A fair bit of carbonised oil in some of the rockers machined pivot hole as it looks like there is wear in the hole and on the shaft.

 

A couple of the valve stem heads look slightly damaged i.e. eroded due to lack of lubrication.

 

The rockers themselves have wear on their contact patches.

 

Pity really as that was a recon unleaded head many years ago and if any worse will now need taking off and new valves fitted.

 

The rocker assembly is original and not part of the recon head kit.

 

Anyway, all is now back together.

 

Ran the engine without the rocker cover and oil appears to be evident out of all the holes on the rockers, well there are spits of it at ticker and up to about 2000 rpm.

 

I guess at normal operating rpm with the pressure up there would be more oil evident.

 

On to the next servicing task tomorrow.

[Pete Lewis]

You can next time its off reface the rubbed worn pad of the rocker

makes feeler fit a better feel

 

wouldnt worry too much about the stem its not uncommon keep an eye on it if tney get noisy due to

the rub of the rocker then think about replacements

 

this is the utopia or compromise conundrum based on how many miles you do and ££££

[JohnD]

OE, the face of the rocker arm where it meets the valve tip was case hardened, so in theory once you wear through that the underlying metal is softer and will wear faster.    Grinding away the face to remove a wear pocket will have the ame problem.    But how fast will wear occur in a hobby car with limited mileage?    And is the underlying, native metal actually that soft?  Marcus has some interesting views (as always!): http://club.triumph.org.uk/cgi-bin/forum10/Blah.pl?m-1384638994/

 

Then, can you regrind the correct shape on the rocker tip? So that it is not exposed to excessive pressure?   I wonder if the tales of rapid wear after regrinding are due to this, not soft native metal.

 

Lastly, if you can work with its intricacies, the "Clickadjust", AKA SPQR tool, is designed to work around any pitting of the rocker tip.  

 

John

[Pete Lewis]

as  an industry normal most rockers are probably induction or flame hardend at the wear face the rest of the rocker is just as cast

 

so the depth of hardness is better than case would develop  .  justa thought 

 

what we need is someone with a hardness meter to check the indentation hardness of a worn face

 

and johns right its careful work to keep the rocker contour close to OE and square to the axis .

 

you cant just hack away with a grinding wheel   we made a wooden jig to control the sweep and suchlike 

 

Pete

[sulzerman]

Hi

I have an external oil feed fitted, can this cause excessive oil consumption?

Thank you

[Pete Lewis]

Paul in a sentence ....yes there are no oil seals on the valve stems and the excess oil gets vacuumed down inlet guides and gravity down the exhaust when standing

can be enough to give you whiffs of blue smoke after overrun.

 

If you like the idea it needs plugging to restrict the flow , or you take valuable oil supply away from the crank, to supply something that doesnt really need it

 

The rockers will probably wear due to the loads and rubbing design with or without the extra feed

 

its the oil quality that makes more difference, need plenty of zz'ds

 

pete

[Clive]

yes.

you usually end up with loads of oil around the rockers, most of which would be better off at the bottom end.

And the excess oil finds its way down the valve guides, making the engine smoke or at least burn it off.

 

O know of one, fully rebuilt engine that was done to a high spec, supplied with an external feed. Chap mentioned it was burning oil, I suggested revoving the external feed, and indeed that did the job.

 

If you want the external feed, then blank off the original oil feed in the block and the head, then the high pressure feed needs a restrictor,  under 1mm bore IIRC.

 

(great minds eh Pete??)

[Pete Lewis]

Clive , Oil be seeing you

 

sorrry cats got me up early

 

need to let the parrots out and MOT at 9

 

no stress ha !

 

pete

[Clive]

WARNING...thread drift

I have to work today,but taking the spit for EFI mapping tomorrow. But it is over 100 miles, and the basemap is very iffy. Then got to get the car finished off to take to Spa. Where I fully intend to give it a damn good thrashing.

How hard can it be??

 

as you were....

[Pete Lewis]

 Clive,  is that a john cleese damn good thrashing or a tyre squealing errotic burst of enthusiasm  ??

 

since when have we worried about a bit of 'drift'  on ere

 

Pete

[Clive]

If it fails at one, it will be getting the other.

Last time a german bloke in a Cobra (ish) thing with a V8 came and wanted to see under the bonnet. He was struggling to keep up. That was with teh other engine, and EFI 1800 zetec. This one is 2 litre with a bit of VVT chucked in. Exciting stuff, I hope.

Ought to report back re power etc after tomorrow. I just hope I won't be disappointed....

[JohnD]

I'm looking forward too to Spa, but in June, at the CSCC's Summer Classic.

http://spasummerclassic.com/en/

 

John

[AtRo Racing]

     I installed the External Rocker Oil Feed Kit over 50,000 miles ago on my 1972 Triumph GT6 MK 3. I installed this to quite down the noisy rocker chatter caused by lack of oil. when installing this kit I installed a “Tee” into the oil pressure sending port on my engine. I have been setting the rocker clearance at .010 COLD. I do not have any valve seals on the head. I only use Brad Penn Oil and have never had any smoke at startup or while running at any speed. The valve train is surprisingly quite. The engine uses 1/2 -3/4 of a quart of oil between oil changes which are done at 3000 miles.  Perhaps the others bad experience with the External Rocker Oil Feed Kit is caused by a worn engine or the wrong grade or type of oil.

just my two cents,

Robbie