The valvegear on the 2000's always been a bit clattery but not unusally so for an OHV engine with 80k on the clock.

It seems to have been getting worse recently so I adjusted the valve clearances this morning which, if anything, made it worse. They hadn't really closed up a great deal but I did have to loosen a few off slightly. I set them at .25mm (not 25 thou!!) although bearing in mind that the arms are probably worn, that's only approximate.

I had another tinker with it this afternoon in an effore to quieten it down and 'found' a stripped locknut on one rocker. It had been holding, but today's work finished it off.

One thing I did notice was that a few of the adjuster balls which locate in the top of the pushrods are worn and ridged. Is this normal?

I guess that the combination of worn out balls, shaft and rocker arms would certainly explain the noise and means that I may as well replace the lot. No way it's ever going to adjust properly if the balls are knackered.

Should I replace the pushrods too? Are the adjusters supposed to wear with the pushrods?

There's plenty of oil there so I don't think that's an issue.

Worn out rockers usually means - worn out rocker shaft. That is what makes the rattling noise. Originals were correctly hardened but NLA. As with many re-manufactured parts they never quite made such a good job, and they just wear out due to lack of hardening. An external rocker oil feed sort of helped the problem, but finally a specially hardened shaft is available; and that must be used. I can send you another rocker, or two. forward facing or rear ? Grind flush the rocker tips if the valve has indented; don't touch the actual rubbing surface which will be nicely case hardened. Pushrods rarely wear or fail - what sort of marks ? As long as the ball and cup is mostly polished metal, you can re-use them after a clean up. The ball should touch mainly around the edges and be a good snug fit in the cup. Very unusual to have to fit new pushrods.

Thanks for your offer of rockers, much appreciated, however I have access to some spare rocker arms should I need them.

I wouldn't be surprised if the parts on my car are the originals. It's always been noisy and has been on my list of things to do. 5 of the rockers are quite deeply indented and the shaft is worn. I'd say that 4 of the adjusters aren't fit to be re-used.

I've had a look at the pushrods and they all seem fine so I'll re-use them.

I take your point about the hardness of the rocker shafts. As an interim measure and in the interests of keeping the car mobile I've ordered the rocker overhaul kits from Rimmers. I'm hoping to get a few years out of this! My mate fitted one last year and after an intial period of bedding in, it seems to be bearing up well. Long term, sourcing a hardened shaft and re-facing some original rocker arms may be a better idea.

CW does hardened rocker shafts. He also lists rockers, but I'm unsure if they are originals or not.

My experience is that both the shaft and rockers tips wear. The shafts often because the oil holes get blocked so there is little lubrication between shaft and rocker. In fact the shaft can get so worn it's very difficult to get the rockers past the ridges!

When the tips are worn, it makes adjustment difficult. You either need a very narrow feeler or use one of those 'click' things. They do seem to work.

However, in general, it's better to have the adjustment too wide that too narrow!

Cheers,
Mike.

Excellent advice from Steve, and good follow-up from Mike. Herewith my own thoughts, for what they are worth...

I have doubts about the expectation that a rocker overhaul kit from Rimmers will last for years.

Does the kit include a hardened rocker shaft, i.e. made from hardenable steel, and actually hardened? Do the rockers have hardened tips? (Rockers of very similar design at Perkins were chill-hardened).

I'm confident that CW's hardened rocker shafts will be fine, but if buying from elsewhere I'd ask for the material spec in advance, in writing. It should be something like "BS 970 grade 080A47, hardened" (the old EN43B). If it is "BS 970 grade 220M07" (i.e. free-machining mild steel, EN1A as was), your money would be better kept in your pocket.

Mine was noisy all the time I had it and a previous owner said it was noisy when he had it 11 years ago!!1

Hi Dizzy, I’m interested in hardness quality ( of rocket shafts for instance ) Does EN … hardness increase with the number. I recommend EN24T for anti roll bars. EN36T would be hard enough for a tool cutter. So how hard is EN43 - but that is B ? Where does A fit in ?.
And how does all this compare with Rockwell or Hardness Vickers. What system is used for checking to-day. I know I should join Eng-Tips to find out.

Hello Steve,

I've been retired for nine years now, it's more than 20 years since I was directly involved with steel specs, and I was never a metallurgist, so don't expect a detailed answer! I'll do my best though...

EN numbers (which were formally dispensed with as long ago as 1972 if I recall correctly) related only very broadly to ultimate tensile strengths. Carbon steels for general engineering were mostly single digit numbers, alloy steels were mostly numbered in the teens and 20s, case-hardening steels were mostly in the 30s and nitriding steels in the 40s. Corrosion resisting steels were in the 50s as were some steels used for engine valves.

There are exceptions. For instance, EN43A was a carbon steel in amongst with those with single digit EN numbers. I don't know how that happened but, since it comes between EN8 and EN9 (the strongest of the carbon steels) in strength, it may have been a later addition. All three can be hardened and tempered but I suspect not case carburised (i.e. 'case hardened' though this term is a bit colloquial, meaning any process where a hard surface overlies a softer core, such as in gas nitriding.)

I'm not sure where EN43B fits but suspect it is similar to 43A but with better control of chemical composition to give more reliable hardening. Certainly the "A" in the 080A47 that replaced 43B means that it must have a certain chemical composition. The mechanically similar EN8 was replaced by 080M40 where the "M" means it must meet certain mechanical requirements, the chemical composition being more open.

So, a rocker shaft made from 080A47 will be at the upper end of the carbon steel range and specially formulated for hardening. One in the very common, free-machining, 220M07 will be of a mild steel that cannot be hardened - probably OK as a door stop though.

Rockwell and Vickers numbers indicate the hardness irrespective of the material the part was made from, so difficult to correlate. We always used Vickers at Perkins but I think I came across Rockwell in US specs. As you probably know, the Vickers test (and perhaps the Rockwell) is carried out by dropping a round-ended 'pin' onto the surface of the metal with a certain force, then measuring the depth of indentation.

That was exciting stuff, wasn't it?

I think all of Chris Witor's stuff is reproduction.

My old rocker shaft certainly has some good wear ridges although I'm not taking it apart until I have the new bits in front of me. Without a reference, I'll never remember how it goes together!

The wear to the adjuster balls was causing an issue too. Some didn't seat in the pushrods correctly due to a wear ridge which I think was leading to variable levels of rocker noise which I had begun to notice. The wear ridge also meant that accurate adjustment was impossible as depending on where it caught the pushrod, it either had no effect or a huge effect on the valve clearance! On the most worn of the arms, there was barely any more adjustment to tighten the valve clearance.

One of the first things I noticed about my car was its clattery valve gear so, 4 years later on, I think I've had my money's worth!

If I recall, the original rocker arm pads were hardened to a depth of 1.5mm and the workshop manual advises against re-facing them.

I'm aware that there is a lot of talk about the quality of remanufactured items but as I say, my mate has fitted the Rimmers rocker kit to his car and seems happy with it. It's not as if I cover a massive annual mileage or spend a lot of time at high revs so it should keep the car mobile for some time to come. I don't want to have the car off the road for any longer than necessary. If I have concerns about the quality of my new parts then I'll have time to source some better quality replacements whilst still being able to use the car.

Hello Sorbs,

I understand the advisory of not re-facing rocker tips, but what Steve referred to was to grind away the overhang portion on the tip, leaving the area that directly operates the valve (It would be difficult, if not impossible for most of us to grind that area accurately enough anyway). This will remove any error due to wear when carrying out the measurement with feeler gauges. For all out performance engines, this means that quite a bit of excess weight can be trimmed from the rockers to minimise the inertia in the valve train.

Alec