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Off my rocker

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OK, sorry to keep this going but...if in fact your "rockers are tight" as others have mentioned the test for this would be to check the valves that are fully shut (valve side up, pushrod side down) and see if it moves freely, it should. In fact unless your engine (or at least your rockers and shaft)was recently rebuilt it would be very unlikely that your rockers are tight. If they were too tight the valves would not close and the engine would not run, if they are were a little tight they would loosen up on their own over time, so if the engine has been running for several thousand miles since the thing was monkeyed with I doubt if the rockers being tight is your problem.

If they are in fact too tight, and I doubt they are, this sounds like perhaps a misunderstanding or mistatement by your mechanic, but if they are too tight but loose enough for the motor to run, removal of the rocker assembly and some careful work with some fine sandpaper would probably be all that would be needed to get that slight bit of clearance needed to loosen it up.

I assume it was your valve lash that was too tight, as others have mentioned this is a routine maintanance job that should be checked/adjusted as stated in the owners manual, and it will make a difference in how much noise or clatter your car makes from the valve train, and can be very bad if you get too far out of adjustment.

Excuse me if everybody already knows this, but the rockers being tight would relate to their fit on the shaft that runs the length of the engine on top of the head, visable with the rocker cover off.

The valve lash and general pictures of the head and valve adjustment are illustrated and explained pretty well here.

https://www.macysgarage.com/myweb6/valve_adjustment.htm
 
Hello, glemon,

My engine was rebuilt back in Jan-May 2010, and I have been driving the car since then (about 6000 miles so far). The engine runs very well on the highway (idling is another matter, but I'm working on that). I was unaware that anything was wrong with the valves or rockers until my mechanic told me that someting (valve? rocker?) was too tight. He adjusted the valve lash, and was satisfied that all was well. I couldn't tell any difference in the way the car ran, but it did seem to be a little less noisy.

From all these good forum responses, I believe that what I need to do is to check the rocker clearance (valve gap?) when I work on the car this winter. In fact, some people have told me that I should check this periodically or from time to time since it is not a difficult process.

I thought I was raising a simple question, but, as usual, I see that there is much more to all this.

Sun is shining in the Shenandoah Valley!.... time to hit the road.

Happy Thanksgiving.

BTW: I finally found a really good definition of valve lash: "Valve lash is the measuremet of air space between the rocker arm and the tip of the valve stem during that portion of cam revolution where the lifter is riding on the base circle, the valvetrain is relaxed, and the valve spring is holding the valve fully closed. It is usually a pretty small gap, enough to be measurable with a thin metal feeler gauge between 10 and 20 thousandths of an inch (0.010-0.020). The lash can be changed by adjusting a screw on the head of each rocker arm, to bring it closer to or farther away from the valve stem."
 
Really, I don't charge much for recharging your lightening rods!!

Ed, I have chased my tail for weeks of my life over what a "someone" mechanic has said in passing. I guarantee your rocker shaft is fine, and you don't need to be in any hurry to check the valve clearances (or lash). The engine will talk to you...either making a lot of noise, or running very poorly...if anything was far off in the valve train. Just occasionally check the clearances at your convenience, and...

Just have fun!

Happy T-day and happy driving for those last few miles this year!

John
 
John,

My thoughts exactly. No problem checking the clearances from time to time.

As for lightening rods, Lucas made mine and they never need recharging.

Happy T-day to you, too.
 
One thing to take away from this thread is that not everyone uses the same terms for the same thing. I don't know what "someone" meant when they said one of your "rockers was too tight"; but there is a good chance they were talking about the valve lash being too small. (Especially since, as noted, it's almost impossible that one or more rockers is too tight on the shaft. The rockers have to slide down the shaft during installation, so it's quite obvious if they are tight enough to bind.)

Probably it's less true today, but the classic mechanic was someone who was very "good with their hands" and at visualizing mechanical things, while not so good at "book learning" and rote memorization. So it's not unusual to find a good mechanic that can't express themselves very well.
 
Randall,

As usual you have hit the nail right on the head! Are you sure you are not actually a philosopher?

The mechanic I am talking about (one of the very best), though relatively young, is one of your classic mechanics. Good at mechanical things, but not so skilled at communicating them to non-mechanics. The problem is not be that he cannot express himself well, but -- as with so many experts -- that he knows so much that these matters seem so simple to him that he believes that his explanation should be completely understood by anyone. What he doesn't realize, or perhaps has forgotten, is how hard it is to learn something entirely new.

When I went back at looked at the statement that accompanied is bill, I saw that he had "adjusted valve lash." So, there you have it....

As always, very beholden to you for your information, observations, and wise advice.
 
So going back to your very first post on this subject, Ed, was the "someone" who told you that your rockers were "too tight" the mechanic of which you now speak ?

Next time if you value the person's opinion, yet do not comprehend what he means, perhaps you could ask right then and there "What's that mean ?''
 
Ed - In one of your messages above, you wrote that the engine was re-built 6000 miles ago. If you look again at your definition you included, and the words "valve clearance" in Macy's diagram, you will get noisy valve gaps if there are indents or flats pounded into the curved end of the rocker are where the rounded end slams hard onto the flat top of the valve stem. I have used a hand grinder on mine in my 1958 TR3A several times over that past 53 years (189,000 miles) to get rid of this "flat" spot impacted into the originally rounded end. This lets me get the corect 0.010" valve clearance again. If you remove your rocker assembly and turn it over - and you find you have flat spots, you will need to grind or file them curved again. This can be done with the rockers still assembled to the rocker assembly. If, for example, you find some flat spots that have been pounded by 0.005" into the curve, then the 0.010" you are setting is really coming closer to a true gap of 0.015" - and this will make for noisy valve clearances.

If you also had new valve guides installed when the engine (and I assume the head was done at the same time) maybe the bores for the valve guides were not reamed enough (or at all) and it's possible that one or more of the valve stems are too tight in the valve guides due to the differences in the co-efficients of expansion of dissimilar metals, and this tightness may be slowing the valve in the guide leading to the noise and the idle problems you mention.
 
Poolboy,

Good point. I had the car in the shop to have a number of things done to it. The "adjusted valve lash" was not one of those things, and the mechanic mentioned the "too tight" thing just in passing. My focus was on the other things that he worked on at my request. My questions about valve lash have come only later, as I begin thinking about checking the rocker clearance.

If I asked him "what's that mean" every time he mentions something new, we'd be there all day. Great thought... but hard to pull off with a busy mechanic. Also, my little projects pale beside the restoration work this guy does. Most of the cars he works on are $150,000 to $400,000 cars. He's actually doing me a favor by taking time to work on my car, though he never says this. In this part of the world, there are very few mechanics who can work on British sports car, so there are few viable alternatives.


As a former Secretary of Defense once said: "You fight with the army that you have."

But I am learning... thanks to this forum.

Don,

You got my attention, but if this is to be done on my car, someone with more knowledge and better equipment than I have would have to do it, i.e. the mechanic who worked on it in the first place.
 
Boy that guy must really be special where a customer feels too intimidated to ask questions. Maybe the "soup Nazi" has a new occupation.
 
my opinion the mechanic probably gets less headaches from Ed, who appreciates him working on his British sports car, I bet those guys with the 400K cars go over their bill and complain about every minute he spent working and try to get the bill reduced to 0, I know people like that

Hondo
 
Soup Nazi! Ha, ha. That's a good one. Nooooo... he's not a soup Nazi, just very, very busy all the time. I don't feel intimidated at all, just don't want to take too much of his valuable time.

Here's a guy who, when he is restoring a $000,0000.00 Alard will drop things to balance my carburetors if I drop in unannounced.

Hondo is right. This fellow seems to appreciate the fact that I drive my car and that many of the expensive ones are "trailer queens."

Soup Nazi..... heh, heh, heh....

Boy, do I miss that Seinfeld....
 
Don Elliott said:
If you look again at your definition you included, and the words "valve clearance" in Macy's diagram, you will get noisy valve gaps if there are indents or flats pounded into the curved end of the rocker are where the rounded end slams hard onto the flat top of the valve stem. I have used a hand grinder on mine in my 1958 TR3A several times over that past 53 years (189,000 miles) to get rid of this "flat" spot impacted into the originally rounded end. This lets me get the corect 0.010" valve clearance again.
Click to expand...

Don,

I recall having the machine shop take care of this when I had them install new rocker arm bushes (course this was 25+ years ago so memory could be "fuzzy" at this point!). But now I'm wondering, are the rocker arm faces hardened in any way to reduce wear or are they supposed to be the wear point instead of the end of the valves?

Scott
 
Scott - The rockers themselves are made of cast "something-or-other" and I don't know if they ever get a hardening heat treatment when new. I just get rid of the excess and try to grind a curve back onto the rounded end again.
 
IMO, if the rocker tips are worn enough to worry about, then the bushings & shaft are probably worn just as bad, which can also cause noise and make it difficult to set the lash properly.

I sent mine off to RAS to be reconditioned some years ago, and I was very pleased with the result. For about what the parts would have cost me to do it myself, I got back a rocker shaft assembly that literally looked like it was new. The shaft, springs, adjusters and locknuts were definitely new; I am still not certain if they replaced the rockers or just did an outstanding job of reconditioning my old ones. If they were my old ones, they apparently plated them with copper or something, so they looked new. Only the pedestals and end caps were clearly the originals, nicely cleaned but obviously not new.

https://www.rockerarms.com/gallery.htm
 
I am a fan of Rocker Arm Specialist as well, thanks to Randall's tip a couple of years ago. Very nice work, I've used one on the 3A engine, and another is coming my way this week for the TR4 which is about to get some well earned rehab work?
 
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