Rule of nine

[142 Guy]

Originally Posted by c1800

I haven’t cross referenced this valve adjustment method to the other methods mentioned, may be similar, or not.

Phil Singher is a noted B18/B20 performance engine builder. You might find the other topics on the VClassics website interesting too. Just go the Archive Index.

http://www.vclassics.com/archive/vadjtip.htm#top

Cheers

The Rule of Nines and the method described by Phil S require that you evaluate the point at which a valve is fully depressed. Depending on the profile of the cam that may not be so easy. Since you should not rock the crankshaft back and forth to determine the max point you potentially could be rotating the engine a lot more to confirm the full open point than with the Volvo FSM method. Camshafts with a 'broom stick' profile will be a particular problem. You probably should be using a dial gauge to confirm maximum opening. Rotating the crank to the TDC marks and checking to confirm whether it is cyl 1 or 4 that has both rockers loose eliminates the subjective assessment of whether a valve is fully depressed or not (if you lack a dial gauge).

For those newish to the game, the bigger factor is the feeler gauge used to set rocker clearance. If you have an engine that has not had its rockers reprofiled in the last 10 - 20 k miles do not use a conventional flat feeler gauge. The rocker shoe develops a wear groove where it contacts the valve stem tip. You need to use a feeler gauge with a fine Vee tip and insert the gauge from the side of the valve (don't attempt to move the gauge front to back). You need to measure the clearance between the tip of the valve and the worn area on the rocker shoe. A large fat feeler gauge will give you the clearance between the tip of the valve and the unworn surface of the rocker shoe with the result that your actual clearance will be greater than the measured clearance.

[Ron Kwas]

Forum;

RoN requires me to remember some abstract rule...I don't bother because its all right there in front of me...staring at TDC#1 -Valves for No1 get adjusted, then I turn Crank 180Deg, adjust Valves for No3, then turn to Timing marks to TDC again (which is No4), adjust Valves, and finally, 180 Deg to No2, and adjust those...done! ...the only thing to remember is firing order...

I wasn't going to chime in on this much ado about nothing, but now I would like to thank 142 guy for mentioning an important factor: The error due to Rocker Wear Gap ...this adjustment error can simply be eliminated by narrowing your feeler gauge to less than Valve OD, like so:

Source: https://www.sw-em.com/service%20notes.htm

Cheers

[Bigbunt]

Thanks Ron.. the visual seals the deal. That's what I was remembering about the narrow feeler. Didn't mean to make a big deal of the valve clearance...I just got a little torqued about "other" comments. Nonetheless, good little reminder of this wear issue.
Right now I'm just trying to rebuild my crushed car shed before the New England winter settles in!

[Army]

Originally Posted by Ron Kwas

Forum;

RoN requires me to remember some abstract rule...I don't bother because its all right there in front of me...staring at TDC#1 -Valves for No1 get adjusted, then I turn Crank 180Deg, adjust Valves for No3, then turn to Timing marks to TDC again (which is No4), adjust Valves, and finally, 180 Deg to No2, and adjust those...done! ...the only thing to remember is firing order...

I wasn't going to chime in on this much ado about nothing, but now I would like to thank 142 guy for mentioning an important factor: The error due to Rocker Wear Gap ...this adjustment error can simply be eliminated by narrowing your feeler gauge to less than Valve OD, like so:

Source: https://www.sw-em.com/service%20notes.htm

Cheers

I can kinda see where you are coming from with that Ron...

...but if we're delving into details I'd like to make the following points:-

1) It seems like I've become an avid collector of feeler gauges - in an attempt to "always be able to find a set" I've ended up collecting many. All of the commonly available sets I have, have tapered ends and a final rounded tip that's about 5mm wide.

In my experience this width is comparable with the contact areas (you are meant to measure for maintenance purpses) in most automotive valve trains.

In practice I think it would be difficult to replicate the left hand situation in your graphic - but fair enough - it is something to consider

2) In my experience even the best engine builders seem to pay very little attention to the "actual contact" surfaces in valve trains. Sure people look at the wear of parts when dismantled but they tend not to focus on how these parts actually fit together.

On many different engine types I've noticed that if you shine a torch on one side of the engine and look through the clearance the gap, more often than not the contact is visibly out of whack.

With experience you can feel this with feeler gauges - you can feel the unevenness of clearnace gaps.

This is not necessarily wear at the clearance gap. In my experience this is due to poor fitting parts and wear at the pivot points.

Keep an eye out for new parts - rocker arms for example are not always as nicely reamed as they should be (yes FEBI - I mean you - sorry Mercedes reference...)

######

In the past when I have rebuilt engines I have done my best to make sure that the valve clearance gaps are as even as possible when I have been reassembling with new parts:- It takes a lot of time. I'm guessing that's why many engine builders - even the good ones - prefer to spend their time and your money polishing valves and porting heads instead of select fitting rocker arms!

######

If people wish to delve into the detail of these mechanisms I think their time is best spent considering the wear of the pivoting parts and ensuring the lubrication of the top part of the engine is working correctly.

For the old fashioned push rod engines that more often than not in modern traffic have to work a bit harder than the more modern engines (with camshafts positioned higher up closer to the valves) I think that looking for bent push rods is a good plan.

######

I'm NOT saying people should be taking valve train components apart with frequencies of the valve adjustment service intervals.

After removing spark plugs / glow plugs on diesel engines - simply watching the valves rise and fall as you turn the crank and making sure the distances are similar whilst you are adjusting valve clearances is more than sufficient.

I'm just saying "look at the trees and the wood"!

When you are adjusting or checking a particular valve clearance I think giving a rocker arm a sideways wiggle is also worth while. Compare that feeling with the others. If you find one that is particularly loose it might be worth your time taking things to bits to see if there is trouble,

If your valve train is rattly - particularly after you have adjusted the valves - stop! Think about it! Perhaps you need to have another look at it...

[Laird Scooby]

Originally Posted by Army

If your valve train is rattly - particularly after you have adjusted the valves - stop! Think about it! Perhaps you need to have another look at it...

Something not yet mentioned is feeler gauge technique. Many people don't get them exactly square to the gap they're measuring and don't realise there will be friction on the blades as they are dragged through the gap. They won't fit in if the gap is too tight but will drag a lot if it is correct. A smooth, easy sliding fit means the clearance is loose as there is obviously clearance for the blades which there shouldn't be when measuring the gap.

[Underdrive]

Originally Posted by AndrewBrown

Bigbunt

It seems that at the moment the world is full of people who seem to think
they know everything about your current President and are experts in his
personal traits and personality


I think I've heard it called T.D.S or Trump Derangement syndrome*


*Although present in some people in the United States of America the condition mainly affects
people who don't actually live in the United States of America and are not United States citizens
so do not have the ability or right to vote in elections held in the United States of America.

most of these people don't actually have a valid opinion of the president's ability to govern the country
due to a lack of experience because they don't live there. This condition is usually made worse in their minds
because as a foreign national living outside the United States of America they think they know what's best for
the United States of America and because they don't experience everyday normal life in the United States of America.
As a result they think they know better than the north Americans who live work and pay taxes there.

In reality they should have the common decency to be quiet on the subject because
manners used to be taught as if you have nothing informed to say or nothing nice to say you should say nothing at all.

In short everybody berates your president knowing nothing about the man or his personality
and what he is really like and just repeat media driven lies.

Kind regards from The United Kingdom of Great Britain and Northern Ireland.

You don't need to be a genius, or live in America to recognise an arrogant, racist, narcissistic liar when you see one. I just hope there aren't too many of them driving around in classic Volvos letting the rest of us down.

[Army]

@Underdrive

(I was doing my best to ignore the post that you quoted)

I completely agree with you. After my personal experiences I have also been known to describe the country mentioned in post #2 in a much more derogatory way...

...however...

...this is a technical forum. I do my best to try and avoid subjects such as politics because such subjects can sour a forum and start needless ego rectifying actions that spill over into the technical domain.

This is not "my" forum

I'm not in charge

But I for one really would prefer not to see such posts.

[simonvolvo]

Who needs a feeler gauge?

16 threads of a tappet screw span a distance of 17mm.

Which means: For the required valve clearance of 0.50 to 0.55mm (B20B engine), you need almost exactly half a turn (28 to 31 minutes of arc, to be more exact).

Therefore: Loosen the lock nut; turn the tappet screw in lightly until it touches the valve stem; turn it back out half a turn; nip up the lock nut again (while holding the tappet screw with a screw driver to keep it from turning); and you’re done.

No worries about “Rocker Wear Gap”.

[Ron Kwas]

Simon;

...a great observation and comments...I'll have to try that next time, but it shows once again, that when you know what you're doing, or even have thought about things a bit, you can come up with multiple workable (and perfectly acceptable!) solutions...

Cheers

[Derek UK]

The Gunson Clickadust version of the original SPQR too works on that principle.
I've commented before on Ron's reasoning on grooved rockers. I've never see anything other than a shiny witness mark. The surfaces are hardened. Not long ago I did a light smoothing to a set I had on the shelf. Easy to do. That was to replace the ones on my Estate as I thought they might need a little TLC. When I took those off they looked just the same as the ones I'd refurbed. I think I posted some pics. I think I also asked for people to check any that they had or were willing to take off their engine. I asked for pics if they found any worn into a trough. No pictures were forthcoming. I'll repeat that request.
Do you have pics Ron? I've seen this fault in diagrams on the web but have not seen any actual picture of it in the metal. It would have to be caused by lack of oil to the rockers along with considerable neglect over a long period. IMO.