Valves

[TR674]

Gents
I had my valve replaced and the rocker shaft cleaned. I re-assembled the engine with all the required new gaskets and torqued everything as per the Triumph manual.
I tried to start the car and it will only run on 5 cylinders and it makes a 'chuff, chuff' sound from no.1 cylinder. A sound similar to a partially unscrewed spark plug or a removed injector nozzle.
There are no leaks from the inlet/exhaust manifold, tappets set correctly, injectors working and in correct order and also the spark plug leads as they should be.
I will check compression on no.1 to see it the head gasket has failed or a valve is not seating, other than that I am stumped as to what is going on here. Any suggestions would be appreciated.
Regards
Craig

 

[aeronca65t]

Turn it over with the igntion disabled and the valve cover off.
Observe the valves on the "dead" cylinder. Are they snapping closed like all the others? Or are they "hanging open" for a moment.
You may have a partly seized valve in a valve guide. Sometimes, a solvent forced down the guide can help (plus just running it for a while).

 

[Andrew Mace]

Craig, the "chuff, chuff" sound worries me. Hopefully this is NOT the case, but that noise might well be the result of a hole in the piston or similar cylinder problems. Years ago, I burned a piston on a Volvo B-18 engine, after which that cylinder made pretty much that exact "chuff, chuff" noise. :frown:

 

[TR674]

Aero
that makes sense. I will lubricate valves 1 & 2 stems and see if that helps.
Andrew, pistons are all in good condition when I put the head back on. I'm inclined to think it is a dry valve guide causing the valve to close slowly (I'm praying actually!).
Thanks
Craig

 

[TR674]

I hesitantly decided to close this post, very red faced, just so others might not do this.
I rechecked my tappet clearance over the long weekend and found I have the sequence out, resulting in valve 2 and 5 being partially open on the compression stroke. How did I manage that I ask....
Oh well, she is purring like a kitten now........all is well (with the motor anyway).
Regards
Craig

 

[Brosky]

Craig,

Anyone here from the "old days" who had to learn to adjust valves screwed up something along the way, or they never got their hands dirty.

All it takes is one distraction and you can skip a cylinder or miss something.

You can guess how I know this to be true.....several times.

I learned to never completely put the tools away until the car was warmed up and idled quietly for a while.

 

[Tinster]

Yo Paul ---

Remember when this non-mechanic tried my very
first valve adjustement? I think it took me an entire
day, maybe longer!


I posted a video so the members could listen to my valves going up and down-

clickety=clack!!
d

 

[DrEntropy]

A valve tappet adjusting "tool" I find very helpful is a yellow "construction" crayon. Run the adjustment in sequence using the crayon to mark each adjusted rocker as it's done. Then RUN THRU them again(!) to double check and wipe the mark OFF each as it is done. You'll become so practiced at this it'll become second nature and take no time at all. AND the peace of mind that you've done it correctly.

 

[Roger]

I always used the "Rule of Nine". When no 8 is fully open, no 1 is fully closed, so adjust its clearance. Then in sequence of valves, not cylinders. I also used a little blue instead of chalk - you don't have to wipe it off!

 

[TR3driver]

I hesitantly decided to close this post, very red faced, just so others might not do this.

Naw, I've never done anything like that ... NOT !

Just glad it turned out to be nothing serious !

And that's exactly why I don't use the "rule of nine" ... with my method (turn cylinder to TDC then set both valves on the cylinder that is between compression and power) I don't have to worry about whether seven plus three is nine or not (it's 12 in octal).

Just turn the engine through two complete revolutions, doing one cylinder every time one comes to TDC, and it's done. Every time, no matter whether it's 4, 6 or 8 cylinders; in-line or Vee. Don't even have to know which cylinder number is which (they are confusing on the Stag V8, since it's timed at #2); only which one is at TDC with the valves closed.

 

[martx-5]

I used to use the rule of nine on the four bangers, but when I was adjusting the valves on the rebuild, I ran into problems. I therefore have adopted the <span style="font-weight: bold">"Randall Rule"</span>, and find it much easier. Since on a four cylinder, once you have the first or fourth cylinder at TDC (where the timing mark is), the next one is exactly 180 deg from that. Since the engine was out of the car, this was easy to do with a rachet and socket. Stick the ratchet handle straight up, then turn the crank 'til it's straight down. I then filed a mark for TDC at the 180 deg position. Future valve adjustments in the car will now be a breeze. For you six cylinder guys, the marks would have to come at 120 deg and 240 deg I'd imagine...giving you three sets of TDC marks.

 

[piman]

Hello all,

the thing is the Triumph six cylinder manual lists the order of setting, and I have never come across another engine where you set two valves at the same time. (Maybe the four cylinder Triumph is the same?) It does follow the rule of 13 for a six though.

To clarify, the book starts with valves 10 and 12 fully open, adjust valves 1 and 3 etc.

Randall, I'm not so sure about your method, as don't believe that the followers are truly on the base circle of the cam so there is room for error I feel?

Alec

 

[TR3driver]

Both valves are fully closed for both compression and power strokes; so both lifters should be well onto the base circle with the piston at TDC between compression and power. The only room for error is if the base circle is mis-ground on the cam (and then who is to say which part of it is 'right' and which part is 'wrong' ?)

BTW, this is the method given in the TR2-3 factory workshop manual; although the driver's handbook ("Practical Hints") gives a different procedure. The "Rule of 9" is only mentioned in the Haynes manual.

And for "even fire" engines (which includes all Triumphs AFAIK), an easy way to see when when a cylinder is at TDC is to look for both valves moving at once. When they are at roughly the same opening, that cylinder is at TDC between intake and exhaust, which means the opposite cylinder in the firing order is at TDC between compression and power, hence ready to have it's valves set.

 

[Roger]

Randall's way is O.K., just more crank twiddling than the rule of 9.

Indicentally, is it common parlance over here that 'TDC' means Top Dead Centre (Firing)? Back home we always distinguished, where necessary.

 

[TR3driver]

Randall's way is O.K., just more crank twiddling than the rule of 9.

Actually, no more crank twiddling than the other way. With either method, you have to move the crank 4 times (for a 4 banger) or 6 times for a 6. Turn it either forwards or back (I usually find backwards to be easier for me, just put it in 4th gear and push the car back) through one complete cycle (two revolutions).<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Indicentally, is it common parlance over here that 'TDC' means Top Dead Centre (Firing)? Back home we always distinguished, where necessary. [/QUOTE]Can't speak for everyone, but I try to always distinguish where necessary.

Another one of those fun mistakes to find : setting up the ignition to fire the cylinder that's at TDC with the valves open ... nearly got frostbitten toes trying to figure that one out !

 

[tomshobby]

Learned how to adjust valves in the 50's. Did not know it was so complicated.

I like Doc's explaination because it is simple and it works. Other ways are fine after the concept is understood and practiced.

A valve tappet adjusting "tool" I find very helpful is a yellow "construction" crayon. Run the adjustment in sequence using the crayon to mark each adjusted rocker as it's done. Then RUN THRU them again(!) to double check and wipe the mark OFF each as it is done. You'll become so practiced at this it'll become second nature and take no time at all. AND the peace of mind that you've done it correctly.