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Discussion Starter · #1 ·
How did you check yours?
I`ve made a disc from stiff card which will go onto the exhaust camshaft. This is the Mk2.
I made one earlier, the Mk1, which was a complete failure. Got so many results it was a mess, took the best part of the afternoon.
I think the only way to do it, is to treat each cylinder as an entity.
Starting from TDC and turning backwards on the exhaust stroke, mark where the inlet valve opens. Then continue forwards for the other marks.
Also the exhaust cam shaft is rotating at half speed, so I got in a mess halving the angles.

Btw, on mine the spec says inlet opens 34 degrees (.8 in) BTDC, on the exhaust stroke (cant be any other)...so the hot exhaust gas is not only being pushed out of the exhaust port, its also being pushed into the inlet port until TDC.
Equally, for 34 degrees of induction both valves are open.??????
Or am I more confused than I thought?
 

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valve timing

How to do this takes too long to explain on a link like this and I'll probably still inadvertently mislead you somehow.

Google timing wheel pictures and get one you like and print and glue it to a piece of cardboard

Anyway, the timing wheel is centered on the crankshaft not the cam. I made up a needle that attached to the crank while keeping the timing wheel with 0 set to 12 noon. As the crank turned the dial turned with it to indicate its position. The dial is initially set to 12 noon with the cylinders at TDC. I marked the wheel where both valves should be opening and closing. Valve clearance must be set to 20 thou for this test. When the valve engages/disengages, that's your actual open and close. If actual matches spec your a winner.
Double check your engine number to confirm the valve timing specs but I think it is: IN from 34 deg BTDC to 55 deg ABDC and
EX is from 55 deg BBDC to 27 deg ABDC
 

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Also the exhaust cam shaft is rotating at half speed, so I got in a mess halving the angles.

Btw, on mine the spec says inlet opens 34 degrees (.8 in) BTDC, on the exhaust stroke (cant be any other)...so the hot exhaust gas is not only being pushed out of the exhaust port, its also being pushed into the inlet port until TDC.
Equally, for 34 degrees of induction both valves are open.??????
Or am I more confused than I thought?
Caulky,

Well both camshafts are a half speed. One valve action for
every two stokes of the crank.

As for the 34 degrees BTDC, you do not have a full grasp of
what is really going on in the engine, hence your confusion.

Think of the exhaust gas as a liquid like water. As water flows
it does not want to change direction once moving in a certian
flow path. This is way pipes water hammer. Anyway the exhaust
gas flow follows the same conditions. Once it starts to flow
out the exhaust valve it tends to make the rest of the gases
follow. Now here is the odd effect of a cross flow design.
As the intake valve opens, the perdetermined flow of the exhaust
tends to pull in the fresh intake charge into the cylinder.
Works just like a syphion jet well pump, again just like water flow.
So the intake gas charge is really dragged into the cylinder by
the exhaust event.

Now for us, a number like 34 degrees sounds like a lot, but not in
racing engines. Remember that your unit goes to 7,000 rpm at
will. Also large amounts of overlap are usually used in poor flowing
heads to start with so the exhaust event can drag more of the
intake charge into the cylinder.

Furthermore, you also have to overcome Valve lag. This is just
the amount of time when the engine is running, it takes for the
valve to actually open. It of course has to take up the clearence
of all the parts, some parts will actually compress a few thousands
of an inch and then the time it take to accelerate the valve
itself. All of these factors will lead to the need at higher revs to
open the valve at such an early point. Because the valve does
not follow the camshaft perfectly.

I hope this helps out,

Pookybear
 

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Discussion Starter · #4 ·
Thanks guys!
For this bike, the spec is as follows:
Inlet opens 34 BTDC (on the exhaust stroke)
Inlet closes 55 ABDC (on the compression stroke)
Exhaust opens 55 BBDC (on the power stroke)
Exhaust closes 34 ATDC (on the induction stroke)
Can anyone confirm the above, WRT to the strokes?
The timing case is on, so that`s why I`m using the exhaust (ignition timing) shaft.
This means that 34 degrees becomes 17, and 55 degrees is 27.5 degrees. Or have I cocked it up? It really depends on your datum.
I think I have to take the total angular distance (inlet 34 + 180 + 55 = 269), divide by 2 (134.5) and take it from when the inlet opens. And ignore what it looks like. Then calculate the result onto another disc.
I suppose the alternative is to use the alternator shaft, but this rotates anti-clockwise, and I couldn`t use the kickstart lever.

Now I`m not checking these in the `normal` fashion.
The head is not on...dont want to compress the new `thick` gasket. Which is .070 thick incidentally.
I`m doing the checks by pressing on the pushrods and feeling when the begin to move (or stop).
That`s a point, are the cams the same shape pushing up, as going down? (not faster [steeper] one way or the other). What I`m trying to say is, is the top of the cam central and equal, for both valves?
The reason for all this is because of the other thread...`nasty clicking on kickover`. The old piston crowns (+.040) LOOK exactly like the new ones. I`m trying to diagnose why and how this tick-tick occurs, and why only on the exhaust valves. At TDC both the inlet and exhaust valves are open at certain periods of the cycles. [I`m not even convinced that the pistons are hitting the valves...but what else is there?]
So I`m also checking where (angular) the valves are fully open, in comparison with the pistons.

Thanks for the explanation PB, its hard to grasp what`s happening at speed. To me, winding by hand, the 34 degrees (.8") seems enormous, but its only microseconds at high revs.
More fun/frustration today I expect.
 

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Thanks guys!
For this bike, the spec is as follows:
Inlet opens 34 BTDC (on the exhaust stroke)
Inlet closes 55 ABDC (on the compression stroke)
Exhaust opens 55 BBDC (on the power stroke)
Exhaust closes 34 ATDC (on the induction stroke)
Can anyone confirm the above, WRT to the strokes?
The timing case is on, so that`s why I`m using the exhaust (ignition timing) shaft.
This means that 34 degrees becomes 17, and 55 degrees is 27.5 degrees. Or have I cocked it up? It really depends on your datum.
I think I have to take the total angular distance (inlet 34 + 180 + 55 = 269), divide by 2 (134.5) and take it from when the inlet opens. And ignore what it looks like. Then calculate the result onto another disc.
I suppose the alternative is to use the alternator shaft, but this rotates anti-clockwise, and I couldn`t use the kickstart lever.

Now I`m not checking these in the `normal` fashion.
The head is not on...dont want to compress the new `thick` gasket. Which is .070 thick incidentally.
I`m doing the checks by pressing on the pushrods and feeling when the begin to move (or stop).
That`s a point, are the cams the same shape pushing up, as going down? (not faster [steeper] one way or the other). What I`m trying to say is, is the top of the cam central and equal, for both valves?
The reason for all this is because of the other thread...`nasty clicking on kickover`. The old piston crowns (+.040) LOOK exactly like the new ones. I`m trying to diagnose why and how this tick-tick occurs, and why only on the exhaust valves. At TDC both the inlet and exhaust valves are open at certain periods of the cycles. [I`m not even convinced that the pistons are hitting the valves...but what else is there?]
So I`m also checking where (angular) the valves are fully open, in comparison with the pistons.

Thanks for the explanation PB, its hard to grasp what`s happening at speed. To me, winding by hand, the 34 degrees (.8") seems enormous, but its only microseconds at high revs.
More fun/frustration today I expect.
Caulky,

Ok easy things first...

Yes it is very hard to see what is going on in something that
works is the scale of 1/1000th of second. So it is always
helpful to see it with other expamles. This will aways help
with problems as well if you know what is going on in there.

Next unless you have coustom ground shafts I do think that
they are a mirror image from start to finish.

I also do not have the specfic specs for your ride, but it sound
like you have the order right for the valves in reference to the
strokes.

However, the ignition timing shaft, are you refering to area of points
plate? That shaft will run at the same rpm as the camshaft. So the
angles will not be halfed in number.

Finally I do not really know what you are doing with the numbers.

I do know with the numbers you give the duration is 269 degrees
for both intake and exhaust. But note this is the total time and
not the standard durations given by most camshaft makers which
are usually set at degrees of movement at .050 inch of lift.

68 degrees of overlap on the valves. Good for this kind of engine.

And 250 degrees of seperation between the intake closing and
the exhaust opening. Not the same as lobe seperation. So if
the profiles are the same we can work out lobe seperation with
some fancy math. You come up with 201 degrees of lobe
seperation.

Ok if I am off because it is getting late and I do have stupid
moments, someone correct me, it will not hurt my feelings.

Pookybear
 

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Discussion Starter · #6 ·
I`ve got some results of this valve timing check, at last.
Left inlet opens 38 BTC ....34 quoted
Left inlet closes 110 ABDC ***ouch! into the induction stroke
Left exhaust opens 55 BBDC.... correct
Left exhaust closes 41 ATDC....34 quoted

Right inlet opens 38 BTDC....(34)
Right inlet closes 70 ABDC....(55)
Right exhaust opens 64 BBDC....(55)
Right exhaust closes 61 ATDC....(34)

This only a tentative effort to assess the situation. The test was done with no head torqueing and no rocker boxes. I tried to make a mark on my disc as soon as a pushrod moved up or stopped going down. Error margin probably a few degrees.
The left inlet closing will need to be repeated, but there was something odd.
Knackered camshaft??? Bent??? Oval bearings/shaft???
Overall, it appears that all of them are closing very late.
Maybe this is a worthless exercise. Hasn`t given any answers to my `clicking`. At their respective TDC the exhaust valves are closing and the inlet valves are opening...dont think the pistons are touching them. I dont think a thick head gasket is going to cure this problem.
Thought: I wonder if the exhaust valve stems are sticking in their guides? Or perhaps I`ve just cocked it up.
 

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I`ve got some results of this valve timing check, at last.
Left inlet opens 38 BTC ....34 quoted
Left inlet closes 110 ABDC ***ouch! into the induction stroke
Left exhaust opens 55 BBDC.... correct
Left exhaust closes 41 ATDC....34 quoted

Right inlet opens 38 BTDC....(34)
Right inlet closes 70 ABDC....(55)
Right exhaust opens 64 BBDC....(55)
Right exhaust closes 61 ATDC....(34)

This only a tentative effort to assess the situation. The test was done with no head torqueing and no rocker boxes. I tried to make a mark on my disc as soon as a pushrod moved up or stopped going down. Error margin probably a few degrees.
The left inlet closing will need to be repeated, but there was something odd.
Knackered camshaft??? Bent??? Oval bearings/shaft???
Overall, it appears that all of them are closing very late.
Maybe this is a worthless exercise. Hasn`t given any answers to my `clicking`. At their respective TDC the exhaust valves are closing and the inlet valves are opening...dont think the pistons are touching them. I dont think a thick head gasket is going to cure this problem.
Thought: I wonder if the exhaust valve stems are sticking in their guides? Or perhaps I`ve just cocked it up.
Caulky,

Yes by all means check the left inlet again, also check the right
exhaust closing time as well. You maybe looking at the wrong
stuff for the ticking. Engines are great transmitters of sound.

In the end you might just have to take the timing chest cover off
of the engine and take a look inside. Maybe a bad keyway or
key on the timing gears.

But first since you do have the head off of the engine. How are
the pistons for their clearance? Might be piston slap you are
hearing.

I wish I could have heard the noise you ride was making.

Would not hurt to look at the valve guides since you are this
close.

Pookybear
 

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i'm still at a loss over how you could be checking cam timing using a degree wheel mounted to the ex cam ?

did your piston to valve clearance tests check out ? sorry i'm trying to recall your previous thread .

just a thought , an exhaust leak at the head can sound exactly like a loud valve .

cheers Woody
 

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Discussion Starter · #9 ·
"i'm still at a loss over how you could be checking cam timing using a degree wheel mounted to the ex cam ?"

Well it aint easy. That was why I asked, in the first post, `how did you check yours? The latest timing disc is the Mk3:eek:
I find TDC...stick in plug hole...stick a piece of masking tape on the the case marked with a TDC line, turn the disc without moving the engine, to align and begin turning the engine forward in gear.

This way up is for the right cylinder...i.e. the right-hand inlet valve is opening at the top TDC, and the right-hand exhaust valve is closing.
As I knew roughly where/when the other valves were opening or closing, I continued to turn the engine forward.
But it may be better to do the right side first, and then find TDC for the left side and rotate the disc as appropriate. (turn the the disc 180 degrees) to the TDC marker. (the stroke info will be reversed)
The dotted lines are the `book` data.
Because this covers the full 4 strokes, it`s rotating half as fast as the crankshaft...so when I mark the valve timings, the angles have to be doubled...e.g. right inlet 34 degrees BTDC would be 17 degrees, etc. (mine was actually 18...36 degrees BTDC)
Of course, this not very accurate...one degree error on this results in two degrees really. And checking the the pushrods is easy when they`re opening, it`s not so easy when they`re closing...has it closed now or have I gone too far???
I do hope I`ve done this right:confused:
 

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In order to accurately time your CAM, you need to index it relative to your CRANK.

The ultimate setup is a degree wheel on the crank, index referenced to TDC, and a degree wheel on each cam, indexed via cam lobe reference markers.
 

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Discussion Starter · #11 ·
Yes GPZ I can understand that, thanks.
Latest results, taking care.
Left inlet opens 25 BTDC (34)
Left inlet closes 72 ABDC (55)
Left exhaust opens 56 BBDC (55)
Left exhaust closes 40 ADTC (34)

Right inlet opens 34 BTDC...correct
Right inlet closes 66 ABDC (55)
Right exhaust opens 66 BBDC (55)
Right exhaust closes 34 ATDC...correct
The left inlet is still awry closing, 17 degrees late but it`s also 9 degrees late opening. Given the inherent inaccuracies, method, no load, transposing the readings, angles measured by protractor, etc, I`m fairly happy.
Incidentally, in my previous post I said rotate the disc 180 degrees for the other side...this is nonsense! Both cylinders must start at the beginning of their cycle.
Now what? What the hell is causing this lumpy clicking, when the rockers are on? Pushrods and cups checked. Without the rocker boxes, it`s smooth as silk...? Rocker boxes...new mushroom-headed adjusters??? Timing case off? Check pinions, shafts and keys, backlash and looseness.
I remember when I took the timing case off last time, the intermediate pinion and shaft could move inwards and outwards about 1/4" or so, normal? I thought to myself thats OK `cos the shaft fits into a housing in the cover.
 

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Sounds to me like your intake cam pinion is incorrectly installed.

You are damaging your valve faces by the intake & exhaust touching each other at one point in the rotation. You may have already caused irreparable damage to one or both pairs of valves.
 

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Discussion Starter · #13 ·
That`s a new angle, valves hitting each other, for investigation.
But GPZ, I could only feel it on the exhaust valves.
There`s no discernable marks on the valve heads.
 

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In my younger days, I was trying to re-shim the valves on a Kawasaki KZ1000 and wondered why the book said not to rotate the cams independently until the first time I rotated one and heard a "click". I flipped the head over, rotated it again, then realized I had now damaged TWO sets of valves. I stopped at two, replaced the dinged valves, and re-did the top end by the book.

Similar concept applies, you have independent cams. When they are timed properly, the valves fly right past each other on thier merry way. When improperly timed, the valves can attempt to occupy the same miniscule available space inside the combustion chamber, and then they aren't so happy.
 

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I've recently done mine on my 76 T140 as I'd been told Triumph detuned the bikes to comply with emissions in the US by retarding the intake cam to a centre line of 90 degrees. After checking the factory timing marks it did seem that this was the case. I did a lot of research on this and was advised to time the cams using the 'centre line ' method and set them as close as I could to 102 C/L on the intake and 103 C/L on the exhaust. I was also told the exhaust should always follow the intake, ie, the exhaust should have a larger number than the intake. Yours is the other way round, you've got too much overlap, your valves are clashing! . In the event I managed to obtain centre lines of 102 intake and 104 exhaust.
Looking at your numbers I think GrandPaulz is spot on, your valves are touching. I don't think your method is showing accurate results but if they're anywhere close I think you've got a centre line on the intake of 113.5 degrees and on the exhaust 98 degrees.
To do it properly and easily you need the head off, a degree wheel on the crank and a dial test indicator to measure tappet lift. Measurements are taken at 0.020 " or 0.5 mm of lift and the centre line is calculated by adding degrees the tappet lifts 0.020 BTDC to 180, minus degrees 0.020 on the tappet before the valve closes. Add the larger number and deduct the smaller number. Then divide by 2, this gives the valve centre line. To use your numbers; 180+72=252-25=227/2=113.5
I should point out although I'm new to Triumphs I have worked on old brits before. I'm no expert so I ask questions and do research. Don't mess with cam timing unless you're going to really look into it mate.
John
ps; Having said all this I've yet to start my bike, it could go bang first kick
 

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How to do this takes too long to explain on a link like this and I'll probably still inadvertently mislead you somehow.

Google timing wheel pictures and get one you like and print and glue it to a piece of cardboard

Anyway, the timing wheel is centered on the crankshaft not the cam. I made up a needle that attached to the crank while keeping the timing wheel with 0 set to 12 noon. As the crank turned the dial turned with it to indicate its position. The dial is initially set to 12 noon with the cylinders at TDC. I marked the wheel where both valves should be opening and closing. Valve clearance must be set to 20 thou for this test. When the valve engages/disengages, that's your actual open and close. If actual matches spec your a winner.
Double check your engine number to confirm the valve timing specs but I think it is: IN from 34 deg BTDC to 55 deg ABDC and
EX is from 55 deg BBDC to 27 deg ABDC
Or you could stick a copy of the timing disc on an old CD
Webby
 

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Webby,

Now there is a little jewel of thought.

Caulky,

The reason of why you are not feeling it with the rocker boxes
and and head off could only be two reasons:

First it has to do with the upper valve train.
Second the spring pressure does place a load on the timing
gears and keys and keyways. No pressure no problem.
Could be either.

However:

Paul has an excellent point about valve timing. Worth looking
into for sure.

With the new numbers you have posted, I do have to ask. Are
these cams aftermarket or original Triumph parts? Even with
how your are comming up with the numbers, it looks like a sloppy
grind job. This problem happens all the time even with the big
name suppliers of camshafts so it would not be suprising to me
at all.

Pookybear
 

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Discussion Starter · #18 ·
Thanks for your thoughts guys!
The inlet and exhaust camshafts have been in the engine since I bought the bike...about 40 years ago. I have never split the engine case. I presume they are standard, but I really dont know.

Paul, my lumpy clicking cant be the valves bashing each other, because it happens even without the inlet rocker boxes on.

Today I`m going to put weight onto the exhaust pushrods and kick it over, to see if I can create the fault without the rocker boxes fitted.
But, I have a sneaky feeling that the trouble concerns the rockers...something not right there.
If this fails, I will remove the timing case again and fiddle.
 

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Hi Cauky,

Have you had a look at the rockers? Maybe it's possible you have something worn or seized in the rocker boxes. I've got 2 sets of spare rockers/shafts etc. if you need anything.

Webby
 
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