Clicking noise as followers move on and off base circle

Fast Eddie said:

Dennis, the point is that sometimes, with a more radical cam, the valves will actually touch each other, they can bend each other, jam each other open, etc. This is what is meant by "valve tangle".

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Oh wow! Never thought there would be that possibility...explains the noise too. Thanks.

One can also get a click from normal range cam profile by advancing or retarding it a tad too much so touches pistons. Don't take much off center to foul on big cams.

dennisgb said:

Fast Eddie said:

Dennis, the point is that sometimes, with a more radical cam, the valves will actually touch each other, they can bend each other, jam each other open, etc. This is what is meant by "valve tangle".

Click to expand...

Oh wow! Never thought there would be that possibility...explains the noise too. Thanks.

Click to expand...

Pretty much with every modern spark ignition internal combustion engine, as the piston travels up to and past TDC at the end of the exhaust stroke the exhaust valve is closing and the intake valve is opening. You have probably heard of the term cam or valve overlap; this is what they are talking about and it is usually expressed in terms of crankshaft degrees.

Also reason hemi's can't get as much valve area as flatter chambers, hemis point the valves at each other near center and require reangling to get any with much size and big cam lifts. So looks like just a normal noise making the 'novice' nervous like me each new start up with something I handled. A video would be great if worth the extra surface wear on non cam surfing rpm.

I don't think I am a novice - with all those good parts installed, I'd find the source of the click before starting the motor. Try changing the tension on the timing chain and check that none of the cam followers or valve gear are binding. It is possible that something is sticking and letting go as the motor is turned over - that is the best situation. The others can be horribly expensive.

acotrel said:

I don't think I am a novice - with all those good parts installed, I'd find the source of the click before starting the motor. Try changing the tension on the timing chain and check that none of the cam followers or valve gear are binding. It is possible that something is sticking and letting go as the motor is turned over - that is the best situation. The others can be horribly expensive.

Click to expand...

Well Al...that is what I have been thinking for some time....something sticking and letting go...and the valve clicking back on its seat......but now I don't think so...but until I sort it I can't say. Jim and Ken have given me inputs that include clear checks and a suggestion that I may never really isolate it. That last bit is as important as the rest of the inputs I have had.

I did have the pushrods marking up where they touched the tunnel in the barrels..... I am pretty sure I have fixed that.... but I still have the noise.....see above and I have changed the tension of the cam chain...from extremes, even tried a different chain in there.

Also read what I said....one more check of the valves at overlap, one more lift of the head and check everything for witness marks....then if nothing shows up.....reassemble....get it on the rollers and get oil all around the place....then think about firing it up......but I won't till I am ready....

I have assembled this motor so many times now I am getting pretty good at it! But also please understand when I say I don't hear well, my hearing aids alter the volume of sounds at certain frequencies....I can't trust it like I did 40 years ago. Only someone who lives with hearing aids every day will know exactly what I mean....they dont fix hearing, they are just an aid to communicating, they can have effects you don't always expect.

And Steve, I take your point, but I don't trust me and my Nokia smart phone, even if it is a 1020 with a 41MP camera, to video it with enough video clarity, or record with enough audio clarity, to put it on here and have someone diagnose it....even if I wasn't just 800 miles away from it right now.

Wait for the next installment guys.....when I have checked based on the inputs I have gotten here......it was worth posting...thanks

SteveA said:

Jim and Ken have given me inputs that include clear checks and a suggestion that I may never really isolate it. That last bit is as important as the rest of the inputs I have had.

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I would trust these two guys and follow what they have said. I really learned from this thread and my mind is going 100 MPH thinking about what I used to know...stuff like valve flutter comes in my head and using stronger valve springs which caused the valves to hammer the seats...how that would come into play with the timing of the cam, etc., then I realize I don't know crap compared to Jim and Ken...they have dealt with this stuff and know what works and doesn't. Some secrets they may not share though

I totally understand why you are being cautious.

Dennis

For what it is worth SteveA, I had an 850 Commando that went together for a second time with some after market parts several decades ago. A clacking started upon one of the rebuilds and I never could isolate it nor did it ever hinder the bike. Best as I could tell it sounded like it was coming from the cam followers. Still bothers me that I could not identify the cause. This is the only bike I had that did this.

I thinking you are tracking alright with checking the critical stuff and if/when that dead ends, oil it up and fire it up.

Dances with Shrapnel said:

For what it is worth SteveA, I had an 850 Commando that went together for a second time with some after market parts several decades ago. A clacking started upon one of the rebuilds and I never could isolate it nor did it ever hinder the bike. Best as I could tell it sounded like it was coming from the cam followers. Still bothers me that I could not identify the cause. This is the only bike I had that did this.

I thinking you are tracking alright with checking the critical stuff and if/when that dead ends, oil it up and fire it up.

Click to expand...

Here here , just the sounds i got ,never heard them on my other Commando, only this one fitted with a 4s cam + the valves had been re-angled so it wasn't them touching ,sounded like follower noise to me , i ran it , and am still running it after 10000 miles , it still click clacks , goes like a scalded cat and sounds great .

chilly said:

Dances with Shrapnel said:

For what it is worth SteveA, I had an 850 Commando that went together for a second time with some after market parts several decades ago. A clacking started upon one of the rebuilds and I never could isolate it nor did it ever hinder the bike. Best as I could tell it sounded like it was coming from the cam followers. Still bothers me that I could not identify the cause. This is the only bike I had that did this.

I thinking you are tracking alright with checking the critical stuff and if/when that dead ends, oil it up and fire it up.

Click to expand...

Here here , just the sounds i got ,never heard them on my other Commando, only this one fitted with a 4s cam + the valves had been re-angled so it wasn't them touching ,sounded like follower noise to me , i ran it , and am still running it after 10000 miles , it still click clacks , goes like a scalded cat and sounds great .

Click to expand...

Interesting, thanks both.

I know nothing,,except after fitting a Dunstall head on a 650 the engine had a "click" when turned over with the kicker, a torch in the plug hole showed the valves kissed each other on the over lap. I replaced the head with the original and all was OK.
I think the DunstalL head also required the cam with a profile to suit?

Dances with Shrapnel said:

dennisgb said:

Fast Eddie said:

Dennis, the point is that sometimes, with a more radical cam, the valves will actually touch each other, they can bend each other, jam each other open, etc. This is what is meant by "valve tangle".

Click to expand...

Oh wow! Never thought there would be that possibility...explains the noise too. Thanks.

Click to expand...

Pretty much with every modern spark ignition internal combustion engine, as the piston travels up to and past TDC at the end of the exhaust stroke the exhaust valve is closing and the intake valve is opening. You have probably heard of the term cam or valve overlap; this is what they are talking about and it is usually expressed in terms of crankshaft degrees.

Click to expand...

I have come late to this and see you have covered the three issues that have given me clicking sounds in the cam area.

1. Clearance of the PW 3 to the crankcases
2. A problem you dont have - backlash in a worn camshaft vernier sprocket
3. Perhaps one worth checking again. I found this after running the cam through a full rotation with a dial guage on the pushrods and head off. I was checking the cam build quality and found the "straps" that hold the followers in place (the ones held in by screws and lock wired) needed a bit more clearance to stop the followers binding on the PW3. You said they fall under their own weight so maybe this is ok but it did happen on my bike.


Other than that I would be left with cam chain tension or valve clashing as well. Can you get hold of a cover which has been cut open to do the chain tension and then see if the click matches the cam chain loosening/tightening.

You dont have a loose cap on a push rod ??

johnm said:

I have come late to this and see you have covered the three issues that have given me clicking sounds in the cam area.

1. Clearance of the PW 3 to the crankcases
2. A problem you dont have - backlash in a worn camshaft vernier sprocket
3. Perhaps one worth checking again. I found this after running the cam through a full rotation with a dial guage on the pushrods and head off. I was checking the cam build quality and found the "straps" that hold the followers in place (the ones held in by screws and lock wired) needed a bit more clearance to stop the followers binding on the PW3. You said they fall under their own weight so maybe this is ok but it did happen on my bike.


Other than that I would be left with cam chain tension or valve clashing as well. Can you get hold of a cover which has been cut open to do the chain tension and then see if the click matches the cam chain loosening/tightening.

You dont have a loose cap on a push rod ??

Click to expand...

Thanks John. You are looking at things I did to. PW3 has no maks and has left no marks on crankcase or barrel. But yes I worried about the retainers, originally the new followers themselves were tight, but hand finishing has made the followers move as I said under there own weight. I do see witness marks on the followers, on the inside flat face that shows they have been tight, but they seem to move freely now.

So chain tension...well I turned it over with the cover off completely, and with one of the AN tools that substitutes for a cut away cover fitted.....I could feel the cam moving as the noise happened.....

The issue with 'doing the chain tension' is having one of comnoz' hydraulic tensioners and no original tensioner parts....I have primed the hydraulic tensioner...and managed to get the chainn pretty tight, but not really 'overtight' I had thought to try and get some of the original tensioner plates and try it with that as a way of eliminating things, but since this is a totally new build I don't have the parts.

The original bits are pretty simple so shouldnt cost to much.

I have some spares but unfortunaly they are stored about 20,000 km from my present location and will be for the next year sorry.

johnm said:

The original bits are pretty simple so shouldnt cost to much.

I have some spares but unfortunaly they are stored about 20,000 km from my present location and will be for the next year sorry.

Click to expand...

Ordered from Mick Hemmings this morning....use em or not something will go in the spare engine box..... which already has more in it than I originally intended

comnoz said:

SteveA said:

comnoz said:

As far as I can tell the noise is not at overlap.... and I am pretty sure the valves at overlap are clear, but I don't find it an easy thing to check and I am always willing to check again...

Standard size valves...even with PW3 they should be OK....but....

Click to expand...

Click to expand...

Some heads will have valve clash with a PW3 -particularly if the seats are new and high.

To check it use a piece of .030 wire with a bend near one end. Look through the ports and turn the engine till the valves are at their closest point. Insert the wire through the spark plug hole and see if the bent end of the wire will pass between the valves. Jim

Click to expand...

Did this check and it is fine, room for way more than a piece of 0.030" wire.... so....

lcrken said:

comnoz said:

The clicking noise is likely the cam taking up the play in the timing chain as it trys to move faster than the crank on the downside of a lobe. If that is the case then it is nothing to worry about.

Check to make sure you have valve to valve clearance at overlap. Jim

Click to expand...

I think Jim hit it on the head here. I've encountered this particular click many times. It only goes away if you adjust the cam chain way too tight. And the looser the chain, the louder the click.

Could still be something else, but it sure sounds like it's the change in direction of tension in the cam chain as you go past the lobe center.

Ken

Click to expand...

Yes, this is definately the case, so to get control over chain tension for testing I got a standard tensioner from Mick Hemmings, took out the hydraulic tensioner and fitted that....

With the chain fairly tight (but not overtight as far as I can see) the noise is quiet enough that my wife doesn't notice it....

....but because I a the one turning it over and know where it is in the rotation, and thanks to my hearing aids and concentration, I do hear something, but next step is in the frame and start her up, probably early March now as I am busy packing up in Italy and heading home....

So I get all of March to get it running before the first race meeting of the season at Pembrey....I only entered my other bike for races, but there is also a test day.....

When it is all bedded in I may want to try the hydraulic tensioner again, but I don't want to get too ahead of myself here....

Jim. "Nothing to worry about" Now me i removed the spare keys [car] from the bunch because they drove me bonkers rattling together! Now that's Nothing to Worry about...but ..and they where marking the dash! So a rattle from anyones pride and joy Commando is major :!:
You are obsessed with the noise, driving is less enjoyable and dangerous! Keep leaning forward listening , to try and pin point the issue.
plus when you have a crowd ,admiring your work...then start it up and watch the frowns....NO. NO, No Jim .this is major!

comnoz said:

The clicking noise is likely the cam taking up the play in the timing chain as it trys to move faster than the crank on the downside of a lobe. If that is the case then it is nothing to worry about.

Check to make sure you have valve to valve clearance at overlap. Jim

Click to expand...

john robert bould said:

Jim. "Nothing to worry about" Now me i removed the spare keys [car] from the bunch because they drove me bonkers rattling together! Now that's Nothing to Worry about...but ..and they where marking the dash! So a rattle from anyones pride and joy Commando is major :!:
You are obsessed with the noise, driving is less enjoyable and dangerous! Keep leaning forward listening , to try and pin point the issue.
plus when you have a crowd ,admiring your work...then start it up and watch the frowns....NO. NO, No Jim .this is major!

comnoz said:

The clicking noise is likely the cam taking up the play in the timing chain as it trys to move faster than the crank on the downside of a lobe. If that is the case then it is nothing to worry about.

Check to make sure you have valve to valve clearance at overlap. Jim

Click to expand...

Click to expand...

Yes, but......hearing aids out, earplugs in, helmet on, fire up on the rollers.....warm through.....with 105 db race exhaust....then wind noise....will I?

Jim . Did your gear driven cam cure the clacking?

SteveA said:

lcrken said:

comnoz said:

The clicking noise is likely the cam taking up the play in the timing chain as it trys to move faster than the crank on the downside of a lobe. If that is the case then it is nothing to worry about.

Check to make sure you have valve to valve clearance at overlap. Jim

Click to expand...

I think Jim hit it on the head here. I've encountered this particular click many times. It only goes away if you adjust the cam chain way too tight. And the looser the chain, the louder the click.

Could still be something else, but it sure sounds like it's the change in direction of tension in the cam chain as you go past the lobe center.

Ken

Click to expand...

Yes, this is definately the case, so to get control over chain tension for testing I got a standard tensioner from Mick Hemmings, took out the hydraulic tensioner and fitted that....

With the chain fairly tight (but not overtight as far as I can see) the noise is quiet enough that my wife doesn't notice it....

....but because I a the one turning it over and know where it is in the rotation, and thanks to my hearing aids and concentration, I do hear something, but next step is in the frame and start her up, probably early March now as I am busy packing up in Italy and heading home....

So I get all of March to get it running before the first race meeting of the season at Pembrey....I only entered my other bike for races, but there is also a test day.....

When it is all bedded in I may want to try the hydraulic tensioner again, but I don't want to get too ahead of myself here....

Click to expand...