SuzukiSavage.com - Cam chain tensioner revisited

justin_o_guy2

Serious Thumper

Offline

What happened?

Posts: 55279
East Texas, 1/2 dallas/la.

Re: Cam chain tensioner revisited
Reply #75 - 05/23/16 at 12:20:46

The pawl latching into the teeth on the tensioner tube is what contains the chains pressure on the tensioner. The spring forces the chain In and allows the pawl to advance a notch.

If someone would look into the spring and see if the new one is stronger than the old one and see when that changed and compare that to what year models tended to get a better service life out of the chain, we might have data to lead toward a better understanding of WHY it is the way it is. I suspect the spring is stiffer now. That would explain a lot..

Back to top

The people never give up their liberties but under some delusion.- Edmund Burke.

IP Logged

Dave

YaBB Moderator
ModSquad

Offline

SuzukiSavage.com
Rocks!

Posts: 17867
Camp Springs, Kentucky
Gender: male

Re: Cam chain tensioner revisited
Reply #76 - 05/23/16 at 13:06:03

Armen wrote on 05/23/16 at 11:43:36:

Go back to the earlier description. The idea is to set up the tensioner with enough slack to allow for the cylinder expansion. Leave the spring in there to take up the slack until the cylinder heats up. No pawl.
This is kinda turing into teenage sex-months of talking, a few seconds of activity, and months of exaggerating afterwards Grin

-Armen

I understand what the spring is supposed to do - I just don't know that the stock spring is the proper tension for that. My guess is that the stock spring does nothing when the engine is running...the pawl does all the work when the engine is running. Once the engine cools off and contracts and sits still, likely nothing happens - then when you hit the starter button and the engine starts moving....the front side of the cam chain is tightened and the back side gets a bit of slack....and maybe the tensioner plunger moves enough to move a tooth - then by the time the engine is running the tensioner spring is doing nothing and the pawl is taking any load that is created.

I think that the idea of having a spring in there is a good idea for the "warm-up" slack.

Back to top

Someday I will be old......But not today!

IP Logged

norm92de

Serious Thumper

Offline

SuzukiSavage.com
Rocks!

Posts: 1180
El Paso TX
Gender: male

Re: Cam chain tensioner revisited
Reply #77 - 05/23/16 at 13:34:05

I think that if the chain tension is correct when the engine is cold, i.e. has just taken up a new notch on the ratchet. The tension on the chain will be tremendous when it reaches operating temperature.

Maybe if we have a real engineer amongst us they can give us some idea of the expansion of the cylinder?

At the moment, I like the no pawl, metal rod in the spring idea the best. It doesn't change very much from the stock engine setup and it will eliminate the excessive tension with little risk. It could surprise us how long it lasts between re-adjustments.

Back to top

2014 S40. Raptor. idle mixture adj.Needle raised one notch. 4000' altitude. Stock jets. Shell Rotella synthetic.

IP Logged

Dave

YaBB Moderator
ModSquad

Offline

SuzukiSavage.com
Rocks!

Posts: 17867
Camp Springs, Kentucky
Gender: male

Re: Cam chain tensioner revisited
Reply #78 - 05/23/16 at 13:45:36

Well......I are a "real" engineer - at least for my day Job.

But to calculate how much the cylinder and head grow...you need to know a lot more about what case, cylinder, head and chain are made out of, and what temperature they are when the engine is up to temperature. I do know that the top of the cylinder head can reach 300 degrees on hot days - I have no idea what temperature the cylinder or case or chain operate at.

Back to top

Someday I will be old......But not today!

IP Logged

Armen

Serious Thumper

Offline

Half-Witted
Wrench-Jockey from
Jersey

Posts: 1433

Re: Cam chain tensioner revisited
Reply #79 - 05/23/16 at 14:02:52

Oh boy....
I looked up the thermal expansion tables for aluminum.
If I have my decimal places correct, it seems there should be about .020" of expansion of the aluminum involved with 170F increase in engine temp.
Since the chain doubles over, that means .040" difference in chain length.
That's using 10 to the -6 power times 13.5" expansion per degree F times 170 F and 8" of aluminum (guessing at that number, as the bike is not next to me).
Anyone more awake than me care to redo the numbers?
-Armen

Back to top

In theory, theory and reality are the same. In reality, they aren't...

IP Logged

verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28804 L.A. California Gender:	Re: Cam chain tensioner revisited Reply #80 - 05/23/16 at 14:11:24 The cylinder has an iron core. So you're only looking at the head and case for thermal growth. The case and chain will be at the oil temperature for the most part. and the chain is longer on 1 side.
Back to top	Versey's Place Tech Section Index IP Logged

gizzo

Serious Thumper

Offline

SuzukiCabbage. It's
Savage.

Posts: 1318
Australia

Re: Cam chain tensioner revisited
Reply #81 - 05/23/16 at 14:51:23

norm92de wrote on 05/20/16 at 17:05:55:

Why wouldn't it be possible to simply break the chain and feed in a new one? Surely it is possible to re-rivet a cam chain???

I have done that, plenty of times. No idea if its doable on a ninja but no problem on the thumpers I've done it to. Not done one in a long while but the chains we used came split and you rivet it togther. Never had one fail.

Back to top

IP Logged

justin_o_guy2

Serious Thumper

Offline

What happened?

Posts: 55279
East Texas, 1/2 dallas/la.

Re: Cam chain tensioner revisited
Reply #82 - 05/23/16 at 14:53:28

verslagen1 wrote on 05/23/16 at 14:11:24:

The cylinder has an iron core.
So you're only looking at the head and case for thermal growth.

The case and chain will be at the oil temperature for the most part.
and the chain is longer on 1 side.

The understanding that I have about How this problem exists doesn't help me understand what you are saying. Please don't expect me to be able to change horses midstream and suddenly grasp what you are saying. I really need you to explain that, from having seen everything I have thus far concluded. I've been explicit in what and why I see it the way I do. If you think I'm not seeing it right, and, after all, you're only an engineer and how could I be wrong, right? Anyway, if you can get it in Readers Digest terms and help me see it clearly, I would be thankful. I'd rather change my thinking and learn to be right than argue a point , be unwilling to change and be factually incorrect.
If you have read what I have said, then you understand what I see. Correct me where I'm not seeing how it really is.

Back to top

The people never give up their liberties but under some delusion.- Edmund Burke.

IP Logged

verslagen1

YaBB Moderator
ModSquad

Offline

Where there's a
will, I want to be
in it.

Posts: 28804
L.A. California
Gender: male

Re: Cam chain tensioner revisited
Reply #83 - 05/23/16 at 15:00:29

gizzo wrote on 05/23/16 at 14:51:23:

norm92de wrote on 05/20/16 at 17:05:55:

Why wouldn't it be possible to simply break the chain and feed in a new one? Surely it is possible to re-rivet a cam chain???

I have done that, plenty of times. No idea if its doable on a ninja but no problem on the thumpers I've done it to. Not done one in a long while but the chains we used came split and you rivet it togther. Never had one fail.

On our chain the pins are headed on both sides.

Back to top

Versey's Place
Tech Section Index

IP Logged

verslagen1

YaBB Moderator
ModSquad

Offline

Where there's a
will, I want to be
in it.

Posts: 28804
L.A. California
Gender: male

Re: Cam chain tensioner revisited
Reply #84 - 05/23/16 at 15:06:55

justin_o_guy2 wrote on 05/23/16 at 14:53:28:

verslagen1 wrote on 05/23/16 at 14:11:24:

The cylinder has an iron core.
So you're only looking at the head and case for thermal growth.

The case and chain will be at the oil temperature for the most part.
and the chain is longer on 1 side.

The understanding that I have about How this problem exists doesn't help me understand what you are saying. Please don't expect me to be able to change horses midstream and suddenly grasp what you are saying. I really need you to explain that, from having seen everything I have thus far concluded. I've been explicit in what and why I see it the way I do. If you think I'm not seeing it right, and, after all, you're only an engineer and how could I be wrong, right? Anyway, if you can get it in Readers Digest terms and help me see it clearly, I would be thankful. I'd rather change my thinking and learn to be right than argue a point , be unwilling to change and be factually incorrect.
If you have read what I have said, then you understand what I see. Correct me where I'm not seeing how it really is.

You can't just simply say 12" between centers times the alpha for aluminum at 400 °F and say AHA! smoking gun and be done. After I B N ingin with ears too.

Back to top

Versey's Place
Tech Section Index

IP Logged

norm92de Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1180 El Paso TX Gender:	Re: Cam chain tensioner revisited Reply #85 - 05/23/16 at 16:04:43 If the ratchet has just taken up a tooth and the chain is taut. .020" increase between centres is enough to make the chain bow tight. Ouch! Take that! Chain and cam bearings. :'(
Back to top	2014 S40. Raptor. idle mixture adj.Needle raised one notch. 4000' altitude. Stock jets. Shell Rotella synthetic. IP Logged

justin_o_guy2

Serious Thumper

Offline

What happened?

Posts: 55279
East Texas, 1/2 dallas/la.

Re: Cam chain tensioner revisited
Reply #86 - 05/23/16 at 16:19:40

You can't just simply say 12" between centers times the alpha for aluminum at 400 °F and say AHA! smoking gun and be done.

Okay, that is something You understand. I don't. Either the distance between centers changes or it doesn't. My understanding has been that it does. If it's Less than what I have been thinking, it's Still a change. IF that changed is Greater Than the chains length change, then the concept is still valid, though the pain induced on the chain is lessened.

After I B N ingin with ears too

Aaaaand, I'm so totally Not getting that..

Back to top

The people never give up their liberties but under some delusion.- Edmund Burke.

IP Logged

Dave YaBB Moderator ModSquad Offline SuzukiSavage.com Rocks! Posts: 17867 Camp Springs, Kentucky Gender:	Re: Cam chain tensioner revisited Reply #87 - 05/23/16 at 17:48:53 With a cast iron sleeve, and a bonded aluminum outer shell.....the expansion for the darn thing is going to be different than it would be if it was just made out of one or the other. That would have been discussed in some advance course....that I didn't take!
Back to top	Someday I will be old......But not today! IP Logged

norm92de Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1180 El Paso TX Gender:	Re: Cam chain tensioner revisited Reply #88 - 05/23/16 at 18:03:31 I really like Armen's idea. It is like Batmans only with a bit of insurance. Who knows, along with Versy's mod we may see 50k out of a cam chain I think when I go into the clutch area I will take out the pawl and install a metal rod in the spring. Maybe my engine will self destruct,
Back to top	2014 S40. Raptor. idle mixture adj.Needle raised one notch. 4000' altitude. Stock jets. Shell Rotella synthetic. IP Logged

gizzo

Serious Thumper

Offline

SuzukiCabbage. It's
Savage.

Posts: 1318
Australia

Re: Cam chain tensioner revisited
Reply #89 - 05/23/16 at 18:47:09

verslagen1 wrote on 05/23/16 at 15:00:29:

gizzo wrote on 05/23/16 at 14:51:23:

norm92de wrote on 05/20/16 at 17:05:55:

Why wouldn't it be possible to simply break the chain and feed in a new one? Surely it is possible to re-rivet a cam chain???

I have done that, plenty of times. No idea if its doable on a ninja but no problem on the thumpers I've done it to. Not done one in a long while but the chains we used came split and you rivet it togther. Never had one fail.

On our chain the pins are headed on both sides.

Sure. You just need to either grind the link on one side and use your chain breaker (a decent chain breaker will break a cam chain without grinding anyway) or snip it with bolt croppers. then just use the old chain to pull the new one through. Of course you need to release any tension from the chain tensioner. The new link can be rivetted with the chain tool or by hand with a little anvil and hammer & punch. That's how I did it.
I did that job loads of times back in the day. The station (ranch for you) owners used lots of XR, XT, TT 250 and 350 and would do the cam chain every 20,000km to be on the safe side. It's a lot quicker to split the chain than pull the motor down. No flywheel off, no camshaft out. Anyway that's getting off topic so back to the programme.

Back to top

IP Logged