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/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> cam tensioner yet again /cgi-bin/YaBB.pl?num=1462632398 Message started by batman on 05/07/16 at 07:46:38 |
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Title: cam tensioner yet again Post by batman on 05/07/16 at 07:46:38 has anyone ,I did, left the tiny spring out of cam tensioner to allow it to act as a shock? |
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Title: Re: cam tensioner yet again Post by Serowbot on 05/07/16 at 07:55:26 You may be the first... no prizes though,... it really needs to be in there... :-? |
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Title: Re: cam tensioner yet again Post by norm92de on 05/07/16 at 08:04:52 I'm not quite sure what you are saying but if you mean allowing the tensioner plunger to move in and out freely instead of only applying pressure prevented from retracting by the pawl. Don't do it! It is recipe for disaster. If the cam chain comes loose or off the sprockets the engine will self destruct. The tensioner pawl is there for a purpose. To prevent the cam chain from pushing the plunger back into the body and thus becoming loose. :'( |
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Title: Re: cam tensioner yet again Post by verslagen1 on 05/07/16 at 08:20:37 If I understand you correctly, you left the pawl spring out. While the stock adjuster has a tight fitting plunger and bathed in oil it can get hydro locked in position. You can't guarantee it. So a quick twist of the throttle may press it all the way in and let the chain loose. |
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Title: Re: cam tensioner yet again Post by justin_o_guy2 on 05/07/16 at 08:25:39 I don't know. I think we've debated the idea that the warm up, cool down cycles on the short trip riders bikes just might be why the big difference between how many miles some people get before the tensioner is out too far. While it's running, and the tension on the chain is pulling the cam around, and the slack is being controlled on the back side, it should be okay, but a little scary at RPM, because the chain is gonna push the tensioner to full collapse position, without the pawl to stop it. Then, you shut down and the piston is headed into compression. And backs the crankshaft up, pushing the chain up from the crank, towards the cam. When you hit the starter, it's gonna jerk the snot outta that chain. I don't know how a tired old chain is, but a new one is a trick to get on without having the tensioner in the way. If you are gonna play that game I would suggest getting it in gear and rolling forward until the motor stops you before you hit the starter, every time you push that button. You need to know that the slack in the chain is on the back side. I've wondered about doing this. Wish you well. |
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Title: Re: cam tensioner yet again Post by DesertRat on 05/07/16 at 10:53:19 EVERYTHING you could ever possibly want to know about the Cam Chain Tensioner is covered here: http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1191167029 it IS a known issue, and for quite a LONG LONG time now ... but our resident guru, Verslagen1, also one of the YaBB Moderator ModSquad members, has given us this data. Enjoy the read ... ;) |
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Title: Re: cam tensioner yet again Post by Dave on 05/07/16 at 13:26:13 The big danger that I see...is that when you are at low rpm, or the engine is being started or coasting to a stop - is that the lobes of the cam can be pushed around by the valve springs. If you have ever rotated the engine with the spark plug out - you can feel when the valve springs are trying to rotate the crankshaft through the camshaft. Even worse might be what would happen on those occasions when the engine kicks backwards at shut down.....where all the available slack in the tensioner will suddenly be kicked in. A few of us have tried (are trying) very light springs inside the tensioner - but the pawl must be operational....or bad things could happen. |
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Title: Re: cam tensioner yet again Post by norm92de on 05/07/16 at 16:10:41 One danger that I see is anything that causes the engine to decelerate rapidly, for whatever reason, will load up the backside of the cam chain. The camshaft is going to try to continue what it was doing-inertia- pulling the rear of the cam chain tight and allowing the front side to go slack or at least to be less than optimum tension. Just my thoughts. :) |
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Title: Re: cam tensioner yet again Post by batman on 05/08/16 at 21:37:52 I must explain I have extended my tensioner, by 15mm at 19000 mi. I then road tested my bike with the spring for the paw(?) removed. It was a ride for a Fssnoc club ride in rugby Tn. from my home in N.Y. 2100mi. round trip, super slab on the way secondary roads back ,in three days.That was in 2014. I checked the tensioner last week , saw no damage on chain or guide wear,25000mi. It looks like I should get another 10000mi out of this original chain. stock motor except air filter ,150 main jet,harley pipe. |
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Title: Re: cam tensioner yet again Post by norm92de on 05/09/16 at 08:47:28 This is going to cause some consternation. You mean you have driven many miles with the spring for the cam chain tensioner pawl removed and the plunger can be pushed in and out freely? Wow! |
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Title: Re: cam tensioner yet again Post by justin_o_guy2 on 05/09/16 at 08:59:55 787B6E777B742E221A0 wrote:
Would have been a good place to start. As it wears the amount of slack in the chain increases. How that plays out could be interesting. For now, it Looks like you're getting a lot of miles/mm of extension. I've thought about the tooth spacing on the pawl, seems like it clicks into a new notch too soon. I'm seriously tickled someone is doing this test. I hope it works out, extends the life of the chain and does no damage. |
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Title: Re: cam tensioner yet again Post by norm92de on 05/09/16 at 10:20:17 Could it be that the cam chain "normally" runs with too much tension due to expansion of a rather tall engine? Dunno, but it might be possible. If so Batman may have come up with something. Batman. Why did you decide to remove the pawl spring? |
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Title: Re: cam tensioner yet again Post by justin_o_guy2 on 05/09/16 at 11:09:23 Could it be that the cam chain "normally" runs with too much tension due to expansion of a rather tall engine? The topic of several in depth threads. The heat expansion tugs on the chain while the tensioner pawl refuses to yield. There are ifs and thens, but that's the core. |
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Title: Re: cam tensioner yet again Post by norm92de on 05/09/16 at 11:20:49 jog, I have never been comfortable with the ratchet and pawl mechanisms because of its unyielding nature as an engine expands and contracts. The tension on the mechanism must be very high until the chain stretches a bit. Then here comes another tooth on the ratchet and it starts all over again. It may be why people who tend to run longer trips get more life out of their cam chains. :-/ |
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Title: Re: cam tensioner yet again Post by norm92de on 05/09/16 at 11:23:09 I can't wait for batman to give us an update. It sounds dangerous but the proof of the pudding etc. :) |
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Title: Re: cam tensioner yet again Post by justin_o_guy2 on 05/09/16 at 11:32:49 47465B44101B4D4C290 wrote:
Egg screaming zaklee... Manny Groh,, And yes, that's how I talk.. |
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Title: Re: cam tensioner yet again Post by Dave on 05/09/16 at 11:54:59 I believe the theory is correct, that the tensioner grabs a new tooth when the chain/engine is cold....then overtensions the chain when things warm up. It doesn't take a new tooth every time the engine cools down - but evidently it gets a new tooth too often. We are not the only bike that has tensioner issues - and a lot of the sport bikes have aftermarket manual tensioners that can replace the automatic tensioner. I am tempted to just take the spring out of my tensioner - but leave the pawl in place to prevent the tensioner from collapsing (or putting a very weak spring in the tensioner). This would in effect convert the stock tensioner into a manual one. |
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Title: Re: cam tensioner yet again Post by norm92de on 05/09/16 at 12:10:17 What we need is a secondary tension mechanism that allows some expansion to take place without putting too much tension on the chain. Perhaps by bending the rear guide into an arc so that it can bend a little to relieve the extreme tension. I know somebody did bend the rear guide but apparently only to adjust it. |
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Title: Re: cam tensioner yet again Post by verslagen1 on 05/09/16 at 12:26:48 56574A55010A5C5D380 wrote:
Bending the rear is a thought, but I don't think it will offer much relieve. It is pretty stiff and the my main concern with bending it is popping off the plastic guide. |
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Title: Re: cam tensioner yet again Post by norm92de on 05/09/16 at 12:46:33 Good point versy. |
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Title: Re: cam tensioner yet again Post by norm92de on 05/09/16 at 12:50:12 A manual adjustment taken up every service would be nice. I have friend who races and they manually adjust their chain every race. On a Kawasaki I believe. |
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Title: Re: cam tensioner yet again Post by justin_o_guy2 on 05/09/16 at 12:57:55 It's been a long time since I looked at it, but IF the tensioner mount post was spring loaded, that would do it. All it would need is an eighth of an inch of play and a stout spring, putting a wimpy spring in the tensioner. Dunno if that's even possible, might not be room. Of course,there's the clutch disk design, like on a pickup. |
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Title: Re: cam tensioner yet again Post by batman on 05/09/16 at 21:31:12 I left the spring out thinking that when the motor heats up the chain expands ,the tensioner moves out but when it cools it did not move back which stressed the chain. Some have rotated their motors when working on their bikes without the tensioner in place and not had the chain jump a single tooth on the timing gears. how much tension do we need? When I redid the plunger I ground three small flats on it to prevent any hydraulic lock up, the bike runs strong ,gurgles on decell ,never,backfires,and rarely poofs on shutoff (150 main jet may be a little rich but this protection . I haven't got the new anti kickback starter gear its a 95) |
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Title: Re: cam tensioner yet again Post by batman on 05/09/16 at 22:10:02 Norm92da said that on deceleration inertia of the cam might load up the back side of the chain ,but the chain is driven by the main shaft which has much more inertia (fly wheel ,rotor,piston ,rod ,counter weight,even the trany gears and shafts). turning at twice the speed of the cam so I dont think this happens . Locking up the rear wheel at speed without pulling in the clutch might do it,but not something I'll be trying real soon. :) |
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Title: Re: cam tensioner yet again Post by Art Webb on 05/10/16 at 07:15:45 I think you guys are on to something, the whole locking ratchet isn't very good design once you study on it Actually a simple change to a pawless, spring-loaded tensioner could be a good solution note that automotive serpentine belt tensioners use simple spring tension |
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Title: Re: cam tensioner yet again Post by verslagen1 on 05/10/16 at 08:33:54 36352039353A606C540 wrote:
4 speed or 5? |
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Title: Re: cam tensioner yet again Post by Dave on 05/10/16 at 08:41:27 60737576646363010 wrote:
The belts with spring tension are all driving things like water pumps, power steering pumps, air conditioners....things that don't kick back. Every cam chain or cam belt tensioner I have ever seen is either manually adjusted and locked in place - or is self adjusting and has something to resist instantaneous movement.....either a pawl, one way rod/ball clutch, or anoil/piston device that tensions and also restricts fast movements if the chain is loaded in the wrong direction. The problem that I see with no pawl....is the valve spring will attempt to push the cam forward at low rpm, and it could result in some weird vibrations of the cam chain. When the valves are opening and closing the exhaust valve opens first and requires a strong force in the cam chain, then as the exhaust valve closes the valve spring will push on the rocker arm and cam lobe and push the cam chain forward causing slack in the cam chain, and then just before the exhaust valve closes the intake valve begins to open and it will require a strong force in the cam chain - then as the intake valve closes the valve spring will again try to push the cam chain forward and could result in some slack. When the chain tensioner locks the movement of the chain...the different loading conditions will not cause the chain to jump around. I believe that there must be a reason that "all" engines have a cam chain or cam belt tensioner that restricts the movement "backwards". Some are sophisticated enough to allow excess tension to be released slowly as the engine warms up....the Porsche tensioners have springs that set the tension, and a hydraulic piston that restricts fast movements. Originally these tensioners worked fine - but on occasion the hydraulic part would wear out and the chain would rattle....so later on an improved version was developed that was pressure fed through a small supply line and the tensioner got a fresh supply of engine oil. Below is a photo of the early Porsche tensioners, and the spring is inside, and the tensioner is filled with oil, and there is piston that will allow the tensioner to move slowly in/out, and for installation you put the tensioner in a vice and compress the shaft slowly - then install it before the piston extends. |
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Title: Re: cam tensioner yet again Post by batman on 05/10/16 at 08:59:31 Verslagen, 5 speed but I thought the starter clutch didn't come on bikes until 96 .If I'm mistaken you've made my day! |
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Title: Re: cam tensioner yet again Post by batman on 05/10/16 at 09:17:48 dave,can we get Porsche to design our tensioners ,spring/hydraulic piston would be perfect !!!!! |
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Title: Re: cam tensioner yet again Post by verslagen1 on 05/10/16 at 10:50:26 585B4E575B540E023A0 wrote:
I thought the starter clutch came in with the 5 speed. If you haven't looked, then we've yet to confirm either way. PS, I checked the fishe, and 95 does not have the clutch, 96 does. |
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Title: Re: cam tensioner yet again Post by batman on 05/10/16 at 19:58:59 verslagen,it might be a buying point +/- if your looking for a used savy to know only 96 and up have the starter clutch. |
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Title: Re: cam tensioner yet again Post by verslagen1 on 05/10/16 at 19:59:47 yes, but you can pick up a torque limiter and a stator case off fleabay and be in business. |
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