Crazy custom timing chain tensioner

[JMortensen]

ZERO evidence has been shown that it doesn't improve cam timing. I have presented several pieces of evidence that show that it has benefits other than just the timing issue.

[HS30-H]

ZERO evidence has been shown of ANY benefits from using this setup. If there is any, present it. All else IS hype.

 

How unfortunate for Kameari that they have had their product ( and by inference, their reputation and good name ) in front of the Judge, the Jury and the Executioner without having been invited to the trial.

 

It is not for me to present any "evidence" and frankly I doubt that it would make any difference to you one way or another. You have pronounced your judgment and the sentence has been passed. "Dead man walking" is the term I believe......

 

As for being condescending, I don't mean it that way. But in the immortal words of Randy Newman, "I'm not saying I'm better than you. But maybe I AM."

 

Sir, you are missing the point completely. I don't give a damn what you think of me. If you truly think you are "better" than me, then I will concede the point. I am nobody, and my opinion on engineering theory also means 'sweet FA' ( as we say here in London ).

 

The problem as I see it is that you are passing comment on something that you have never seen, and have never had explained to you properly. You do however seem to think you have enough "evidence" to damn the product. You are also making negative inferences against Kameari, who are not even here to defend themselves or their product, let alone present whatever "evidence" you would decide they ought to put before you.

 

Is there a little button under your user name that I can press to decrease your site 'cred' rating?

 

 

 

Here's my oh-so-clever and relevant Randy Newman song reference: "Maybe I'm Doing It Wrong". Perhaps you could teach it to Kameari, and play along on your "GEEtahr"?

 

I can do dick-headed and asinine too.

 

Have a nice evening

[Forrest]

ZERO evidence has been shown of ANY benefits from using this setup. If there is any' date=' present it. All else IS hype.

[/quote']

That's incorrect. Alan's testimony itself is evidence, and very good evidence at that. Given the circumstances, you'd have to go to some pretty extreme lengths to get anything further. (Like, flying to Japan yourself.)

[Dan Baldwin]

No evidence that this setup is better in any way is presented anywhere in this thread.

[edit: I also readily agree that no hard evidence is presented in this thread that this setup is WORSE in any way.]

BTW, EVIDENCE means that with an otherwise identical car/setup, this device demonstrably improved performance or reliability or both. That it has been used successfully by a race team is not evidence that it is better than a stock setup. It is evidence that it does perform its function under race conditions, which is surely a good sign.

 

Unfortunately, you're absolutely right that in order to sell hop-up parts to a public that has no capacity for scientific reasoning, there is no burden on any aftermarket supplier to provide any real evidence of actual benefit.

 

I have given my *impressions* of this setup, I have not done any kind of real analysis. I have presented my impressions FOR WHAT THEY ARE WORTH (which should go without saying). Obviously, I'm not a big fan of the concept, but I have NOT made up my mind. I am totally open to any and all evidence one way or the other.

[Tony D]

Far be it form me to jump into a fray like this...

 

But my understanding on the development of this product involved stroboscope observation of the TIGHT SIDE chain action.

 

With their components installed, the observed deflection of the tight side of the chain at times was noticably reduced, as well as action over the formerly "slack side" portion.

 

Watching a camshaft jump relative position advanced/retard due to throttle position changes is relatively disconcerting, and that is MY understanding on what prompted this development project.

 

It is my understanding that after installation of these components the said deflection from timing in the cam was noticably reduced.

 

Like some have said, while it may not be an "ideal" solution, it is one that in the practical application showed a marked positive effect on solvingthe problem they were attempting to address.

 

In the end, that is really what is important.

 

While draining the reservoir of water, and cutting out the leaking portion of the dam is the "proper" way to fix the leak from an Engineering Standpoint, dumping dirt down the backside ot the dam till it covers the hole also performs the same function...

 

I don't use that example in any way to equate Kamearis' solution to the problem they discovered, only to illustrate that there may be more than one way to approach something, and BOTH will work.

 

To Alan, I address the question: Is this your understanding on how it was developed, or was someone blowing smoke up my posterior? I now recline to nibble on my Dragonfruit.

 

BTW, it is my understanding someone has one of those kits and is trying to replicate it stateside. I DON'T have any knowledge of it beyond that, so you all will have to do your OWN research work. I have no problem with the price, nor buyying direct from Japan should it tickle my fancy to posess one of these units.

[Dan Baldwin]

Far be it form me to jump into a fray like this...

Heh heh! Dude, jump right on in!

 

But my understanding on the development of this product involved stroboscope observation of the TIGHT SIDE chain action.

With their components installed, the observed deflection of the tight side of the chain at times was noticably reduced, as well as action over the formerly "slack side" portion.

 

Since the tight side motion was noticeably reduced, the chain tension must have been greater. Coupla questions: how much chain tension is too much (causing increased wear and/or frictional losses), and how much motion is really a problem vs. what appears to be a problem?

 

Like some have said, while it may not be an "ideal" solution, it is one that in the practical application showed a marked positive effect on solvingthe problem they were attempting to address.

 

In the end, that is really what is important.

 

If you ask me, what is important is whether or not the "solution" does indeed provide increased performance (or performance potential) and/or reliability.

 

I don't use that example in any way to equate Kamearis' solution to the problem they discovered, only to illustrate that there may be more than one way to approach something, and BOTH will work.

 

I'll agree with that statement. My personal preference is to conservatively stay with the setup that I have seen on more factory-developed high-performance applications.

 

I would suspect that WHEN the camchain does begin to move around with the Kameari setup, it would go unstable very quickly and violently. rpm at which this would occur would be highly dependent on pretension, which of course it has already been stated would have to be checked and maintained.

[JMortensen]

Since the tight side motion was noticeably reduced, the chain tension must have been greater. Coupla questions: how much chain tension is too much (causing increased wear and/or frictional losses), and how much motion is really a problem vs. what appears to be a problem?

Since the chain tension isn't a factor of the oil pressure in this system, I don't know that this is necessarily true. Plus the chain effectively has a "tensioner" (idler) at both ends, so it should be less reliant on tension to keep it steady. As you said earlier:

Lesse, if you constrain it on both sides halfway between the two tensioning sprockets, you can either cut the chain tension or increase the rpm. Constrain it again at 1/4 and 3/4 length, and again you can reduce tension and/or increase rpm. Continue ad infinitum and you end up with with zero tension and with physical lateral support (i.e., a GUIDE) for the chain all along the slack side.

I think you were right in showing the superbike chain tensioner and that looks like a good system, but again, it looks to me as if the WHOLE guide moves and the WHOLE guide acts as a tensioner, not just a shoe at the bottom of the chain. So your argument for the superbike tensioner is compelling, but the argument for the L series tensioner is not IMO.

 

If you ask me, what is important is whether or not the "solution" does indeed provide increased performance (or performance potential) and/or reliability.

I'd like some of the other benefits too, personally. I'd love to mill the crap out of my head and not have to deal with any of the other BS, just adjust my chain tension and cam timing and call it done.

 

I would suspect that WHEN the camchain does begin to move around with the Kameari setup, it would go unstable very quickly and violently. rpm at which this would occur would be highly dependent on pretension, which of course it has already been stated would have to be checked and maintained.

Well apparently they think it is good to 13,000 rpm, so that doesn't look to be much of a problem on a L series unless you downshift from 5th to 2nd, in which case there will be plenty of other problems to deal with.

[HS30-H]

No evidence that this setup is better in any way is presented anywhere in this thread.

 

Because the people who designed, developed, engineered and productionised this setup ARE NOT PARTICIPATING IN THIS THREAD.

 

Has it crossed your mind that Kameari's test data will all be in Japanese? I've seen their test data on other products and this is the case. Perhaps you would like them to translate it into English before presenting it to the 'Judge'?

 

Tony D,

I know that Mori san and his colleagues had been working on the twin-idler tensioner for a matter of years before it was sold to the general public. They did embark on a serious test programme and I know that this actually cost them a lot of time and money. Some of the research was carried out by outside agencies with the relevant facilities. Even if I had any of this test data - which of course I don't - I certainly wouldn't post any of it on this thread.

 

When testing the stock tensioner, Kameari saw some interesting things. One of the phenomena described to me was of a 'wave' effect of chain whip, much like the kind of wave that we used to send down a skipping rope when we were kids. It was explained to me that this 'wave' was observed running both ways up and down the chain as the test-bed engines were accelerated and decelerated, causing cam timing to advance and retard depending on where the forces were directed and where the chain slack was. Kameari had seen engines on their dyno fail because the cam timing was moving out of sync with the crank, and they believe that they solved this with the Twin Idler setup. The stock tensioner, when blueprinted and optimised, was doing fine up until the very highest levels of tune - and Kameari still sell, fit and use the stock type tensioners of course - but their most extreme engine specs needed some extra control of the chain.

 

I suspect that if the front cover on our highly tuned L-series engines was made from glass, some of us might be surprised and somewhat perturbed to see the effect of harmonics and other forces acting on our timing chains. Do you agree?

 

Mori san told me that their best-performing engine so far was fitted with the Twin Idler, and that he really believes in it.

 

And as jmortensen has been pointing out whilst being ignored - it kills more than two birds with one stone too.

[greenmonster80]

It probably will not help any but I printed out the instructions that where posted. With the help of the Little Lady I can post an English translation. Give me a couple days to get it done and figure out how to post it here.

[ww]

You could explain it like that all day and it still doesn't make sense. it doesn't matter if the crank is being driven by the pistons or by the drive wheels via the transmission. It is always spinning in the same direction and it is always pulling tension on the tight side of the chain to drive the camshaft. Chain tension only swaps sides if the output side and input side have their roles reversed. In order for the situation that you are explaining to happen the transmission would need to be driven off the camshaft!

 

The rotating mass of the cam continues even though the crank shaft is being slowed by the drive shaft.

 

It doesn't cause the tension to move to the slack side and stay there, but it causes the slack to oscillate back and forth between the two during deceleration as the camshaft is being slowed down by the slack side of the chain attached to the 'more rapidly' decelerating crank shaft. The more slack there is in the chain the more these oscillations will affect timing accuracy during this period.

 

During continuous acceleration this is not so much of a concern, but in a drag race where you’re shifting gears or a road race where you’re accelerating, decelerating and shifting gears, it can cause a significant impact to the performance of a highly tuned vehicle.

[Dan Baldwin]

I think you were right in showing the superbike chain tensioner and that looks like a good system, but again, it looks to me as if the WHOLE guide moves and the WHOLE guide acts as a tensioner, not just a shoe at the bottom of the chain. So your argument for the superbike tensioner is compelling, but the argument for the L series tensioner is not IMO.

 

My only argument for the L-series tensioner is that it has worked for myself and others up to pretty high-ish rpm. I always thought crank torsional stability became the limiting factor at rpm ~8000+ anyway...

FWIW, a solution for noisy cam chains that is regularly implemented in motorcycles is to do away with the oil pressure tensioning and replace it with a mechanical screw-tensioner (still operating on the stock chain guide).

 

Well apparently they think it is good to 13,000 rpm, so that doesn't look to be much of a problem on a L series unless you downshift from 5th to 2nd, in which case there will be plenty of other problems to deal with.

13,000?! That's certainly impressive, if true, but of course overkill for any L6 I'm aware of! I would still be very interested to see what the required chain tension is compared to a curved chain guide.

 

Has it crossed your mind that Kameari's test data will all be in Japanese? I've seen their test data on other products and this is the case. Perhaps you would like them to translate it into English before presenting it to the 'Judge'?

That'd be swell!

 

In truth, it looked to me like a solution to a problem that didn't exist. But of course if they were running into destructive instability problems at (presumably) very high rpm and very tight piston/valve clearances...

 

It *seems* to me the better solution would be a mechanical screw-type tensioner for the curved guide, though. That would *I think* require less chain tension.

 

In any case, I'm not having any reliability problems at usually 7000rpm, sometimes up to 7300rpm for a few timed laps. But of course there are applications that go well beyond that, but still the ones I know of still use a stock-type curvedguide.

 

I would of course be very interested to see any test data if available.

 

yr. devil's advocate,

[JMortensen]

My only argument for the L-series tensioner is that it has worked for myself and others up to pretty high-ish rpm. I always thought crank torsional stability became the limiting factor at rpm ~8000+ anyway...

Me too. The only problem I've come across that directly relates to the tensioner is the chain guide getting torn up on the bottom. That is a real bummer when it happens because little pieces of metal get in the chain and fall into the pan.

 

FWIW' date=' a solution for noisy cam chains that is regularly implemented in motorcycles is to do away with the oil pressure tensioning and replace it with a mechanical screw-tensioner (still operating on the stock chain guide).

[/quote']

This sounds like a great idea, but it also looks like the tensioner bolts into the side of the timing cover, so it would be MUCH easier to modify the superbike tensioner for manual tension than an L series. Even a spring tensioner would be better than the oil tensioner IMO, but that'd have to be one hell of a spring.

[rc's240z]

Guys, getting one of these are not a big deal, I have had one (although not installed it yet) for 6+ months. I believe I paid closer to $450.00 USD for it.

 

All it takes is someone in Japan to buy one and ship it to you. There are modifications necessary depending on what head you install it into...

 

Ron

[Tony D]

"When testing the stock tensioner, Kameari saw some interesting things. One of the phenomena described to me was of a 'wave' effect of chain whip, much like the kind of wave that we used to send down a skipping rope when we were kids. It was explained to me that this 'wave' was observed running both ways up and down the chain as the test-bed engines were accelerated and decelerated, causing cam timing to advance and retard depending on where the forces were directed and where the chain slack was. Kameari had seen engines on their dyno fail because the cam timing was moving out of sync with the crank, and they believe that they solved this with the Twin Idler setup. The stock tensioner, when blueprinted and optimised, was doing fine up until the very highest levels of tune - and Kameari still sell, fit and use the stock type tensioners of course - but their most extreme engine specs needed some extra control of the chain.

 

I suspect that if the front cover on our highly tuned L-series engines was made from glass, some of us might be surprised and somewhat perturbed to see the effect of harmonics and other forces acting on our timing chains. Do you agree?"

 

Oh, for sure! That is the phenomenon that you have to observe through a variable-speed stroboscope. I believe they most likely had a transparent cover made to set up the stroboscobe and observe the cam chain. This is a very common test procedure.

 

I have someone who was concerned about timing variations install one in his engine, and depending on how it works, I may be using it in the Bonneville Racer we are building. The L20A will need to go to 9000 (right to the crank breaking torsional area) to make the HP we are hoping to make to break the record, so our concerns on cam timing have us looking at this device pretty closely. With our compression ratio (well above 14.5:1 being vague...) our vavle to piston clearances are extremely close, and any variation on the valvetrain will make it a short season in the G-Pro Class!

We have the spare L28 ready to go again---that engine had pressed-in piston pins WALK to the cylinder walls, something nobody we talked to ever saw before... And that engine was only running 8500 for five minutes at a stretch...

So there may be situations where conditions exist that this will help. I hope we won't need it, but given there are no practical alternatives, and it seems to be doing the job, it is the only viable alternative at this time!

 

The Japanese had 9 second Drag cars and 500+Hp Street L-Gatas for well over 20 years. I would say they are still at the pinnacle of R&D simply like the USA is at the Peak of R&D for a Small Block Chevrolet...

[Guest dfn_doe]

Guys' date=' getting one of these are not a big deal, I have had one (although not installed it yet) for 6+ months. I believe I paid closer to $450.00 USD for it.

 

All it takes is someone in Japan to buy one and ship it to you. There are modifications necessary depending on what head you install it into...

 

Ron[/quote']

 

Pitroad quoted me 586.00 shipped to the SF Bay Area, I'd be curious to hear where you got yours for 450.00.

[HS30-H]

Guys, getting one of these are not a big deal, I have had one (although not installed it yet) for 6+ months. I believe I paid closer to $450.00 USD for it.

 

The kit retails at 48,000 Yen in Japan. At roughly 103~104 Yen to the $US currently, this works out at around $460 USD.

 

I presume you are not including shipping charges and Import Duty based on a truthfully-stated value in your "$450.00 USD"?

[Dan Baldwin]

Needless to say, I'm VERY interested in following the development of this 9000rpm 14.5+:1 CR monster L6 development!

 

Totally different world from my 11:1 7300rpm application.

 

If the Kameari chain tensioner controls the camchain oscillations at 9000 where a properly set-up stock-type curved guide won't, I'll be among the first to laud it here.

[HS30-H]

Needless to say' date=' I'm VERY interested in following the development of this 9000rpm 14.5+:1 CR monster L6 development!

 

Totally different world from my 11:1 7300rpm application.

 

If the Kameari chain tensioner controls the camchain oscillations at 9000 where a properly set-up stock-type curved guide won't, I'll be among the first to laud it here.[/quote']

 

Kameari have been building and using Nissan L6 engines that spin over 9000rpm for many years.

 

This is one of the reasons why they developed the 'twin idler' cam chain tensioner.

[dragoontwo]

hmmmmm................. I don't suppose you would be able to tell me where in Japan I could physically pick one up? I'd be a short plane ride for me to get one if I was so inclined to.

[jeffp]

Lets look at the chain and gear(sprocket) first. The roller chain and sprocket configuration, although very srtong, promotes and instable operation pretaining to relative contact area of the chain to sprocket area. The chain, as drag, torque, and speed are increases has an effect to attempt to push the chain towards the top of the sprocket gears. What this does, for one is to try to stretch the chain, and wear the gears. The more important thing in the engine, is that when this occures, the chain riding toward the top of the gear teeth, CHANGES THE CAM TIMING!

You can not maintain a consistant torque and power curve with the cam changing its timing under various conditions.

Now, Nissan designed the system to turn clockwise, thus the reason for the strait chain to the crank on the right side of the sprocket, to promote a more stable positioning of the gears and chain assembly, and to make the system maintenance free for the most part.

Now, since the cam, valve springs offer a SIGNIFICANT opposition to the cam turning, that transfers to the SLACK in the timing chain. So when you stop the accelleration of the engine in a clockwise direction, turning the cam, providing tensioning of the chain due to the drag on the cam/valve train. The cam and valve train components will provide opposition or resistance on the chain on the opposite of the sprocket, or left side of the cam gear. The cam then again changes its timing until the tension is enough to overcome the oppostion to the turning og the cam and valve train components.

So what you get is a variable cam timing when you dont want it, it decreases performance, engine response and inconsistant operation of the rotating chain assembly. You want to see just how much change there is? turn the engine clockwise, take a reading on the timing marks, then rotate the engine counter clockwise, and note when the can starts turning, take the timing marks total, divide that by 2 and that is the amount of change in the cam timing you can expect to see.

The hydrolic tensioner Nissan came up with works very well for a stock engine that wont see RPM levels over 5500 rpm's for the most part, but it really falls down after that rpm level. ASlso, since the hydrolic unit operates with the engine oil pressure, it to will vary in it's effectiveness.

The unit that has been made to replace this system is very good. You can preload the chain trension, you have much beter control, as Tony mentioned, the effects of the thain that is spinning very fast. The cam timing is stabelized, the engine performance in stabilized. You dont have to worry about the plunger coming out, and that is worth 200.00 LOL so that is it in a nut shell. The part works well, and it is worth the money in my opinion.