Crazy custom timing chain tensioner

[Guest dfn_doe]

My buddy in Japan sent me some pictures he found online of a nicely

done 240z. While perusing the detailed photo build up of the car I

noticed the builder had done a custom timing chain tensioner after

(I'm assuming from the pictures) he had the factory setup fail.

Anybody know if someone in the states is making something like this

already?

 

http://ninjasuit.org/gallery2/v/CarStuff/DSC00002.JPG.html

http://ninjasuit.org/gallery2/v/CarStuff/DSC00052.JPG.html

http://ninjasuit.org/gallery2/v/CarStuff/DSC00051-1.JPG.html

http://ninjasuit.org/gallery2/v/CarStuff/DSC00083.JPG.html

 

Here's a link to the site of origin as translated from Japanese by

Google, definatly a sweet build, with all sorts of nifty custom

bits...

 

http://tinyurl.com/9gfl7

[JMortensen]

Nobody makes one in the states. The manufacturer is Kameari. A couple people on this board bought them through one of our English members, HS30-H.

[Guest iskone]

Hmmm. Tthat looks interesting. Wish i had one in my car about a month or two ago. This will sound dumb but wouldn't you think that would put a drag on the motor. I'm sure you wouldn't notice the difference in a street car, or any car that's not on a dyno.

 

 

John, BTW I still havn't touched the car, but I will soon. I know it sounds bad for me to say it but I try and have a life outside my car. SHHHHH...... I'll be on top of it real soon though.

 

Isk

[JMortensen]

Well the stock setup drags the chain across the right side guide. This has no guide on the right side at all, so it would probably lessen the drag. Plus it should alleviate chain whip. It should be a much more stable way to run the chain in theory. The manufacturer made some mention that you could spin it to 13,000 rpm or something like that IIRC. Not that the rest of the motor would be capable of that, but apparently the chain is...

[Guest iskone]

Waht!? I spin my motor to 13k all the time..... I wish

[Guest dfn_doe]

Nobody makes one in the states. The manufacturer is Kameari. A couple people on this board bought them through one of our English members, HS30-H.

 

Any chance you remember who on the board bought them or who they bought the through? I'd really like to get ahold of one of these for the 2.3l L4 in my 510. I know it's not a Z, but share and share alike

[JMortensen]

HS30-H is the member's name. You can also search for Kameari and you should find a couple posts about it.

[mario_82_ZXT]

HS30-H is the member's name. You can also search for Kameari and you should find a couple posts about it.

 

You might also find him on classiczcars.com. I'm pretty sure thats where he has pics of is 432R reproduction.

 

Another member is JapanZ from the zcar.com forums. He hangs around the 90-96 forums and the people there seem to really like his service.

He will ship stuff bought through auctions too.

 

Mario

[HeatRaveR]

Any idea how much that thing costs?

[JMortensen]

Over $400 IIRC, which is the only reason I don't have one. If you search the price is probably in that previous thread.

[BlackBeaut]

Spooky, I came across this fancy thing at the weekend whilst trawling the web:

http://nkondo-web.hp.infoseek.co.jp/Kameari_L6_2.htm

Looks like a slight mod to something is needed to make it fit:

http://nkondo-web.hp.infoseek.co.jp/kameari/L/L_Tw-Ag_2.jpg

Think I could live with that though!!

 

Cheers,

Rob

[datsunlover]

Dang.. after droping my tensioner (re-building the re-build.. long story) for the THIRD time, I started to think about actually building something like this.. would make things a lot easier, and I'm sure it would work quite well.. but for $400 I think I'll pass, or build my own eventually. Heck, if there were a bunch of people interested, I'd look into it further to see what costs would come out to...

[Dan Baldwin]

Without the curved guide, chain whip should be WORSE with this setup. Think about it, between sprockets it is TOTALLY free to TWANG like a GEEtahr string. It would require a lot more tension to keep the mass of the chain under control. The curved guide prevents "whip" with relatively little tension.

 

Looks like a bad idea to me.

[JMortensen]

Without the curved guide' date=' chain whip should be WORSE with this setup. Think about it, between sprockets it is TOTALLY free to TWANG like a GEEtahr string. It would require a lot more tension to keep the mass of the chain under control. The curved guide prevents "whip" with relatively little tension.

 

Looks like a bad idea to me.[/quote']

Well nobody is making you buy one Dan, but I still see some pretty good benefits to be had with this thing.

 

You would never have to fear dropping the tensioner because you could just fish the chain back out and hook it up. Never again would you have to fight the damn chain to get the cam sprocket on. It would be possible to run any head thickness without having issues with the tensioner and the chain guide getting torn up, or ever having to screw with the lash pads again unless you changed the cam. Literally you could mill your head and adjust the chain with the gears (and adj cam sprocket), rather than with shims. Plus, it does look like a more reliable setup to me, and possibly less drag too (maybe that's because I've seen quite a few curved guides chewed up and I've dropped the tensioner into the timing cover before). If you liked all the other features but were still worried about the twang between the two idlers it wouldn't be hard at all to make a short little guide to run between the idlers.

[greenmonster80]

Sounds like there is some question about the durability / design of this piece. I would like to remind some that Kameari has almost 30 years in hardcore L series racing. If they make it and put it out, it may be more than you need; But definitely not a fly-by-night, new fangeled do-da to waste money on.

[quicker240]

Thats the first time I've ever seen that setup.Looks like a great upgrade to me.Obviously much more accurate cam timing control.But given the amount of expense,why not rig up a belt drive?or has someone done that already too?This chain setup allows for precise adjustment of the gear and compensates for chain and gear wear,plus easy cam changes without jamming a stick down into the TC cover.I hardly see "twang" as an issue,but then again,I arnt no engineer.Nissan ever to something like this in competition?

[HS30-H]

Without the curved guide' date=' chain whip should be WORSE with this setup. Think about it, between sprockets it is TOTALLY free to TWANG like a GEEtahr string. It would require a lot more tension to keep the mass of the chain under control. The curved guide prevents "whip" with relatively little tension.

 

Looks like a bad idea to me.[/quote']

 

Looks to me like you don't understand how it works. Have you actually seen one in the metal? Have you used one?

 

With the Kameari chain tensioner, there is no more chain whip because the tension is held constant at all times. The stock tensioning system - whilst good enough for what it was designed to do, effectively has a spring in it ( the oil-pressure / spring assisted 'foot' ) and this can easily be overcome by the forces acting on it. When this happens, the cam and crank are no longer in a fixed relationship with regard to timing. Effectively, they were looking at uncontrolled variable cam timing with the stock tensioner.......

 

Kameari first starting developing their chain tensioner system because they were noticing chain whip on their engine dyno. They saw that the chain was free to move as it wished when throttling-off suddenly from high rpms, with the cam turning from the driven gear to the driving gear - reversing the forces acting on the stock tensioner. Even when the chain whip was not severe enough to cause piston-to-valve contact, it was noticed that performance was being affected due to the changes in cam event timing.

 

With the Kameari tensioner installed, the relationship between the cam and the crank is fixed. I don't understand how you can imagine that it is "TOTALLY free to TWANG like a GEEtahr string." because it is nothing of the sort. It is fixed. Where is the "TWANG" going to occur?

 

I'm not a spokesman for Kameari, but I've known them for many years now and have bought and used their products for just as long. They categorically don't make products like this just for any *bling* factor, and it is a pity that they cannot answer questions and criticism about their products in threads such as this themselves.

 

Alan T.

[AK-Z]

I know that this thread is about the chain tensioner but looking in the site that blackbeaut posted,I saw the they had a crank, then was thinking what factor limits the rpm capabilities of these l6 engines? Is it the balance of the crank, is it timing and/or fuel, or proper lubrication?

 

For the crank, wouldn't it be just a matter of having a speed/machine shop balance it at an rpm that you are looking for or is there more to it than that?

[Ruben]

Alan,

 

Can you still get these from Japan? If you prefer to discuss this offline pm me or send me an email.

 

Thanks,

[Dan Baldwin]

With the Kameari tensioner installed' date=' the relationship between the cam and the crank is fixed. I don't understand how you can imagine that it is [i']"TOTALLY free to TWANG like a GEEtahr string."[/i] because it is nothing of the sort. It is fixed. Where is the "TWANG" going to occur? .

 

In the world of structures, NOTHING is "fixed". Metal stretches, parts deform. The higher the rpm, the greater tension in this tensioner is going to be required with this setup to keep that chain from whipping all over the place. Greater tension = greater friction and greater wear.

 

I'd MUCH sooner modify the existing curved-guide setup than go for this arrangement.

 

If this were such a great idea, you'd see similar arrangements on superbike engines. But no, you ALWAYS see curved guides on well-developed high-performance engines. With a timing BELT, this is the way to go. With a heavy chain, I don't think it is.

 

Here's an image of the chain guides on a 13,000rpm Kawasaki ZX-10R motor:

http://www.ronayers.com/fiche/400_0572/tensioner/tensioner.bmp

 

And here's the setup on a 13,750 rpm(!) Yamaha R1:

http://www.ronayers.com/fiche/501_2451/camshaft_chain/camshaft_chain.bmp

 

Both these bikes make on the order of 160rwhp out of 1000cc.

 

I'm sure this company means well, but I'd put my money on Kawasaki's and Yamaha's engineering and development over Kameari's when it comes to designing a camchain layout that maximizes output and revs and valve control and minimizes losses.

 

Obviously, I don't like this design, but this is my engineering judgement. Do what you will, of course!