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Most all of the chain breakage issues I have seen, all seem to have excessively stretched chains. As the chain stretchs the piston is extending out of the tensioner and the internal spring cant apply enough tension during start-up and on-off the gas situations.

When I swapped over from a A2 head to the Z3 head I replaced the timing chain and all the guides with NIB. I put both chains up to each other and the old chain was appreciably longer.

A stronger spring and possiblly a SMALLER oil exit hole in the piston to maintain hydraulic damping would help
i ordered a new chain, but not new guides. would new guides help at all? :confused: lol
 

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Here you have some pics of my Toda tensioner Vs. the old Honda one.







 

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whoa i have extra b series dowel pins laying around...so i just cut these to 15.5mm?
Check post #57 on page 3 by Hybrid_Hatch. He's the one that posted how to do it. You use the 14x20mm b-series head dowl pin and cut to length, then install it behind the piston and reassemble the ratchet. I've done it already, it was pretty easy with a 16oz ball pin hammer and small punch. 15.5mm Convertered to inches is .580
 

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Check post #57 on page 3 by Hybrid_Hatch. He's the one that posted how to do it. You use the 14x20mm b-series head dowl pin and cut to length, then install it behind the piston and reassemble the ratchet. I've done it already, it was pretty easy with a 16oz ball pin hammer and small punch. 15.5mm Convertered to inches is .580
Iam going to post this here to try and keep all the info in one spot, hope you dont mind.

so my buddy with a K24A4/K20A2 frank comes by saying his car is "clattering" so I pull the valve cover and see the timing chain is really loose, so we run to the dealer, spend 43 bucks and get a new tensioner, low and behold IT LOOKS THE SAME!! so I tear into it to find its all the same. well he did not want to have the chain slip/come off (got lucky this time) so I modded the sucka..from what I found the tensioner rides at about number 3 click on the ratchet assy and needs to go in to about 2 1/2 teeth showing to get it installed. well I used a rod before that broke the oil intake port check valve so I was trying to figure out a good way to pull this off. I did not want to use washers or a longer spring because coil bind can be very bad if the spring was to break so it dawned on me..shim the piston!!! so I looked around for something worthy, at first I was going to cut a old piston to insert in the tensioner but right before I was to cut it I look over an see a B series head dowel pin, thinner and the perfect size to fit in the valve body while allowing the spring to go thru the middle so as to not block the high pressure releaf in the piston and not break the check valve in the valve body. so after about an hour of trail and error I got it done..I cut the dowel down to 0.580 inches and slid it in the valve body then got a spring that had 8 more psi of pressure to it and re installed it then put it on the car..

cliff notes

B series head dowel
cut to 0.580 inches
installed in the tensioner
8 psi stronger spring
fail safe so chain does not slip or come off.

just copied and pasted for the lazy :)
 

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I made a more correct measurement:


 

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ok, so im confused, a lil help please. so is it suggested to do this mod to the chain tensioner when doing any K-swap? what necessitates the reason for this mod?
It's what has been found threw trail and error to be a problem with stiffer aftermarket valve springs. So, yes it's recommended as a safety check and in most cases found to be the solution. It's cheap insurance against major interenal damage, but not a guaranty ofcoarse. (you can't ever rule out human stupidity)

If you're running stock cams and valve springs in the rev range their designed to run in than you shouldn't have a problem. This is only for those of us that are trying to push the limits of the k-series.
 

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Discussion Starter · #214 ·
ok, so im confused, a lil help please. so is it suggested to do this mod to the chain tensioner when doing any K-swap? what necessitates the reason for this mod?
I would NOT modify the stock tensioner with a fixed stopper. I repeat, i would NOTmod the stock tensioner with a fixed stopper. I have developed a newer design that utilizes a dual spring that will not cause chain breakage due to repeated hard stopping of the tensioner piston.
 

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I would NOT modify the stock tensioner with a fixed stopper. I repeat, i would NOTmod the stock tensioner with a fixed stopper. I have developed a newer design that utilizes a dual spring that will not cause chain breakage due to repeated hard stopping of the tensioner piston.
OK, so what's the price chunky?

The stopper was just what others found to work or just found out what Toda did for their fix. I'm glad you were able to research this further chunky.
 

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Discussion Starter · #216 ·
OK, so what's the price chunky?

The stopper was just what others found to work or just found out what Toda did for their fix. I'm glad you were able to research this further chunky.
As of right now, I sell them individually for $100 + shipping. That includes a brand new tensioner. I will not modify used tensioners.
 

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As of right now, I sell them individually for $100 + shipping. That includes a brand new tensioner. I will not modify used tensioners.
Hey Chunky, you still selling the modified tensioners?

Also I wanted to bump this post to see if there has been any new developments. Are the tensioners that you guy shimmed still holding up?

I have a built k24/k20 swap with Crower valvetrain and BC Stage 2 cams that I'm tearing down after only about 10k. A new OEM tensioner which was installed 4k ago is absolutely hashed!!! :(

I think I'll be going with a shimmed new OEM tensioner unless Chunky can give us more info or cut me a deal. ;) I can't see shimming the tensioner causing any problems.
 

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to my knowledge and what I saw on stock tensionner, the Toda isn't better than OEM according to those pictures

the big problem with the OEM tensionner isn't the springs but the axial play on the shaft, if the shaft rotate the teeth on the lock broke since the holding surface is really small

 
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