hey guys was just looking at the page on here that talks about changing the fj timing chain tensioner witha mazda one.... all i wanted to ask was is this the chain tensioner that sits on the front of the motor bottom left side of the head??
once the cover is removed, the tensioner i'm talking about has 2 10mm headed bolts holding it on.
just wanna know if this is it so i can take it off and go for the upgrade

Yes thats the one.

I resolved the issue by having a button made to go over the orginal tensioner.

I was going to install the mazda tensioner but was told that the teeth on the mazda one were too long so that the chain tension was alway too tight, washers were placed under the factory tensioner so the when the tensioner is not under pressure it does not retract so far and only has a small distance to travel to put the chain under the correct tension.

Thats crap about the chain being too tight. For the tensioner to gain another tooth the piston has to be pushed out under normal oil pressure and operating conditions therefore the chain will remain at a tolerable tension. Yes it may remain at its maximum tension, (seen at high revs) even when the engine is turned off, but thats probably a good thing. Well its better then having the chain hitting the rocker cover and other places on start up and leaving metal filings behind.

Another benefit to this is it should also create more accurate camshaft timing throughout the rev range by maintaining a constant amount of slack in the chain hence keeping the cams timed the same.

The only bad thing that might happen is the chain guides wear a tiny bit quicker but these last for 300,000km+ normaly so who cares?

Its not like its going to put soo much tension on the chain it'l snap, unless you go and pretension it with a big assed screwdriver and force the tensioner to take up excess teeth...

ok guys i've done the install but my question is to those who've done the install aswell.... did you remove all the rubber off the end of the new piston and leave just the metal plate to push against the chain guide (similar to the original hydraulic tensioner) or did you only trim the rubber down??

hey guys... i know my last question hasn't been answered yet but i just wanted to ask another one... i spoke to a guy this mormning who said that the mazda ratchet chain tensioner also requires oil pressure to make it operate properly... so if you bolt it straight in without worrying about oil feed (like i have) it won't last long at all
anyone else got any opinions to add to this?

Can someone post a pic of what this chain tensioner looks like?

I dont get how it can "catch" teeth though in its name "ratchet" I can kinda guess of it mechanism of action.

It works much the same way as a self adjusting drum brake

Oh and bexi i thought that you opened up the oil gallery with a die grinder to match up to the fj20 one so it does get oil pressure behind it?

I haven't done this mod to mine but thought the mazda one has a small oil hole just offset to the standard fj one, so you just modify the gasket and extend the oil passage on the mazda part so it reaches the fj oil hole. I could be wrong but have a look, you should be able to figure it out

I am definately not a fan of the mazda ratchet tensioner. It has no "give" in the mechanism. I have had two of these break on me. So I modded the FJ tensioner by welding on the end of the piston to make it longer, only giving a few millemeters of slack to the chain, this stops the rattle, and I've had no probs since.

yeah it seems like the way to go damo after speaking to a few guys. they're all saying the same thing. sounds like i better just chuck the mazda one

Here is some pics of my mazda tensioner.. I removed the all the rubber.
Used it for one year now without any problems!

Here is the orginal from mazda, before moding..
[IMG][/IMG]

Removed the rubber thing.. You can se the teeth..
[IMG][/IMG]

And trimmed the side it to make it fit on the engine..
[IMG][/IMG]

If you're going to chuck all your mazda chain tensioners, chuck them to me. theyre brilliant little pieces of kit and I can't imagine how you could have problems with them. Just modify the FJ gasket so they get oil pressure and remove the rubber and away you go. E-mail me at ben@digsfish.com if you still want to get rid of them - i'll take the lot

Hi Guys
I did mine in my race car and the Mazda unit has the guide on it but if you hacksaw and the end it breaks away and the tensioner piston is almost the same the orginal.
Made an awesome difference.

My question to those who "broke" a mazda tensioner, exactly which part of the tensioner did you break and are you certain you actually had oil pressure at the tensioner which does the tensioning.
They dont break on Mazdas and their chains are much longer than ours.

Are you absolutely sure that the oil hole on the back of the tensioner lined up with the original FJ one in the head?
I know mine didnt and i had to offset drill the hole way oversized to make it line up sos oil actually did its intended job, tensioning.

The ratchet itself is there to prevent the piston from being forced back into the tensioner body when there is no oil pressure, not to provide primary adjustment.

So what exactly broke?

L8tr
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BTY BenD, theyre worth barely 20 bucks new from anywhere! LOL

he he, send em all COD, I'll pay the $5 postage....

I've had two of them break, it was the little ratchet lever which broke off at the end, and then jammed the tensioner inwards so not even the oil pressure would hold it out. No damage to any other engine parts, but a pain in the arse. I grooved a slot in the rear of the tensioner to line up with the oil feed hole in the block.

You guys can do what you want, but I'll never use another one of these. After modding the nissan tensioner, I've had no problems, and no rattle. Been running like that for two years now.

There are a legion of Mazdas running around with these tensioners working on far longer and heavier duplex chains that Mazdas use now and they almost never give dramas.

I reckon you have been unlucky M8 but whatever floats your boat!

L8tr
E

I'd say that the pressure on the tensioner would be more in an FJ than a mazda. FJ's had quite aggresive cams from the factory, and only small drive sprockets. This amounts to a lot of chain slap. I believe that some "give" is required by the tensioner, the mazda tensioner has no give with the ratchet design.

Why would there need to be any "give" dude?

The tensioner is on the return side of a fairly light, single row and short chain run.
How agressive the cam is is hardly a valid point since the tensioner does not see much on the return side of the chain.
The chain tensioner is merely a back-idler to take out slack on the loose side. It only really has to cope with the engine rolling slowly backwards when its shut off.

Have a look at the ratcheting snail-cam chain tensioners on older pushrod Fords. Its a snail cam design with a laughably tiny pressed metal follower/rubbing block that have very fine meshing teeth, its almost a knurl with no lash and the chain goes tight and stays tight. They dont break often and pushrod Fords usually require extremely heavy springs to control very heavy follower/pushrod/rocker/retainer/springs components at high revs compared to the buckets and shims needed to control our relatively tiny cam-on-little valve clobber.

However, whatever!

L8tr
E

I have had a mazda tensioner fail and it wasn't because of the cam or chain
There is 2 different heads late and early models
1 of the heads the Mazda tentioner will go in perfectly with no mods to the Mazda tensioner body
The other head has been machined differently and the tensioner body fouls on the machined face on the head which cracks the tensioner body where the ratcheting mech is causeing it to fail.
So the failures of the Mazda tensioner could come down to which head is on you FJ

Ben D
You know these 323 mazda tentioners are only $25 new from Autopro.

Yep thats right M8 and that very issue is covered by the pictures above.
L8tr
E