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| undertow |
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I know this is an old thread, but it's full of good info so it seems better to post this here rather than in a new thread.
My timing chain has been rattling at low rpm since I changed the head gasket a couple of months ago. The tensioner is definitely in the released position (I've locked and released it several times with the rocker cover off to be sure), it just doesn't seem to be pushing hard enough on the chain. The o-rings on the tensioner filter have gone hard, but as far as I can tell from the pics, any oil that makes it into the retainer will end up pushing on the piston anyway, regardless of whether it sneaks around the filter or not. Or is there a drain somewhere in the retainer body? |
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| Shortshift |
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undertow wrote: My timing chain has been rattling at low rpm since I changed the head gasket a couple of months ago. The tensioner is definitely in the released position (I've locked and released it several times with the rocker cover off to be sure), it just doesn't seem to be pushing hard enough on the chain. The o-rings on the tensioner filter have gone hard, but as far as I can tell from the pics, any oil that makes it into the retainer will end up pushing on the piston anyway, regardless of whether it sneaks around the filter or not. Or is there a drain somewhere in the retainer body? Any chance one of your chain guides is broken or badly worn? After fitting and releasing the chain tensioner, I rotate the crankshaft by hand (with plugs out) and check the tension again. Any chain slack should have been taken up. If the tensioner is suss, get a new one (which includes the O-rings). How many kms have the chain guides & tensioner done?
_________________ AU2 XR8 with Raptor VL, ported Yella Terra GT40P heads, Scorpion 1.6 RRs, XE264HR-14 Comp Cam, ceramic coated Hurricane Headers, 60lb injectors, Walbro 255, 200cfi cats, 3" exhaust & Snow Performance water methanol injection |
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| undertow |
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Chain has 340,000 kms on it. The guides have noticeable wear grooves but still have plenty of meat left in them. It didn't really rattle before I did the head gasket so I suspect the tensioner.
When I release it, it feels like the dowel on the piston goes past all the ratcheting parts on the sleeve's spiral groove and comes out the end of the slot on the sleeve (if that makes sense!). The guide can therefore be pushed in against the spring tension probably 3mm or so before it is stopped by the ratcheting mechanism. Is this normal, or does it mean the chain/guides have stretched/worn to the point where the tensioner can't take up the slack? If this is the case, maybe I can get away with it by shimming or stretching the spring? Thanks! |
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| Shortshift |
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Seems like the chain tensioner was at it's limit before the head was planed. My guess is that the chain & guides need replacing, but then someone else on here might have another solution. I wouldn't recommend shimming the tensioner or stretching the spring.
_________________ AU2 XR8 with Raptor VL, ported Yella Terra GT40P heads, Scorpion 1.6 RRs, XE264HR-14 Comp Cam, ceramic coated Hurricane Headers, 60lb injectors, Walbro 255, 200cfi cats, 3" exhaust & Snow Performance water methanol injection |
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| undertow |
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Thanks Shortshift. I ended up pulling the tensioner out, cleaning it, and fiddling with it a few times to see exactly how it works. Then put it back in, pulled the rocker cover off and re-set it properly. Only needed about 1/3 of a turn anti-clockwise to set the tension, so it could still take up heaps more chain stretch. No rattles at all now. The trick seems to be to push and turn anticlockwise a little to get it over the initial "hill" on which it locks, then you will feel it want to rotate itself as the spring pushes the sleeve out. No pushing in required at this stage. When it stops wanting to rotate itself it's done; don't keep pushing in and turning like I did the first time...
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| Shen Long |
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Age: 49 Posts: 391 Joined: 22nd Aug 2008 Ride: 2002 AUII Fairlane Sportsman V8 Location: Roxby Downs |
i realise this is an older thread however i removed my tensioner yesterday due to an oil leak from that area.
Anyhow the O rings were all hard as plastic so i replaced all 3 + the 1 really big O ring as well. Anyhow when i re-installed the chain tensioner mechanism i wasn't 100% sure how to put it back in, so this is what i done. I FULLY locked the tensioner to its shortest position inserted it into the chamber on the block/head & then with my finger pushed on the tensioner & released it about 1 or 2 clicks. I then went ahead & installed the large threaded bolt mechanism then i inserted the smaller bolt mechanism with the filter inside (which i had previously cleaned). Does this sound right? |
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| TROYMAN |
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not quite
once you push the tensioner in( in its shortest position) you put the larger retainer in and do it up tight, then you fully release the tensioner, then you screw the threaded plug in last... |
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| Shen Long |
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Age: 49 Posts: 391 Joined: 22nd Aug 2008 Ride: 2002 AUII Fairlane Sportsman V8 Location: Roxby Downs |
now i see what you mean.
When the tensioning mechanism is at its shortest length it has no effect on the chain itself. When i put in the large bolt/retainer that actually supports/holds the tensioning mechanism in place. Only then should i release the tensioning mechanism that way it will only tension the correct amount rather than too much or too little. I see what you mean now. I will redo it once again in a few days when i replace the serpentine belt tensioner. For some reason the front of the serpentine belt is rubbing against the tensioner pulley's inner metal arm (if you get what i mean). |
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| Shen Long |
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Age: 49 Posts: 391 Joined: 22nd Aug 2008 Ride: 2002 AUII Fairlane Sportsman V8 Location: Roxby Downs |
i took mine apart the other day & found that the filter unit was missing.
Does this matter? |
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| phongus |
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Shen Long wrote: i took mine apart the other day & found that the filter unit was missing. Does this matter? Better to find a spare filter unit...it keeps crap from going into the assembly which might jam the tensioner, thus not tensioning the chain properly. Just a wild guess though.
_________________ phongus = Post whore 2006 |
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