timing chain tensioner question
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- Start date
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IWRECKEDMYSHO
New Member
Yamaha V6
SHO Enthusiast
Ok, here's some more info:
The picture showing the chain cutting into the tensioner is performing as it should over time - the chain wears away through the plastic / nylon & cuts grooves. Eventually, the insulator gets cut all the way through and the pieces go into the head / down the oil return passages to the pan (if you're lucky & they don't block the return line).
When a tensioner fails due to the tension no longer being able to take up the slack in the chain, the exhaust cam is no longer directly "slaved" to the intake cam, there is movement / slack in the cam chain, and you hear a "slapping" of the chain on the cam cover or head. The exhaust cam is able to spin at a different rate for very brief periods as the exhaust cam valve springs "shoot" the cam forward after being pulled by the chain / intake cam. Of course, after the exhaust cam has "overshot" the intake cam, there is slack and the intake cam jerks on the cam chain to bring the exhaust cam back into swing. This naturally increases chain stretch.
Once the insulator is gone, you'll hear a metal on metal grinding as the chain passes over the tensioner. However, as long as the tensioner is able to take up the slack, there won't be any "slapping", just the constant metal on metal.
Those are pretty much the 2 tensioner failure situations I've had to repair - worn through insulator (but good tension), and good insulator & no tension.
Hope this didn't confuse anyone.
The picture showing the chain cutting into the tensioner is performing as it should over time - the chain wears away through the plastic / nylon & cuts grooves. Eventually, the insulator gets cut all the way through and the pieces go into the head / down the oil return passages to the pan (if you're lucky & they don't block the return line).
When a tensioner fails due to the tension no longer being able to take up the slack in the chain, the exhaust cam is no longer directly "slaved" to the intake cam, there is movement / slack in the cam chain, and you hear a "slapping" of the chain on the cam cover or head. The exhaust cam is able to spin at a different rate for very brief periods as the exhaust cam valve springs "shoot" the cam forward after being pulled by the chain / intake cam. Of course, after the exhaust cam has "overshot" the intake cam, there is slack and the intake cam jerks on the cam chain to bring the exhaust cam back into swing. This naturally increases chain stretch.
Once the insulator is gone, you'll hear a metal on metal grinding as the chain passes over the tensioner. However, as long as the tensioner is able to take up the slack, there won't be any "slapping", just the constant metal on metal.
Those are pretty much the 2 tensioner failure situations I've had to repair - worn through insulator (but good tension), and good insulator & no tension.
Hope this didn't confuse anyone.
Slo-Sho
It wasn't me!
Are there any special techniques to keeping everything lined up? Do the cams themselves have to come out?
ionerI have been using Mobil 1 15W50 for about 20 years on all of my car and have had very good results. It holds good oil pressure as the enginge gets to running temperature, and the engines I have dissasembled have always shown very little wear with no carbon deposits at all and no oil consuption. (Except for a junkyard '92 5.0 which I have in my Bronco II and that enginge always consumed oil, I do not know if it is because of the forged pistons or previous history.)
Also Miami, FL is hot in the summer which lasts about 9 months.
I am going to install mechanical gauges when I put my SHO back together to monitor my engine more closely. I may also install an engine oil cooler. My 5.0 runs at 260 to 280 degrees without a cooler, with the cooler it runs between 180 and 200 degrees.
How do I change that plastic wear part on the tensioner? Or do I have to change the whole assembly?
Also Miami, FL is hot in the summer which lasts about 9 months.
I am going to install mechanical gauges when I put my SHO back together to monitor my engine more closely. I may also install an engine oil cooler. My 5.0 runs at 260 to 280 degrees without a cooler, with the cooler it runs between 180 and 200 degrees.
How do I change that plastic wear part on the tensioner? Or do I have to change the whole assembly?
Yamaha V6
SHO Enthusiast
No, the cams do not have to come out. If the cams ARE out, it's a whole lot easier to fit the tensioner & line up everything - then drop the cams in. However you then get into installing the caps & cam seals again...
As far as the plastic / nylon piece, there is no replacement that I'm aware of - to the best of my knowledge you have to replace the whole tensioner.
gosho89
New Member
Yamaha V6,
I did a valve adjustment today on club members 93 ATX w/154K, the owner had complained of lots of engine noise. During start up I heard a least one chain clattering. Once the valve covers were removed the RH chain tensioner plastic / nylon strip was missing. I could not determine whether the LH chain tensioner plastic / nylon strip was missing as well, how can you tell? the chain was still tight on the cam gears and I could not see the area very well. And most importantly what is the procedure to replace the tensioners without removing the camshafts and would you recommend the replacement of both chains? and lastly can this also be accomplished without removing the cams. MUCH appreciated in advance!
<small>[ December 07, 2002, 01:09 AM: Message edited by: gosho89 ]</small>
I did a valve adjustment today on club members 93 ATX w/154K, the owner had complained of lots of engine noise. During start up I heard a least one chain clattering. Once the valve covers were removed the RH chain tensioner plastic / nylon strip was missing. I could not determine whether the LH chain tensioner plastic / nylon strip was missing as well, how can you tell? the chain was still tight on the cam gears and I could not see the area very well. And most importantly what is the procedure to replace the tensioners without removing the camshafts and would you recommend the replacement of both chains? and lastly can this also be accomplished without removing the cams. MUCH appreciated in advance!
<small>[ December 07, 2002, 01:09 AM: Message edited by: gosho89 ]</small>
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