Hi all,

I have just finished checking my timing chains and both banks have metal bodied tensioners... now, I think I have a slight rattle on start up now and then when cold, and the right hand bank secondary chain has a small amount of play in the chain.

Should there be any backlash in the timing chains? or should the tensioners keep them tight?

To me I think they should be tight, so I am wondering if there has been any report of the metal bodied tensioners failing, or maybe it wasn't installed right.

To be honest I'm a little perplexed by this as I was hoping that checking them would bring peace of mind.

Thanks in advance for any advice that comes my way.

 

The tensioner pumps up fully with oil pressure. I changed mine and one would always lose oil pressure overnight and give a slight rattle in the morning. I have heard but not install them yet that the newest tensioners ratchet up to maintain pressure and don't rely on just the oil. I have put 10,000 mile on mine and haven't had a problem other than the 3 seconds of rattle on overnight start up. Surprisingly it takes a good 12 hours of sitting to rattle. Anything less and it starts up noise free.
a good check is to pull the fuel pump relay and roll the engine over with the cam cover off and see if it pumps up. If so it is the tensioner losing pressure which could also be caused by the mounting surfaces not being clean or the hold down bolts not torqued correctly.

 

Thanks very much. I will check it out. It is only a second or so of rattle and only when very cold, so could be the same as yours.

 

Could the 'rattle' be the PRIMARY chain/guide blade/tensioner making the noise????

The primary tensioners could be the original plastic body and rely 'solely' on oil pressure to tension the curved blade. The later metal body units have a 'ratchet' mechanism to hold the tension as well as oil pressure.

bob gauff

 

Does this mean there were two metal designs -- one that used pressure that leaked down overnight, much like the very first generation plastics -- a second with a ratcheting mechanism to hold tension much like second gens with their spring loads?

 

Did you use new, shorter bolts for the metal tensioners?

As far as I know, all the metal tensioners have a spring to hold them tight for startup until the oil pressure comes up. That is why there is the long shaft orange push pin in them when you get them that you remove once assembled. That allows the spring to release and put pressure on the secondary chain.

Did you remove the orange "push pin" retainer before you buttoned it up?
Vector

 

I typed PRIMARY!!!!!!!!!!!!!!!!!!!!!!!!!!

I was referring to the PRIMARY tensioners as having a ratchet inside.

bob gauff

 

Hi Vector. I didn't fit the tensioners, they were in place when I got the car. I may have to take the suspect one out and check it as I'm not overly happy with the way it looks. The chain on the top between the two sprockets can be moved easily on top of the tensioner, when I checked the other side it was pushing up under the chain.

 

"I typed PRIMARY!!!!!!!!!!!!!!!!!!!!!!!!!!

I was referring to the PRIMARY tensioners as having a ratchet inside."

Bob, understand; however, I was responding to Vern's comment.

 

If I recall correctly, the left side tensioner pushes up on the chain as it crosses on the top of the sprockets, while the other pushes down on the chain as it leaves the underside of the exhaust cam.

Using a 24mm socket on the end of the crankshaft apply pressure clockwise facing the engine and see if both chains are now tight.