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Beer and Cheese
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Discussion Starter #1
Just when I thought I had everything dialed in and ready to make a trip to Logan motorsports to put the car on the dyno I start to hear a rattling sound coming from the front of the engine. At first I thought it was the belt tensioner and removed both the SC and serp belt and no change. The rattling sound only comes about at low RPM of 900-1100. But if I give it a little gas and open the throttle blade by hand the noise immediately goes away. As if oil pressure builds up and tightens the chain tensioners. To my relief, I changed the oil before taking the timing cover off and the oil looks good. I also cut open the oil filter and nothing serious.

I was able to get the timing cover off last night and I think I found the problem, but I'm not sure. In the picture I have an arrow pointing at the Left side bottom chain. I made a red line showing the amount of slack I can pull up. But all of the other chains are tight. Does this mean I have a bad chain or tensioner?


Thanks,

Josh

 

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Look closely at the tensioner just under the tensioner piston. The black tab needs to be removed.
 

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Sorry - I had a dumb. Disregard and carry on...
 

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Beer and Cheese
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Discussion Starter #5
haha that's ok, thanks tho. But would you say that is not right? The bottom chain has about 1/2 inch of slack? I'll have to take the chain off and see if it was damaged or the tensioner is not working.
 

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Yeah, there should be no slack at all in the chains.
 

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Beer and Cheese
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Discussion Starter #8 (Edited)
Here is a little video, there is no oil in the system so the tensioners don't have any pressure. The ratchets are out towards the guides. In the video you can see that the chains are slapping the top guides. Not sure if that is normal with no oil pressure.
 

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I would think that without the tensioners under proper oil pressure, that video looks perfectly normal, but I haven't seen a lot of these engines running without a timing cover, so .... :zdunno:

Like Brandon said, once these engines have been running, those tensioners should be pumped up hard and the chains tight.

If that was my motor and I was having your issues, I'd put new hydraulic tensioners and see if the problem goes away.
 

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Beer and Cheese
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Discussion Starter #10
See that's the thing, these are brand new tensioners. I have maybe 2 hours of idle time and 8 miles on the engine. How could they fail right off the bat?
 

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Remove those rusted tensioners that came from God knows where and inspect them thoroughly. They shouldn't be collapsing in like that. That is exactly what the ratcheting mechanism is supposed to prevent---oil pressure is a backup that aids the operation when at speed.
 

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The pistons on the tensioners shouldn't budge at all like that. As soon as you remove the locking pin and they extend, they're out.

edit: GM beat me to it. ;)
 

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The slack is across the whole chain, it just shows up there because the valve train is holding the slack to that side; it should shift side-to-side as you rotate the engine, and go 'over the hump' on the cams.

Too much slack is the tensioner, there's not much else.

That one looks rusty; the piston could be stuck.

I cleaned a set with carb cleaner, forgot about them, and let them rust solid; they would not come apart. :)

(Push the lock back with a pick, pull out the latch, and the piston will pull out. Of a good one, lol.)

I ended up buying a new set from MHS. :)
 

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It seems to be a consensus that those tensioners aren't acting right, new or not.

I guess that's the first thing you're going to try?

When you pull those, see if you need a vice to compress them like normal!
 

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New, clean ones will push right in; there a spring, and tight tolerances, but nothing holds them together other than the ratchet.

The ratchet is supposed to sit against the back of the guide, and keep the guide from loosening up after it sets.

The piston just has spring pressure; look at one of the later plastic ones if you want to see how easy they are to compress. :eek:

There's a pic in Sean Hyland's 4.6 book; it shows how it comes apart, and their mod for them.

If they're really hard to compress, I'd worry about deposits in the oil passages; but your engine looks pristine. Except for those, lol.
 

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Beer and Cheese
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Discussion Starter #17
I bought them new from RockAuto. They are the CLOYES, the same stuff that is made for Ford from what I was told. Yea I was concerned when I saw the rust on the L side. I'll have them off and replace with new Ford stuff on Thursday. Thank you for the replies!
 

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Glad to help; that is one Bad Azz ride. :D
 

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Beer and Cheese
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Discussion Starter #19
The ratchet teeth on the lock side got chewed up causing the ratched arm not to lock giving slack in the chain. Learn from my mistake people, only buy Ford. On the bright side I have a stress reliever, I can collapse the whole thing with one hand.

 
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