Can you have your Timing chains too tight?

[LM3929]

I replaced the timing chains and old tensioners in my engine with Carrera tensioners and then added the safety kits into the tensions themselves.

now when I run my motor I get what sounds like a chain slap after the motor runs for about 3 or 4 minutes, nothing at first the the noise starts slowly

I pulled the covers off to see if I had a collapsed tensioner but both looked good, the chains were tight, I checked the ramps and all looked good, is it possible that I was to tight on the first setting of the tensioners?

Thanks Lorne M.

[Walt Fricke]

Lorne - I think that when setting cam timing one could get the chain too tight, so that the timing moved a smidgen when just under chain tensioner pressure in a running engine.

But the chain tension in a running engine is not adjustable. The spring inside the tensioner is what does the tensioning. The oil just acts as a shock absorber to keep the spring from oscillating.

If your safety kit is one of those two bolt collars, you'd really have to work at it to get the collar bolted on so far down the shaft that the resting position of the tensioner shaft head was pressing too hard on the idler arm. And those kits say you need a gap - maybe 1/8th inch - between the collar and the body of the tensioner anyway.

If your safety is to insert a short tube inside the tensioner under the moving shaft, and it was too long, I don't see how you could get the tensioner into place to start with.

I'd look elsewhere for the cause of this noise, which I suppose is new?

[LM3929]

Well apparently you can have them too tight. I pulled the timing chain covers off again (for the second time) to check for clearance on the tensioners.

The left side tensioner had over 1/8" clearance between the tensioner and idler arm and 1/4 " clearance after I removed the safety cap and the right side tensioner had .10 thou clearance between the tensioner and idler arm, so I removed the safety cap, put it all back toghter and ran up the engine and wallah no noise

[Walt Fricke]

Huh? What clearance between tensioner and idler arm? The tensioner piston tip rests directly on the idler arm. The only clearance specification I know about involves the space between the body of the tensioner and aftermarket devices which clamp around the piston to prevent it from retracting too far if it should fail. Are those what you call safety caps? Maybe 1/8th of an inch between cap and body, to allow some tensioner movement.

I suppose if one put those clamp devices on resting on the tensioner body, that could lead to noise as the tensioner piston moves up and down a bit during normal operation? Which would be why they are sold with instructions on a gap for them? But having too small a gap there wouldn't be quite the same as having too much chain tension, though. Just not enough available tensioner movement.

[E Sully]

Very confusing. There can't be too much tension, it is set by the spring in the tensioner. The oil is there to act to dampen up and down movement like a shock absorber. There should not be any clearance between the tensioner and the idler arm, the area in red. If you have any something is very wrong. The only clearance is between the collar and the tensioner body, as shown in yellow. This keeps the arm from moving far enough to allow the chain to jump a tooth.