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Any suggestions on diagnosing a " rattle " ?

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I have a distinctive rattle coming from the engine of my carbed 73. It appears right at 2500 rpm and seems to be more noticable when off the throttle. I've tried to pin it down with a stethescope but it just seems to be coming from the front upper area but it is clearly being transmitted all over. It really seems like it is a timing chain noise, but I can't imagine it sounding like that.

I replaced the timing chain tensioner and the valve adjustment eccentrics. The valves are at .008 cold. The alt bar is snug, and the water pump is brand new.

The car runs perfectly, I guess I'm wondering if I have to replace the timing chain tension rails or if someone's run into the easy solution. Thanks for any suggestions.

Scott

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its def the timing chain my car does the same thing. I havent fixed it yet cause i just havent had time but i think it is the timing chain or the rails or maybe a combo

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timing chain tensioner (install a new one this time)

chain rails

loose valve clearence

worn rocker / rocker shaft bearing surface

exhaust touching body

exhaust manifold gasket leak

leak in exhaust system

. . . . . . . . ............. ?

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A few other places to check before ripping the timing cover off:

1. check for loose pads on the rocker arms themselves. Rotate motor until valve is closed, then take your hand and press the rocker against the cam, while looking for oil "seeping" from between the pad and aluminum arm portion of the rocker arm.

2. loose internal baffle inside a center resonator / muffler? If it's an Ansa...that's part of their reputation. Check for any loose heat shielding also - such as any original shields on manifold, downpipe, firewall, etc (depending on year - later cars had more stuff to rattle)

3. If the car has a header - that's common - and the reason I removed mine after only a few months.

I had a small rattle at 890 rpm idle that drove me nuts for months - it turned out to be the throttle linkage where it goes into the firewall on a std carbed car...a little grease inside the socket/plate solved it!

I personally have never had a car with a noisy timing chain - so my opinions about how common / rare that problem is are a bit skewed. it would be my LAST suspect though, in my search!

HTH

Paul Wegweiser

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clearance between the air cleaner's underside and the fuel pump. There should be a rubber plug where they hit, but it's probably died of old age.

If they're touching, you'll see a shiny spot on the fuel pump...and it'll eventually wear a hole in the pump! (ask me how I know!). You can adjust the air cleaner so it tilts away from the pump, and replace the rubber buffer. Hope that's it--an easier fix than the timing chain!

mike

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I have the cheesey filter that comes with a 32/36 ( jetted CD's way of course) so it's not that.

The idea of installating a used tensioner piston never occured to me,maybe I should have tried that first.

I changed the eccentrics as I've had trouble with other cars trying to get the adjustment right when they get flat spotted. But I will look for loose rocker pads, thanks Paul.

Looks like the front comes off. Or maybe I'll rebuild the one I have on the stand.

Appreciate all the suggestions.

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Mike's suggestion is I think the best.....and guess what, if

you put an inline fuel filter, especially if its the larger metal

one, that makes a vibrating sound against the top of the engine or

bottom of the air cleaner. Zip tie it in place or put a rubber

or foam rubber patch between the metal surfaces. GL

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If you want to give it a shot you can just replace the chain and tensioner without pulling the front covers. It just requires that you get a chain with a master link.

If that doesn't work then you could pull it apart- but I'm always concerned about screwing up the head gasket and having a leak there.

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One more place to look-

the distributor!

If the mechanical advance weights wear out,

they can hit the outside of the housing and make a tremendous racket.

The stethescope should be able to rule that out pretty quickly...

t

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I'll check out the dizzy tomorrow, thanks. PO put on a new ID48X but you never know.

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One more place to look, when my 32/36 throttle shaft bushing was going bad (unbeknownst to me) had a similar rattle, couldn't find, once I replaced the carb, rattle gone.

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