bad idle, valves, timing chain?

Rusty Muffler

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Petaluma, Ca.
Hi,

Just got my 66 Fury III 318 and runs fine except it's rough at idle. Vacuum is normal but shakes or flutters. Compression is good 180pounds per cylinder, just rebuilt the Stromberg 3-261 carb.

Still idles rough. Can the compression still show good but the valves be too tight (I haven't checked the valves)?

Also, could a loose timing chain cause this? Did they use a nylon sprocket
on this engine?

Engine has 125k miles on it.

Thix!
 
Thx Rapid,

You may be mistaken about the rockers. I have a tuneup receipt that says they adjusted the valves.
 
If you have had the carb off recently check for a bad seal/vacume leak at the base of the carb by spraying some carb cleaner or ether around the base gasket while the engine is running, if the idle picks up you may have a leak there, also check the idle jet screws for a blockage under them, take them out (count how many turns ittakes to remove them so you can put them back roughly where they were.) Blow out the jets with an air gun, put the adluster screws back in and re-adjust.
Hope that helps
 
Thx Rapid,

You may be mistaken about the rockers. I have a tuneup receipt that says they adjusted the valves.

I'm no mechanic but I think the '66 used the 'wide block' or 'poly' 318. Somewhere in the back of my mind I'm thinking they were indeed adjustable on this engine, but not on '67 and later.
I don't have a Motor Manual here to check but maybe someone can make sure.
Dallas
 
Thank you all for your responses!

I took the carb apart again and rechecked everything and is ok. Idle is still poor so on to the valves!
 
Update: I adjusted the valves and found about 5 exhaust valves too tight. It idles great now!! Thx for all the responses.
 
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