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Discussion Starter · #1 ·
Hello everyone I am needing a little help with a 460 that is in a 1976 Ford T bird. The engine was just rebuilt and is being used as a daily driver in the mentioned t bird. The issue is that i can't get this engine to idle smoothly to save my life. Now I do have 460's in two other cars and they idle perfect no issues. please any suggestions would be helpful.
The engine is question has had the following done to try and locate the reasons for not idling smooth.
1) checked compression. All right around 155-160
2) went over ignition system plugs ,wires, distributor, cap and rotor spark box replaced coil checked all good
3) carb installed Holley warrior brand new 650 cfm (replaced an older carter AFB) Made no difference.
4) timing set at 14 BTDC ( increasing timing would not smooth out idle)
5) checked for vacuum leaks none found
6) engine runs great right off idle at any speed plenty of power.
7) cam is a stage II trailer towing
8) 9.0:1 compression
9) 1970 timing chain set
 

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Discussion Starter · #3 ·
Engine idles @700 RPM with about 17 inches of vacuum. I assembled the upper half. The shop did the lower half including installing the timing chain. timing chain is a stock single keyway 1970 unit. They did degree the unit and he told me it was perfect. I installed the distributor Timing @ 14 BTDC (again stock type) and the unit when in without any issues.
 

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Hi,
Did you use a timing light to set it to 14* while it was running?? The way you said you installed the distributor it doesn't sound like it... Timing is not a guessing game and must be set with the motor running and with a timing light.. Some people don't know that so i'm just saying..
Idle speed should be 650 with a manuel transmission and 750 with an automatic.. or what ever the cam calls for if it says something else.

good luck take care be safe
tim
 

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HI
OK great... I'd get a vacuum gauge and see what it says it well tell you a lot.. Here's a link to reading on and what it can tell you about your motor...


good luck take care be safe
tim
 

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If you find no line related vacuum leaks remove the pcv valve and plug it.
Stuff a rag into the oil fill on the drivers side valve cover. Start engine and check for vacuum at the other valve cover.
There should be none.










Scotty J. "AKA" The "Mad Porter"
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Ported BBF iron head specialist & Aluminum heads from all sources.
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See our products in the Vendor for sale section
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Discussion Starter · #11 ·
If you find no line related vacuum leaks remove the pcv valve and plug it.
Stuff a rag into the oil fill on the drivers side valve cover. Start engine and check for vacuum at the other valve cover.
There should be none.

Here is what we have done:
1) disconnected all vacuum lines hooked up vacuum gauge - no change same 17 inches of vacuum with needle slightly wavering
2) while lines were disconnected removed PCV from engine capped off carb and one valve cover - good news no vacuum at other valve cover engine RPM slowed a bit but continue to run rough.










Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
ParklandAutoMachine.com
R-H-P.biz
"Parkland Performance Auto Machine" Formerly RHP
(253)-988-6648
Parkland Auto Machine
 

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This problem has been consistent since the engine refresh?

How did the spark plugs look when you had them out for the comp check?

Is it possible the rockers are improperly adjusted without affecting the comp check?
 

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Discussion Starter · #13 ·
This problem has been consistent since the engine refresh? YES AND BEFORE AS WELL (WANT TO ADD SWAPPING CARB MADE NO DIFFERENCE)

How did the spark plugs look when you had them out for the comp check? AT 1000 MILES PLUG ELECTRODE CLEAN SLIGHT TAN/WHITISH COLOR. CENTER INSULATOR BRIGHT WHITE.

Is it possible the rockers are improperly adjusted without affecting the comp check? POSITIVE STOP NO ADJUSTMENT
 

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Check spark plug wire resistance, coil resistance, spark quality/color-of course blue/white is better than orange, magnetic pickup resistance, if using a Duraspark module-try swapping it out for a known "good" unit, also check the resistance between the distributor cap's outside coil terminal and the inside center spring loaded "button" that touches the rotor, I've personally seen big ohm reading differences on different manufacturer caps. Hope this helps
 
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