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Ron
Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 33407
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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My issue is a 79 460 rocker arms bolt down. Do

Customer Question

***** ***** my issue is a 79 460 rocker arms bolt down. Do I need to do tdc on each as I tighten down to ft. Lbs specs?
JA: Thanks. Can you give me any more details about your issue?
Customer: The 460 out of the blue started to rough idle. I had it in a shop and not satisfied i decided to tackle myself. I had a slight rocker noise I thought so I went through loosen up rocker passenger side only and torque to 20ft. Lbs . now I have carburetor backfire and the exhaust seems to be sucking air.
JA: OK got it. Last thing — Ford Mechanics generally expect a deposit of about $28 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 7 months ago.
Category: Ford
Expert:  Ron replied 7 months ago.
Hello and thank you for your question,Your stock 460 should not require any adjustment as they are considered positive stop valves. Positive stop equipped rockers are adjusted by turning the adjusting nut down until it stops. It dose not matter it the engine is at TDC. The nuts are tightened to 18 to 25 Ft Lbs. See the link below. Copy and paste the link to your browser to open and view it.https://dl.dropboxusercontent.com/u/104923897/Head%20gasket%20Apr%2021.pdf
Customer: replied 7 months ago.
Ok what would cause the carb and exhaust problems right after that? This motor has original 112k and prior securing bolt to spec I didn't have this problem. Would backing the ft Lbs to say 18 he'll or tighten down to say 22
Expert:  Ron replied 7 months ago.
There self locking nut so you should be fine anywhere from 18 to 25 Ft Lbs. What type of problem are you having with it?
Customer: replied 7 months ago.
Ok sent a ? That hasn't been answered
Expert:  Ron replied 7 months ago.
What type of problem are you having ?
Customer: replied 7 months ago.
What would cause the carburetor and exhaust problems right after?
Expert:  Ron replied 7 months ago.
Can you explain what type of problem you are having?
Customer: replied 7 months ago.
Once again after I tighten to specs the carburetor backfires and sounds like the exhaust is sucking air. Runs rougher now and can't drive
Expert:  Ron replied 7 months ago.
If you have a stock engine then it should not be caused by tightening the rocker studs. Are you sure you do not have a bent push rod? Id the firing order right? What was the reason you had to adjust the valves?
Expert:  Ron replied 7 months ago.
What happens if you back the nuts off a bit, dose the engine smooth out?
Customer: replied 7 months ago.
Thought I had rocker loose driver side. So I backed off the bolts and torque to specs. Know will hardly run. It was drivable before .
Expert:  Ron replied 7 months ago.
So what happens if you back the nut up , dose it smooth out?
Customer: replied 7 months ago.
Have not tried.
Expert:  Ron replied 7 months ago.
Try that, that would at least determine which cylinder is causing the problem but it really should not matter on a stock engine, are you sure this engine is stock?
Customer: replied 7 months ago.
Best I know.
Expert:  Ron replied 7 months ago.
Okay then try loosing them up but not more the 18 ft lbs and see if it solves the problem.
Customer: replied 7 months ago.
Ok wont start at 18
Expert:  Ron replied 7 months ago.
I have to wonder if perhaps you have worn lobes on your cam, this engine should run just fine with the rockers tightened to 25 FT Lbs per factory specs.