Valve noise
Thread Starter
|
New User
Joined: Feb 2008
Posts: 23
Likes: 0
Valve noise
First time user great site! Problem 77 ford with a 390 600 cfm carb. If I set the timing to factery the valves rattle BAD when you hit the gas or pull up a hill and it also starts had after it warms up. I know it sounds like its advanced to high that was my first guess. Mybe timing chain? 
Postmaster
Joined: Aug 2000
Posts: 3,312
Likes: 1
From: Eldorado Ca. USA
I agree with RCcrawler, I think its detonation. Back off your timing a few degrees, and run higher octane gas. The proper fix would be to get your distributor re-curved. There are seveal writeups on the internet on how to do it yourself. Do a search on google for duraspark distributor re curve.
Also you might be running a touch lean? I dunno. Try backing off your timing first, see what happens.
Also you might be running a touch lean? I dunno. Try backing off your timing first, see what happens.
Postmaster
Joined: Aug 2000
Posts: 3,312
Likes: 1
From: Eldorado Ca. USA
So you are saying that as the chain stretches, the timing retards? I hadn't thought about the effects of a chain stretching, I would have thought that it would not give that much unless seriously worn.
Trending Topics
Post Fiend
Joined: Feb 2007
Posts: 7,191
Likes: 4
From: Blairsville,Ga
the will streatch a good bit and still run and the more wear the more timing retards
pretty easy to check with timing light
pretty easy to check with timing light
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Postmaster
Joined: Aug 2000
Posts: 3,312
Likes: 1
From: Eldorado Ca. USA
Originally Posted by rbaker6336
the will streatch a good bit and still run and the more wear the more timing retards
pretty easy to check with timing light
pretty easy to check with timing light
Logistics Pro
Joined: Jan 2001
Posts: 3,740
Likes: 37
From: Central NYS
I think of a sloppy chain as alowing the cam/valves/distributor to lag behind where they should be. Or, to say it the other way around, the crank gets ahead of the distributor. When the distributor calls for spark at, what used to be 6* BTDC, the crank is already at ATDC, causing the spark to be retarded.
To verify chain slop, rotate the engine until the timing marks are roughly lined up. Pop the distributor cap and watch the rotor. Rotate the engine CCW until the rotor JUST starts to move. Note the timing marks. Then rotate the engine very slowly CW until the rotor JUST starts to move. Read the timing marks. If you can rotate the crank over 10 degrees without the rotor moving the timing chain and/or sprockets are pretty loose.
To verify chain slop, rotate the engine until the timing marks are roughly lined up. Pop the distributor cap and watch the rotor. Rotate the engine CCW until the rotor JUST starts to move. Note the timing marks. Then rotate the engine very slowly CW until the rotor JUST starts to move. Read the timing marks. If you can rotate the crank over 10 degrees without the rotor moving the timing chain and/or sprockets are pretty loose.