timing problem on 86 460
Thread Starter
|
Freshman User
Joined: Nov 2004
Posts: 30
Likes: 0
timing problem on 86 460
i have an 86 f250 with a 460. its got the shakes and rattles at 1500 rpm and up. i set the base timing at around 8-9. when i bring it up to 1500 rpm or higher the advance timing goes up around 30 degrees. when i removed the vac advance hose from the dizzy the shakes and rattles went away. what would cause the advance timing to go so high and what is causing the shakes and rattles? its really getting on my nerves. please help. thanks in advance.
Post Fiend
Joined: Mar 2004
Posts: 6,056
Likes: 8
From: Union, Washington
The timing is advancing so far because you are causing a high manifold vacuum and the ported vacuum fitting is pulling the timing around. Does it do this shaking thing when driving down the road? Probably not, as the vacuum would be lower because the throttle plates are open farther. I wouldn't worry about it as long as it only does it in neutral. BTW you should be doing it anyway, it's hard on the engine.
Post Fiend
Joined: Mar 2004
Posts: 6,056
Likes: 8
From: Union, Washington
You could disconnect the ported vacuum but it will hurt your gas milage a whole lot. Did this just start happening all at once or was it a long time is getting worse? I suspect you need to check your total mechanical advance and also how strong your spark is at the plugs. I think you are having and ignition system break down. When you back off on the timing you make the ignition not work so hard. Plug wire could cause this also.
Post Fiend
Joined: Mar 2004
Posts: 6,056
Likes: 8
From: Union, Washington
Originally Posted by kermmydog
The first thing that came to mind as I was reading this is: The Harmonic Balancer have the timing marks rotated? If memory serves me they advance. Food for thought.
Thread
Thread Starter
Forum
Replies
Last Post
78f250351cleveland
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
17
Mar 6, 2015 01:27 PM
