Timing help
Thread Starter
|
New User
Joined: Apr 2020
Posts: 2
Likes: 0
Timing help
I am not able to time my 79 Bronco properly.
Background: ‘79 Bronco with a 351M, EGR, A/C, Auto Transmissiom. I recently replaced the stock distributor with a Proform HEI distributor. The EGR is capped at the carburetor due to the connecting point on the temp switch being broken. I do not have the spec sticker on the glovebox door.
I thought I found the correct emission control information sheet, and tried to tune it to those numbers (4BTDC @ 500 RPM), and the truck ran horribly. When I connected the vacuum advance, the engine stalls. After messing with it for a little bit, I can get it to idle, but any time I press on the gas, it stutters and stalls.
Right now I do not have the vacuum advance hooked up, and the engine runs okay. I would like to be able to connect the vacuum advance, though. Any advice?
please let me know if you need more information.
Background: ‘79 Bronco with a 351M, EGR, A/C, Auto Transmissiom. I recently replaced the stock distributor with a Proform HEI distributor. The EGR is capped at the carburetor due to the connecting point on the temp switch being broken. I do not have the spec sticker on the glovebox door.
I thought I found the correct emission control information sheet, and tried to tune it to those numbers (4BTDC @ 500 RPM), and the truck ran horribly. When I connected the vacuum advance, the engine stalls. After messing with it for a little bit, I can get it to idle, but any time I press on the gas, it stutters and stalls.
Right now I do not have the vacuum advance hooked up, and the engine runs okay. I would like to be able to connect the vacuum advance, though. Any advice?
please let me know if you need more information.
Thread Starter
|
New User
Joined: Apr 2020
Posts: 2
Likes: 0
Thank you, SDDL-UP. I will give it a shot in the morning. Even if it does not work, you just made me realize that I have never made a baseline of what has worked.
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
If setting the base ignition timing to factory spec makes it run "horrible", that is a big clue to back up a bit and do some vestigatin'. Make sure that the TDC "0" mark on the crankshaft balancer is still accurately located. The easiest way is to use an inexpensive tool called a piston stop. This is very important because everything mechanical inside the engine that has to do with setting up ignition timing or the valvetrain is based on this point.
Common problem and causes lots of head scratching. The heavy steel outer ring on old balancers slips because the rubber bonding dry rots. See this all the time here at FTE.
From the factory, just about every OHV V8 ever made by anybody for the last 65 years wants 34° to 36° BTDC "total" ignition timing. This would be without vacuum advance. When the vacuum advance is connected ignition advance be about 50° when cruising on flat ground. Honest Injun!
Common problem and causes lots of head scratching. The heavy steel outer ring on old balancers slips because the rubber bonding dry rots. See this all the time here at FTE.
From the factory, just about every OHV V8 ever made by anybody for the last 65 years wants 34° to 36° BTDC "total" ignition timing. This would be without vacuum advance. When the vacuum advance is connected ignition advance be about 50° when cruising on flat ground. Honest Injun!
Thread
Thread Starter
Forum
Replies
Last Post
smith1978
1973 - 1979 F-100 & Larger F-Series Trucks
30
May 27, 2015 02:26 PM
1986F150six
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
6
Aug 28, 2012 12:46 PM
atomicjoe23
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
7
Mar 12, 2010 04:08 PM
