Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - timming
Thread: timming
View Single Post
  #2 (permalink)  
Old 11-09-2012, 01:59 PM
cobalt327's Avatar
cobalt327 cobalt327 is offline
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 598 Times in 547 Posts
Quote:
Originally Posted by Bronco75 View Post
I have a been working on a 1975 Ford Classic Bronco for some time now. I have built a 302 engine which I tought would perfrom better than it does.

I had a solid lift cam built. I told them all the variables of my engine and they built me a cam to match. so I fugured all was good, but I am not impressed at all. I do have a few issues that I know I need to correct, but here is the question.

The cam I had built has a 351W fireing order, so looke up the correct firing order for a 351w and used that. But I did buy a MSD Dist. for a 302 if i remeber right
The distributor is fine. Just be sure the firing order is correct for the cam- if you wired it wrong, like for the non HO 302, you'd know it- it wouldn't run, period. Info on Ford firing orders can be seen here.

The cam specs and ignition timing specs will help, but it's a very good chance you need more initial timing. Take a look at the info here on timing. Even though the page was originally written about the GM HEI, the timing section still applies to you.

The problem w/not using enough timing is caused by the overlap, reversion and late intake closing point that gives a high performance cammed engine that sound we all know and love. The fuel/air charge is diluted and very lean. This means the ignition timing needs a lot more advance than a stock cam to get that lean charge lit soon enough that it is mostly burned while it can still do work inside the cylinders.

Other things that could be a problem is if the engine wasn't built w/enough compression for the cam, or a too-tight torque converter, or too high rear gears. Carb tuning can cause problems, fuel delivery has to be adequate, even something as simple as a bad plug or plug wire, or a carbon tracked or cracked distributor cap can cause problems like you have. And on and on. But for now I'll see what you can add to help diagnose this.
Reply With Quote