428 Timing
 

Guys - I have a relitively stock 428 FE in an ERA. Were should I set the timing? I seem to have high exhaust temps (over 600 degrees) with 36 degrees total timing. Thanks for the help. Matt

Is that the temp taken by an IR Gun on the header at maybe an inch or so from the engine?

Yes, that is correct.

If your headers are not ceramic coated then that is not an unusually high temperature. Ceramic coated headers are generally lower than that, assuming you haven't really been getting on it hard.

Thanks for the quick reply. I have not had them coated yet. So I guess thats fine. As a general rule where should I set the timing?

36 total timing is fine. Your initial setting will depend on the bushing that limits the mechanical advance. I have mine set at 10 initial, with the bushing limiting the mechanical to 25, for a total of 35. Others have 14 initial or so with a total of 38, etc. The total amount is the key, and 36 is very common on a 428 FE. One of the Kirkham brothers just posted a good article on timing curves and how quickly it should come in, etc.

Here is a link to my other post:
http://clubcobra.com/forums/showthread.php?t=97890

Something to consider is most of us are not running vacuum advance. So our cars are typically cruising down the road with the ignition retarded from optimum. This means wasted fuel, poorer throttle response and higher under hood temperatures. In a light car with a manual transmission, a SMART driver, and a start retard a good case can be made for looking out the advance.

Matt - here's one thing to watch out for when you get your headers ceramic coated. You don't want to ruin the slip fit where the primary pipes slip in to the sidepipes. Here, I took a picture of what I'm talking about.

http://www.clubcobra.com/photopost/data/500/cob002.JPG

I have a 427 and I'm using a Mallory HYFire VI box. It has the option of programing in the degree of spark retard. It affects the ignition timing under 500 rpm(starting). I'm running 18° iniial with 14° retard and centrifigal advance 0f 10°x2=20° for a total of 38° total. I found that I had to reduce the idle stop screw( close the carbruetor) the more I advanced the initial timing. I also have the rev limiter (maximum RPM) programmed at 6,000 RPM just to be safe. It hits that mark in a hart beat. in the first two gears.

I run 28 Deg intial and 38 max with my non-vacuum dist. And I have run it higher with no issues.

A vacuum unit would be better as I could then set the intial around 16 (for my cam at max power) and the vacuum for 38 Deg at idle (best idle pulling 20 in Hg @ 38 @ 800 rpm).

To set my non-vacuum dist at 16 idle, the enigne gets hot quickly with a lot of excess heat from the headers. It also bogs when i try to gun it. Up at 28....works awesome.

I think for now that I'll stick to the theorey that if an engine needs a ton of advance with no-load, and very little advance under full load, then a vacuum advance would be a terrific help. And since I don't have one yet, my car benifits from timing somewhere in-between.

:rolleyes:

I agree, although maybe not locking out the advance. I had a slipped balancer plus a non-vacuum dist which had mech adavncve already partlky in place at idle (bad idea, but helps with cranking). After many years of good performance, I got tinkering with the timing. Bad idea...I wound up breaking a piston by detonation. I can't hear pinging with the sidepipes being so loud, but I could tell it was fighting higher rpms.

So....I jsut finsihed getting my timing set where it seems to be fine again, and those figures are:

23 Deg @ zero rpm
28 Deg at 800 rpm idle
38 Deg max advance

For my cam in the 290 region (I forget the exact spec, but it's a Crane Fireball solid lifter cam), an initial timing should be 14-16 BTDC. But it runs hot there, plus it gave me a bog for some reason. Best idle (highest vacuum and rpm) was at 38 Deg (just co-incidence it's the same number as max advance), but leaving it at 38 at an idle would surely mean knocking once the throttle was opened.

I think max advance is well known not to exceed 38, but again, that is for max power, so I'll see how it runs at highway cruising speed.

I am of the opnion that if an engine needs a ton of advance with no-load, and very little advance under full load, then a vacuum advance would be a terrific help. And since I don't have one yet, my car benifits from timing somewhere in-between. After all, I only give it from 1/3 to 1/2 throttle when taking off.

WOW 28 intial is extremely high. Your right 16 to 18 would be much better.

Yes, I have it at 20 initial and 38 total now. A little higher than the 16-18 for my cam, but it helps keep the heat down, doesn't detonate as far as I can tell and the car being light helps.

I swapped out my MSD dizzy with no vacuum advance for a Ford upgraded with a Pertronix with both mechanical and vacuum. What a difference. A non vac. advance dizzy is great for drag racing where 95% of the time you are a WOT. How many of us drive our car like that? Vacuum advance with mechanical advance permit these engines to perform as the engineers designed them to. What I have experienced is, smoother transition from idle to hard acceleration, quieter note an idle with the indisputable roar of a BB when the pedal is down, cooler temps and no fuel noted in the oil analysis from running retarded timing. Every oil analysis until I made the change showed a significant and troubling fuel contaminate in the oil. Talk to a powertrain engineer and ask them if vacuum advance is important on a high performance street engine and you will get the same answer every time. Just my 2 cents. Rick 428 FE