Is there a proper order to tuning a edelbrock 1405?

Base timing is kinda weird for some reason... I run 91 octane and this last summer I did have it at 8 degrees than I had to back it down to 6 to reduce/get rid of detonation. by using a vacuum gauge for the idle circuit do you do that by adjusting the idle mixture screws till you get the highest vacuum? I've thought about and wouldn't mind going with fuel injection but I just can't see myself getting that conversion done in a day or two on my budget... I still can't figure out why I'm getting detonation though... to big a plug gap for the plugs? running to rich?... I just can't think straight anymore...

 

Slipped balancer? Verify the balancer is correct using a positive piston stop in spark plug hole and verify timing marks on blancer.

Yes on vaccum gauge for highest reading. also keep in mind you have a different cam so your not likely to see 17-20 prob more like 12-15ish.

DETONATION IS NOT RUNNING TO RICH ITS RUNNING TO LEAN.

If your audibly hearing detonation you are causing damage to the pistons a long ways before you actually hear it. Take a google search to an inexpensive home made tool for tuning called detonation cans. They work pretty good and its always nice to make your own tools


Detonation,

to quick advance (springs and weights in disty) or to much total timing adding up on top of your base timing.

to lean of jets

vacuum leaks

poor fuel

high cylinder head temps

to hot of plugs

plugs not indexed in cylinder correctly

to high of compression/low octane fuel



Fuel injection with a couple guys that are good and quick workers MIGHT get it ALL done in a weekend. MIGHT and I would assume 2 LONG days

 

I have a balancer from summit, about 7 years old now...
Where could I find colder plugs? I've been running Autolight Platinum AP45's so far but they are atleast 3 to 4 years old, I've been searching for plugs that'll fit and 1 heat range colder but I haven't been able to find any... preferably ones I can get locally. I've never indexed plugs before, I know how just never have.
I only have 2 vacuum lines under the hood and they both look good.
I don't think I'm running lean... is it possible to run lean on one cylinder? the last time I had my plugs out only one looked on the hot side.
I have about 9.5:1 compression and I've been running 91 octane with a gap of 0.045" with my mallory VI AL ignition and mallory coil...

 

Try finding an AP44. The only other alternative is to go to racing plugs and they are 5 times the price.

 

I searched ap44 but couldn't find any even the autolite website doesn't have it listed at all... only referance I could find for it was a general web search which brought up some other forums discussions...

 

I had to pull out my old (2002) catalog to get this so you may want to write it down.

14mm Ford plugs 25, AP25, AR25 are all the same heat range. A list of plug #s from hot to cold:
Hot 25, 144 & AR24, AR135 & AR13 & AR23, AR134 & AR12, AR133, AR132, AR131 Cold

18mm Ford plugs from hot to cold:
Hot 46, 45, 124, AR33, AR32 COLD

The 46 is used on the six cylinder engines as stock. All numbers are Autolite.
Hope this helps.

 

thank you... after afew hours of searching and crossreferancing and calling tech lines I found the autolite 124 and ngk 3323 which are the same plug I guess. the thing is the differance between the 45 and 124 besides heat range is that 45 is a projected tip and 124 is not, I don't know what differance that makes...
I had been running AP45's but today I just picked up some regular 45's and see if that helps. if not I guess I'll pick up some 124's and see where that leads me. I was told that platinum runs hotter than copper, is that true? I don't consider my source on that very reliable (autozone sales clerk).
I'm changing plugs right now, taking a break at the moment and so far I got 5 plugs changed, 4 of the 5 are white and the 1 of the 5 is brown/red... yeah there running hot and the gaps are from 0.050 to 0.058 I'm not sure now what I origenaly had them set to... going with 0.045 with the new ones... wish me luck

edit: just got the other 3 they were all white as well

 

can you post some good high resolution pictures of the plugs, description of last run ( was it idling a little before you changed or....) and describe when it is detonating at what rpm full throttle light load, cruise speed with foot deep in the go pedal.

Just need some more info here, I do not think a plug change is an end all to the problem, but its a good start.

 

I pulled in revved it turned it off. the detonation usually happens when I'm cruising on the highway at 60-70mph (5th gear, 2500rpm - 2800rpm) and I give it a little more (to speedup another 5 or 10mph) to get around someone.

 

Refresh my memory;
What is your compression and where do you have the engine timed?

 

Paul base timing supposedly at 6 degrees, 9.5 compression with iron 289 heads if I remember correctly. The best we got around here at the pump is 91 octane

Do you have adjustable vaccum advance on it?
What distributor plate and spring combo is in there?

With all them plugs looking like that I would say you can rule out a leaky intake manifold unless its leaking on base of carb.

I think you just got that carb setup way too lean, there might be a problem in the ignition advance setup by looking at your low base setting.

I think richening it up is the first place I would start, then look into getting more base timing into it again and keep adjusting from there.

 

If you can get an "on road" analysis of your air/fuel ratio you won't have to guess about your mixture. If you are running 91 octane you shouldn't have a problem with timing at 6 BTDC but I would want to be sure its correct. (find TDC with a mechanical stop and check the balancer marks) It might be carbon build up in the chambers and that can be cured with some SeaFoam through the carb - follow the directions. Try reducing the gap on the plugs to .030" and run "extended tip plugs to help keep them cooled by the intake charge.

 

Vacuum advance in on, stock distributor (stock plate and spring). on the carb I have it set with stock primary jet and rod with the blue (3"hg) spring with one size down on the secondary jets (it used to bog down when I really stepped on it). I'll try the next richer rod... should I go one rich on the cruise or power section of the rod or both? thank you.

on a side note I put some gumout octane boost in it today and it didn't ping at all but this is a first time I've had to do that with 91octane. I also noticed a little loss of power with the new plugs... maybe gapping them at 0.045 instead of 0.055 wasen't a good idea.

 

the 45's are extended tip, I'll try seafoam next, I have been using Lucas fuel treatment (the big one quart bottle, using 1 oz per 4 gal of gas or so). haven't tried the positive stop check yet, not entirely sure what I'd use to do it.

 

You can make a positive stop out of an old spark plug and a bolt.

And for not pinging today we did have some superb horsepower weather today