dream02transam

I installled a MSD 6A on my 2.8L 89 firebird. its stock plug gap is .045 MSD recommends to get the full potential out of the box to increase the gap to .050 - .060 I have an accell super coil, accell ignition module, accell cap and rotor msd plug wires with a lower resistance and will put in a/c delco rapid fire plugs. Now has anyone with a simialar setup ever found the best gap with this? should i go with a .050 .055 or .060 gap. Any and all opinions are welcomed! Thanks..... Erik

FAST RS

I trid gapping mine at .50 but later found the stock gap seems to feel best. And i have a very similar setup as you what you have accell i have MSD

dream02transam

Ok thanks, I will take that into consideration! I appricate it. I see your car is a 3.1L does that have any different stock gap then the 2.8L (.045)? Any other opinions?

TomP

Ya know... I don't think I ever tried screwing with my plug gap (0.045") after I put the MSD box in.

I -did- try a larger gap when I "just" had an Accel Supercoil. It didn't help anything. I tried 0.055 and 0.050 - 0.055 made the car sluggish, and it reeked of gasoline. 0.050 also stunk of gas, but not too bad. So I kept it at 0.045. But I never thought to try it with the MSD box.

If you try it out, let us know how it goes! Use gloves tho, those plugs get damned hot after a few minutes

dream02transam

Once I do this I will let you all know. Thanks for the advice. I think I will try different gaps with 1 plug grounded with wire on and plug out of the hole. I will look for the best gap with a good blue spark. I know if its white its too hot and could stand to be a bigger gap and if its yellow or so the gap is to large.

BitchinRS

When I had the Accel Supercoil I ran a .050 gap and I felt like I was getting a better burn. No gas smell and felt a better throttle response. Also at the higher RPM the engine felt more stable. No high RPM missifre or stumble.

When I switched back to a stock coil while trying to trouble shoot what ened up being a dead fule pump I had to put the gap back to .045. Stock coil and a gap of .050 made it run rich and slugish. I also had a Holy Annihilator ICM at the time I had the Accel Supercoil, but switched back to the stock ICM when I reverted to the stock coil.


This was on a 1992 3.1L Stock gap for the 2.8L and 3.1L is .045

dream02transam

Tom P I just messed with the gap today. I pulled the #2 plug (fwd drivers side) since it is the easiest to get at and has the longegest plug wire. I put a plug on the wire after I removed the plug routed the wire under the prop valve and grounded the plug by placing it on the metal portion of the strut tower brace. Make sure you clean some of the rust and paint to get a good ground. I started it up (keep your face away from the open plug hole or I guess you could put a spare plug in it) with a .045 gap I got a blue - white spark at .050 I got a good solid deep blue spark and at .055 I got a blue - yellowish spark. So I went with the .050. as a reminder this is with a MSD 6A box, MSD lower resistence wires, accell super coil and accell ignition module. It seems to idle better and run smoother. No gas small, so I think I have a winner with the .050 Also I removed the bosch +4 platnuims that came with the car when I got it since you really cant gap them and replaced with ac delco split fires. I know that you will not get 20 hp out of them ... heck you proballwont even get 1/2 hp out of them but I like that the spark is more open to the flame might help make it run better... Nascar uses cut plugs i heard and this is the same idea. I was looking for the rapid fires but advance auto parts and walmart no longer carry them. Do they make rapid fires anymore? My only options were the ac delco base model and ac delco platnuims. I didnt want either I heard platnuims can give our cars problems and wont put that kind in a car unless it came from the factory that way and I was reading (i think from you Tom) that the platnuim tip has been know to come off. Tom could your problem with the splitfires (or any other plug) wearing too fast be because of the .045 gap your using? Make too hat a spark causing that and gaping it out to .050 might help? One last thing when I was looking through walmarts book on plugs I noticed that the 2.8 in 82 - 84 (carb) uses a different plug than the 85-88 (fuel injection) Whick is understandable but What I dont get is that the 89 2.8 uses a diffent plug that the 85-88, actually its the same as the 82-84 carb. That and I also notced that my old 85 2.8 used a smaller oil filter than the 89 2.8 that I have now... Does anyone know the reasons for these differences?

FAST RS

Autozone, Pep Boys, Krage, Checkers all sell AC Rapid Fires

dream02transam

Unfortunatlly in Bangor Maine area there are none of those stores you listed. Only NAPA, Advanced Auto, and VIP and then theres Walmart. The closest one you listed is Auto Zone which is in Waterville, about and hours drive 55-60 miles away.

FAST RS

aDVANCED AUTO MIGHT carry them i havce never been to there store since there are none in CA. NAPA might have them as well.

dream02transam

Advance Auto doesnt i tried them already, either did walmart so I got the splitfires. I didnt try NAPA or VIP because I didnt feel like driving all over town.

FAST RS

I would just call around and see who carrys them. They are a very good plug. I never tried split fires because i have herd mixed things about them. I have also seen them on ebay for 2.00 a plug which is very cheap. Maybe a chevy parts dept by you may stock them. Dont know how much they would ask though.

coolrimsatleast

Been gone a few weeks and just noticed plug gap discussions. Anyway, I have an MSD 6A, blaster coil, 8.5mm superconductors, and a stock module for now. My plugs are gapped at .049 and everything runs fine. Maybe I'll try .05-.052 next time and see how it does. Using stock AC delco plugs for now too, maybe i'll try something different next.

Like I said before I get at least 340 miles to a tank so I gotta be doing something right

87CamaroMan

Advance Auto is the same as checkers. Go to www.partsamerica.com Thats the website for all of the different names it has all in one

TomP

Dream02, ya know, I never thought of that- you could be right! (About normal gap w/MSD box ruining my plug's center electrodes) I'll have to open it up one of these days and see how the car acts.

The main change along the years for spark plugs concerned the heat range of the plugs. If you're getting a lot of ping, the plugs themselves are so hot they're setting off the air/fuel ratio by themselves, so you might want to step down to a plug that's one notch colder. If your plugs are coming out oily and dirty after long trips, that means the plugs aren't reaching their self-cleaning temperature, and you may want to go one notch higher.

dream02transam

Hey if your try it let us know how it works....Maybe we can find out what most people use for a gap with an MSD 6A and help the next guy putting in one of these boxes. With the spark plug changes mine is fine.... the old ones I pulled out were normal and I have never heard any pinging. I used an SF2D. thats what the book said to put in for the 89's as well as the 82-84's So did GM find they were haveing problems when they switched the heat range for the 85-88's and in 89 the switched it back?