Plug Gap

RoadWarrior · 03-01-2004, 10:42 PM

Just wanted to see what i should be gapping my plugs at. Its a pretty much stock motor out of a 95 gt and its been converted to carb using a performer rpm air gap manifold and a demon carb.

Ieatcamaros · 03-01-2004, 10:51 PM

.054 is a good starting point.

speedster84 · 03-02-2004, 12:04 AM

Yeah that should be fine. I know off hand that fox body 5.0's have a recommended gap of .050 I believe.

Dark_5.0 · 03-02-2004, 09:46 AM

The factory gap is .044, dont go over .050 unless you have an aftermarket ignition system.

302 LX Eric · 03-02-2004, 09:48 AM

Quote:

Originally posted by Dark_5.0
The factory gap is .044, dont go over .050 unless you have an aftermarket ignition system.

That's interesting! I thought factory gap was .054". I guess you learn something everyday.

Thanks, Dark.

E

QuantumMotorsports · 03-02-2004, 04:56 PM

Factory gap is 0.054 inches.

GhettoPop · 03-02-2004, 09:52 PM

isn't factory gap .054?

Dark_5.0 · 03-03-2004, 11:43 AM

Please excuse my retarded post stock plug gap is .054.

I meant to say dont go over .060 without an aftermarket ignition.

GhettoPop · 03-03-2004, 12:06 PM

Quote:

Originally posted by Dark_5.0
Please excuse my retarded post stock plug gap is .054.

I meant to say dont go over .060 without an aftermarket ignition.

i installed the following:
FMS 9mm wires
autolite plugs @ .054
msd blaster coil
msd cap/rotor

how much can i increase the gap?

will be installing an msd6a soon,
how much can i increase the gap after the ignition is in?

302 LX Eric · 03-03-2004, 12:08 PM

There's no need to increase the gap past .054". With a healthy inginition system and proper timing you should be getting a complete burn without any issues.

E

Dark_5.0 · 03-03-2004, 01:10 PM

In one of my 5.0 tuner books they picked up 8rwhp on a stock engine with an ignition system and increasing plug gap to .060

They picked up like 10rwhp with an aftermarket ignition and a plug gap of .060 on a modified motor.

Both compared to the stock ignition. I wouldnt doubt if they messed with the timing to achieve those numbers

I have my plug gap set at .060 and I shift @ 6000rpms without any issues.

302 LX Eric · 03-03-2004, 01:54 PM

Quote:

Originally posted by Dark_5.0
In one of my 5.0 tuner books they picked up 8rwhp on a stock engine with an ignition system and increasing plug gap to .060

They picked up like 10rwhp with an aftermarket ignition and a plug gap of .060 on a modified motor.

Both compared to the stock ignition. I wouldnt doubt if they messed with the timing to achieve those numbers

I have my plug gap set at .060 and I shift @ 6000rpms without any issues.

8 RWHP gain on a stock motor with only an additional .006" gap?

That sounds like F&F talk to me. Maybe more of the gain was attributable to the aftermarket ignition system? Of course, I thought the stocker was fine for minor bolt-ons.

E

Dark_5.0 · 03-03-2004, 04:35 PM

Yeah the .060 in conjunction with the ignition system is what attributed to the HP gain.

The stock ignition is fine for a modified 5.0 but there is power to be had by increasing plug gap with an aftermarket ignition.

They didnt see much of a gain until they increased the plug gap so I guess what they were saying is you have to increase spark plug gap to take advantage of your after market ignition.

302 LX Eric · 03-03-2004, 04:46 PM

Cool. Thanks for the info.

E

84LX89GT · 03-03-2004, 10:01 PM

I've also heard of filing back the ground electrode on the plug to be even with the + electrode to unshroud the spark for more initial burn area, just a thought - seemed to work on my friend's SAAB turbo but i have nothing to back it up

USMC302 · 03-04-2004, 03:29 PM

Better ignition system = more gap
blown application = less gap

better ignition with a blown app = somewhere in the middle?

03-01-2004, 10:42 PM	#1
RoadWarrior Registered Member Join Date: Apr 2000 Location: Edmonton,Alberta,Canada Posts: 317	Plug Gap Just wanted to see what i should be gapping my plugs at. Its a pretty much stock motor out of a 95 gt and its been converted to carb using a performer rpm air gap manifold and a demon carb. __________________ Fast Company

03-01-2004, 10:51 PM	#2
Ieatcamaros Domestic Rice really sucks! Join Date: Apr 2002 Location: KY Posts: 973	.054 is a good starting point. __________________ The sig says it all.

03-02-2004, 09:46 AM	#4
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	The factory gap is .044, dont go over .050 unless you have an aftermarket ignition system. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-02-2004, 04:56 PM	#6
QuantumMotorsports Registered Member Join Date: Jul 2000 Location: Norman, Oklahoma, USA Posts: 597	Factory gap is 0.054 inches. __________________ Michael Black QuantumMotorsports Norman, OK 1984 LX Hatch 306 w/ TRW forged flat toppers, Comp Cams Magnum 292H, GT40P heads w/ 3 angle valve job, .550 lift springs, Angus Racing Roller Rockers, Weiand Stealth Intake, Holley 4150 650cfm carb, MAC 1 5/8 Long Tubes, Single Chamber Flowmasters, 91' T5 w/ Pro 5.0 shifter, Turbo Coupe 8.8 Rear w/ 3.55 gears, QA1 Motorsports tubular K member, no interior except steering wheel and seat. Coming soon: 6 or 8 point cage, Fuel Cell, Weld Draglites

03-02-2004, 09:52 PM	#7
GhettoPop Gimme a Drink! Join Date: Dec 2002 Location: NYC Posts: 694	isn't factory gap .054? __________________ 1990 GT,stock T-5,K&N w/o air silencer,March underdrives,FMS wires,timing@14*,PA Perf 130amp alt,Steeda Tri-Ax Shifter,Steeda adj quadrant/clutch cable/firewall adj,Centerforce II clutch,o/r x-pipe,Magnaflow SS catback,g-load brace, subframes,Bilstein struts/shocks,Autometer gauges, 136k and running strong!

03-02-2004, 12:04 AM	#3
speedster84 Registered Member Join Date: Mar 2004 Location: champaign, illinois Posts: 10	Yeah that should be fine. I know off hand that fox body 5.0's have a recommended gap of .050 I believe.

03-03-2004, 11:43 AM	#8
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Please excuse my retarded post stock plug gap is .054. I meant to say dont go over .060 without an aftermarket ignition. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-03-2004, 12:08 PM	#10
302 LX Eric or '331 LX Eric' Join Date: Jan 1999 Location: Columbus, Ohio Posts: 2,142	There's no need to increase the gap past .054". With a healthy inginition system and proper timing you should be getting a complete burn without any issues. E __________________ 1991 5.0 LX Coupe - 40,750 miles 331 cu. in. / Tremec 3550 / BFG Drag Radials 12.22 @ 114.31 mph - w/1.89 60'

03-03-2004, 01:10 PM	#11
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	In one of my 5.0 tuner books they picked up 8rwhp on a stock engine with an ignition system and increasing plug gap to .060 They picked up like 10rwhp with an aftermarket ignition and a plug gap of .060 on a modified motor. Both compared to the stock ignition. I wouldnt doubt if they messed with the timing to achieve those numbers I have my plug gap set at .060 and I shift @ 6000rpms without any issues. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-03-2004, 04:35 PM	#13
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Yeah the .060 in conjunction with the ignition system is what attributed to the HP gain. The stock ignition is fine for a modified 5.0 but there is power to be had by increasing plug gap with an aftermarket ignition. They didnt see much of a gain until they increased the plug gap so I guess what they were saying is you have to increase spark plug gap to take advantage of your after market ignition. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-03-2004, 04:46 PM	#14
302 LX Eric or '331 LX Eric' Join Date: Jan 1999 Location: Columbus, Ohio Posts: 2,142	Cool. Thanks for the info. E

03-03-2004, 10:01 PM	#15
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	I've also heard of filing back the ground electrode on the plug to be even with the + electrode to unshroud the spark for more initial burn area, just a thought - seemed to work on my friend's SAAB turbo but i have nothing to back it up __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

03-04-2004, 03:29 PM	#16
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	Better ignition system = more gap blown application = less gap better ignition with a blown app = somewhere in the middle? __________________

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