SOHC plugs


--weezl--

June 2011 OTOTM Winner
Law Enforcement
OTOTM Winner
TRS Banner 2012-2015
Joined
May 26, 2010
Messages
8,500
Reaction score
181
Points
0
Location
hell
Vehicle Year
2007
Make / Model
Ford
Engine Size
4.0
Transmission
Manual
What are we all running in our SOHC's these days? my truck has taken an extra crank or two to start recently, and it's occurred to me that it's got the factory plugs and wires in it, so I figure it's probably time to swap them out. I was looking at rock auto, and from what I can remember autolite is what ford puts in it from the factory, and i've always been told to stay away from platinum in fords, but on rockauto it looks like oe is platinum, and possibly autolite?

google said use motorcraft plugs, but they aren't on rock auto... should I spend extra money for bosch at nearly double the cost or stick with autolite, which i've never had problems with?

platinum though right?

edit:

also, double platinum, iridium??
 
Last edited:


Rock Auto 5% Discount Code: 32B05A80BF19AF Expires: July 1st, 2020

Sasquatch_Ryda

Well-known member
Ford Technician
OTOTM Winner
Solid Axle Swap
Forum Staff - Retired
TRS Banner 2012-2015
Joined
Aug 8, 2007
Messages
7,914
Reaction score
89
Points
48
Age
32
Location
Terrace, BC, Canada
Vehicle Year
1991
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0L
Transmission
Automatic
2WD / 4WD
Solid Axle Swap 4x4
Tire Size
40s
Stick with autolite/motorcraft platinum. Bosch are junk.
 

--weezl--

June 2011 OTOTM Winner
Law Enforcement
OTOTM Winner
TRS Banner 2012-2015
Joined
May 26, 2010
Messages
8,500
Reaction score
181
Points
0
Location
hell
Vehicle Year
2007
Make / Model
Ford
Engine Size
4.0
Transmission
Manual
cool, glad someone I trust replied! double platinum a waste of money also?

thanks ryan!

edit:

how about wires? I'm looking at them online, i've used bosch wires before, had no problems, there's a set from federal for $11.00 because of a wholesaler blowout... though it's looking like the bosch for $30.00 is going to be the best deal when combined shipping is taken into consideration...
 
Last edited:

PlumCrazy

Schotty Fab & Offroad
Supporting Member
OTOTM Winner
Solid Axle Swap
2014 Truck of The Year
TRS Banner 2010-2011
Joined
Sep 22, 2008
Messages
4,402
Reaction score
42
Points
48
Location
Pataskala, OH
Vehicle Year
19951986
Make / Model
Ford
I have had an awful time with Motorcrafts in my 4.0 (OHV) I used to run them in all my Fords, but out of the last 12 I installed 7 of them had the porcelain crack and fall off before the first oil change. I blamed the first few on the parts guy or delivery man dropping the box or something, but the second set was a different month/truck/store.lol

Im an NGK guy now (V-Power). I never had an issue with them in my ATVS or Hondas...so I threw them in my Fords too. Work as they should and look perfect after 20k.
 

gw33gp

Well-known member
U.S. Military - Veteran
TRS Banner 2010-2011
Joined
Aug 7, 2007
Messages
1,117
Reaction score
55
Points
48
Location
Costa Mesa, CA
Vehicle Year
2002
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0 SOHC
Transmission
Manual
2WD / 4WD
4WD
Tire Size
33"
I run Autolite double platinum plugs. The regular platinum plugs are fine because Ford installs Motorcraft platinum plugs from the factory. The double platinum plugs just last longer without the gap getting to large.
My original plugs lasted about 60K miles before the gap got too large. With the double platinum plugs the gap is still good at 100K miles.
 

BRUTUS_T_HOG

New member
Article Contributor
ASE Certified Tech
TRS Banner 2010-2011
Joined
Aug 26, 2008
Messages
2,222
Reaction score
35
Points
0
Location
Rainier, OR
Vehicle Year
89
Make / Model
Ford
Engine Size
2.3L
Transmission
Manual
Use double platinum plugs due to waste spark ignition. 3 plugs fire positive 3 plugs fire negative. Never had a problem with auto lite
 

AllanD

TRS Technical Staff
TRS Technical Advisor
Joined
Jun 1, 2001
Messages
7,891
Reaction score
106
Points
63
Age
58
Location
East-Central Pennsylvania
Vehicle Year
1987... sorta
Make / Model
Ford
Engine Size
'93 4.0
Transmission
Manual
The factory plugs on a 4.0OHV are NOT double platinums, but the recommended replacements are...

The original factory plugs have a platinum center electrode on one bank and a platinum "button" on the ground electrode on the other bank. these engine assembly plant plugs are not available in commercial channels the "PP" plugs are the ones in the replacement part supply chain, because these can be installed in any location on the engine.

And it is because of the "waste spark" from the ignition system.

The Waste spark happens in a partial vacuum and works like a plasma cutter
on the electrodes.




Back about 20 years ago I was running an Early Saab 900Turbo, the first few years they used a Bosch ignition system known as the Magnetic pulse generator ignition. (this being a year or two before Bosch licensed rights to manufacture their later Hall effect system

The MPG ignition had some unique properties and was more capable of firing a spark under conditions that other systems couldn't easily match.

Understand that air/fuel mixtures are increasingly hard to fire a spark through
with increasing pressure, on a sufficiently boosted engine this eventually leaves
you painted into a corner... The rub was that under certain conditions this was bad...

Running at high boost or high load and getting everything heat soaked then a brief moment with the throttle closed (engine braking) and rolling back into the throttle, you'd have nothing, the engine would quit running because in the space of 5-10 seconds the spark plug gap would open from 0.055" to twice that, which the ignition simply could not fire. the Spec plugs were Champions which you could kill as dead as Julius Caesar in 2-3 miles if you knew how to do it. the Issue with Bosch plugs is that you could completely FRY the "weak" resistor element in the plug after which it would never fire again

The "Fix"? NGK Gold Palladium "EV" series racing plugs.
 


Top