Go Back  Offshoreonly.com > Technical > General Q & A
Spark plug gap confusion, 502MPI >

Spark plug gap confusion, 502MPI

Notices

Spark plug gap confusion, 502MPI

Thread Tools
 
Old 06-10-2016, 06:49 PM
  #1  
Registered
Thread Starter
 
aquaforce's Avatar
 
Join Date: Aug 2005
Location: Stockbridge, Ga.
Posts: 1,556
Received 6 Likes on 6 Posts
Default Spark plug gap confusion, 502MPI

The engine plate says the MR43T plug gap is .035 but tune up info for this 1997 502MPI mag says .040 so what is right??????
The new plugs came gapped at .040. I know there are updates and new releases on information with all kinds of equipment after mfg so I wonder if there is an update where this set up is supposed to go to .040?? Anyone have current info or knowledge of why the engine plate and the tune up info say different numbers?

Also, if I change to .040 then I will have to adjust timing for the different gap I guess. What is the procedure for setting timing on this engine?
TIA
aquaforce is offline  
Old 06-10-2016, 08:36 PM
  #2  
Platinum Member
Platinum Member
iTrader: (6)
 
F-2 Speedy's Avatar
 
Join Date: May 2012
Location: Midwest & T-Rock
Posts: 10,418
Received 3,051 Likes on 1,357 Posts
Default

no timing change, gap to .035 and go have fun
F-2 Speedy is online now  
Old 06-10-2016, 08:47 PM
  #3  
Registered
iTrader: (3)
 
Join Date: Oct 2007
Location: yorkville,il
Posts: 8,427
Received 87 Likes on 49 Posts
Default

Originally Posted by 33outlawsst
no timing change, gap to .035 and go have fun
or .040.nobody will know that they are gapped at .040 except you.
mike tkach is offline  
Old 06-10-2016, 09:11 PM
  #4  
Platinum Member
Platinum Member
iTrader: (6)
 
F-2 Speedy's Avatar
 
Join Date: May 2012
Location: Midwest & T-Rock
Posts: 10,418
Received 3,051 Likes on 1,357 Posts
Default

whats 5 thou among friends, unless were talking bearings, lifter bores ect...........lol
F-2 Speedy is online now  
Old 06-10-2016, 09:21 PM
  #5  
Platinum Member
Platinum Member
 
Join Date: Dec 2002
Location: Dallas, TX
Posts: 2,195
Likes: 0
Received 2 Likes on 2 Posts
Default

DO I NEED TO SET THE GAP WHEN INSTALLING A NEW SET OF PLUGS?
A: Maybe. A spark plug part number might fit hundreds of different engines from many different manufacturers. Although the NGK factory will set the gap to a preselected setting, this may not be the right gap for your particular engine. The incorrect plug gap for your engine can contribute to a high rate of misfires, loss of power, plug fouling, poor fuel economy and accelerated plug wear. It is always best to check the gap against the manufacturer's specifications. If adjusting the gap on fine wire or precious metal plugs such as platinum or iridium, be very careful not to apply any pressure or prying force to the fine wire center electrode or insulator as they can be damaged. The gap should be adjusted by only moving the ground electrode.

Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005".

If you have any questions, please contact the NGK Spark Plugs Tech Staff:
Tech Support - Click here

The manufacturer of your vehicle, the company that produced the aftermarket products you've used and/or your service technician are all additional sources of gapping information if you've modified your vehicle.

Last edited by BenPerfected; 06-11-2016 at 05:40 AM. Reason: Less BS
BenPerfected is offline  
Old 06-11-2016, 05:20 AM
  #6  
SB
Registered
iTrader: (1)
 
Join Date: Nov 2004
Location: On A Dirt Floor
Posts: 13,546
Received 3,116 Likes on 1,403 Posts
Default

.035 just buys you more time before misfire. LOL.

I set up all normal Chevy V8's with regular Delco plugs at .035" because that is what works for me.

Last edited by SB; 06-11-2016 at 05:22 AM.
SB is offline  
Old 06-11-2016, 07:05 AM
  #7  
Registered
iTrader: (3)
 
Join Date: Oct 2007
Location: yorkville,il
Posts: 8,427
Received 87 Likes on 49 Posts
Default

ac delco plugs MUST be gaped at .0375 or they will misfire,lol.
mike tkach is offline  
Old 06-11-2016, 07:10 AM
  #8  
SB
Registered
iTrader: (1)
 
Join Date: Nov 2004
Location: On A Dirt Floor
Posts: 13,546
Received 3,116 Likes on 1,403 Posts
Default

What ? Me no comprendo. Or are you joking around too ?
SB is offline  
Old 06-11-2016, 07:20 AM
  #9  
Registered
iTrader: (3)
 
Join Date: Oct 2007
Location: yorkville,il
Posts: 8,427
Received 87 Likes on 49 Posts
Default

Originally Posted by SB
What ? Me no comprendo. Or are you joking around too ?
haha.
mike tkach is offline  
Old 06-11-2016, 07:21 AM
  #10  
Registered
iTrader: (2)
 
Join Date: Aug 2011
Location: bel air, md
Posts: 2,733
Likes: 0
Received 6 Likes on 6 Posts
Default

Just make sure there is a gap. They don't fire well when you drop a plug and the gap closes.
Black Baja is offline  


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.