Effect of the wrong spark plugs? - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 02-11-2017, 12:40 PM   #1
Newb
Thread Starter
 
Join Date: Oct 2015
Posts: 34
Total Cats: 0
Default Effect of the wrong spark plugs?

I just swapped out my plugs and realized the old ones installed by previous owner were not correct - NGK TR5GP was printed on them.

The electrode looked completely different! Theyve been in there since I bought the car - buy i never realized they were "wrong"

I havent had a chance to drive the car yet - but has anyone seen these plugs in a miata ?
TheCanadian is offline   Reply With Quote
Old 02-13-2017, 11:45 AM   #2
Junior Member
iTrader: (1)
 
Join Date: Feb 2016
Posts: 90
Total Cats: 14
Default

I just checked the NGK site to compare specs on those plugs. Two differences, A) not a big deal but the ones that came out were 1mm shorter reach (18mm vs 19mm stock), B) the possibly bigger issue, the ones that came out were tapered seat plugs. The miata head uses gasket seat (crush washer) on the flat head surface.

If your lucky, having the tapered plugs in the head didn't deform the seating surface of the head enough to cause any issues with the new proper plugs to seal. Best way to check if they are all seated OK would probably be to rotate the engine by hand and listen for and air leaking out from the plug wells in the head under the compression stroke of all 4 cylinders. Good luck man.
MetalMuffins is offline   Reply With Quote
Old 02-14-2017, 09:00 AM   #3
Newb
Thread Starter
 
Join Date: Oct 2015
Posts: 34
Total Cats: 0
Default

I will double check and report back - but I think I am lucky. The car seems to drivectge same as before ( if not better) over these past few days
TheCanadian is offline   Reply With Quote
Old 02-14-2017, 10:41 AM   #4
Ich verstehe nur Bahnhof
iTrader: (3)
 
psyber_0ptix's Avatar
 
Join Date: Mar 2012
Location: Northern VA
Posts: 3,804
Total Cats: 341
Default

What did you end up replacing them with?
psyber_0ptix is offline   Reply With Quote
Old 02-14-2017, 11:38 AM   #5
Slowest Progress Ever
iTrader: (26)
 
thirdgen's Avatar
 
Join Date: Oct 2007
Location: The coal ridden hills of Pennsylvania
Posts: 5,886
Total Cats: 201
Default

The number in the middle (such as BR8ES) designates the heat range. If I'm not mistaken, the higher the number, the hotter the plug.
I've never noticed a major difference in cars when running different plugs, but I can tell you this, I bought a yz 250 2 stroke dirt bike a few years ago. The thing wouldn't idle for anything. If you didn't constantly blip the throttle it would stall, so I went over the thing and started by pulling the plug. It was wrong, and the gap was way off. I put in the recommended plug and set the gap according to spec and have yet to have idle issues or foul a plug.
thirdgen is offline   Reply With Quote
Old 02-14-2017, 12:44 PM   #6
Elite Member
iTrader: (1)
 
DNMakinson's Avatar
 
Join Date: Jan 2013
Location: Seneca, SC
Posts: 2,830
Total Cats: 298
Default

Quote:
Originally Posted by thirdgen View Post
The number in the middle (such as BR8ES) designates the heat range. If I'm not mistaken, the higher the number, the hotter the plug.
Higher the number, the colder the plug. (NKG)
DNMakinson is offline   Reply With Quote
Old 02-14-2017, 08:58 PM   #7
Newb
Thread Starter
 
Join Date: Oct 2015
Posts: 34
Total Cats: 0
Default

I replaced them with some NGK BKR5E-11.

I still haven't checked the air but I'm fairly confident I made it out fine - the car runs as well as before (if not better!)
TheCanadian is offline   Reply With Quote
Old 02-15-2017, 12:55 AM   #8
Slowest Progress Ever
iTrader: (26)
 
thirdgen's Avatar
 
Join Date: Oct 2007
Location: The coal ridden hills of Pennsylvania
Posts: 5,886
Total Cats: 201
Default

Quote:
Originally Posted by DNMakinson View Post
Higher the number, the colder the plug. (NKG)
Thanks for the correction.
thirdgen is offline   Reply With Quote
 
 
Reply


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 03:54 AM.