The Jensen Owners' Club A technical and discussion forum for all Jensen enthusiasts It is currently Sun Jul 12, 2020 3:04 am

V-8 Engine Tech

Spark plugs

Mopar Big Block Talk

by johnw » Wed Jun 20, 2018 10:51 pm

I normally use NGK in everything too. However one of the usual suspects back in 1996 sold me some Autolite 85s, and I am pretty sure they came with a 100,000 mile warranty on the box back then. They really worked well, so I stuck with them. Very concerned about these Chinese Autolites, and would like to see pictures.

There are lots of variables these days, changing oil and fuel formulations, plus tuning options, alloy heads etc, electronic ignition. The last thing I would want is worries about poor quality varying thicknesses of porcelain causing irregular heat build up and the failing of a poorly welded electrode wrecking the engine!
John Wild
User avatar
Posts: 629
Joined: Wed Sep 15, 2010 7:38 pm

by Steve Payne » Thu Jun 21, 2018 6:10 am

slotcarone wrote:Champion RJ12YC have worked in my car for the over 30 years I have it. :)

You are lucky, I stopped using Champion when I got a misfire in under 1500 miles from a new set. Since I have been using Autolite AP85's and NGK I have had no problems.

JOC official Lightning engineer
User avatar
Steve Payne
Posts: 5613
Joined: Thu Nov 17, 2005 4:51 pm
Location: Witney , Oxfordshire

by RayR » Thu Jun 21, 2018 9:07 am

I'll go with slotcarone, never had a Champion fail, I tried a set of NGK BP5S (short threads) on a recommendation and had one fail and went back to Champion RJ12YC. Now running the hotter RJ14YC which keeps the plugs much cleaner on my old engine with no signs of plug distress.
MkIII Interceptor (140 8488)
User avatar
Posts: 223
Joined: Mon Mar 05, 2018 4:43 am
Location: New Zealand

by Fredrik » Thu Jun 21, 2018 3:36 pm

This is a djungel with spark plugs but I understand that it is the short type that is correct. I have change back to the old ones for now. Here in Sweden I think NGK is the most common brand but there is many to choose from, but BP5S should be ok?
1970 Interceptor Mk2
Posts: 28
Joined: Thu May 18, 2017 8:45 pm
Location: Helsingborg, Sweden


by Jorrocks » Fri Jun 22, 2018 7:13 pm

dermot wrote:My vote is for NGK. Probably more expensive but "fit & forget" as mentioned...

I've fitted them to every vehicle I've owned since I discovered them in mid 70's sometime. Never once had an issue, that includes endurance race bikes, where we ran whole seasons on them! (they were race variants though).

kr D.

Sorry, thread hijack... what endurance team were you involved with? I sponsored Phase One in a very small way back in the day. Just LOVE motorcycle 24 hour endurance racing, absolutely hands down the ultimate motorsport!

Re. Plugs, I too wouldn’t use anything other than NGK or Denso.
1972 Interceptor MkIII (128/4886)
User avatar
Posts: 364
Joined: Sun Jun 07, 2015 1:15 pm
Location: Buckingham

by Moparguy » Tue Mar 19, 2019 1:43 pm

Bosch platinum is available again in USA if anyone is interested , best non fouling and for CD igs is Champ j12y ....Bosch platinum was an old favorite too
Posts: 18
Joined: Wed Jan 16, 2019 3:06 pm
Location: USA

by Joe Schiavone » Sat May 23, 2020 11:54 pm

The Champion 11Y And 12Y were the specific plug of choice. If your engine has wear and soots up the plug then try a hotter plug or freshen up your motor. A hotter plug may be your problem because your motor needs it. A very cheap lesson in mechanics. Try it. RacerJoe
Joe Schiavone
Posts: 692
Joined: Wed Apr 30, 2014 7:28 pm
Location: United States


Return to V-8 Engine Tech