After some research on-line and after comparing the OEM plug specs (thread size, hex size, reach, heat range, seat type, etc), I have compiled a list of aftermarket copper-core plugs that are direct replacements. It seems that, on some sites, the standard plugs aren't listed (only Iridium / Platinum). Presumably, this is because the OEM plugs are Platinum. Anyway, here's the list:

NGK BPR5EFS
Champion RS14YC
Autolite 605
Bosch HR8DCX

Cheers,
Ian.
:cheers:

 

hello, I want to add some info on the correct Autolite Spark Plug for Corvettes. The info about the Autolite 605 is not entirely correct...let me explain.....For 2002-2001 the correct plug is a Autolite 5245. 2000-1999 use Autolite 5243. While I don't know exactly what plug AC supplies as stock, the cross reference in our catalog is AC 41-952 (Autolite 5245). Interestingly enough there is no direct cross reference from NGK for these plugs. The Autolite 605 cross references over to the NGK TR 5 series plug. I was curious about this so I got a plug of each type for comparison. I found that while all the plugs have the same THREAD REACH, HEX SIZE etc as mentioned, the Autolite 5245 and AC 41-952 actually have a longer center wire stick out than do the NKG TR5 or the Autolite 605. What this means is the AC and Autolite plugs put the actual gap further into the combustion chamber. (the difference between the AC 41-952 and a
NGK TR 55vx is .0401)...That seems to be a big difference...Now why do you suppose Chevy and AC wanted the gap to be further into the combustion chamber? something to think about......


Here is a list of Autolite plugs for vetts back to 1994.

2002-2001 Autolite 5245 gap .060

2000-1999 Autolite 5243 gap .060

1998-1997 Autolite 104 gap .050

1996 Autolite 106 gap .050

1995-1994 Autolite 106 gap .050 for ZR1 DOHC 32V
Autolite 605 gap .060 For pushrod motor (LT1)

Hope this helps.....if you want info for other years let me know...


Danny Overton
Principal Engineering Technician
Autolite Spark Plug Company
Division Of Honeywell Transportation Product Group

 

http://sparkplugs.com/results_app.as...1&AAIA=1380024

 

Hmm... interesting. But, how can the REACH be the same, but the gap be further into the combustion chamber?? :confused:

What's also strange is that the Autolite 605 cross-references to the NGK TR5-series plug (which seems to be one of the most popular after-market plugs for the C5), yet the Autolite catalogue does NOT list the 605 for the Vette!

Also, NGK don't list the BPR5EFS for the Vette, but I found a cross-reference in the NGK catalogue to another plug that IS compatible. I'm assuming this is because the BPR5EFS is a regular copper-cored plug and the OEM plug is platinum. Therefore, NGK probably only list direct like-for-like replacements.

Heck, I've been running for the past week with an Autolite 3923 in my No.2 cylinder, which is completely the wrong plug and the car's running fine! Basically, I broke the insulator on the OEM plug when trying to remove it to inspect (if it ain't broken, blah, blah!) and I just happened to have a few Autolite 3923's in the garage from a previous car... just so happened the thread and hex sizes were the same. The reach was +1mm over OEM, so I just used another gasket washer (the 3923 is a gasket seat).

The impetus behind me posting this thread is that plugs for the C5 are tricky to get hold of in the UK... the Vette is not listed in 99% of catalogues over here and the TR55's aren't available. As it is, I'm gonna be paying around $3.50 EACH for regular NGK copper plugs! Platinums (if I could get 'em) would be around $6 or $7 each, I should think.

 

The THREAD REACH is the same on all the plugs..however the AC plug and Autolite 5245 have longer centerwires and insulators. That is why they have the gap location further into the combustion. I'll 1/2 section them for inspection and measurements....What part of the UK are you in?

Danny

 

I'm in the county of Northamptonshire (about 55 miles North of London).

Cheers,
Ian.

 

I've done some testing in Northhampton at Cosworth....and over in Milton Keynes at what is now Pro Drive. It was another test house but for life of me i can't remember the Name now. do you do Curries? Ever been to a resturant called the IMRAN in North Hampton? Best Curry resturant I've ever been to!!!! :0) Lamb Jalfreizie...yum yum!!!! it's worth the drive....I'll post info later on plugs. Also a warning...be careful using the gasket seat plug if the head isn't machined for it. Yes it may seal ok but I would be worried about damaging the tapered seat and causing problems when you do get the correct plug.

Danny

 

UNBELIEVABLE!! I actually live in Northampton... the 'Imran' is about 3 miles from my house! I drive past Milton Keynes on my way to work (in Luton) and went there just recently to get a helmet from a bike shop for RWYB events at the Strip. TALK ABOUT SMALL WORLD!! Northampton is great for bars and curry houses... the Wellingborough Road has it all... every other door is either a bar or a curry house! :)

Anyway, back to topic, I hope I haven't done any damage to the head :eek:
I only torqued the plug down fairly lightly, so hopefully I'm OK.

Cheers,
Ian.
:cheers:

 

I just installed the NGK TR55IX plugs and MSD wires and the car idles like a Lexus. Seems crisper throttle response too.

Tom
USAF Retired


[Modified by AFVETTE, 10:54 AM 6/14/2003]

 

It's the plugs. I just put them in and you'd swear it's a different motor :thumbs: