Spark Plug Question #3,642 - 86 vette
Thread Starter
Instructor
Joined: Jul 2006
Posts: 102
Likes: 0
From: Cary North Carolina
Spark Plug Question #3,642 - 86 vette
I have a 1986 coupe. The first few made had iron heads, the later were aluminium. I read somewhere on this forum, that if the valve covers have 4 screws in them (which mine has), I have the aluminum heads. Is this true?
Also, everyone is writing about the NGK tr-55's
There are 2 kinds:
NGK TR-55
NGK TR-55 IX
Which is best for my 86?
Thank you
Also, everyone is writing about the NGK tr-55's
There are 2 kinds:
NGK TR-55
NGK TR-55 IX
Which is best for my 86?
Thank you
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
If the valve cover has four bolts in the center of it they are aluminum. It is has four nuts (two on the top sides and two on the bottom sides) the it is cast iron. The TR-55 IX is a Iridium plug and not really need or any better. I use NGK in all my vehicles and the TR-55 will be fine for you.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
False. You have the iron heads.
RACE ON!!!
PS. To clarify: RRT vette and I were both writing at the same time. My "False" is in response to shilly's, "Is this true?" question.
If you have 4, 1/4" screws around the lip (perimeter of the valve cover, you have iron heads. If you have 4 bolts down the center of the valve covers, you have aluminum heads. I keyed on your usage of the word, "screws".
RACE ON!!!
PS. To clarify: RRT vette and I were both writing at the same time. My "False" is in response to shilly's, "Is this true?" question.
If you have 4, 1/4" screws around the lip (perimeter of the valve cover, you have iron heads. If you have 4 bolts down the center of the valve covers, you have aluminum heads. I keyed on your usage of the word, "screws".
Last edited by CFI-EFI; Jul 28, 2006 at 11:02 AM.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
If your production number is 3,642 then you have Cast iron. They didn't start with Aluminum until after production number of 5,000 +. All convertables had aluminum heads. Unless someone previously changed heads to aluminum.
Team Owner
Joined: Oct 2000
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From: Fort Knox, KY
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You'll be very pleased with the NGK TR-55 Double Platinums. I've had mine installed nearly six months and they're excellent performers.
Thread Starter
Instructor
Joined: Jul 2006
Posts: 102
Likes: 0
From: Cary North Carolina
Originally Posted by CFI-EFI
False. You have the iron heads.
RACE ON!!!
PS. To clarify: RRT vette and I were both writing at the same time. My "False" is in response to shilly's, "Is this true?" question.
If you have 4, 1/4" screws around the lip (perimeter of the valve cover, you have iron heads. If you have 4 bolts down the center of the valve covers, you have aluminum heads. I keyed on your usage of the word, "screws".
RACE ON!!!
PS. To clarify: RRT vette and I were both writing at the same time. My "False" is in response to shilly's, "Is this true?" question.
If you have 4, 1/4" screws around the lip (perimeter of the valve cover, you have iron heads. If you have 4 bolts down the center of the valve covers, you have aluminum heads. I keyed on your usage of the word, "screws".
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Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Any plug that sparks is a good plug. The cheaper the better. Platinum, double platinum, iridium, silver, gold, unobtainium, etc, cost more and last longer. If you are one to not touch your plugs for 80,000, 100,000 miles, or more, the expensive plugs are probably worth it, especially if you are paying someone else to change them for you. I would think that most of the readers of this section of the forum wouldn't tend to leave them alone that long and would be checking and changing them themselves.
RACE ON!!!
RACE ON!!!
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Not much point in putting in an expensive plug in an L98, stock Delco is more than adequate, and expensive plugs dont do it any better.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I've always had good luck with ACDelcos...that's my only explanation, they seem to perform and last.The plug I use on my 87 is ACDelco 41-629. At least the stock plug for an 87 was the ACDelco. Generally these C4s have quite a few miles, mine has 103,000, so I change plugs every couple years. NGKs are good too, I've used them in other vettes.
As far as platinum or any of the precious metal plugs..to me it's a waste of $$$, and any plug with a puck..I won't use.
Been turning wrenches for over 40+ years, so I've played with alot of plugs, and my decision is based on cost/performance/longevity.
As far as platinum or any of the precious metal plugs..to me it's a waste of $$$, and any plug with a puck..I won't use.
Been turning wrenches for over 40+ years, so I've played with alot of plugs, and my decision is based on cost/performance/longevity.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
What Rick said is true. It's all about what you have used and what worked. I have used mostly NGK and have had no problems with them so far. My Father likes ACDelco. Just a matter of opinion and experience.
