Spark Plug Change

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365 GT 2+2
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Spark Plug Change

Post by 365 GT 2+2 »

Team Tomyang.net -

ANy advice as to what tool(s) will work best to change the spark plugs on the Queen? And what plugs are you guys using these days?

TB
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tyang
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Re: Spark Plug Change

Post by tyang »

Hi Tom,

The Vintage Archive has a thread on which plugs to use.

The best combination for plugs is a plug socket with a u-joint on a 3/8 ratchet.

When installing the plug there are two really important steps.

1. DON'T CROSS THREAD THE SPARK PLUG! The tool Francois taught me to use is a spare rubber boot that fits on the top of a spark plug with a 1/4 extension on the other end. This allows you to reach the hole for the spark plug to start turning the plug. You should be able to feel the plug engaging the threads. If something feels wrong, stop, and try again. Cross threading the aluminum with the steel threads of the plug will make for a big problem.

2. Use anti seize compound on the threads of the spark plugs. It can be purchased at any autoparts store.

Tom
'63 330 America #5053
Jimmyr
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Re: Spark Plug Change

Post by Jimmyr »

A short length of small diameter rubber hose sliped over the plug can also be used to start the plug threading. NGK plugs have served the Ferraris well over the years.
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TOMKIZER
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Re: Spark Plug Change

Post by TOMKIZER »

tyang wrote:Hi Tom,

The Vintage Archive has a thread on which plugs to use.

The best combination for plugs is a plug socket with a u-joint on a 3/8 ratchet.

When installing the plug there are two really important steps.

1. DON'T CROSS THREAD THE SPARK PLUG! The tool Francois taught me to use is a spare rubber boot that fits on the top of a spark plug with a 1/4 extension on the other end. This allows you to reach the hole for the spark plug to start turning the plug. You should be able to feel the plug engaging the threads. If something feels wrong, stop, and try again. Cross threading the aluminum with the steel threads of the plug will make for a big problem.

2. Use anti seize compound on the threads of the spark plugs. It can be purchased at any autoparts store.

Tom
In my opinion, that's the best advice anyone can give. I use the plug socket (one with the rubber retaining sleeve inside and with the 1/2 inch socket extension plugged into it) to start the plugs, just to the point of completely seating the plugs by hand. If I can screw the plugs all the way to the seat by hand, then I know the threads are clean. If there is resistance, I try to clean the threads by threading in and out a rifle cleaning brush of the appropriate size. When I can seat them cleanly by hand, I snap on the handle and tighten them the rest of the way. I try to make sure the only resistance is due to the viscosity of the anti-seize compound. The anti-seize is MANDATORY if you don't want to eventually remove the heads to have one or more plug holes welded up and remachined. I can't imagine that a stripped plug hole can be repaired any other way.

Does anyone here actually torque the plugs? I just snug them to the point of collapsing the sealing washer. I've never had one loosen up. I'm paranoid about stripping aluminum threads with steel threaded parts - whether they be bolts or spark plugs.

Tom Kizer
So many sidewalk cafés - so little time left.
1969 365 GT 2+2 S/N 12293 (Gone but not forgotten)
1967 230 SL 4-spd (Currently on CPR)
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tyang
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Re: Spark Plug Change

Post by tyang »

Hi Tom K.,

Having just installed a set of NGK BP6ESs on my heads, I snugged them up a little after feeling the crush washer collapse.

Stripping spark plug threads is really bad news, so I'm really careful around them. All the spark plug thread fixers or re-tappers all seem to take too much room, requiring removing the heads. Considering a set of head gaskets are over 300 bucks, not to mention the time it will take to get the heads off, I can't emphasize how a simple spark plug change can quickly turn into a $$$ nightmare!

I don't mean to scare Tom B from doing this, but understanding the caveats before jumping it will save him from making a costly mistake.

Tom
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250GT
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Re: Spark Plug Change

Post by 250GT »

Hello Spark plug changers among us.
take out the plugs when the motor is slightly warm NOT hot.
put in the new plugs when the motor is COLD . You will have the right feeling .
That make sense( diff. coeffiecent of two meterials : alu versus steel)
ALWAYS check the distances of the electrodes , even new plugs can be have problems.
When doing this the first time take 3- 4 hours time.
I think nothing can went wrong.
Owner with small nearow motor bays like SWB, TDF,CARL SPYDER . need a special wrench.
no problems with GTE,LUSSO,PF.

its only a hobby here
ciao
Cornelis
365 GT 2+2
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Re: Spark Plug Change

Post by 365 GT 2+2 »

Gents -

Thanks as always for the great resonses. Fat bald and stupid is no way to go through life, but somehow I've figured out a way to make it this far --- but I am having trouble visualizing the 'rubber' sleeve...do the tools come with a rubber boot and does one use it to get the plugs out, back in or both?

Sorry men - I'll get to more technical questions at some point...
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TOMKIZER
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Re: Spark Plug Change

Post by TOMKIZER »

Here's what I was talking about. It's a standard spark plug socket with a foam sleeve inside to hold the plug so it doesn't fall out of the socket. Tom Y. was talking about a spark plug wire boot (with a 1/4 inch socket extension shoved in where the wire normally goes.

Tom Kizer
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So many sidewalk cafés - so little time left.
1969 365 GT 2+2 S/N 12293 (Gone but not forgotten)
1967 230 SL 4-spd (Currently on CPR)
365 GT 2+2
Posts: 77
Joined: Wed Jan 21, 2009 4:32 am

Re: Spark Plug Change

Post by 365 GT 2+2 »

Hi Tom K. Got it. Very helpful. Thank you for taking the time to post that picture. I'll keep you guys posted on how it goes...
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