AC Delco Rapidfire #4 plugs in a slant six

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dane1968

dane1968

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I bought some AC Delco #4 Rapidfire platinum plugs from Autozone today.
Do I need to use the washers for a '63 225/6? Thanks in advance.
 
It is said you can go without on the drool tube head.
 
I tried to look them up on autozone web to see if they are the right ones.Showed nothing for AC Delco #4 Rapidfire.
Supply the autozone part number for us. So we can check for you.
 
These NGK plugs have been great for me and others, let us know how they work out..
These are in a 66 model /6 with drool tubes
 

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In my experience, platinum plugs don't fire very well and NGK's kick the crap out of them performance wise.
I have put platinums in cars that wouldn't even start with them in it.
 
You should remove the washers on an early engine with spark plug tubes. This puts the spark gap in the optimal position.

Most important to check the length of the plugs against your current ones, just to verify the Autozone book. You wouldn't want them hitting your pistons (turn engine over by hand first to verify, by pulling on fan belt). If they fit any slant engine, even 1980's, they will work.

If you have the original points ignition, or even the later Mopar ignition, set the plug gap at 0.035". If you have an after-market ignition that doesn't need the ballast resistor, or a CD or MSD ignition, you can set to 0.055" or whatever that manufacturer recommends. If it misses under WOT at low speed, decrease the gap a bit. I had to do that with my factory 2.4L Mopar engine.

This is an opportune time to change the rubber seals on the spark tubes. Wags term them "drool tubes". The seals are real cheap (rockauto, maybe Autozone). Down the road consider an HEI ignition if still running points. It is simple and cheap.
 
In 1995 when they were newly released, I tried those RapidFire plugs in my '65. Got a bunch of ping and removed them to find tiny globs of metal on the tips (yep, ping). Never tried them again. Use NGK ZFR5N (stock #3459). Remove the metal ring washers whenever installing plugs (of any brand) on a '63-'74 slant-6 head. Tune-up parts and technique suggestions in this thread.
 
I'm with you Dan,That's why I asked for a number to see what they were.
 
You may want to check with Autozone, but I am pretty sure the Rapidfire are not meant to be gapped. They are supposed to come preset at the proper gap, and if they are the right ones for your car, they are probably already there.

If you have a flat plug mount, yes, you should use the crush washer. If you have a tapered plug mount, they are the wrong plugs.
 
Update: Thanks guys for the sparkplug advice. I wasn't happy with the ACDelco Rapid fire plugs. Bought the suggested NGK's. 63 Dart GT's 225/6 seems to welcome the new power increase from the 3459's.
 
Darter6 said:
It is said you can go without on the drool tube head.
Click to expand...
new to this /6 thing, what's a drool tube head? Kid has a 74 swinger /225. And slant6dan we just got the car and put in new plugs they gave us ngk bpr5es-11 stock #7634, are these good and I need to take them back out and remove the washers? Thanks :prayer:
 
Your engine has a solid head and should use the gaskets.

"Drool tube" is a clever euphemism for early slant six's (1962 - 1973?). The spark plugs mount inside removable aluminum tubes. The tubes seal against the head with a large rubber washer that is notorious for seeping oil in poorly maintained engines, hence the term. The washers are available and cheap, so change whenever the rubber hardens.

An engine with good rings and functional PCV should have a slight vacuum in the crankcase, so shouldn't leak since it sucks. A simple test is to remove the oil filler cap when running and see if fumes come out. If a lot, then the crankcase is pressurized, in which case you will see leaks from most crankcase seals.
 
plum crazy dart said:
new to this /6 thing, what's a drool tube head? Kid has a 74 swinger /225. And slant6dan we just got the car and put in new plugs they gave us ngk bpr5es-11 stock #7634, are these good
Click to expand...

They're good quality plugs, but they're not the correct ones, they're a wide-gap variant. You could close their gap down from the 0.044" they come at to the 0.035" your stock electronic ignition wants, but that's not as good as getting plugs designed for the correct gap, because if you close down the wide-gap plugs the electrodes won't be parallel, which they should be. The #3459 (ZFR5N) is better. And yes whichever plug you install, you need to remove, omit, leave out, not use the metal ring washers. The ring washers are not to be used on '63-'74 slant-6 heads.
 
BillGrissom said:
Your engine has a solid head and should use the gaskets.
Click to expand...

His engine has a "drool tube" head made between '63 and '74 and should not use the gaskets.

"Drool tube" is a clever euphemism for early slant six's (1962 - 1973?).
Click to expand...

'60-'74.

The spark plugs mount inside removable aluminum tubes. The tubes seal against the head with a large rubber washer that is notorious for seeping oil in poorly maintained engines, hence the term. The washers are available and cheap, so change whenever the rubber hardens.
Click to expand...

Those are called "spark plug tube seals", as distinct from spark plug gaskets (the metal items that need to be removed).
 
Sold parts,20+ years.Stick with NGK coppers,Warrantied most,of the Rapidfires,in my life.Unless,OBD-2,,useless.....
 
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