Spark Plug Gap

[vping]

What is the SPG for my "H" Engine? Haynes lists it as .032 if I have a 25D4 Distributor or .035" if I have the 45D4 Distributor.

Autozone siad to set it at .024"

How can I tell which dizzy I have and then, what's my gap?

 

[kennypinkerton]

On the dizzy, if you look hard, it's stamped with the model number (25D, 45D, etc) along with some other numbers.

I'd set it for what Haynes says if you got regular plugs... A few of the weird design plugs are preset to optimum for the plug (bosch +4, for example).

The Autozone guy's no squat about old car engines. .024 is probably for some new honda - whatever...

 

[vping]

The Gap on the new plugs is about .032" out of the box so I decided to check the book. I will look for the number on the dizzy tomorrow.
Oddly enough, when I called autozone to get a battery and told them on the phone what kinda car I had, the guy on the phone said "gee sir you have one of the nicest car in the world" Kid musta been about 25 and told me he had a 79 B. Strange.
Still they all seemedlike "honda" guys in the store.

 

[Steve_S]

Points? Stock coil? If you have changed anything it will affect the spark gap. I installed a Lucas Sport coil and opened up my spark gap .004" and may go more.

 

[vping]

All stock.
I have a new cap, points & condenser I will be installing as well.

 

[DrEntropy]

.028"~.030" would be my choice. Points @ .015".

 

[vping]

It seems that the gap can be "Users Choice"?
What determines how you would personalize your plugs?

 

[Steve_S]

Set them as wide as you can get away with. The more power supplied to the plugs, the wider they can be.

 

[DrEntropy]

On "conventional" systems (points/condenser) a Lucas Sports Coil can give great "fire" and you can gap the plugs at around .035" and get the best Bang fer the Buck, so-to-speak.

 

[vping]

I have the 25D dizzy so I will start off with .032" and adjust if ness.
What are my benefits if I go to .033"-.035"?

 

[DrEntropy]

Generally, as Steve said, the wider the gap the hotter the spark...but there's a point of diminishing return. If you've a "hot" coil you can likely go to .033"-.035" but much more and it will not be of benefit.

 

[Dave Russell]

Keep in mind that if you have the gaps set at maximum, any further increase in gap will cause missfire. You have already used up all of the "reserve" voltage.
D

 

[Steve_S]

Exactly. Too much gap and you don't have enough voltage to create a proper (large enough) spark.

 

[vping]

Thanks for all the replies. I will keep all of this in mind.