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Crusader 270 swapped in Pertronix distrubutors.....Spark Plug question?

lforgue8

lforgue8

New member
Installed new distrubutors in both engines on my father-in-laws 1984 31' silverton with twin 270's. Want to change plugs at the same time and was wondering if i should get a new plug heat range and if the gap should be increaesed.

Ive looked through this web site and its great so i hope my first post isnt to bad! :)
 
You will want to stay with the same heat range spark plugs.

The only time that you'd want to increase the electrode gap, would be if you increased the secondary voltage.
The new distributors will not increase secondary voltage unless you went to high output ignition coils.

Side note: be certain that when you re-set the ignition advance, that you not only set Base advance, but that you also check/set/adjust the TA (total advance).
See the OEM specs for this number.
Better yet, see if you can find the OEM advance curve graph for these engines.


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thanks for the repsonce......so i was wondering if i should also change out the coils so if i got just replacments to match the dist i still shouldnt change the gap huh?

The pertronix website said that increasing the gap .005 would be recomended from a change from points to this new dist, but i just wanted some other confirmation you know!
 
lforgue8 said:
1.... thanks for the repsonce......so i was wondering if i should also change out the coils so if i got just replacments to match the dist i still shouldnt change the gap huh?

2.... The pertronix website said that increasing the gap .005 would be recomended from a change from points to this new dist, but i just wanted some other confirmation you know!
Click to expand...
1.... Change the coils if you want to, but perhaps go with what Pertronix recommends.

2... Triggering is triggering.... kettering system (contact points) or electronic triggering. But if they say to increase the gap by .005", then I guess you can.

The spark that jumps the gap must do so under cylinder pressure.
Physics plays a role in this, and I don't claim to fully understand the physics of this, but the more cylinder pressure, the more voltage is required in order to jump the same gap dimension.
This is why HEI systems allow us to increase the gap dimension, thus resulting in a better ignition spark.

I don't believe that you can achieve HEI output with a standard style ignition coil.


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You can get a higher voltage out of a coil but you have to increase what the primary side sees.

When selecting the spark plugs, the best bet is to check the PLUG OEM's application guide vs the original owners manual...especially for 25+ year old engines...What was gasoline back then isn't close to what bears that name today...
 
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