Can U use 13b spark plug in a 12a?

 

Yes. You can use them in the leading side if you do the 2 gen coil upgrade.

 

Yes, they will fit fine. However, they are designed for a more powerful ignition setup than the stock 1st gen. They will probably work okay, but they might not be optimal unless you also upgrade to the 2nd gen ignition setup as well (instructions in the FAQ section).

 

Yeah, they're not optimal because they were designed for a direct fire ignition system, but they do work in a stock 1st gen cap n' rotor system, if that's all you can find. For instance, the '83 GSL I just got has a set of BUR7EQ in the leading holes and the ignition is still stock. Fortunately the engine is a recent rebuild and doesn't have common problems of older engines like too much oil, low compression etc making life harder for the spark plugs.

 

The only 13B plug that will work decently in the 12a without the coil upgrade is the Se plug which is the BUR9EQ-14 and that's only because it is 1 step colder than the stock 12A plug.
Even the 2nd gen plug in a stock Se 13B without the 2nd gen coil upgrade does not work worth a crap.

 

Well the 2nd gen plugs work at least semi decently in a 12A with a stock ignition system, but I know they aren't optimal. Of course I could upgrade the ignition system to match the plugs. Maybe. It depends on how long it's going to take to do the 20B. If it's far off in the future, I might as well maximize the 12A right now, right?

 

I agree. Take the 15 minutes and atleast put the 2nd gen coil on it.

 

I don't mean to come in on this late.....but I was wondering how often you change your plugs on a stock 12A? Thanks for the input.

 

i change mine once every two years or 10K, which ever comes first. i upgraded to the dlidfis in my 85 S and still use the stock 12A plugs, BR8EQ-14's, but am consitering switching to BUR6EQ on the leading plugs. not sure if i will though. it runs fine with the BR8EQ-14's.

 

Thanks. I thought I noticed a difference in power and have only put approx 2k on the car since I changed out my BR8EQ-14's.

 

Damn...on my DD 48 ida fed SP, I change plugs every 5000 at least. More when running hard....good thing I get 'em cheap