First time changing spark plugs - help?

[thebends]

Hey guys. Bought my 302 bronco last year, have no idea if PO ever changed them but I thought I'd go ahead and do it. It takes a while to warm up before it won't stall and I read sometimes new plugs help that.

What's the preferred brand? Also how should I gap them? Any issues I need to look out for in terms of getting at the plugs or getting them loose? Thanks.

 

[70_Steve]

Hey guys. Bought my 302 bronco last year, have no idea if PO ever changed them but I thought I'd go ahead and do it. It takes a while to warm up before it won't stall and I read sometimes new plugs help that.

What's the preferred brand? Also how should I gap them? Any issues I need to look out for in terms of getting at the plugs or getting them loose? Thanks.

I would help to know some details about the Bronco and engine. Are you running a carburator or EFI? If a carb, do you have points inside the distributor, or is this an electronic ignition system, like Fords Duraspark?

As far as having to warm up before it won't stall, the first thing I'd look at, if you're running a carb, is the operation of the choke. That's what's responsible for keeping the engine running smoothly when cold.

I prefer Autolite plugs, but have used just about every old-school copper core plug. I'm not particularly impressed by the newer plug technology like the E3 or Platinum or Irridium tip plugs. I've run copper core plugs for 60K miles in my LS1 Daily Driver and they looked new when I replaced them.

Plug gap will depend on the ignition system. Gap at 0.035 for a points ignition, 0.045 for an electronic ignition.

Oh, and make sure you have the spark plug socket on the plug straight when tightening. The porcelain insulator will crack and break!!!

 

[RODRIG3911]

I like Autolite 25s with .44 gap in mine. It runs better with the cheap autolites, than with the expensive one

 

[ilovemaui]

It's obviously carbed or there would be no warm up issues. I would just buy a good set of Ford plugs. I don't think you would really notice much difference on a stock motor. You should do the points while you're at it or which out to pertronix.

Is the choke operating?

 

[thebends]

Thanks - this is a carb. Not sure on distributor - how can I verify that?

Thanks on choke advice.

Should I replace wires too for plugs?

 

[thebends]

The choke is operating

 

[thebends]

Okay I have it open and this is very different than my Nissan

How do I remove the wires? I don't want to snap off anything. Also do I need a universal joint to reach these? What size spark plug socket?

Thanks so much.

 

[70_Steve]

The choke is operating

And how did you verify the operation of the choke?

 

[ilovemaui]

I would do a search for firing order pics and mark the wires before you pull them. Put a little piece of tape with the cylinder numbers so you don't mix them up. Grab them by the plug, don't tug on the wires themselves. Don't pull the wires out of the distributor cap unless you're planning to replace them. You can pull the distributor cap off with the wires intact.

As for plugs just try a few different plug sockets until you find the right one. Carefully remove them so you don't break anything. If they are old they could be pretty tight.

Google is your friend. http://www.carmemories.com/cgi-bin/viewexperience.cgi?experience_id=232

 

[thebends]

Well - the choke is plugged in. How can I verify it works?

Re: firing order: CRAP! I realized that after I pulled them. I pulled them off distributor and plug because I figured I would replace them while I hbe everything out.

Am I screwed??

 

[Explorer]

May I suggest purchasing a Chiltons or Haynes manual for your Bronco. Not the best reference book in the world, but I think you will find it handy. These vehicles do require care that you may not be used to.

 

[thebends]

https://www.google.com/search?q=302...yHAQ&ved=0CHgQsAQ&biw=1366&bih=638&norc=1#p=0

Found that....that's looking from front of car right?

 

[ilovemaui]

Well - the choke is plugged in. How can I verify it works?

Re: firing order: CRAP! I realized that after I pulled them. I pulled them off distributor and plug because I figured I would replace them while I hbe everything out.

Am I screwed??

Google an image of Ford 302 firing order. Firing order

 

[70_Steve]

Well - the choke is plugged in. How can I verify it works?

Remove the air cleaner so you can see the top of the carb. With the engine cold, and without touching anything, the choke plate should be open, left that way from the last time the engine was run and hot. Actuate the throttle (pump the gas once) and the choke plate should flip closed or almost all the way closed. Start the engine and the choke plate should open just a little more, and the engine speed should be about 1200 RPM (fast idle) As the engine warms up the choke should open more. Tap the gas pedal, and the engine should idle at normal idle speed (~600 RPM) and the choke plate will be full open.

There should be one wire plugged into the black housing on the passenger side of the carb. That wire puts power to a heater inside the choke housing that will open the choke over time. There is a bi-metal spring inside that choke housing that will wrap and unwrap with temperature, to make the choke plate move. That black housing is the choke adjustment. Adjusting the position of that housing will make the choke plate open or close farther when the engine is cold, making the fuel/air ratio richer or leaner.

There should also be two tubes from the carb down to the exhaust manifold. The choke housing has a small hole into the inside of the carb to create a vaccum. That vacuum will suck fresh air from the tube connection at the top of the carb, through the exhaust manifold, and up to the choke assy, to further heat up the choke bi-metal spring as the exhaust manifold heats up.

 

[thebends]

Thanks a million steve.

 

[70_Steve]

Thanks a million steve.

Yeah, no problem. Hope at least some of that makes sense.

You also might want to consider becoming a Contributor at $12 a year. That $12 helps support the site and allows you to upload pictures directly into a post. Might come in handy when asking questions! Plus you get the cool-looking Contributor under your user name. Heres a link with more info. http://classicbroncos.com/forums/showthread.php?t=34373

Or find a site to host your pictures, then post the link, using the little postcard-looking icon at the top of the message window.

 

[thebends]

Got all the driver side plugs off so far.....the one near firewall is a pain!

These look pretty old and rusted, they are autolite 25s.

These look like they were gapped at .035, but I see a duralite ignition sticker over wheel well ?:?

 

[thebends]

Does anyone have advice on rear passenger plug? Cannot get socket over it

 

[70_Steve]

Does anyone have advice on rear passenger plug? Cannot get socket over it

I've had a 351 in mine for a while, so it's tough to remember issues with the 302. Try putting the spark plug socket by it's self on the spark plug first, then attach the ratchet to the socket.

 

[thebends]

Okay I put everything back except air filter/housing and tried starting it. Engine turns but no start, once i got a loud pop/bang from engine, any any thoughts?