1968 spark plugs

[Powell]

I have been chasing a missing problem for about a year now. This is the first of many questions I will be posting here, but my question is what spark plugs should I be running in my 302 4V with a mild cam and 10-1 compression engine. The ones I have been using are autolite 45 which I think are 1 step hotter than normal. Does anyone out there have a suggestion as to a different plug?

Ralph

 

[Russ]

If you can find NOS Autolite BF-42 plugs, that is the way to go. I had similiar problems with my '68 GT/CS and the original plugs solved the missing problems of the new plugs. Hope this helps, Russ

 

[Mosesatm]

Here's what I've been able to gleen from the various sites. Please take it with a grain of salt because I know just enough to be dangerous.

As I understand it the new 45s are the same (or nearly the same) as the old 42s, and they will work for a completely stock engine, but if you increase the performance of the engine these plugs will run too hot. Autolite no longer makes a plug for our engines that are just a little cooler. They used to make 34s but supposedly discountinued them.
AR32s are available but they may be a little too cold for a mild to medium rebuild because they are recommended for '63 Shelbys.

Again, I may have no idea what I'm talking about so please proceed accordingly!!!

ETA:
Here is a site that talks about the Motorcraft BF32 plug being used in small block Ford engines.
http://www.ammotorsupply.com/products/featured/

If you don't mind using a non-Ford product the Champion RF9YC or RF7YC may be good choices.

 

[green56]

go to google Type in wanted BF42 spark plugs there are quite a few they said should be set at .035

 

[robert campbell]

Ralph,
Let's talk. All ignition misses are either carb, valve adjust, or timing. Seldom a random plug or plug wire.

Rob

 

[Powell]

First of all, A big thanks for all the input.
Rob, I would love to have that talk, my problems seem to have started when I decided to "clean up the spark plug wire look". I replaced the plugs and installed new Taylor spiro 8mm wires. I used the taylor wire seperators and ran all the wires along the front and down the side of the valve covers. Looks much cleaner than over the top of the valve covers. Installed new rotor and cap, but under extreme load I am getting a real miss. Having replaced the distributor and carb and retimed numerous times I am now beginning to wonder if I have somehow created a crossfire with my wire routing.
Any thoughts about this are greatly appreciated.

Here is a picture of the new plugs after a year and 2200 miles and a new carb and distributor.

Ralph

 

[Powell]

Just a bump to see if anyone has ideas
Ralph

 

[Mosesatm]

Normally when 1 & 5 are bad I'd look for a spark jump between their wires because they are next to each other in the firing order, but you have 4 bad plugs so it's tough to say what's going on there.

It may be just a coincidence that those 4 particular plugs look bad.

I had a couple similar plugs a year or so ago that we figured out was due to worn valve guides. Fixed the guides and the problem went away.
Do you ever see a puff of blue smoke out of the tail pipe?

 

[Powell]

Arley, I never see the smoke from the exhaust but thru all this time I have had all the pinging and backfires that may have destroyed the plugs or ??? Thank you for your reply, I am at very frustrating place right now. One of the things I discovered when I took the plugs out is that they were gapped at .045 instead of the recomended .035

Ralph

 

[Mosesatm]

Too wide of a gap can certainly create problems. Have you run the car since you reset the gaps?

Pinging and backfiring is normally a timing issue so here are a few things to check.

- Are the vacuum hoses hooked up correctly? Make sure there is no vacuum at idle in the hose that goes to the front vacuum advance port on the distributor.
- Does the vacuum advance work?
- Is the initial timing set at 6 BEFORE top dead center?
- Are you running premium or regular gas? If you run premium you should be able to advance the timing a little (more power) without pinging.

 

[robert campbell]

Ralph,
This looks very interesting. Give me a call at (360) 377-5164. I talk way faster than I type! I am off work today and can talk. Other days you can call me at 4:00ish in the afternoon.

Rob