Bf-42 replacement /Autolite 45's - Ford Muscle Forums : Ford Muscle Cars Tech Forum
FordMuscleForums.com is the premier Ford Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools
Old 04-13-2008, 09:22 AM   #1 (permalink)
Subscriber
 
Join Date: Sep 2006
Location: Vancouver, Canada
Posts: 1,664
Bf-42 replacement /Autolite 45's

Is the heat range of the Autolite 45 close to the original Bf-42 or is there a better choice. I have to change the plugs and the shop recommened NGK V Power .

Greg
__________________
1966 Sahara Beige Mustang Coupe ... my baby since 1981
foleysfriend is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 04-13-2008, 10:43 AM   #2 (permalink)
Registered User
 
Join Date: Feb 2001
Location: SoCal
Posts: 493
Re: Bf-42 replacement /Autolite 45's

By the book, today's Autolite 45 is the same plug as the old BF-42.
I use a step colder non-resistor Autolite 34 in the 289 in the GT. I always
found the 45's to be too hot. Unfortunately the 34's aren't available anymore.
(AR 33, which is an Autolite racing plug, is pretty close - just a bit cooler than my favored 34's)
__________________
66GT289 is offline   Reply With Quote Quick reply to this message
Old 04-13-2008, 11:14 AM   #3 (permalink)
Subscriber
 
Join Date: Sep 2006
Location: Vancouver, Canada
Posts: 1,664
Re: Bf-42 replacement /Autolite 45's

What is the difference in the two plugs when it comes down to performance and does it effect idle quality to go to a colder plug or type of octane you can run

Greg

Greg
__________________
1966 Sahara Beige Mustang Coupe ... my baby since 1981
foleysfriend is offline   Reply With Quote Quick reply to this message
Old 04-13-2008, 01:46 PM   #4 (permalink)
Registered User
 
Join Date: Feb 2001
Location: SoCal
Posts: 493
Re: Bf-42 replacement /Autolite 45's

Quote:
Originally Posted by foleysfriend View Post
What is the difference in the two plugs when it comes down to performance and does it effect idle quality to go to a colder plug or type of octane you can run

Greg

Greg
Colder plug = higher compression & the attendant need for higher octane fuel
Hotter plug = stock compression, stock engine, or worn out engine

If the plug reads "hot" for your combination, you'll need at least a range cooler. (The temperature of the plug is how fast if transfers heat from the tip)

As far as idle quality, colder isn't a problem as long as it isn't loading up and fouling out..... that would be a problem, as you can probably imagine.
Octane requirement is mainly a function of compression.
It's always safest to be too cold and foul plugs, than to have the plugs be
too hot and have pre-ignition/detonation issues.
__________________
66GT289 is offline   Reply With Quote Quick reply to this message
Old 04-13-2008, 04:36 PM   #5 (permalink)
Subscriber
 
Join Date: Sep 2006
Location: Vancouver, Canada
Posts: 1,664
Re: Bf-42 replacement /Autolite 45's

Excellent information. I have a 289 that has been worked on and the compression ratio is 9.5-1 on the shop work order. My fuel of choice has been 94 octane and as I try lower octane the engine idles poorly. The 89 octane is a disaster. Recurve on the dizzy works well on the 94 . The car has a very slight miss which may be a timing or pre-ignition problem or plugs.

Thanks
Greg
__________________
1966 Sahara Beige Mustang Coupe ... my baby since 1981
foleysfriend is offline   Reply With Quote Quick reply to this message
Old 04-13-2008, 08:09 PM   #6 (permalink)
Subscriber
 
Join Date: Sep 2006
Location: Vancouver, Canada
Posts: 1,664
Re: Bf-42 replacement /Autolite 45's

Found the AR-33 spark plugs today and they are around $5.00 each. Not much in stock so I wonder if they don't sell too many or they may be on the discontinue list. May be able to negotiate a price with them.

Greg
__________________
1966 Sahara Beige Mustang Coupe ... my baby since 1981
foleysfriend is offline   Reply With Quote Quick reply to this message
Old 04-14-2008, 07:24 AM   #7 (permalink)
Registered User
 
Join Date: May 2007
Location: Orting, Washington
Posts: 1,122
Re: Bf-42 replacement /Autolite 45's

This is link to a cross reference chart.

http://www.cvproducts.com/cv/technical/sheets/spark/Autolite.pdf
McCutcheon4 is offline   Reply With Quote Quick reply to this message
Old 04-14-2008, 04:51 PM   #8 (permalink)
Subscriber
 
Join Date: Sep 2006
Location: Vancouver, Canada
Posts: 1,664
Re: Bf-42 replacement /Autolite 45's

The chart shows the Autolite 45's near the top of the chart and the 33's down near the bottom as a cold plug, nothing just after the 45's.

Thanks
Greg
__________________
1966 Sahara Beige Mustang Coupe ... my baby since 1981
foleysfriend is offline   Reply With Quote Quick reply to this message
Old 04-14-2008, 07:29 PM   #9 (permalink)
Registered User
 
Join Date: Feb 2001
Location: SoCal
Posts: 493
Re: Bf-42 replacement /Autolite 45's

Quote:
Originally Posted by foleysfriend View Post
The chart shows the Autolite 45's near the top of the chart and the 33's down near the bottom as a cold plug, nothing just after the 45's.

Thanks
Greg
Yeah, the "hole" in the chart is where the discontinued 34's go.......
I hope they don't discontinue the AR33's..... that would piss me off.
Particularly after they did away with the 34's......
(really stupid because if you have a cold plug that fouls, you can always
use an MSD to minimize the problem, but if all you have is a hot plug
available & you need something cooler, you're SOL)

Try Sparkplugs.com, they have AR 33's cheaper than $5 ea.
__________________
66GT289 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Ford Muscle Forums : Ford Muscle Cars Tech Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Holley or Autolite ? condor4 All Ford Techboard 3 04-22-2007 05:28 PM
Anyone tried the Autolite XP plugs? f100cleveland All Ford Techboard 3 09-13-2005 01:01 PM
Autolite saves the day. ScreaminC All Ford Techboard 2 09-12-2005 05:00 AM
Autolite sparkplugs PONY1 All Ford Techboard 0 10-29-2002 07:14 PM
autolite 2100??? 64 TBOLT All Ford Techboard 21 10-29-2002 04:33 AM


All times are GMT -7. The time now is 11:36 PM.



Powered by vBulletin® Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Friendly URLs by vBSEO 3.6.0
 

Garage Plus vBulletin Plugins by Drive Thru Online, Inc.