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Which Spark Plugs to Use
Posted by: OHIOTOM ()
Date: June 23, 2010 10:18AM

I am tuning up my 1966 Monza Coupe with a 110 auto. The plugs that were in it when I bought it 9 years ago are Bosch Super W8AC. They actually still look decent but not good enough to put back. I have a brand new set of ACR44F that came with the car. Are the ACs the correct plug or should I search for the Bosch?I have seen so many opinions on plugs but I know this site is the best. Thanks!!!

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Re: Which Spark Plugs to Use
Posted by: Gregory_Miller ()
Date: June 23, 2010 11:13AM

R44F are the stock plug that was used in my 68, I'd think that they would be a good choice.

Greg Miller
Eugene, Oregon

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Re: Which Spark Plugs to Use
Posted by: jimc ()
Date: June 23, 2010 11:40AM

AC was the factory plug. Depending on your motor, the heat range could be a 42 or 44, but the (double) "FF" designation, refers to the length of the plug. For example, my 140hp, takes the AC44FF. Some later day AC replacements were the single F designation, but still shorter than the ideal length.

The R was for "radio suppression".

The single series "F", you mentioned, is slightly shorter by several threads. Ideally the proper length puts the plug at the correct location for the combustion process, if the plug is shorter it will be "shielded" and might hinder the flame propagation of the spark.

The AC "FF" is still available on ebay, but somewhat expensive.

I used Bosch plugs in my older Porsche 911 and they were a great plugs, BUT you still should be using the proper length as in the "FF" plug.

Hopefully some real wrench heads will confirm my observations.

jimc
1965 Corsa

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Re: Which Spark Plugs to Use
Posted by: 62corvairjunky ()
Date: June 23, 2010 12:21PM

NGK BP5HS for naturally aspirated stockers is a great choice. The BP6HS is a step colder, and a good choice for turbo and high compression engines.
All my opinion of course.drinking smiley

Junky
Hurricane Utah.
Home of the "Red Desert Corvair Sanctuary."

<a href="[photobucket.com]; target="_blank"><img src="[i866.photobucket.com]; border="0" alt=" photo 7121255b-53ac-4335-a3ba-83724bf6f396_zps111b404a.jpg"/></a>

62 Rusty Rampy
62 wagon under construction.(Taking all my time and $$)
61 lakewood parts car.
61 Lakewood wagon project.
half a dozen parts cars n trucks or more.
20x40 garage full of greasy parts.

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Re: Which Spark Plugs to Use
Posted by: Paul Kehler ()
Date: June 23, 2010 01:58PM

The "R" on the AC plug is for resistor. The center electrode has an extra gap inside to intensive the spark.....the coil has to build up enough voltage to jump [ionize] two gaps instead of one. This type of spark plug was developed in the middle "60's" to cut down the smog emmisions. It has nothing to do with the radio as the TVRS wires do [TV and Radio suppresion}.I see in Clark's catalog a reference to the R plugs as radio suppresion,which is in error. The resistor plug can be used in older engines that are fouling the plugs from oil and carbon build up. This plug can go a lot longer between tune-up's before misfiring,but you will notice a drop in gas millage.

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Re: Which Spark Plugs to Use
Posted by: lgoodwin ()
Date: June 24, 2010 12:25AM

I asked for AC 44F for my 68 with 110 engine at Baxter Auto Parts and was told that they are no longer made and the Autolite 425 are the equivalent part.

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

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Re: Which Spark Plugs to Use
Posted by: Phil Dally ()
Date: June 24, 2010 05:20AM

Quote
62corvairjunky

NGK BP5HS for naturally aspirated stockers is a great choice.

Junky is right...only way to go.

I use 7's in the racecar!!


Paso Robles CA-Sidewinders (SCTA Charter Member 1934)-CORSA Member-Central Coast Corsa-Ventura County Corvair-Corvanatics-California Angels Fan Since 1978...World Series Champions 2002 & 9 AL West Division Titles-So Cal Gas Since 1974 (Now Retired Again) Rehired as Contractor Seasonally-RACECAR 148.253 MPH Unsafe at Any Landspeed F/BGALT Late Model Coupe-ZONKER 1965 Monza Weber Turbo 95/PG Coupe-GEM 1966 500 140/PG Sport Sedan Factory A/C 36K Original Miles-SANDRAIL B&M Blown Methanol 3.1L Mid Engine Funco-DUCK 1965 110/PG Monza Coupe Parts Car-CRUSTY 1966 110/PG Factory A/C Coupe Parts Car-2013 Ford F250 Super Duty XLT Four Door Crew Cab Short Bed 6.7 Powerstroke-Grand Design Momuntum 350M Luxury Toy Hauler-When I Grow Up I'm Selling Everything and Buying a Vintage Triple Weber 911S Because I'll Never be Able to Afford the Miura!!!

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Re: Which Spark Plugs to Use
Posted by: eaglefm ()
Date: January 13, 2020 11:28AM

What are best 65 monza 110 pulled out R44Fis their a better plug

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Re: Which Spark Plugs to Use
Posted by: joelsplace ()
Date: January 13, 2020 11:57AM

What did the old plugs look like? That will tell you if you can go colder.

Joel
Northlake, TX
5 Ultravans, 114 Corvairs and counting...

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Re: Which Spark Plugs to Use
Posted by: larry202br ()
Date: January 13, 2020 12:00PM

lgoodwin Wrote:
-------------------------------------------------------
> I asked for AC 44F for my 68 with 110 engine at Baxter Auto Parts and was told that they are no longer made and the Autolite 425 are the equivalent part.

I use the Autolite 425's with good results.

1961 rampside with a 65 / 67 110 engine, car four speed.
1965 convertible
1966 Custom two door/four door 180 Turbo.

KC0SKX
Olathe, ks
HACOA

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Re: Which Spark Plugs to Use
Posted by: Caraholic4life ()
Date: January 13, 2020 02:16PM

The Autolite 425 is often stocked at Auto Parts stores and works well in our cars.

1962 95 F.C. Van
1965 Monza Coupe
1965 Monza Convertible
Westminster, Maryland

MID ENG enthusiast &
prior Kelmark owner.

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Re: Which Spark Plugs to Use
Posted by: TerribleTed ()
Date: January 13, 2020 02:30PM

The Bosch Super W8AC or WR8AC are a great choice in most Corvair engines. I Have run them pretty much exclusively in my cars for years (mostly 110 engines). The ones I have gotten recently are made in Russia and have blue stripes instead of green but they seem to work fine. I have not had great luck with the similar Bosch WR8AP platinum tip plugs as they seem to foul pretty easy.

---------------------------------------------------------------------------------------------------------

Avid Corvair hobbiest since 1984.
I have personally performed ground up restoration on over 20 Corvairs.
I currently work full time at restoring and repairing Corvairs.
Located in the Atlanta Georgia area.
[www.facebook.com]

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Re: Which Spark Plugs to Use
Posted by: JimBrandberg ()
Date: January 14, 2020 08:15AM

I used to use Bosch W8AC (7502) and also W8AC+ (7902) when they changed to that.
When Bosch was no longer at O'Reillys I got them from NAPA. When NAPA no longer had them I switched to NGK.

I generally use B6HS (7534) in 180, 140, 110 and 102HP. For a dollar more there's BR6HS (3922) resistor. They're comparable to AC44.
For low C/R 95 and 80 HP I would use B5HS (4210) I don't have the resistor number. It's a little hotter and comparable to AC 46.

For your 110 PG I would use the B6HS and only go hotter if needed. I've seen engines with holes in the pistons so I'm cautious. Others may have a different opinion.

I consider Autolite 425 comparable to AC 44. Autolite 275 is extended tip and I would probably not consider them.

I liked the Bosch for a long time but like to use things that are easy to find for someone later. You could get some easy enough if that's what you like.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Which Spark Plugs to Use
Posted by: Seth Emerson ()
Date: January 14, 2020 10:09AM

I have run Denso (formerly called Nippon Denso) stock #3034 plugs in 110/140/180 engines. Typical Japanese quality - very good - Also called "W16 FSU" It is a VW (air-cooled) replacement. Available many places.

Seth Emerson

Check my new Performance Corvair Web site [www.perfvair.com]

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Re: Which Spark Plugs to Use
Posted by: vairmech ()
Date: January 14, 2020 06:59PM

If you have the AC R44F spark plugs don't go buy any plugs, use what you have!



To correct what was said earlier The AC 44FF and later years R44FF was the standard plug for all engines except the low horsepower 80hp-95hp and they used the 46FF or R46FF. I don't ever recall a 42FF plug ever coming standard in any Corvair. The racers use them because they are a cooler running plug for mostly full throttle operation.

The way the AC plug numbering system works is
R=resistor;
4= 14mm thread;
4= heat range 4 =1400 degrees, 6= 1600 degrees as I recall.
F= 7/16" reach
F= fully threaded.

The differences in the FF and the F spark plug is NOT that it is "shorter", the single F only means there is 1 1/2 threads less on the shell. Everything else is the same. The plug is NOT shorter nor shrouded in any way!

I order and use the AC R44F in everything, even the 80 hp engines! If the engine is in good running condition the 44F(F) plugs work very well and do not foul.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Which Spark Plugs to Use
Posted by: Frank DuVal ()
Date: January 14, 2020 07:16PM

Ken is RIGHT about the AC description!

Frank DuVal

Fredericksburg, VA

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Re: Which Spark Plugs to Use
Posted by: joelsplace ()
Date: January 14, 2020 07:52PM

Except they are 1/2" reach not 7/16".

Joel
Northlake, TX
5 Ultravans, 114 Corvairs and counting...

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Re: Which Spark Plugs to Use
Posted by: vairmech ()
Date: January 14, 2020 08:24PM

joelsplace Wrote:
-------------------------------------------------------
> Except they are 1/2" reach not 7/16".
>>>>>>>>>>>>>>>>>>>>>>>

That chart is wrong on the length! They are 7/16".

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Which Spark Plugs to Use
Posted by: joelsplace ()
Date: January 14, 2020 08:47PM

? You missed that one. NGK's site shows .5" reach on the B6HS also. 7/16" is a really short plug. I don't think I've seen one except in lawn mowers.

Joel
Northlake, TX
5 Ultravans, 114 Corvairs and counting...

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Re: Which Spark Plugs to Use
Posted by: MattNall ()
Date: January 14, 2020 09:23PM

Lawnmowers were 3/8" for decades.

F's are quite common compared FF's.


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