Can any one recommend an NGK equivalent for the AC R44 spark plug? My Corvette is a '59 with 283 engine. My local parts store recommended NGK BR6S (stock no. 3522) but they caused a lot of "deiseling" when the ignition was switched off - idicating that they may have been too "hot"? Any suggestions?

Thanks!

David

 

I run the 4722s in my BB with TI and they are fantastic. But, they are not the plug recommended for your car. Go to http://www.ngksparkplugs.com for more information. When I look up the plug for your car, NGK says that you need the B6S (stock #3510) with a .035 gap.

I think that your problem is related to using the wrong plug or mayber they are not gapped correctly?? NGK plugs generally do not need to be set. They are right on straight out of the box.


[Modified by 67435animal, 10:19 AM 11/3/2002]

 

For street driving you will probably be happier with an AC 45/46 or equal. As far as dieseling, there are a lot of potential causes other than the spark plug. #1 would probably be excessive idle speed. #2 maybe excessive carbon build up in the cylinders/heads from perhaps too COLD a plug.

 

I failed to notice that the only difference between BR6S and B6S is that the ones you bought are resistor. They should work just fine and 62fuelie has given you some probable causes of your problem.

 

Your engine originally had non-resistor spark plugs, and I would recommend continuing to use non-resistor plugs. Also, the AC heat range "4" is too cold, and in my experience, AC heat range "5" is a better all around street and highway plug for all early small blocks.

The NGK equivalent to the non-resistor AC 45 is the B4. Denso also offers an equivlanent to the AC 45 - the W14-U. I doubt if the spark plugs are causing your dieseling problem.

NGK and Denso are the only plug manfacturers I know of that still offer non-resistor sparks plugs in the proper geometry and heat range for early small blocks.

Duke

 

Thanks for all the responses! The reason I figured the dieseling is plug related is because when I put the BR6S plugs in, the problem started and when I put the AC R44s back in, the problem stopped. I should also add that I'd also installed a pertronix unit and coil.

 

Most of the early Vettes came with AC 44`s. They are no longer available and the only thing close is one step colder and only available in a resistor type which is AC R43. If you have performance vette never use one with an [ S ] on the end or a extended tip, it may hit the dome of an 11.1 compression ratio car. A R45 will work however. But never a R43S or R45S. Keep the S off unless you want to do the job twice. Leaning in on those bastards over a fender and fighting the shielding is not a lot of fun without much room. :cheers: :D :D

 

just index the ground electrode to 9-12-3 oclock position to prevent the the piston dome from hitting the electrode and you can use the S plug. the fuel wash will cool the plug so you can use a hotter plug. :chevy

 

You mean you can actually see around those manifolds? Even if you could they all dont tighten up in the same position. I just use an R43 and I`m done with them. I had a really bad experience with 44S`s on my 61 315 car. In Miami on a hot day, [most of them are] I decided to change my plugs. I sent a fraturnity brother down to a South Miami parts store and he came back with the 44S plugs. I said I wanted a plain 44 plug. He told me the parts store said they were correct. :bs I objected and finally put them in, replaced the shields and started my cold engine on a hot sunny day. Well you know what happened, the pistons closed some of them up. Now the sucker was hot. I pulled the shields and that big air cleaner again, reached in and was getting burned by the manifolds and cut by the shields and madder by the minute. :mad I had the socket and handle in my hand with one of the wrong plugs in it and pulled on the socket to remove it from the handle. Well when I jerked on the socket, the plug flew up in the air and came down on the opposite fender chipping my white paint. :cuss :mad . Well I sent him back and they exchanged them however the damage was done :mad :cuss Now I had to put the damn thing back together. Shields, air cleaner, all on a hot engine. I still get mad thinking about it. :cuss :mad . Sooo, thats why I use AC R43`s, indexing anything is not in my vocabulary :D The right parts work better :cheers: :p: Wally


[Modified by wallyknoch, 3:14 AM 11/5/2002]

 

I hate AC plugs, junk. I also hate to admit that if you want to run a colder plug before I would even consider touching my engine with an AC43, for a true street plug I would go with the Autolite 303's. They have probably the best insulator on the market for a cheap over the counter non-special order non racing designated single electrode style plug. They are getting harder to locate but these will get it done. The NGK are also great plugs.

Do yourself a favor and find the darkest spot you can find and with the engine running open the hood and see if sparks are flying all over your engine compartment. Correct any problems if they exist.

Also even if you think you are jetted right, take it down a few sizes and drive it around the neighborhood a while but don't hurt it with a too lean condition. Pull a plug or two quickly and see if the plugs are as they should be or go buy a rich/lean gauge and install a heated sensor into your exhaust system. At idle you should read good on the gauge (not too rich, not too lean), then go full throttle (main jetting) and check the gauge reading (not too rich, not too lean), then go back and tune your transition from idle to full throttle with your pump shot, nozzles, etc.. to see if the reading stays in the good range during transition. With these gauges you don't have to be an expert on plugs reading anymore. :cheers: