Advice needed spark plugs 1955 235 full pounder engine

I have been using the AC Delco spark plugs which i bought from Classic parts and they have been working fine but i would like to ask members of the chevy forum what other spark plugs are available for 235 inline 6 engine ? I am asking for a recommendations to other brands/numbers plugs which i maybe could buy in Norway or from EU countries ?

Thank you Martinius

 

Using an AC 45 as an example, I looked here: Spark plug cross reference

 

Hi Bill

How are you doing ? Thanks for the cross reference list. This helps much . I will check it out.

Martinius.

 

There is another avenue. It is controversial to those who do not like to test these things, rather go with what has worked for them all their lives. I am an AC Delco Spark Plug fan, but I also like to prove my findings with real testing. So, I put them against the E3.52 plugs. I ran extensive tests and found them to be more efficient by a measurable amount. Since they are gapped to .040 and the gap is not adjustable, I was skeptical. But I went back to what Nate said about gapping your plugs to .040 to get better performance. This helped because the wider gap makes sense now, but in testing, E3 came out as better than AC Delco. Here is the results page... Lots of information here..

HEI for your 216/235/261 The tests also include Stock Points tests as well.

For these 235 engines, it's hands down E3.52 from now on for me. If you are showing off your truck however, there is no doubt AC Delco works very well and is only marginally inferior. If it bothers you to have anything but AC Delco there, go that route for sure. Gap to .040 for better performance.

 

Thank you Deve for your reply on the question . This is very interesting and professional reading and your video at the Tube is easy to understand and instructive


It might also be very interesting to know what kinda spark plugs for the 6 inline engine you recommend when upgrading the standard chevy ignition distributor either with the Pertronix Electronic Ignitor from Delco nr. 1168 ( electronic ignition unit ) , or the complete Mini HEI electronic distributor from Tom Langdon ?

Tom Langdon advised me to buy the Mini HEI distributor for the 235 6 cyl. engine as he says that it goes very well together with the Weber carbs and the dual Fenton setup. I followed his advices. Store - Langdon's Stovebolt

My questions are

I have both units on the shelf and would like to have your advice in the matter which spark plug goes well together when changing to electronic ignition ?

Is the base connector plate behind the new coil that you show on your Tube video possible to use with the other units ( Pertronics ignitor or Mini HEI el. distributor ) ? Both have the red and black wire going out from these units !

Thanks a lot Martinius

 

The HEI System I make for our engines runs great with the E3 .040 gap. The Pertronix would be the same way, and the st0ck system also would be great. There is just no downside to running E3.52 plugs in your 216/235/261 engines. The HEI system uses a 45kv coil and I think the Pertronix does too, so no difference except for performance. HEI is clearly better. You would have to start reading on the home page (devestechnet.com) especially reading the Hemmings Article, then the Kit particulars to really see why. Classic should put it in their catalog!

 

Deve
Then my next questions are about that support base plate behind the new coil you are showing on your You tube instruction video . The wire connector shown on that plate is that a solution pure to connect the main coil wires (red/black) and ground or is the device it self a resistor as well ? Is it made for 12 V electric wiring circuit ?

Martinius

 

The HEI module that is found on board most common HEI distributors is not part of the our original stock Distributor so we need a place to put the HEI module. Bill Hanlon found a nice solution by using the old Regulator location and box. I just include a bracket to mount it. Read the Hemmings article on the website to understand the components that make up a GM HEI system and it will be clear. There are no resistors in the system other than the .7 ohm 45kv coil.

 

Deve

Thank you for your excellent explanation and service. I will follow your advice and read the Hemmings article to understand better.

B.t.w. my son suggested that a Lambda sonde and exhaust reader would be a good thing when updating a 6 cylinder chevy engine with an electronic ignition system , dual carbs and the a dual Fenton dual intake/exhaust setup. He ment that it would be easier to read if the carbs are well synchronised and are not adjusted to rich or to lean !

What are your experiences with an lambda sonde and reader ? Where would you place the Lambda sonde on the 6 cyl. exhaust system to get a good reading ?

Wish you a nice weekend Sinc. Martinius

 

No idea what that even is! I have never owned a vehicle without stock intake/exhaust. I do know that HEI is better no matter what the carb or exhaust setup because it has more to do with adding High Energy and precision to your ignition system.

 

Deve:
Lambda Sonde is an O2 sensor.

Martinus:
I considered putting in a wide band O2 sensor to help in tuning a Zenith 228 carb with an externally adjustable main jet, but being basically cheap and not being a welder (to weld the necessary "bung" into the exhaust pipe for the O2 sensor) I just tweaked the jet back and forth per instructions in the Maintenance Manual.

 

The one I chose was narrow band because I didn't want to use a gauge. The above shows how to use your multimeter to do that. Bill, I watched a show recently where they showcase bungs that do not require welding, so they are out there.

 

Hi Deve

Thank you so much for sharing your knowledge i really like it much .

Is the motor running while you are doing this , i could not here any engine noise ? Where do you connect the multimeter black/red wires to get this instant result ? Your multimeter measures volts right ? I can see that you have installed a bung and a O2 sensor some beneath the flange to read the Co2 and O2 mixture which is practical ! I hear you saying its connected to your computer USB maybe to store these test results ?




Martinius.

 

The Multimeter is connected straight off the O2 sensor. Red lead on the single wire that comes out of the sensor and Black lead on ground. Measure in Millivolt range. The concept is the O2 sensor creates it's own voltage of 1 total volt. Stoic (or the desired mixture of 14.7:1) is 500 millivolts. Yes, the motor is running. If I mentioned USB in the movie it was because I used a USB connector system to connect to the Multimeter. I haven't gotten far enough in all of this to create data storage. YET!

It is a very fun thing to play with. You can not only pinpoint the exact position you need to set the mixture screw, you can also choke it to see what happens. If you find you need more fuel or less fuel you can play with changing the Jet size in the carb. I felt that since I use HEI, I wanted the fuel system to be just as finely tuned as the ignition system.

The non-welding type O2 sensor bung is here: Summit Racing® Easy O2 Sensor Mounts SUM-690120 which uses the common M18 threads for the sensor. This bung would be good for both narrow and wide band sensors. On something that is going on your precious truck however, I would look hard at the quality you will end up with using this style. Drilling a 7/8" hole in your exhaust pipe and having a machine shop do a quick weld in might make you happier in the long run. Be careful where you drill the hole because the sensor sticks out quite a ways and you do not want it interfering with anything.

 

Deve

Your teaching is easy to understand and i love it. I will try your method when starting on the project this coming spring. I am lucky to have a son whom is a pretty good in Tig and Mig welding steel and alluminum , but i will show him the non welding part from Summit Racing and discus the matter. He is very intrested in working with his dad on that truck . I will order the E3 spark plugs as they have there potential . Never seen none adjustable plugs before but i understand that they way well for the 235 6 cyl. engines . The cross-reference list from E3 mentions the 235 CID 3.8 liter engines together with E3.52 plugs.

Thanks again Martinius.

 

Martinus: Deve added the audio track after he recorded the video, therefore no engine noise.

Deve: I think I'll get one of those O2 sensor mounts and try my luck at the Zenith 228 carb with the externally adjustable main jet mixture (not idle mixture) again. No reason it shouldn't tell me what I want to know. My main concern is adjusting it too lean and doing damage to my engine. I assume that I need the same .500 volts at steady speed driving at say 40 and 50 MPH. The Zenith carb also has a "power valve" which takes the mixture richer under heavy loads.

The Summit sensor talks about wide band, not narrow band, sensors. I think the threads in the mount is the same. Am I wrong?

... and I already have a meter, although not a Fluke like yours.

 

Same threads Bill. Narrow band is just so antiquated, nobody lists it anymore. But it is the one you need for using a meter to read it. They are cheap and you can always move to a wide band later. The problem with the narrow band is that you can't get a reading at road speed (35mph up). Too much turbulence in the exhaust stream to effectively measure. It is good to about 1000 rpm or so. To measure higher speeds/loads, you would need to research the concept of a wide band with some gauge solution. I still find it very useful because if the mixture on a Rochester B is good at idle, as it graduates up the rpm scale, it will be good at speed. Its all 1 to 1. Too much fuel in at idle will be too much fuel in at speed. Not sure about the Zenith. In any case, an O2 sensor will give you more information than what you had to start with. Fun Stuff!

 

Problem with the gauge is they are too big to fit into the ABS plastic piece from Vintage Air that follows the bottom of my dash from the right kick panel almost to the steering column. The gauge would need to be 1.5" diameter or less. Smallest I've found are 2".

Why wouldn't a wide band sensor work with a voltmeter? Does it react too fast and make meter readings useless?

Interesting chart I ran across while web surfing:


It explains why Deve had such a hard time adjusting to exactly .5 volts.

 

If you are right about this would it not make more sense to install a wide band sensor and gauge connected to a 6 cyl. engine exhaust system when driving on the road ? There are so many variables that influence efficient engine economy and road conditions , highway driving , city driving . The old style carbs like the Zenith and Rochester B or AB carbs have there limitations but i can understand your point in optimising fuel consumption and energy production.

What brand and model wide band sensor for a 6 cyl. engine has a good quality and a solid gauge reader that would fit nicely somewhere in the old truck together with the other old fashion instruments ?

 

yeah, narrow band has its limitations, but it is far more accurate than the shop manual telling you to turn the mixture screw all the way in, then back it out a turn and a half. I have this idea I haven't explored yet concerning the radio blank-out plate. By making a new plate that is curved to fit on the outside 1/2" or so, but then making the inside flat, I can get two, 2 inch gauges in that space. If made correctly, even angled towards the driver. Use new metal, do not screw up your nice blank-out plate!

I have not tested a wide band to see if it would work with a multimeter. I will put it on my TO-DO list. Most engines equipped with O2 sensors have an ECM that processes the information. The aftermarket kits have that circuitry built in to the gauge. Wish I knew more about it. If the circuit uses PWM it may be possible to read it with an O'scope.