SPARK PLUG HEAT RANGE TEST-JUNKYARD LS. HOT PLUG v COLD PLUG-DOES IT MATTER? TAPERED VS GASKET PLUGS 

I think your tests and shared data is invaluable. I personally appreciate it. Keep it up.

Here’s something I haven’t seen you test and since you’re on a sparky topic, it’s pretty suiting. How much does an MSD box really add to power? Regular ignition, then one with an MSD 💁🏼‍♂️ that’d be an awesome. Thank you for everything you’ve done and continue to do sir!

Just about any question I have with the LS engine. This guy has an answer. Thank you so much

Crazy how engine style changes results. I went through 3 heat ranges and exposed electrode on my 496 and it made best power with the hottest plug that was exposed.

I love your sense of humor in some of these videos

Used to go thru that 'heat range' plug noise with Harleys. Their plugs were made by Champion, which I never liked. I always ran Autolite 4275 (short reach) or 4265 (long reach) and never had any issues.

Richard holdener crushing myths and legends.

A hot plug isn't a hot spark... you learn that with different fuels like natural gas or Propane. Gasious fuels act differently than vapor fuels. Would be interested to see testing around this.

The old rule of thumb I herd was every 100hp over stock go one step colder. Also one colder for hotter ignition, think MSD even says to go one colder for their CD boxes. Of course those are general guidelines and some situations may be diff. And of course of course, colder for higher compression. I still think all your recent plug test show how Good modern EFI, ignition or even head design is.

A dyno test of coils would be interesting. D585 heat sink coils vs square coils vs Ls3 style coils. It’s a deep rabbit hole I went down when I had a 585 die and considered best replacements.

In my opinion, and in my experience, once you have the correct heat range for what you are doing, unless you have an A/F ratio issue around the plug, electrode position isn't really important. However, spark energy is always important. But once you have enough spark energy, more doesn't make much difference, and large excess only hurts reliability. Threads are threads. Gasket or taper seat, is really a packaging issue, which is why we don't see 18mm spark plugs any more.

It's the government it always has been

Thank you fer testin this. So go with what works and does not foul.

In my experience, the gasketed plugs are less likely to break off in the head. So I prefer to use them, when possible.

This is one of those things that most people would never benefit from, but became a myth after awhile. "If you run cooler spark plugs you'll gain some power!". It's just not true for most situations. Yes, if you are running lots of boost and your running hot plugs, you probably WILL see a power increase by switching to cooler plugs, but it's because you were using the wrong plugs to begin with, and that doesn't mean everyone else should change to cooler plugs as well.

Ive always thought it would be cool to see a video on a stock engine, then adding say headers/intake/etc untuned, then tuning it and seeing the difference tuning makes and why it's really necessary.

as for gasket plug vs taper seat. its all about head design. best seal to the chamber. the more the plug protrudes the more it gets in the way flow atomization and piston contact or valves. you dont want it recessed in the threads either just barely in the mix. heat range on plug on the other hand is always application specific but alot of people seem to have it mixed up too. it comes down to what your doing. think of your spark plug as the source of your ignition. think of a glow plug in the same sense. good luck firing most diesels without the glow plugs when its really cold. now think about your fuel injector as also a source for your ignition. trust me it helps the correlation as you need both of these things at the right time. fuel timing is important so this is why spark plugs have heat ranges. say you get fuel early. a hotter plug will help burn the fuel better as it wont atomize well and be more like droplets. with a higher compression motor less heat is needed as heat and the compression will auto ignite the charge and cause detonation. in a 2 stroke application you still only have 2 ignition source per revolution of the crankshaft on a single cylinder. yet 2 strokes usually run hot plugs. they have expansion chambers and scavenge and reburn the previous air/fuel charges that already went through the combustion chamber. hot plug will keep reaction going better and compression is usually low. things being said in the 2 stroke field the amount of the electrode sticking out is becomming more important as comp ratio rises. head gaskets are going away and squish bands are much better tech. it actually changes the flame front and ignition comes more from the edges of the cylinder than the spark plug once the engine warms and makes a ton more power and yet again raises safe compression ratio. cylinder designers design the head for certain plug and you run said plug. its in the right spot plays nice with the fatty pipe and stays out of the way when the magic happens. changes like that allow a tiny single cylinder to make 17-20 hp reliably and run pump gas. with a 15:1 compression ratio. you know engines you know thats alot of comp for pump gas. keep in mind its also not big cc cylinder its only 70cc technically really 68cc. these guys run a "squish" of .7mm you can increase or decrease squish to change compression and flame front characteristics but power suffers obviously. that .7mm is piston to cylinder head clearance you dont get much wiggle room and you have to always be careful when making changes. failure could be catastrophic for many reasons very easily. this one launches at just over 10k rpms and accelerates around 10,800 rpms until the ignition system cuts out at 12k rpms. it hits around 70 mph before the cvt hits its final gear and the rpms climb from its acceleration rpm. with a different exhaust i can raise the engines usefulness to around 14k rpms atleast 13k with a slightly weaker exhaust that also comes in at a lower rpms too so i can have more power everywhere. if i were to raise my power band i cant use longer plugs as the plug could contact the piston under heavy loads. things stretch under crazy high rpms high heat or major forces. always pick your parts not parts off a shelf.

The only thing I haven’t seen you try for spark plugs is the surface discharge plugs like brisk makes. Ngk also makes those style plugs and Indy and formula 1 and the motorcycle racing world exclusively use them. I would think there must be something to those if the oem race teams are using them. I’ve had fouling on long cruises on 9 heat range ngk plugs in my stroker nitrous ls1.

This test shows how good engines and ignition systems are now

A buddy of mine, who builds and tunes engines and loves data. had a 383 on the Dyno used NGK plugs, and then switched to the Autolite same heat range with the ground strap cut shorter, and they gain 6 hp on the Dyno.

Keep telling the folks over on the E85 forums that they don't need or want a hot plug. Mark Sullens swears there is "good power" to be picked up with a hotter plug and that they have dyno tested and proven it. I don't see how. If the plug isn't fouling, no reason for a hotter plug. Or at least that's what I believed.

Depends a lot on coolant temp also.

Resistor vs non-resistor plug test please

Possible spark plug tests: Use " oil foulers " on a good motor. Those spark plug extensions that pull the plug away from the head to increase heat range and the small hole shrouds the plug from liquid oil. ) Does a double ended coil ( waste spark ) affect power due to: Spark occurring in the exhaust stroke / spark jumping from the center to strap on one plug and strap to center on the other plug. An easy way to test spark jumping direction power would be to use one waste spark coil per cylinder and install a dummy plug on the unused end.

I'd love to see how much difference using a anti fouler spacer makes

Great video, Richard! I really like your spark plug videos, they give us valuable data that most of us don't have access to. I would love to see you testing different kinds of spark plugs that utilize the principle of surface air gap. Plugs such as Bosch Platinum Fusion, Brisk Premium Evo/ Premium LGS/ Premium ZC/ZS, Beru Ultra X PLatin and so on. Hope you'll have time to test them and make a video! Best regards.

I had a 1967 mustang 289 that I installed a street master + AFB, a RV cam and headers. Originally the stock configuration would get about 20 - 25 MPG. The modified config gave about 18 MPG. I played with jetting and got into lean serge. I changed to the colder spark plug, Hipo for the 289 and was able to go leaner.

Try doing a test with some of the old anti-foulers and see how much power the cost

I tried some projected nose plugs on my old Suzuki air-cooled four-cyl engine and noticed a very slight improvement in idle smoothness, and perhaps a little bit of extra perkiness on take-off, but nothing that would probably show up on a dyno. I'm not too bothered. A little improvement building upon another little improvement helps, though.

Hotter plugs work well on carburetor cars after a good tune with proper jets/rods one step hotter keeps the plug cleaner also helps acceleration or tip in

i left a comment, actually more of a question, on a 10 month old video. I don't know how far back you on to read comments. those answers will not just suit me, but suit nearly every 5.0 efi sbf being built for street application. granted, a lot of folks won't be able to afford the heads, likewise adding that to the answers, might be helpful for a lot of your viewers (in addition to the questions i asked). the title to the video i left it on is: HOW MUCH POWER IS A 5.0L CAM SWAP WORTH? WHAT IS THE BEST CAM FOR MY 5.0L 302? 5.0L FORD EFI VS CARB much appreciated, yer one damned fine fella. (as is most of the west tech folks) (back in the late 80's, early 90's, absent westech i had to run hard up n down the hill to big bear to test my upgrades!! (those where the days). no longer out there thou.... I headed east eventually... (that elevation change tells a lot of secrets with performance)

I keep having this argument with people who have hot hatches and erformance street cars. I always see questions of what plug to run or what oil to run. I always say it makes SFA difference. I'm constantly getting shot down. As long as the oil is slippery and the spark plug makes a spark on the street, you won't notice a difference!

On my 1985 GPz 750 turbo I had to increase the heat range 2 numbers because above 8500 rpm the boost blew the spark off the plug like blowing out a candle. I used an MSD ignition and coils and Nippondenso 16 copper core plugs and started exploding turbos because the impellers were spinning so fast oil wouldnt stick to the bearings and theyd lock up and explode. Terry Kizer put a Torringinton 2 stage bearing in a turbo and that made my engine live till 4th gear, the turbos exploded under boost in 3rd before I had the new bearings. I was putting 52 psi at the intake valve @ 12,000 rpm and my engine liked hotter plugs and VP C16 fuel.

We should do this test on an older carb and points and HEI setups.

So I wonder if this also applies to high compression na stuff? Say 12:5:1+. I never see u do that kind of testing

Cool. Tyvm Richard

I run Beru ZD-11 without issues. They either work or they don't.

Colder plug definitely costs mileage some. Have tested this on a stock (with bolt ons and tune) street driven 6.0

I would like to see a test of coils… target a rich afr on both and see if a better coil ignites a rich afr better and makes more power.

Great work, as usual ❤

This guy is growing on me. I just wish he was testing some of this stuff with higher boost motors making like 1000 at minimum. 1400-1600 would be nice.

After all this testing You must test the infamous Brisk triple spark sparkplug, You cant leave us hanging on that one 😁

we used to run a small block Pontiac 312ci with 13-1 compression on methanol we used washers on our plugs more so for clearance and which way the tips were facing so they didnt hit the piston we did all these dyno tests on it and we found absolutely no loss or gain from them including temp of plugs there was nothing in it we just ran what type worked better for the compression ratio and fuel the only thing we saw the hotter plug started up easier on methanol

Maybe some video what does make a difference?

Iv noticed that my 2019 2500 silverado 6.0L pings often with the stock plugs and I can feel the computer taking out timing out. Im thinking about getting a colder set to help and go back to hotter plugs once then engine starts to burn oil. You should see if you can make table changes with different heat ranges to see the effects. Like if you can run more timing on colder plugs.

My mechanic father of 40 years says those tapered plugs r crap. Bc u can just can not get those kinds tight enough bc u will mess up the plug thread hole on the head. Especially aluminum LS heads. I can't find a washered seat plug for my LS

I remember on my flex fuel (stock) i set a colder plug to use only ethanol. The car felt way different on lower RPM with load. Felt lazy to rev.

How about testing resistor vs non resistor plugs with the Holley EFI. Do non resistor plugs with stock ls coils on a Holley EFI cause issues due to electrical noise (RFI?) ? Inter webs have varying opinions on this.

Its always a cool test. But do all of these tests on a high compression combo and the results might change.or an older school motor with lower power ignition! The ls-ish ignition is rather good and is masking some issues guys have with plugs. I have a sbc combo that was sensitive to gap and heat range on the street, the better hvc msd coil solved that issue, and have been trying more gap to test, but some cylinders had issues with over .040 gap and 100 miles on the street, even a lean tune. The better coils allows a richer tune and no plug issues after 1000’s of street miles. It might be interesting to test this on and older simpler motor to see what happens. I did plug testing on around a 100hp banshee on the dyno and plugs and gaps were worth 10hp, and another banshee gained 20hp with a different ignition box I think these tests might be more interesting now on a boosted motor

Thx for your knowledge 💪🏽

Is there any sparkplug that has a measurable effect on compression ratio/ combustion chamber volume?

Richard, surly these plug tests would be a lot more entertaining if you were using a 5.4 from the wrecking yard don't ya think.... Okay...but seriously, I do think using an old single coil distributor motor might show some valid differences verses modern multi coils. That being said. I would not be surprised if you cut the ground electrode completely off the plugs if your test engine if it would still run surprising well.. IDK but i'm guessing it would lose considerable power/RPM,and miss fire above 3K or so but?? Overheat and fry coils in the real world of course, but would be a cool DYNO test, or a dud🤣

How about running non-foulers on the plugs with some(4) 1.5mm holes drilled out the side?

While on the subject of spark plugs, how would the difference between a extended tip and a standard plug? For example, a champion n5c and an n4yc?

How many non-foulers would it take to change the compression ratio a full point I wanna run 87 :p

I run ngk 7's on my hot NA motors and ngk 4's on stockers

What about electrode cutting back?

Test massively long plugs vs short ….. you mentioned about the static compression change in this vid .

Only time I have run into fouling issues with cold plugs were with carb blow through engines on the streets. EFI has much better fueling control than carb stuff so makes sense. Unfortunately Tuning carburetors is a dying art.

i have a 1070 318 la engine , i used to run rn14yc and autolite 66 and they both ran the same then i put in a set of ngk gr4 platinum plug and the engine began to run lean and no more raw fuel smell out the tailpipe ...what do you say i should do ,,,keep the platinum plugs and richen the mixture a bit or go back to the coppere plugs and lean it out a bit

Also what effects would the anti fouler spacers have on a boosted application.

I’d like to see a test for if there is a power difference with decapped fuel injectors???

I'd be really interested in seeing a performance shootout on lowbuck wires (AC DELCO) VS some high dollar name brand wires to see if there was a significant increase in performance.

Love the videos, i sm seeking a rebuild recipe for an original L31 in my 98 chevy c1500. I been contemplating 383 / cam / heads rebuild as a daily driver on a budget. Any recipes you can offer are greatly appreciated

So I run an extremely high compression for running on pump gas. My compression ratio is 12/1 ish that number doesn't really matter what matters is compression test 265 PSI. And I've had a problem before with cheap spark plugs that had a little sharp piece of metal on it and caused detonation issues. What I want to know is if you were to polish the spark plugs smooth and point the gap. Could you in theory get one or two more degrees of timing gaining just a few horsepower. I'm thinking maybe even squeeze an extra 10 out of it

As for tests on plugs....not sure. But ignition wires ? coil dwell times ? How nasty is the D585 so many seem to get all hyped about when it fires prematurely as people dwell them too much ? I know the wires probably won't make any difference....or how about long ignition wires all tied together in parallel which has caused people problems ?

Great video series Mr. Holdener! How about resistor vs non resistor plugs? Also, when reading plugs for AF/timing, does changing heat range change anything? Thank you!

I listened to the whole video and have a question. What would happen if you played with the timing in these tests? Could you get a little more timing into a cold plug, or would knock be a little more forgiving on a cold plug? I've heard a lot of tuners make the comment that running a TR6 NGK plug vs the stock TR55 makes it a little easier to tune and dial in the engine because the knock resistance being a bit better makes it more forgiving. Nobody ever makes the comment on if more power can be milked out of one over the other though. In my example there we are talking N/A engines and only one heat range of shift, which is pretty minimal. Though it is interesting I hear that just with one heat range colder than OEM there is a measurable difference in knock resistance. I would love to see you test knock/timing impacts on an LS motor vs heat range.

Test plugs by driving then reading the plug itself for proper fuel and timing.

Great content! Is there a video testing the performance difference only by changing the gap?

It would be cool if you CC measured the cylinder heads with the tapered plug and the gasketed plug to see if that taper plug subtracted like half a cc

Best bang for the buck coils? D585 "heatsink" coil still the best? Test them under high boost and/or wide gap. Can you log coil voltage and current? Solid vs resistive wires? (EMI from solid wires can mess with crank/cam VR signals.)

Keep it up

Does the Craftsman screwdriver mod add any horsepower ?

Please do a spark plug side gap modification test

Did you do a timing/afr sweep when changing from the hot to cold plug?

Great video guys ,have you done a video comparing compression ratios in a big block Chevy ??

Of course you do

I tried a few different taper/gasket plugs in different heads many years ago. For same type of plug, they protrude into the head exactly the same. Denso plugs are good though, 31 is very cold !

In a Live show a couple days ago I asked about the warning BTR has posted, in the Hot Rod camshaft kit page, not to run it above 6500 RPM. I called them to ask about it. They said it's due to the spring retainer included (powdered metal). He said using a titanium spring retainer would eliminate the cause for the warning.

Any videos on recurving a distributor by chance?

You know, heat range yes ok.. But more of a concern is reach, and gap.

Plug needs to be hot enough to live in the chamber and no hotter. It's not about power, it's about suppressing pre-ignition.

What would be the difference if you were to use “race type” surface discharge etc plugs

I always wondered different ring gaps vs different boost! Power outcome

I Got a question. I see you dont have an videos about 2 step so I would like to ask you can I add a MSD 2 step to my stock 4l60e ? What would be my outcome or what do you suggest I do.

Question: I have two cars with the same engines but one low comp supercharged and the other hi compression n/a. Sparkplugs are two heat ranges apart from each other. The question is, what happens if I use the n/a sparkplugs on the supercharged engine? Both stock cars

We like to sound intelligent talking about the things you do,and if there's ever anything we think you missed or didn't mention. But nobody has the, DYNO or test enhines to check anything. Who Knows? WELL probably Richard... We on the other hand have yo learn the hardedt way. Hahaha.

What spark plug and wires combination would be good for a 07 5.3 with truck Norris cam ls7 lifters and 3/4 longtube headers need

Any testing in the future with the older ls1 coils(apparently higher spark output) vs stock 5.3 coils?

Dr. Richard, does the test temp of the engine influence the hot vs cold plug? Did not notice the testing heat of the engine.

Your so lucky not having to change those plugs in a Chevrolet express van

The couple times I have experimented with colder plug I end up fouling it easily and going back to what works. I thought trying it was a good idea as even though I was already one heat range colder then stock since I was adding more boost it might be a good idea, didn’t have any luck with that and haven’t had any issues making 900rwhp on a BR7ef plug.

Richard would these tests matter more on older engines with weaker ignition systems than modern Coil On Plug? As I understand heat range has more to do with keeping the plug from building up carbon over time

How about anti-seize on the threads? Someone recently said it’ll cause misfires due to a bad ground. I would think the ground would be made at the seat, not threads, and I’d like to be able to get them back out down the road. Anti-seize or no, Richard?

Going to a hotter ir stock plug for better idle and longer life. The br6's seem done now after 20,000 miles. Idle is now missing a bit. Put them in with a new set of kooks headers. 2008 ls3 vette. Wanting to see if it can repeat its best 1/4 mile track times with the stock ir hotter plugs. 11.85@121.25. 65* Florida.

single plug heads vs twin plug heads , any difference?

This doesn't really get into WHY you run a hotter/colder plug. You want a plug that's hot enough to burn soot off at WOT but not so hot it becomes a hotspot causing detonation. Too much conductive soot will sap spark energy. Running a really cold plug on the street & driving like a grandma will foul it out fairly quick. The "get heat in the motor" meme actually applies here, winding the engine out occastionally will nuke carbon on the plug.

I wonder going from brand to brand? Like NGK to Denso. AC delco, autolite. Bosh etc

Richard you are crazy man! Ha,HA, JUST KIDDING MAN! Put a set of E3'S in your own Chevy truck! Same heat and everything, take notice of low end, (seat of pants feel, stop and go e every day driving ! That dyno is not the answer to every thing! I put e3,s in my 6.0 truck and felt the low end power !