Which Spark Plugs?! Denso SC20HR11, SC16HR11, or IXEH20TT??

But it is not clear that carbon on the plugs is the ONLY thing that will cause "pinging" noises in the engine.
Because it isn't.

 

All sparks of the same length and same voltage are identical.
All spark PLUGS are not identical.
In addition to different gaps, the plug contributes to the overall "fluid" dynamics inside the chamber and that is important too.
I did NOT say that all plugs are the same.

 

Thank you Sam. I'll pull them and take a look.

 

The 20's are OEM for many car from Toyota, Nissan, and even Mercedes along with other makes. I don't think they are going anywhere if they are used for so many cars. My 2017 Corolla iM and 2009 Corolla S both use the same 20 plug.

 

I tried to find a colder plug to use in my 2009 Corolla S which I turbocharged but nobody made anything colder in this size so I'll stick with the 20's for that car. I wish that Denso made one step colder as that would be preferred with the turbo but it has run great with the 20's. I'm thinking that the Prius will run just fine with the 16 or 20.

 

I hope you don’t miss the time requirement by 2 years....

Regarding which plugs, I'd go with what Bosch says, I believe 9621, for the engine in our v it notes:

http://www.boschautoparts.com

 

Apologies, Canadian schedule is same as the States: 144 mo (12 years) or 192,000 kms (120,000 miles), whichever comes first. Excerpt from a 3rd gen Canadian schedule (2014, which had a nice graph format, for a change):



(Full schedule attached)

Phone up a dealership part dept. to check, but I'm pretty sure they switched to 16 (hotter) for the Prius. Not a lot of difference I think: I've pulled ours (20's) for a look and they looked pretty clean.

 

No need to apologise Mendel. I just noticed the type of math mistake that I make all the time. Thanks for sharing. I didn't know/think about a spark plug needing changing based on time. I've read of it, asked, and was just told not necessary...

moto g(7) power ?

 

Mendel is right. Toyota said switch to hotter 16 plugs to reduce carboning. I swapped in 16s when it was time .

 

Hey, I'm Canadian...

 

Hmmm. Hard to believe, "eh"....

moto g(7) power ?

 

Wow! 192000 km - how is that possibe?
European Auris Hybrid has same powertrain as Prius, but service interval is 90000 km or 100000 km.

 

I have just replaced (90000km): Toyota changed original 20 with new 16.
Original sparks photo is attached.

 

Manual from 2013 says DENSO SC20HR11 Gap: 0.043 in. (1.1 mm)
I ordered a set from eBay a while ago and they came completely damaged (bent electrodes).
Decided to get the spark plugs from a reliable source and went to a dealership.
They naturally sold me hotter SC16HR11. Ten bucks more than eBay but I thought I am set.

The thing is, when I measured the Gap it is at 0.040 in. (0.99 mm) and all four of them roughly within this range.

1. Could anybody confirm what the Gap (measured) is on the new plug?
2. Should I install them as is or gap them to the spec?
I would risk gaping one that is out of the spec but do not want to gap all four as I only have a coin type gap tool. Additionally, they seem to come like this, from the factory.
3. I am at 86k miles. Should I replace them now or wait a bit more?
4. I postponed this a while now as I've got no air compressor to blow dirt from the plug holes. Any hacks? Will canned air be sufficient? Some videos I've seen, they skip this part altogether.

DENSO SC16 Spec is 0.043 in (1.1 mm):
SC16HR11

Car manual says:

Denso says:

Should I Gap My Plugs?

 

You're a bit early for new plugs, by the odometer, but if you have the cowl off for any reason, like for inspecting the EGR system, switching the plugs is easy. Blowing some canned air should do the job--the plugs are covered, so not much dirt or grime is present.

It's a little controversial here, but Denso says not to adjust the gap:

P. 64. DENSO Spark Plugs are manufactured with a pre-set gap. With nickel plugs, especially with motorcycles, the gap may need adjustment. Always use a special spark plug gapping tool to change the gap. Do not change the gap on platinum, iridium or Twin Tip spark plugs, as the fine electrodes may get damaged.

https://www.denso-technic.com/images/document/ignition/en/spark-plugs-manual-en.pdf

 

I'd be inclined to leave them as-is. Unless grossly off, then I'd return/exchange them. I'm in the camp that you don't adjust the gaps on these. Also don't clean with anything abrasive, down the road: just something like carb cleaner and old tooth brush.

Spec for new plugs, from the Repair Manual:



Full info in attached.

 

It's going to be a long while, but I'm going to get Bosch plugs...

moto g(7) power ?

 

THANKS for the manual!
It seems, that they are within the service specified range at rock bottom 0.039 in.


I took some pictures as the electrodes are looking nothing like DENSO pictures (maybe models/renders?).
Denso pics: Clean, cylindrical shape with some height

Real pics: Irregular, flat, weld-like blob


I do not want to do this job twice so wanted to make sure they are the real thing. I have no other plugs to compare with atm.

Is this how the electrode should look like?

 

Good pics. Thanks.

I have never seen anything like that - irregular shaped, looks like a squashed clump of something rather than a precisely cast or machined material.

The ones I have seen (not this specific plug model) always look precise, a lot closer to the stock photo you show, vs. the actual photos.

With spark plugs, fakeness should always be a major concern. Kind of shocking that you got them from the dealer. I'd take them back and see what they have to say about it. And if they don't give you replacements that look closer to the stock photo, I'd return them, and look elsewhere, or leave your original plugs in the engine. Quality, genuine, double Platinum / Iridium / Ruthenium plugs should last well over 100k miles in most engines.

If they try to blow you off and shame / ridicule you for doubting the dealer, that's just what dealers do. Don't fall for it.