Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert!

[2001LC]

You've actually torque to ~16.25 if very accurate torque wrench was used. I say that because you lubed the threads. Denso recommends ~ 20% reduction in torque, when threads lubed. Denso has a higher max spec of 18ft-lbf. I'd not go over that.

One other consideration. The crush washers does not seal as well second time. So a higher torque may benefit reused spark plugs.

It's too soon to say, if these higher torques values being used (above OEM 13ft-lbf) are increasing miles before walk out. Or stopping walk out altogether. We need reports of "second time in" after 50K miles or 90K miles, etc..

I can say:

I've found when factory torqued spec used, with anti-seize on threads. I see plugs frozen in. I found this twice now. Found in only two that had used anti-seize. One, I know, as I put on anti-seize and wiped most off before torquing to 13ft-lbf. About 40k miles later they were frozen in. The other I presumed based on findings. I suspect. That as they start to walk out. That anti-seize is cooked in the spark plugs threads, and carbon builds up. That these needed a 44k treatment, before attempting to removing spark plugs. Or risk of damaging threads is very high.

Also consider that Denso and NGK coat plugs' threads with nickel, IIRC. They do this to stop galling in aluminum heads. So Anti-seize is not needed or recommended.

 

[NoTempoLimit]

You've actually torque to ~16.25 if very accurate torque wrench was used. I say that because you lubed the threads. Denso recommends ~ 20% reduction in torque, when threads lubed. Denso has a higher max spec of 18ft-lbf. I'd not go over that...

...Also consider that Denso and NGK coat plugs' threads with nickel, IIRC. They do this to stop galling in aluminum heads. So Anti-seize is not needed or recommended.

Thanks, Paul! Always appreciate your input.

I do have a certified torque wrench for this purpose, not a cheap one.
[18 lb-ft] 24.5 N-m * 0.80 = 19.6 N-m [14.5 lb-ft] <- This seems like a good torque spec

As I mentioned, I brush on a very light coating of anti-seize since I know that there will be some residue of it on the female thread in the head already. It's just to avoid going totally dry. I mostly put it on the first few threads since it will be distributed once the plug is screwed in. I've never had a plug get stuck in an aluminum head (never owned an engine that wasn't AL head).

I do a lot of thread cutting of fine-pitch threads in aluminum. It doesn't take much to damage a close-fitting female thread in aluminum.

I don't know why that plug got stuck in that BMW head (M52TU engine). It was something that was done before I owned the car. But once I installed new plugs with light anti-size I had no more problems. AND I had to pull the plugs fairly frequently when I was diagnosing a misfire problem. It turned out to be a bad PCV allowing oil to get onto one of the plugs.

 

[NoTempoLimit]

Update:

Checked and torqued my spark plugs (ND SK20R11) after 22k miles at factory 17.5 N-m (13 lb-ft). All of them came out easily without the slight "crack" that you usually feel when loosening a plug. So they were probably already slightly loose.

All the gaps were OK. Insulators were clean. All plugs had same degree of black deposits on the threads. Heavier on the plugs from cylinders near the back (firewall) side of the engine. So it may be some combustion gasses getting through, but it could also be deposits on the female thread in the head transfering to the male thread on the plug.

I cleaned the plug threads with a bronze brush (used for gun cleaning) and naptha. The black stuff came off easily. Didn't touch the electrodes as they were already clean. Put a very light coat of copper anti-size and re-installed the plugs at 19.5 N-m (14.5 lb-ft).

I really feel that the truck is running smoother now. I definitely notice a smother idle.

 

[2001LC]

I've edited OP with this:

Edited 9/26/20:
"Risk"
Anti-seize even a lite coating on threads is a bad idea.

I say this, because I've found evidence this cause plugs to seize in the heads. It seems as plugs start walking out, then anti-seize cooks mixing with hot combustion gasses. This then stop the walking out, but also causes threads to seize in the heads.

I first notice this on WhiteLady (01LX w/214K), my first restore project. I had added permatex standard copper type anti-seize to it's spark plugs at 214K. Out of concern of metal (copper) getting into cylinder camber, I used very a lite coat. Actually litely wiping all threads off, of all but thin coat. 50K miles later "She" came to me for servicing. I pulled the spark plugs to R&R. It was a battle, turning hard all the way out. I had to put my 3/4 breaker bar on, just to nudge them. I then added penetrating seafoam oil to spark plugs (tubes) and 44k to gas tank. I drove for a few hundred miles and went back at plugs with my 3/4 breaker bar.

Naturally I was not really putting my weight behind the 3/4 breaker bar. As that I feared could break spark plugs in the head. 3/4 breaker bar, can break any bolt on the 100 series. Bad boy I call it..LOL. One of my favorite tools. "Bad boy", gave the need leverage, and with 1/2" xtension bar eliminated flexing. As my 3/8 breaker bar extension, was flexing on spark plug.. WOW. That gives an idea of how tight these were

I've since had two more 100 series come in with frozen spark plugs. I can see what appears to by cooked anti-seize on threads. Same looking threads I saw in WhiteLady. One is coming back today to get last two plugs out... hopefully! It will be 3rd time in. I've battle this one for about a month now. 1 can of 44k in 3/4 filled gas tanks mixture, 4 times (4 tanks). Along with penetrating oil in spark plugs tubes. I find coil boots and coils cooked most, from the worst frozen plugs. So they did walk out and then froze in head. This is not typical what I fine. Typically they just keep walking out.

I've found I can tighten a bit then loosen a bit, repeat repeat repeat working in penetrating oil. About 1/16 turns each way working up to 1/2. After adding P. oil & 44k and than repeat after few tank of 44K run through system. On really bads plugs, it feels like running into a wall, so I stop trying to turn out, until next cycle of 44K and penetrating oil. Come back and just keep working, after the 44k & P oil. It takes as long as it takes. Last thing I'd want is to do is a head R&R job or time-sert for damaged threads or busted spark plug in head.

 

[awesomeissquid]

So replacing my plugs right now and one of the holes is pretty dirty. The plug was pretty stuck so I figured the seal was not working well. Finally got it out and it looks like there is some buildup against the surface the crush washer mates against. How do I go about cleaning this to ensure a proper seal?

 

[2001LC]

I've a metal coat hanger wire. That i've a fasten a terry cloth bunched up by wrapping end of coat hanger wire around it. I vacuum out tube. Then I spray seafoam penetrating oil on terry cloth. I swab out the spark plug tube.

Be creative. But take all precautions to not drop crud and sand down into cylinder camber.

 

[awesomeissquid]

Thanks @2001LC. I fitted something up like you suggested and it worked well.

 

[NoTempoLimit]

...
"Risk"
Anti-seize even a lite coating on threads is a bad idea.
...

Thanks for your post Paul, definitely something to keep in mind! I am not posting to argue or refute, but to share my experience:

The way that I apply anti-seize to spark plugs derives from my experience working on fine mechanics (optical lenses for the Cine industry that cost as much as my LC 100 did when new). These lenses have TONS of fine threads with very close tolerance fits.

First I get the thread on the plug as clean as I can. I don't try to clean the female thread in the head because any debris loosened would fall into the combustion chamber.

I use a brush that is about 1/2 as wide as the spark plug thread is long. I put a very small dab of anti-seize (grain of rice or smaller size) on the tip of the brush. The brush is then used to work that small amount evenly on all the threads, starting from the side facing the combustion chamber. I don't apply to the whole plug thread, just the front two thirds. Nothing at all on the washer.

In the end the coating is so thin it looks like copper "sparkle" on the threads. I usually don't re-load the brush until I've done at least two plugs.

This is the procedure I used when I checked the plugs to make sure the original owner had them changed (he had), and then torqued to 17.5 N-m (12.9 lb-ft). I recently checked my plugs again after 28.7k miles. All came out easily. In fact as I mentioned in my recent post I did not even feel a slight "crack" when removing them, which likely means they were slightly loose.

This time I torqued to 19.5 N-m (14.4 lb-ft). After going over this thread from the beginning, it seems that torque is probably too low as well. After seeing one of your posts I am going to order a boot kit and change all the rubber parts on my coils (all seem to be the original ones). At that time I can increase the torque on the plugs.

It seems that a better torque would be 22 N-m (16.2 lb-ft).

 

[2001LC]

Really I appreciate the feedback and your experience.


I finish the month long spark plug removal yesterday. Man was it tough. I spent near one hour on each of the last two plug #6 & #8. Using my 3/4" breaker bar ~1/8 turn at a time. I had to put a more power into turning those spark plugs, than one would thing possible. I mean "possible" without damaging head and spark plugs. If galling was issue, head would now be damage. It's the threads are now enlarged (filled in). Enlarged by a build up anti-seize hard as a rock. Seriously, my right arm bicep is larger today. What a battle. I'm so happy the heads were not damaged! That I could put this much power into cranking these out, without damaging heads, WOW!

I will never, add anti-seize to 2UZ spark plugs again.

 

[2001LC]

Here a picture of a spark plug that I did put anti-seize, 50K miles earlier. I torque to 13ft-lbf, which mean I actually had equivalent (due to lubed threads) of 18ft-lbf of torque.

Notice threads full of crud,. That crud is the anti-seize I used.

Coloration varies with how much combustion gases, passed the thread. This one above, had some combustion leakage. It walked out about 1/4 turn then froze. Some other in same engine, were more golden. Those plugs hadn't loosened, or not much. Others more blackened, they had walk out the most. All 8 plugs' thread where filled with crud. This was first time I'd added anti-seize, which I'll never do again.

BTW: It looks like I added a lot of anti-seize. That is not the case. I wipe lightly after applying the Anti-seize, out of fear I'd get copper in the engine cylinders/rings.

Here pictures of plugs, I believe, without anti-seize at a reported 75K miles.

I've also read that anti-seize with interfere with plug grounding.

 

[Nightbrew]

@2001LC Did you mention somewhere to gap the IK20TT to 1mm instead of 1.1mm? I looked around today but couldn't find that particular thread/post. If that was you, and that is correct, why? Is it because of the twin tip?

 

[midniteRNR]

Good thing I only skimmed this thread before doing my plugs; this thread almost makes me afraid to do spark plug work on any LX/LC, haha.

- If you don't use anti-seize, plugs will get old and will walk out or will seize into the head or require hours of soaking the plug well with PB Blaster.

- If you do use anti-seize, plugs will get old and walk out and will seize into the head because combustion gases will bake the anti-seize into the threads.


Thinking about this, is it almost a better idea to use lesser life (slightly cheaper) copper or platinum plugs and change them more often to avoid issues due to long change intervals?

 

[OwnerCS]

Good thing I only skimmed this thread before doing my plugs; this thread almost makes me afraid to do spark plug work on any LX/LC, haha.

- If you don't use anti-seize, plugs will get old and will walk out or will seize into the head or require hours of soaking the plug well with PB Blaster.

- If you do use anti-seize, plugs will get old and walk out and will seize into the head because combustion gases will bake the anti-seize into the threads.


Thinking about this, is it almost a better idea to use lesser life (slightly cheaper) copper or platinum plugs and change them more often to avoid issues due to long change intervals?

Funny you say that.. I three late 90s vehicles that average 5,000 to 6,000 miles per year. On one Toyota I run the OEM spec Denso dual-tip copper. The other two get NGK v-power.

I usually change plugs on those cars every 4 years whether they need it or not. I like to read the plugs every 4 or 5 years as a check-in.

The old coils all have way over 200,000 miles. I've read on another car club where people believe old coils like copper plugs. Then there are the racers that love copper plugs.

The Iridium plugs that I bought for this 4.7 are the first that I have purchased in 10 years. It ran better after I changed the plugs.

 

[2001LC]

@2001LC Did you mention somewhere to gap the IK20TT to 1mm instead of 1.1mm? I looked around today but couldn't find that particular thread/post. If that was you, and that is correct, why? Is it because of the twin tip?

Yes TT are set with a tighter gap from factory. I use two feeler blades to check gap. I only adjust if out of alignment or gap off. I use .48mm and .51 mm feelers blades stacked, for total.99mm. Those fits very snug.

Good thing I only skimmed this thread before doing my plugs; this thread almost makes me afraid to do spark plug work on any LX/LC, haha.

- If you don't use anti-seize, plugs will get old and will walk out or will seize into the head or require hours of soaking the plug well with PB Blaster.

- If you do use anti-seize, plugs will get old and walk out and will seize into the head because combustion gases will bake the anti-seize into the threads.


Thinking about this, is it almost a better idea to use lesser life (slightly cheaper) copper or platinum plugs and change them more often to avoid issues due to long change intervals?

To each his own.

But it's not the iridum electroid that's the issue. Most all spark plugs threads used in aluminum heads, are a nickel IIRC. It's thread design and low torque "we think." is the Denso issue.

Note: I don't see this freeze-up, unless anti seize used. Walking out and blowing out head yes, without anti S. But to get so bad as to blow out. Takes about 120K to 200K or more miles. It has to due with heating and cooling cycles IMHO. More so than miles. We can hear them leaking exhaust gases, way before that. Just turn down the radio once in awhile.

 

[Nightbrew]

Yes TT are set with a tighter gap from factory. I use two feeler blades to check gap. I only adjust if out of alignment or gap off. I use .48mm and .51 mm feelers blades stacked, for total.99mm. Those fits very snug.


To each his own.

But it's not the iridum electroid that's the issue. Most all spark plugs threads used in aluminum heads, are a nickel IIRC. It's thread design and low torque "we think." is the Denso issue.

Note: I don't see this freeze-up, unless anti seize used. Walking out and blowing out head yes, without anti S. But to get so bad as to blow out. Takes about 120K to 200K or more miles. It has to due with heating and cooling cycles IMHO. More so than miles. We can hear them leaking exhaust gases, way before that. Just turn down the radio once in awhile.

Just curious, why 1mm instead of the standard 1.1mm, for this style plug?

 

[NoTempoLimit]

... It's thread design and low torque "we think." is the Denso issue.

Spark plug threads are standardized for diameter and pitch. Do you think they are making their male thread to the minimum size? I have a thread micrometer that reads to 0.01mm but I'd need to check brand new plugs. It would be neccesarry to check more than one type of plug to see if DENSO is using a different tolerance.

 

[Porter]

I pulled my coils and plugs tonight, as I'm chasing down a driveline shudder (under acceleration) that I initially suspected was a bad u joint. Coils have about 175k (second complete set I installed 8 years ago, OEM Denso) and appear to still be in acceptable condition. Plugs have less than 50k, 2.5 years on them, Denso SK20r11, ordered directly from Denso online. Surprised to see a gap of 1.9 mm to 2.2 mm on these plugs. I don't recall checking gap at purchase, and I understand you are not to adjust gap on Iridium plugs. FYI, no CEL has been thrown. All plugs appear to be of 'normal' condition except for out of spec gap. Certainly sounds like this could be the cause of shudder, and recent rough idle- will find out tomorrow with new plugs. Incidentally, I've always 'torqued to feel' on plugs, and these were certainly not loose and not too tight. No anti seize applied. Any thoughts on this large gap, perhaps these aren't genuine Denso?

Update- I just researched my order back in March 2018. I didn't get Denso direct order- seems I had a lapse in judgement and ordered Amazon, but I remember being careful, so much for that. Seems I was duped. I left a review on the counterfeit plugs. Seismic LLC, Greensboro NC in Part Sales on Amazon. They're not far from me(Greensboro NC), so I'll have to stop by and drop off the crap plugs they sold me a couple years back. LOL.

 

[NoTempoLimit]

Is it only Denso spark plugs that are being counterfeited?

I bought Denso O2 sensors from Amazon. I checked them against the originals and they were an exact match except for no Toyota logo. They seem to be functioning fine. I did save the packaging.

From now on I will only buy Denso parts from real Denso suppliers. Can we get a list going of known good suppliers?

 

[OwnerCS]

Is it only Denso spark plugs that are being counterfeited?

I bought Denso O2 sensors from Amazon. I checked them against the originals and they were an exact match except for no Toyota logo. They seem to be functioning fine. I did save the packaging.

From now on I will only buy Denso parts from real Denso suppliers. Can we get a list going of known good suppliers?

RockAuto, one of our sponsors, sells a genuine product and provides an attribution code for a 5% MUD discount.

The big-box part stores aren't going to deliberately sell known counterfeit products. The reputational and avoidance of logistical issues are worth way more than any minor gains from substituting counterfeits. The only case where someone may walk out of a big box store with a counterfeit would be a case where someone purchased a set of genuine Denso plugs then took them out of the store and swapped in counterfeit,s then returned the counterfeits for refund in the genuine box. It would be a deliberate nefarious action on the part of an end consumer that was missed by a store salesperson that resulted in the sale of a counterfeit.

As a side note, I have received reports that Walmart is keeping Toyota oil filters in locked cases to keep people from swapping Toyota filters in Fram boxes so they check out with a lower cost Fram that contains a Toyota.

I have purchased some genuine Densos from Amazon but I cannot issue a carte blanche recommendation because I have been burned by them on some Aisan injectors. I usually get genuine parts from Amazon when the price is higher than Rock Auto and it is a matter of leveraging Prime for weekend delivery.

I have seen many horrible counterfeit examples on eBay. I have also bought some genuine OEM parts like tilt/telescopic motors from eBay at savings.

It has taken a year for me to learn how to read the Denso and Toyota quality lot numbers that are embossed in the product or stamped on the box to distinguish genuine from counterfeit products. I didn't set out to be a counterfeit product investigator. It was learned from being burned a couple of times.

Parts from any IH8MUD sponsor like Absolute Wits End, Cruiserteq, Cruiser Brothers, Owl Expedition, and many many others will be good.

 

[NoTempoLimit]

As a side note, I have received reports that Walmart is keeping Toyota oil filters in locked cases to keep people from swapping Toyota filters in Fram boxes so they check out with a lower cost Fram that contains a Toyota.

Wow... Wally World sells those Toyota filters for around $7! I thought they were cheap enough already.

Thanks for the info and suggestions. Is there a sponsor area where one can easily link to the sponsor's sites?