Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert! (2 Viewers)

[bloc]

80 series cruisers don’t seem to have this problem, and while I don’t have both plugs to compare side by side they appear to be similar thread size and pitch in pictures I can find.

On a 1fz-fe they call for 14lb/ft

Why would this be happening on 100s but not 80s? Similar plugs, head material, etc

 

[2001LC]

Here is another data point: Just replaced the original plugs in our '00 LX470 with 81k miles. All plugs were tight, without being too difficult to remove. No sign of leakage.

Torqued the plugs to 14 ft.lbf, just to make sure. I did notice that there was quite a bit of creep. When I re-tightened the plugs after about one hour, some of them were turning another 20-30 degrees with the same torque setting. All of them turned at least a little. Waited a bit more and third time there was very little additional turning. Engine was cold and I was using a quality (Norbar) torque wrench, in case there is questions abut the torque wrench.

I saw your post on all bank 1 coils being bad (split open), but yet look like new. I really suspected PO or someone has had hands on.

The only reason I can imagine needing tightening after just resting for a short period of time, is fiction. That is to say you build up fiction heat while threading in. This assumes you held torque wrench properly and extension square to plug.

80 series cruisers don’t seem to have this problem, and while I don’t have both plugs to compare side by side they appear to be similar thread size and pitch in pictures I can find.

On a 1fz-fe they call for 14lb/ft

Why would this be happening on 100s but not 80s? Similar plugs, head material, etc

I've no knowledge of the straight 6 as I don't work on 80's.

I suspect the 2UZ (V-8) heads are heating/cooling unevenly. I say this for two reason.

1. I'm seeing inner plugs more so than corners walking off.
2. I'm seeing (in the rare overheating cases) take out head gasket of inner cylinders.

Here's three different engine examples of 2UZ (98, 00 & 07):

The RH head has 10PSI in 4 & 6 cylinders. You can see separation and curling of head gasket between 4 & 6 cylinders.

LH head gasket also showed separating and curling near inner cylinders.

#4

#6

#5

 

[2001LC]

FWIW: I see Toyota increased torque spec for the 200 series 3UR V-8 (aluminum head and block) to 15ft-lbf.

 

[2001LC]

Denso Iridium spark plugs $1.48 each!

Denso has a rebate of $3 per pluge going on. Advanced auto sold me 8 for $4.48 each (after discount and coupon).

WOW! I may stock up.

 

[TXSunDevil]

Denso Iridium spark plugs $1.48 each!

Denso has a rebate of $3 per pluge going on. Advanced auto sold me 8 for $4.48 each (after discount and coupon).

WOW! I may stock up.

Where did you find the Denso rebate? Advance is showing 8.49

 

[toyotaspeed90]

My money is on people using the touqre specs, I touqre nothing, I tighten until I feel it's good and then call it good.

I'm the same way - only head bolts (which are usually TTY anyways) andcrank/rod bolts do I use a torque wrench.

I'll probably replace plugs soon - it looks like the timing belt has been done, but no wear marks on the coilpack bolts oddly enough (maybe just little force is needed so don't show sings of use?) and will install plugs in the manner I'm used to (hand tight using 1 hand which is far tighter than 13lb).

Personally I would be more concerned about the plug working loose than being a little too tight. If it becomes a problem I will use a small amount of threadlocker at the top. It does take a bit to actually strip the threads - never done it myself and I've had a lot of aluminum head engines.

 

[planomateo]

Where did you find the Denso rebate? Advance is showing 8.49

Advance Auto Parts - Denso Rebate

Get a $3 Advance Gift Card per plug with purchase of 4 or more Denso Iridium Spark Plugs (purchases must be on same transaction). Limit 1.

Rebate Valid March 29, 2018 - April 25, 2018 Redeem By May 25, 2018

 

[Lopott]

Is it the Denso Iridium TT 0.44? thanks

 

[2001LC]

I get good prices at Advance Auto, my particular store. So price was $~5.50 ea.. They also email me coupons after each store purchase ranging from $5 off $20 to $20 OFF $50 and so on that I used after discounts ($4.48). The $3 Denso Advance Auto store credit rebate was a surprise to me yesterday while on parts run.

BTW: I just pulled 8 NGK 1FR6A11 from a 06 GX470 w/98K. The gap was incredible on all 8 at 1.08mm, and no halos on any plug.

Is it the Denso Iridium TT 0.44? thanks

It's the newer design with thinnest electrode (0.4mm). Denso claims greater power output with less input from coil. I've been dying to try them, ever since they update their sales lectures to include "beyond 100K mile". Drawing less energy from coil mean less heat generated in coil. Heat is the enemy of coils, it implies longer coil life.

Iridium is what gives the longest life.

DENSO IRIDIUM TT

The Iridium TT’s revolutionary 0.4 millimeter center electrode means significantly improved combustion and fewer misfires – optimizing power output like never before..

Invented by DENSO, the Iridium TT Twin-Tip Technology enables larger spark concentration and explosion, delivering more complete combustion, which translates to more superior fuel economy.

The unparalleled Iridium TT spark plug is tested to last well beyond 100,000 miles, with minimal loss to performance, contributing to more overall lifetime savings than any plugs available today.

 

[nissanh]

I am running Denso Pt (platinum) TT spark plugs. I also replaced 3 aftermarket coil packs with OEM along with a OEM fuel filter. Did a road trip and noticed an improvement in MPG. I used to receive 14.5 -15 MPG on cruise at 72 MPH, and with the upgrades above I received 16.7 MPG same road and same driving conditions.

One otherthing about plugs coming loose: After 3000 miles I check the plugs and noted the two in the front (1 and 2) and 2 by the fire wall (7 and 8) were bit loose and had to turn about 1/5 turn (72 degrees) to get the 13 ft-lb torque. I use antiseize for spark plug threads.

 

[2001LC]

@nissanh keep in mind the "Platinum" do not last as long.

 

[2001LC]

Here's a link to the Denso line-up. Platinum is rated at 60K, Iridium >100K miles. You'll also see they've more than one type 0.4mm tip.
DENSO Spark Plugs

I've just been buying the original "Iridium Long Life", which is what Toyota Factory installs.

 

[Pyrenees]

Just changed my plugs at 170k on a 2001 LX 470. Three out of eight were finger tight at best. Those coils were browned. Manual says 13 lb-ft but I made it more like 15-16 based on this. Five coils were recently replaced and those spark plugs were snug.

 

[MuseChaser]

Just a quickie add to this older thread... any time you add a lubricant of any kind to threads, the factory torque specs can be tossed out the window unless they're given WITH a specific application of a specific lube. NeverSeize or whatever can be a wonderful thing in all kinds of applications, but I wouldn't advise putting it on plug threads and then torqueing to factory spec. Choose one or the other.

 

[2001LC]

Here's what Denso has to say about lubricating threads and torque:
"Note: The installation torque values shown above apply to new spark plugs without lubricating the threads. If threads are lubricated, the torque value should be reduced by approximate 1/3 to avoid overtightening."

Keep in mind Denso also said "head threads should be clean", which used aren't.

They give torque range and other useful info here:
Spark Plug Installation

I'm on again off again with lubing thread. But when I do, it's very sparsely and even them I wipe most off just leaving just a very thin film on upper 2/3rds of threads. The only reason I do lube, is sometimes when I pull plugs they are so dry and tight coming out. In those case I can't help but think some lube would have been nice.

 

[Spike555]

Here is what I do when it comes to lubing threads of any kind, any pen/lube, spark the spark plug hole, screw in the spark plug until you crush the washer, then give 1/4 turn more. Done. Never had a problem. Ever.

Before removing spark plugs, spray pen/lube into the spark plug hole, it seeps into the threads and out they come, easy as pie.

It's not rocket science, it's spark plugs.

 

[white_lx]

BTW: I just pulled 8 NGK 1FR6A11 from a 06 GX470 w/98K. The gap was incredible on all 8 at 1.08mm, and no halos on any plug.

Same findings with factory Denso SK20R11 plugs on a '08 GX470 197kkm (123K). All gaps between 1.05 and 1.10 mm (my closest feeler gauges). Plugs look brand new.

#8 was very loose. #1 and #3 were hand tight. All others OK.

 

[navydivedoc]

Driving home today, sitting at a stop light and my idle suddenly dropped about 100 rpm and the engine had a slight stumble. Subtle ticking noise, sounded mechanical from inside the truck. I was about 1/2 mile from home, so drove it the rest of the way. Was fine when off idle. Pull into the driveway, pop the hood, and listen while the sound worsens. Shut it off, incidentally note that my radiator now has a slight pink telltale on it...oh well, new one was in the Amazon cart and is now headed my way. Check the fluids, no pink milkshake. Noise is from the driver's cylinder bank. Pull the engine cover, and swear that sounds like gas escaping from somewhere.





Started pulling plugs. Damn if there isn't a plug loose in its hole. No resistance to the socket. Back in, problem solved. Plugs appeared to be in good shape, there was some coil discoloration.

Waiting for the engine to cool to pull and check them all.

For reference, my LX is a 2000 with 279k miles. Every service performed on time and at Lexus, last plugs with last Timing belt at 224k.

 

[LXMUTT]

I've got a question for you spark plug gurus. I checked all eight plugs and coils today after reading this thread and found that 2 coils were brown, and one of them(Cylinder 6) was completely cracked, boot and plastic. I'm not throwing any codes. I pulled the spark plug and it had a bunch of gunk around the washer and the ceramic was browning at the base. So my question is do I need to replace the spark plug, and if yes do I need to replace all at the same time? Or could I just clean the spark plug? They were replaced 50k ago. I plan on replacing the two coils as well. Thanks in advance!

 

[dace voit]

Was the gunked plug loose or is there a spark tube seal leaking? If the seal, that might be the source of the gunk. You can try to retorque the bolts if so. If the plugs have only 50k, you should be able to clean them and reuse providing they are the correct plugs.

Don't replace just one plug, IMHO.