^Lol, how did I miss that?
Real risk of head damage when changing spark plugs
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know i am a jerk for saying this ,but If you need a torque wrench for spark plugs , you shouldn't be changing them .The same goes for lugs. Let the pros at wal-mart do it for u.
Why bother with torque specs at all, if the pros can feel the correct torque i suppose we might as well toss the torque tools in the bin. I guess a pro machinist doesn't need micrometers either, his fingers and feel are good enough.
Shade tree precision at its finest.
know i am a jerk for saying this ,but If you need a torque wrench for spark plugs , you shouldn't be changing them .The same goes for lugs. Let the pros at wal-mart do it for u.
Why bother with torque specs at all, if the pros can feel the correct torque i suppose we might as well toss the torque tools in the bin. I guess a pro machinist doesn't need micrometers either, his fingers and feel are good enough.
Shade tree precision at its finest.
Another self appointed expert is among us. He needs no torque wrench and has the "magic touch"
Who are you referring too?
I thread the spark plug by hand, then a further 1/8 turn or 1/4 turn, if the plug has a crush washer, finishes the job. Works dry or with antisieze without fail.
Originally Posted By: Trav
Quote:
know i am a jerk for saying this ,but If you need a torque wrench for spark plugs , you shouldn't be changing them .The same goes for lugs. Let the pros at wal-mart do it for u.
Why bother with torque specs at all, if the pros can feel the correct torque i suppose we might as well toss the torque tools in the bin. I guess a pro machinist doesn't need micrometers either, his fingers and feel are good enough.
Shade tree precision at its finest.
LOL good point! Things like installing a drain plug or something along those lines I'll pass on the torque wrench, but I grab it for anything else on the engine that has a torque spec. I don't think I can accurately guess how tight I made something. Some people even use torque wrenches for tightening drain plugs, that's not a bad idea either.
Quote:
know i am a jerk for saying this ,but If you need a torque wrench for spark plugs , you shouldn't be changing them .The same goes for lugs. Let the pros at wal-mart do it for u.
Why bother with torque specs at all, if the pros can feel the correct torque i suppose we might as well toss the torque tools in the bin. I guess a pro machinist doesn't need micrometers either, his fingers and feel are good enough.
Shade tree precision at its finest.
LOL good point! Things like installing a drain plug or something along those lines I'll pass on the torque wrench, but I grab it for anything else on the engine that has a torque spec. I don't think I can accurately guess how tight I made something. Some people even use torque wrenches for tightening drain plugs, that's not a bad idea either.
Originally Posted By: Boomer
An old trick to avoid cross threading when screwing in a plug...put a length of small ID rubber hose (vacuum line typr) on the end of the plug where the spark plug wire attaches. Now insert the plug into the threaded hole and trun the rubber hose gently. This alows the plug threads to find their way into the head threads and prevents cross threading as almost no torque is involved. You stioll need to worry about the final torque.
One of the drawers in my roll-away is the "miscellaneous tool" drawer, which contains all kinds of treasures, like the deadblow hammer, the impact driver for screws, clutch alignment tools for cars I don't own any more, the re-formed screwdriver for pulling plug wires, the ground down wrenches for tight clearance, the fabricated strut wrenches and crankshaft pulley holders...and yes...
a 4" piece of fuel line, just the right size to thread the plugs on aluminum heads where my fingers are too big to reach, and sockets don't give you the feel...
An old trick to avoid cross threading when screwing in a plug...put a length of small ID rubber hose (vacuum line typr) on the end of the plug where the spark plug wire attaches. Now insert the plug into the threaded hole and trun the rubber hose gently. This alows the plug threads to find their way into the head threads and prevents cross threading as almost no torque is involved. You stioll need to worry about the final torque.
One of the drawers in my roll-away is the "miscellaneous tool" drawer, which contains all kinds of treasures, like the deadblow hammer, the impact driver for screws, clutch alignment tools for cars I don't own any more, the re-formed screwdriver for pulling plug wires, the ground down wrenches for tight clearance, the fabricated strut wrenches and crankshaft pulley holders...and yes...
a 4" piece of fuel line, just the right size to thread the plugs on aluminum heads where my fingers are too big to reach, and sockets don't give you the feel...
itslimjim - I have found that when the mileage starts to get up there (over 100K) that the threads themselves can get fouled by combustion products and corrosion (or even old anti-sieze if too much was used). If they don't feel right, I would look at the condition of the threads and consider running a tap to clean them out. Had the same experience the first time I changed plugs on the T5 - no. 2 plug was loose when I removed it...and the new plug didn't feel right at all going in...it was fine after cleaning the threads with a tap.
I am sure that the "pro" who installed that plug had the feel just right...
I am sure that the "pro" who installed that plug had the feel just right...
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Agreed on iron heads or on plugs that use a crush washer.
On aluminum heads with tapered seats i always use a torque wrench if possible. A 1/4" drive with a 3/8 adapter or 3/8 inch pound works great for these low torque settings.
Ditto almost anything going into aluminum. Back in the day with all iron engines you really only had to sweat the head and rod/main bolt/nuts, almost everything else was fine by experienced feel.
On aluminum heads with tapered seats i always use a torque wrench if possible. A 1/4" drive with a 3/8 adapter or 3/8 inch pound works great for these low torque settings.
Ditto almost anything going into aluminum. Back in the day with all iron engines you really only had to sweat the head and rod/main bolt/nuts, almost everything else was fine by experienced feel.
Originally Posted By: eljefino
Most new plugs have a squishy gasket; if you get a feel for this gasket crushing you'll be fine.
+1 Most, if not all plugs for import engines with aluminum heads have the crush gasket and the directions usually state to thread by hand until you feel the plug bottom out on the gasket, then turn an additional 1/4 to half turn with a wrench to crush and seal the gasket. Once it's crushed and you start to feel resistance with light to light moderate force, stop and you're good.
Most OHV domestic engines I've worked on had a washer instead of a crush gasket. With those, you thread by hand until the plug bottoms out, then turn an additional 1/8th with a wrench to seat the washer using light moderate force.
That's what I've always done anyways and never had a problem, and never used a torque wrench. In fact, I feel safer NOT using a torque wrench, especially with crush gasket type plugs. After you do it a few times, you'll get a feel for when the gasket is crush/squished all the way and you don't need to torque on the plug any more.
Most new plugs have a squishy gasket; if you get a feel for this gasket crushing you'll be fine.
+1 Most, if not all plugs for import engines with aluminum heads have the crush gasket and the directions usually state to thread by hand until you feel the plug bottom out on the gasket, then turn an additional 1/4 to half turn with a wrench to crush and seal the gasket. Once it's crushed and you start to feel resistance with light to light moderate force, stop and you're good.
Most OHV domestic engines I've worked on had a washer instead of a crush gasket. With those, you thread by hand until the plug bottoms out, then turn an additional 1/8th with a wrench to seat the washer using light moderate force.
That's what I've always done anyways and never had a problem, and never used a torque wrench. In fact, I feel safer NOT using a torque wrench, especially with crush gasket type plugs. After you do it a few times, you'll get a feel for when the gasket is crush/squished all the way and you don't need to torque on the plug any more.
Maybe my case is just weird, but the service manual specs specific plugs (as in, a specific NGK number and a specific Denso number). Both have crush washers. The manual specifically says to use anti-seize and tighten to 18 ft*lbs which works out to more than 1/2 turn with that crush washer in there.
Maybe there's something special about this head's plug seat but I don't know. The oil drain plug goes into aluminum with a crush washer and specs 30 ft*lbs (no anti-seize though of course) and I doubt it has too many more threads than the plugs on this engine.
I'm not trying to argue for lack of common sense, it just seems like with spark plugs there are militant people on both sides of the issues (torque wrench, anti-seize, etc.) and constant warnings, but manufacturer recommendations are all over the place so I'm wondering how big a deal it really is.
Maybe there's something special about this head's plug seat but I don't know. The oil drain plug goes into aluminum with a crush washer and specs 30 ft*lbs (no anti-seize though of course) and I doubt it has too many more threads than the plugs on this engine.
I'm not trying to argue for lack of common sense, it just seems like with spark plugs there are militant people on both sides of the issues (torque wrench, anti-seize, etc.) and constant warnings, but manufacturer recommendations are all over the place so I'm wondering how big a deal it really is.
Man, it makes me feel blessed to have my Taurus with it's SOHC pushrod V6 (The VULCAN). It's Iron, and it doesn't get outstanding mileage, but it can run on crisco and the plug replacement is like stacking blocks compared to some of these procedures.
All kidding aside. I went something around 98,000 miles on my last set of Platinum plugs. I let them cool off overnight, hit them with compressed air, then sprayed some Kroil (penetrating oil) on them and went and ate breakfast. When I came back I hit them with compressed air again (amazing how much crud is in those holes), and they were still tough to remove. (5 years and 98,000 miles is a long long time)
I did apply a small dab of anti-seize to the NGK Double Platinum's I replaced them with. I did so knowing the implications of over-tightening them, however I felt that ease of removal in another 5 years/100,000 miles was worth the risk.
I don't currently own a torque wrench.(Not sure how I would use it on the back bank of plugs either.) All I did was run each plug in by hand as far as possible, then snugged it up with a small 3/8" ratchet.
I too know several guy's who had a Ford Truck that blew a Spark plug through the hood of their car. I'm shocked at how much a difference one more thread of aluminum within the head makes, as that is what Ford (eventually) added to the design to fix the problem.
All I know is that before doing ANYTHING to a vehicle that you are unfamiliar with you need to read up on it. Everyone, from Hyundai to Ferrari has bugs in their new designs that they have to work out. If you learn from someone else's mistakes it can save you a bunch of time and frustration.
All kidding aside. I went something around 98,000 miles on my last set of Platinum plugs. I let them cool off overnight, hit them with compressed air, then sprayed some Kroil (penetrating oil) on them and went and ate breakfast. When I came back I hit them with compressed air again (amazing how much crud is in those holes), and they were still tough to remove. (5 years and 98,000 miles is a long long time)
I did apply a small dab of anti-seize to the NGK Double Platinum's I replaced them with. I did so knowing the implications of over-tightening them, however I felt that ease of removal in another 5 years/100,000 miles was worth the risk.
I don't currently own a torque wrench.(Not sure how I would use it on the back bank of plugs either.) All I did was run each plug in by hand as far as possible, then snugged it up with a small 3/8" ratchet.
I too know several guy's who had a Ford Truck that blew a Spark plug through the hood of their car. I'm shocked at how much a difference one more thread of aluminum within the head makes, as that is what Ford (eventually) added to the design to fix the problem.
All I know is that before doing ANYTHING to a vehicle that you are unfamiliar with you need to read up on it. Everyone, from Hyundai to Ferrari has bugs in their new designs that they have to work out. If you learn from someone else's mistakes it can save you a bunch of time and frustration.
But he had a point. If you work on the car, you need to get a feel for "standard" torque values for spark plugs and lug nuts and something in between. This regardless if you use a torque wrench or not. There are bunch of people who either miss read the torque wrench or the spec (e.g. Nm vs ft-lb or worse inch-lb) and end up stripping a fastener when using a torque wrench.
Originally Posted By: rationull
Maybe my case is just weird, but the service manual specs specific plugs (as in, a specific NGK number and a specific Denso number). Both have crush washers. The manual specifically says to use anti-seize and tighten to 18 ft*lbs which works out to more than 1/2 turn with that crush washer in there.
You know, my Toyota is the same way. It also specs 18 ft. lbs. and it just feels like it's too much torque after the crush washer is fully crushed. It feels like more torque then I'd use with a standard sized wrench on a random bolt. Maybe it's my torque wrench, but I've just gone by the 1/4 to half turn on my car. Mine usually takes 3/8 of an additional turn to crush the gaskets and snug them up.
Maybe my case is just weird, but the service manual specs specific plugs (as in, a specific NGK number and a specific Denso number). Both have crush washers. The manual specifically says to use anti-seize and tighten to 18 ft*lbs which works out to more than 1/2 turn with that crush washer in there.
You know, my Toyota is the same way. It also specs 18 ft. lbs. and it just feels like it's too much torque after the crush washer is fully crushed. It feels like more torque then I'd use with a standard sized wrench on a random bolt. Maybe it's my torque wrench, but I've just gone by the 1/4 to half turn on my car. Mine usually takes 3/8 of an additional turn to crush the gaskets and snug them up.
Originally Posted By: Vikas
But he had a point. If you work on the car, you need to get a feel for "standard" torque values for spark plugs and lug nuts and something in between. This regardless if you use a torque wrench or not. There are bunch of people who either miss read the torque wrench or the spec (e.g. Nm vs ft-lb or worse inch-lb) and end up stripping a fastener when using a torque wrench.
Stated this way I agree. However, even if you have a feel, the ability to measure what you're doing always helps. If you try to measure and you end up having a unit mismatch problem, then you're making a mistake just as bad as you would be if you were trying to use "feel" to end up in the right spot but you forgot you were using a longer ratchet handle or something.
I like being in the middle -- having feel is good but I like having a second verification too. This is why I snug my oil drain bolt down and then use a torque wrench for the last 1/4 turn or whatever. It's really easy and gives me a double check.
My original reason for posting this was because I was doing something similar with my spark plugs (although relying on the torque wrench more than I do for my oil drain, because I have less experience w/ the plugs) but the torque spec in the manual was much higher than what many people expect and very different from an extra quarter turn after gasket contact. Just because hitting the spec "feels" wrong doesn't mean that the spec is wrong necessarily. That's why it's useful to have a second source of information.
But he had a point. If you work on the car, you need to get a feel for "standard" torque values for spark plugs and lug nuts and something in between. This regardless if you use a torque wrench or not. There are bunch of people who either miss read the torque wrench or the spec (e.g. Nm vs ft-lb or worse inch-lb) and end up stripping a fastener when using a torque wrench.
Stated this way I agree. However, even if you have a feel, the ability to measure what you're doing always helps. If you try to measure and you end up having a unit mismatch problem, then you're making a mistake just as bad as you would be if you were trying to use "feel" to end up in the right spot but you forgot you were using a longer ratchet handle or something.
I like being in the middle -- having feel is good but I like having a second verification too. This is why I snug my oil drain bolt down and then use a torque wrench for the last 1/4 turn or whatever. It's really easy and gives me a double check.
My original reason for posting this was because I was doing something similar with my spark plugs (although relying on the torque wrench more than I do for my oil drain, because I have less experience w/ the plugs) but the torque spec in the manual was much higher than what many people expect and very different from an extra quarter turn after gasket contact. Just because hitting the spec "feels" wrong doesn't mean that the spec is wrong necessarily. That's why it's useful to have a second source of information.
Originally Posted By: Drew99GT
You know, my Toyota is the same way. It also specs 18 ft. lbs. and it just feels like it's too much torque after the crush washer is fully crushed. It feels like more torque then I'd use with a standard sized wrench on a random bolt. Maybe it's my torque wrench, but I've just gone by the 1/4 to half turn on my car. Mine usually takes 3/8 of an additional turn to crush the gaskets and snug them up.
Interesting. Does it spec anti-seize specifically too?
To play devil's advocate, it seems like more torque than a standard wrench on a random bolt might be OK, given the spark plug threads are much larger than most random bolts on the car. I just can't believe that companies like Toyota and Honda would put out a spec that's right on the edge of the danger zone.
Note I'm not taking the spec as gospel and saying that I think there's a problem with using a more feel based approach and tightening the plugs less. Obviously that works out fine most of the time too.
You know, my Toyota is the same way. It also specs 18 ft. lbs. and it just feels like it's too much torque after the crush washer is fully crushed. It feels like more torque then I'd use with a standard sized wrench on a random bolt. Maybe it's my torque wrench, but I've just gone by the 1/4 to half turn on my car. Mine usually takes 3/8 of an additional turn to crush the gaskets and snug them up.
Interesting. Does it spec anti-seize specifically too?
To play devil's advocate, it seems like more torque than a standard wrench on a random bolt might be OK, given the spark plug threads are much larger than most random bolts on the car. I just can't believe that companies like Toyota and Honda would put out a spec that's right on the edge of the danger zone.
Note I'm not taking the spec as gospel and saying that I think there's a problem with using a more feel based approach and tightening the plugs less. Obviously that works out fine most of the time too.
No anti-seize is mentioned in the manual. Actually, in the owners manual it doesn't even mention a torque spec - just turn 1/4 past hand tight. Yes, that's right, my Toyota owners manual actually gives information on how to change spark plugs!
The Haynes manual specs 18 ft. lbs. and says to use anti-seize.
The Haynes manual specs 18 ft. lbs. and says to use anti-seize.
To your original question rationull, I doubt 18 ft. lbs with a calibrated torque wrench would trip the threads. You're right, it isn't that much even if it sort of feels like too much.
I'd be much more concerned about hand threading the plugs in first so they don't cross thread. In fact, I've had problems with carbon in the threads and have threaded and removed a plug by hand several times to knock out the carbon so I can get the plug to seat onto the gasket by hand.
I'd be much more concerned about hand threading the plugs in first so they don't cross thread. In fact, I've had problems with carbon in the threads and have threaded and removed a plug by hand several times to knock out the carbon so I can get the plug to seat onto the gasket by hand.
Originally Posted By: Drew99GT
No anti-seize is mentioned in the manual. Actually, in the owners manual it doesn't even mention a torque spec - just turn 1/4 past hand tight. Yes, that's right, my Toyota owners manual actually gives information on how to change spark plugs!
The Haynes manual specs 18 ft. lbs. and says to use anti-seize.
Ah ok. My owners manual doesn't mention anything useful about the spark plugs either -- I'm citing the actual factory service manual (not a Haynes type one).
Originally Posted By: Drew99GT
To your original question rationull, I doubt 18 ft. lbs with a calibrated torque wrench would trip the threads. You're right, it isn't that much even if it sort of feels like too much.
I'd be much more concerned about hand threading the plugs in first so they don't cross thread. In fact, I've had problems with carbon in the threads and have threaded and removed a plug by hand several times to knock out the carbon so I can get the plug to seat onto the gasket by hand.
Good to hear, that's really what I was thinking. Take care not to cross thread (as always ... I always start threading stuff by hand anyway).
No anti-seize is mentioned in the manual. Actually, in the owners manual it doesn't even mention a torque spec - just turn 1/4 past hand tight. Yes, that's right, my Toyota owners manual actually gives information on how to change spark plugs!
The Haynes manual specs 18 ft. lbs. and says to use anti-seize.
Ah ok. My owners manual doesn't mention anything useful about the spark plugs either -- I'm citing the actual factory service manual (not a Haynes type one).
Originally Posted By: Drew99GT
To your original question rationull, I doubt 18 ft. lbs with a calibrated torque wrench would trip the threads. You're right, it isn't that much even if it sort of feels like too much.
I'd be much more concerned about hand threading the plugs in first so they don't cross thread. In fact, I've had problems with carbon in the threads and have threaded and removed a plug by hand several times to knock out the carbon so I can get the plug to seat onto the gasket by hand.
Good to hear, that's really what I was thinking. Take care not to cross thread (as always ... I always start threading stuff by hand anyway).
I rarely use a torque wrench on spark plugs anymore.
My feel is fine.
My feel is fine.
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