Spark Plug Torque Spec.
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Burning Brakes
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From: Santa Rosa Beach, FL
Spark Plug Torque Spec.
I believe the correct tighting torque for the plugs is 18 to 22 ftlb.
Honestly, I have never used a torque wrench on my plugs, only the Porsche tool and tightened them up by hand. Today, after I installed the plugs in my usual manner I took the torque wrench and WoW I had no idea how loose they were when compared to the "hand" job.
I tightened them on down but stopped shy of 18lbs.,actually I chickened out at around 13ftlbs. of torque. It just seem like a lot I didn't want to chance stripping out a plug hole in my new heads!
Is this a concern, or should I just torque away to the 18 - 22 ftlbs.
(I checked with 2 torque wrenches just to make certian I was getting a good reading)
Honestly, I have never used a torque wrench on my plugs, only the Porsche tool and tightened them up by hand. Today, after I installed the plugs in my usual manner I took the torque wrench and WoW I had no idea how loose they were when compared to the "hand" job.
I tightened them on down but stopped shy of 18lbs.,actually I chickened out at around 13ftlbs. of torque. It just seem like a lot I didn't want to chance stripping out a plug hole in my new heads!
Is this a concern, or should I just torque away to the 18 - 22 ftlbs.
(I checked with 2 torque wrenches just to make certian I was getting a good reading)
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That is the correct torque for the Bosch plugs - it's even on the box. Surprised me too, but I torqued the plugs to that number. I usually use the more common 1/4 turn beyond snug for new plugs, but that's not what it says in the WSM or on the plug box.
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Never have looked at the box, I always check the plugs themselves to ensure they are what they are supposed to be then finger tight using hands twisting the 1/2" sq extension, then 1/4 turn.
i once bought 4 sparkplugs for a previous car, installed 3 of them gapping them as I went, opened the 4th box to discover a glow plug for a diesel engine. Looked at the box and it was for a different kind of sparkplug than I bought and not for a diesel glowplug. Some clever shenanigans later I was a free set of spark plugs and £50 richer. Diesel glowplugs are expensive.
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Same here. Going beyond this to 18-22 just feels too tight IMO. So far none of my plugs have come shooting out of my head yet.
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Burning Brakes
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From: Santa Rosa Beach, FL
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It may feel too tight, but I've done it and it works fine. This is done with the threads lubed too (WSM calls for Molykote white paste, whatever that is). I'm not sure there is a real need for 18-22 (18 in 90-95MY according to the tech spec books), but I started doing it once it was pointed out to me by another owner, and the plugs seem no more difficult to remove.
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Looks like Dow-Corning suggests Molykote P74 (search the pdf for 'spark', P74 is on page 3)
http://www.dowcorning.com/content/pu...A_PRODUCTS.pdf
Now there's more goop for Mike to add to his shelf of goops.
http://www.dowcorning.com/content/pu...A_PRODUCTS.pdf
Now there's more goop for Mike to add to his shelf of goops.
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Seen on one of the motorcycle forums, regarding anti seize for aluminum on steel. I've read elsewhere to use zinc-based anti seize in this situation, not aluminum-graphite. The following warns about copper-based anti seize as well.
http://www.advrider.com/forums/showp...07&postcount=9
Maybe one of our resident metallurgists can comment....
This probably applies more to the water pump bolts or external fasteners where water contact is an issue more than sparkplugs.
http://www.advrider.com/forums/showp...07&postcount=9
Maybe one of our resident metallurgists can comment....
from Wally Hartung, an aluminum industry metallurgist, warning about using a copper-based anti-seize on the engine mount support bolts.
In a galvanic corrosion situation involving aluminum and steel, we're not worried about the steel. The aluminum is the
sacrificial metal and will corrode preferentially, protecting the steel. The presence of water is absolutely necessary
for the reaction to occur.
Plated steel bolts (plated with either cadmium or zinc) will afford some protection to the aluminum, but only as long as
the plating lasts. It's being used up as it sacrifices itself to protect the aluminum. As soon as the plating is used up,
the sacrifice of the aluminum parts to the steel will begin.
The white powdery coating on one of the bolts looks a lot like aluminum oxide. Guess what part is really getting eaten up.
That's right, the aluminum case.
Now if you want to really see aluminum go to pieces, get copper involved. Copper eats up aluminum in a situation of
dissimilar metals with water involved. Copper based anti-seize should NEVER be used in contact with, or where it can get
in contact with aluminum. Use the aluminum powder anti-seize, always.
My knee-jerk reaction recommendation to fix this corrosion problem would be to:
1. Clean up the existing corrosion. If the steel bolt hasn't been significantly corroded (just light surface corrosion)
clean it up and reuse it. If there is any question as to a reduction of the cross area of the bolt due to corrosion,
replace it with the proper factory bolt.
2. Spray the bolt with WD-40 or other anti-corrosive that is compatible with the rubber pieces. (I went out to the
garage to look at the mounts and noticed there is a rubber piece in the joint. Like I said, I just got the bike.
Vibration isolation part, or seal to exclude water, or both?)
3. If you've got copper anti-seize where it can get in contact with the aluminum cases, clean it out of there completely.
4. Use a little RTV to seal the assembly. The basic idea is to get rid of the water incursions into the bolted joint.
Without the water, no corrosion.
5. Blue Loctite on the threads, not copper anything.
This is why I never use a pressure washer on a motorcycle, they'll force water into all kinds of places it's not supposed
to be. Also, never use a plain steel or brass(copper) wire brush on aluminum during the corrosion cleanup. Always a
stainless steel wire brush. Steel or copper based wire brushes will leave small particles and lead to pitting of the aluminum.
304 stainless fasteners are fine with in contact with aluminum. There is a surface passivation involving the chrome oxides
that form on the stainless that precludes the formation of a galvanic cell under most conditions.
Wally advises that by just looking at a couple of photos of one component of the problem he really can't offer a professional
opinion from such limited information. There may be other factors involved, but the basic premises of
keeping the water out and not using copper are sound.
In a galvanic corrosion situation involving aluminum and steel, we're not worried about the steel. The aluminum is the
sacrificial metal and will corrode preferentially, protecting the steel. The presence of water is absolutely necessary
for the reaction to occur.
Plated steel bolts (plated with either cadmium or zinc) will afford some protection to the aluminum, but only as long as
the plating lasts. It's being used up as it sacrifices itself to protect the aluminum. As soon as the plating is used up,
the sacrifice of the aluminum parts to the steel will begin.
The white powdery coating on one of the bolts looks a lot like aluminum oxide. Guess what part is really getting eaten up.
That's right, the aluminum case.
Now if you want to really see aluminum go to pieces, get copper involved. Copper eats up aluminum in a situation of
dissimilar metals with water involved. Copper based anti-seize should NEVER be used in contact with, or where it can get
in contact with aluminum. Use the aluminum powder anti-seize, always.
My knee-jerk reaction recommendation to fix this corrosion problem would be to:
1. Clean up the existing corrosion. If the steel bolt hasn't been significantly corroded (just light surface corrosion)
clean it up and reuse it. If there is any question as to a reduction of the cross area of the bolt due to corrosion,
replace it with the proper factory bolt.
2. Spray the bolt with WD-40 or other anti-corrosive that is compatible with the rubber pieces. (I went out to the
garage to look at the mounts and noticed there is a rubber piece in the joint. Like I said, I just got the bike.
Vibration isolation part, or seal to exclude water, or both?)
3. If you've got copper anti-seize where it can get in contact with the aluminum cases, clean it out of there completely.
4. Use a little RTV to seal the assembly. The basic idea is to get rid of the water incursions into the bolted joint.
Without the water, no corrosion.
5. Blue Loctite on the threads, not copper anything.
This is why I never use a pressure washer on a motorcycle, they'll force water into all kinds of places it's not supposed
to be. Also, never use a plain steel or brass(copper) wire brush on aluminum during the corrosion cleanup. Always a
stainless steel wire brush. Steel or copper based wire brushes will leave small particles and lead to pitting of the aluminum.
304 stainless fasteners are fine with in contact with aluminum. There is a surface passivation involving the chrome oxides
that form on the stainless that precludes the formation of a galvanic cell under most conditions.
Wally advises that by just looking at a couple of photos of one component of the problem he really can't offer a professional
opinion from such limited information. There may be other factors involved, but the basic premises of
keeping the water out and not using copper are sound.
Pro
Joined: Oct 2006
Posts: 569
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From: Long Island
Old Thread Revival:
18 lbs of torque seems way to high. I made very snug, then added about 1/4 turn or so - seems very tight to me. When I did the first plug, I stopped before I reached 18lbs. Seems like its way to much - any updates on this.
18 lbs of torque seems way to high. I made very snug, then added about 1/4 turn or so - seems very tight to me. When I did the first plug, I stopped before I reached 18lbs. Seems like its way to much - any updates on this.
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From: Up Nort
Brand new plugs or removing, checking, installing the old ones?
Sometime after this thread, I read the torque specs are for new plugs to crush the washer on the plugs. If said washer is already crushed, the torque specs are too high so "snug" or the old adage "Hand tight plus 1/4 - 1/2 turn" is probably sufficient.
Just my $.02 and how I've been installing plugs ever since I also never use a "click" wrench on the engine, only the old fashioned split beam with the moving arrow.
Sometime after this thread, I read the torque specs are for new plugs to crush the washer on the plugs. If said washer is already crushed, the torque specs are too high so "snug" or the old adage "Hand tight plus 1/4 - 1/2 turn" is probably sufficient.
Just my $.02 and how I've been installing plugs ever since I also never use a "click" wrench on the engine, only the old fashioned split beam with the moving arrow.
Pro
Joined: Oct 2006
Posts: 569
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From: Long Island
Relatively new but removed for the cam cover refinish and gaskets so yes the crush washers have already been seated. I'm going with tight plus 1/4 turn. Click torque just too tight at 18.
I also checked the gap and all were 28 - same as when out of the box.
Thanks
I also checked the gap and all were 28 - same as when out of the box.
Thanks
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From: Oman
When I have a new set of plugs I wind them in until there is firm resistance, I then turn them a flat or so, I then undo them, rinse and repeat. Never had a plug leak after nigh on 50 years of dicking around with them.
On other cars I always used to put my oil filters on hand tight- nothing more- never leaked. On the 928 I chickened out and use a torque wrench to spec and that does feel tight!
On my British motorcycles I never used a torque wrench on the head bolts and I never purchased a new head gasket- just annealed the copper little buggers with a blow torch and a bucket of cold water- never had a problem until one day I did use a torque wrench and snapped a head bolt!- I could feel the thing was yielding, turned it a little more and twang- to be fair I used a wrong torque setting!
On other cars I always used to put my oil filters on hand tight- nothing more- never leaked. On the 928 I chickened out and use a torque wrench to spec and that does feel tight!
On my British motorcycles I never used a torque wrench on the head bolts and I never purchased a new head gasket- just annealed the copper little buggers with a blow torch and a bucket of cold water- never had a problem until one day I did use a torque wrench and snapped a head bolt!- I could feel the thing was yielding, turned it a little more and twang- to be fair I used a wrong torque setting!
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From: Oman
Nowadays I have one of those $5 digital luggage scales for calibration and ac charging- it works really well.
