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Re: Cross threaded Spark plug threads
scott wrote: > > "Cali89Honda" <netguyscott1@yahoo.com> wrote in > news:1149194071.659476.177910@f6g2000cwb.googlegro ups.com: > > > I was replacing the spark plugs in a 1989 accord, something I've done > > many times on many different vehicles. It's never been a problem until > > this instance. When I used the socket to loosen Plug #1, it eventually > > loosened but didnt screw out with ease. The other plugs 2-4 came out > > with ease and I installed new plugs in them, however everytime I > > attempted to install the new plug in the first plug hole I couldnt get > > it to screw in. It just wouldnt catch. I then used a light and have > > determined that the threads on this first spark plug hole were cross > > threaded last time the plugs were changed (by a mechanic) I also > > noticed on the block around this spark plug hole its kinda black and > > the other 3 spark holes arent black on the metal outside their hole. > > Has anyone ever ran into this situation and if so how did you solve the > > problem. Someone I work with suggested I get a 14mm thread chaser and I > > tried that and it wont catch either... cant repair any of the threads > > if it wont screw in. Any help or comments would be appreciated. > > > > Hi, > There are specialty tools that would make your job a lot easier. I work > at a small engine shop and we regularly face this problem. I bought a nifty > thread chaser from Lawson Products that is adjustable for hole size, you > can collapse it to fit into the hole, insert five threads or so deep, > expand to cut and it cleans the threads on the way out. Works very well. By > starting in the good threads it works a lot better than starting on the > damaged threads. When you use this tool on an assembled engine, hook up a > shop vac or vacuum cleaner on the blower side and pressurize the exhaust, > turn the engine slowly until air blows out the plug hole and chips won't go > into the cylinder. The only drawback I can see is it may be necessary to > remove the valve cover to get it into the plug hole and see what you are > doing. I also suggest that you try it out first on a nut near the same size > to familiarise yourself with the way it works and to develop a good "feel" > for how it works. > Good luck > Scott This used to be a common malady with VW beetles. Often, the cure was reaming and tapping the hole to an oversize to accommodate a helicoil. That would be the option if the threads cannot be cleaned up. JT |
Re: Cross threaded Spark plug threads
"Elliot Richmond" <xmrichmond@xaustin.xrr.xcom> wrote in message
news:acku72plod6ui9h7h1oagh4oehjf029ch5@4ax.com... > On 1 Jun 2006 13:34:31 -0700, "Cali89Honda" <netguyscott1@yahoo.com> > wrote: > >>Has anyone ever ran into this situation > > Yes, several decades ago on an old Ford push rod V8. > >>and if so how did you solve the >>problem. Someone I work with suggested I get a 14mm thread chaser > > The thread chaser worked great for me. > >>tried that and it wont catch either... cant repair any of the threads >>if it wont screw in. Any help or comments would be appreciated. > > If you can't make it work, you are probably looking at a new or > rebuilt head. I doubt that a Helicoil would work, but even then you > are going to have to remove the head. > > Hope this helps > > A thread chaser is not likely to be useful on the aluminum head; the remaining metal won't support the spark plug well enough. Got the tee shirt on that, just with worn threads! Helicoils work superbly in aluminum heads, and the head doesn't have to come off. Some people (including the pros where I used to take my cylinder heads in Phoenix) advocate not worrying about the aluminum shavings; they blow out when the engine is started. More commonly, people put the engine on the beginning of the compression stroke for that cylinder and squirt a bunch of shaving cream into the cylinder. They do the tap and helicoil thing and then turn the crank until the shaving cream, with the shavings, is expelled through the spark plug hole. I suppose they change the oil soon afterward <8^P All in all, you may want to have a cylinder head shop do the work. Fewer unknowns that way. Mike |
Re: Cross threaded Spark plug threads
"Elliot Richmond" <xmrichmond@xaustin.xrr.xcom> wrote in message
news:acku72plod6ui9h7h1oagh4oehjf029ch5@4ax.com... > On 1 Jun 2006 13:34:31 -0700, "Cali89Honda" <netguyscott1@yahoo.com> > wrote: > >>Has anyone ever ran into this situation > > Yes, several decades ago on an old Ford push rod V8. > >>and if so how did you solve the >>problem. Someone I work with suggested I get a 14mm thread chaser > > The thread chaser worked great for me. > >>tried that and it wont catch either... cant repair any of the threads >>if it wont screw in. Any help or comments would be appreciated. > > If you can't make it work, you are probably looking at a new or > rebuilt head. I doubt that a Helicoil would work, but even then you > are going to have to remove the head. > > Hope this helps > > A thread chaser is not likely to be useful on the aluminum head; the remaining metal won't support the spark plug well enough. Got the tee shirt on that, just with worn threads! Helicoils work superbly in aluminum heads, and the head doesn't have to come off. Some people (including the pros where I used to take my cylinder heads in Phoenix) advocate not worrying about the aluminum shavings; they blow out when the engine is started. More commonly, people put the engine on the beginning of the compression stroke for that cylinder and squirt a bunch of shaving cream into the cylinder. They do the tap and helicoil thing and then turn the crank until the shaving cream, with the shavings, is expelled through the spark plug hole. I suppose they change the oil soon afterward <8^P All in all, you may want to have a cylinder head shop do the work. Fewer unknowns that way. Mike |
Re: Cross threaded Spark plug threads
"Elliot Richmond" <xmrichmond@xaustin.xrr.xcom> wrote in message
news:acku72plod6ui9h7h1oagh4oehjf029ch5@4ax.com... > On 1 Jun 2006 13:34:31 -0700, "Cali89Honda" <netguyscott1@yahoo.com> > wrote: > >>Has anyone ever ran into this situation > > Yes, several decades ago on an old Ford push rod V8. > >>and if so how did you solve the >>problem. Someone I work with suggested I get a 14mm thread chaser > > The thread chaser worked great for me. > >>tried that and it wont catch either... cant repair any of the threads >>if it wont screw in. Any help or comments would be appreciated. > > If you can't make it work, you are probably looking at a new or > rebuilt head. I doubt that a Helicoil would work, but even then you > are going to have to remove the head. > > Hope this helps > > A thread chaser is not likely to be useful on the aluminum head; the remaining metal won't support the spark plug well enough. Got the tee shirt on that, just with worn threads! Helicoils work superbly in aluminum heads, and the head doesn't have to come off. Some people (including the pros where I used to take my cylinder heads in Phoenix) advocate not worrying about the aluminum shavings; they blow out when the engine is started. More commonly, people put the engine on the beginning of the compression stroke for that cylinder and squirt a bunch of shaving cream into the cylinder. They do the tap and helicoil thing and then turn the crank until the shaving cream, with the shavings, is expelled through the spark plug hole. I suppose they change the oil soon afterward <8^P All in all, you may want to have a cylinder head shop do the work. Fewer unknowns that way. Mike |
Re: Cross threaded Spark plug threads
Elliot Richmond wrote:
> On 1 Jun 2006 13:34:31 -0700, "Cali89Honda" <netguyscott1@yahoo.com> > wrote: > > >>Has anyone ever ran into this situation > > > Yes, several decades ago on an old Ford push rod V8. > > >>and if so how did you solve the >>problem. Someone I work with suggested I get a 14mm thread chaser > > > The thread chaser worked great for me. > > >>tried that and it wont catch either... cant repair any of the threads >>if it wont screw in. Any help or comments would be appreciated. > > > If you can't make it work, you are probably looking at a new or > rebuilt head. I doubt that a Helicoil would work, helicoils work just fine. > but even then you > are going to have to remove the head. no, it's done in situ. > > Hope this helps > > |
Re: Cross threaded Spark plug threads
Elliot Richmond wrote:
> On 1 Jun 2006 13:34:31 -0700, "Cali89Honda" <netguyscott1@yahoo.com> > wrote: > > >>Has anyone ever ran into this situation > > > Yes, several decades ago on an old Ford push rod V8. > > >>and if so how did you solve the >>problem. Someone I work with suggested I get a 14mm thread chaser > > > The thread chaser worked great for me. > > >>tried that and it wont catch either... cant repair any of the threads >>if it wont screw in. Any help or comments would be appreciated. > > > If you can't make it work, you are probably looking at a new or > rebuilt head. I doubt that a Helicoil would work, helicoils work just fine. > but even then you > are going to have to remove the head. no, it's done in situ. > > Hope this helps > > |
Re: Cross threaded Spark plug threads
Elliot Richmond wrote:
> On 1 Jun 2006 13:34:31 -0700, "Cali89Honda" <netguyscott1@yahoo.com> > wrote: > > >>Has anyone ever ran into this situation > > > Yes, several decades ago on an old Ford push rod V8. > > >>and if so how did you solve the >>problem. Someone I work with suggested I get a 14mm thread chaser > > > The thread chaser worked great for me. > > >>tried that and it wont catch either... cant repair any of the threads >>if it wont screw in. Any help or comments would be appreciated. > > > If you can't make it work, you are probably looking at a new or > rebuilt head. I doubt that a Helicoil would work, helicoils work just fine. > but even then you > are going to have to remove the head. no, it's done in situ. > > Hope this helps > > |
Re: Cross threaded Spark plug threads
Michael Pardee wrote:
> "Elliot Richmond" <xmrichmond@xaustin.xrr.xcom> wrote in message > news:acku72plod6ui9h7h1oagh4oehjf029ch5@4ax.com... > >>On 1 Jun 2006 13:34:31 -0700, "Cali89Honda" <netguyscott1@yahoo.com> >>wrote: >> >> >>>Has anyone ever ran into this situation >> >>Yes, several decades ago on an old Ford push rod V8. >> >> >>>and if so how did you solve the >>>problem. Someone I work with suggested I get a 14mm thread chaser >> >>The thread chaser worked great for me. >> >> >>>tried that and it wont catch either... cant repair any of the threads >>>if it wont screw in. Any help or comments would be appreciated. >> >>If you can't make it work, you are probably looking at a new or >>rebuilt head. I doubt that a Helicoil would work, but even then you >>are going to have to remove the head. >> >>Hope this helps >> >> > > A thread chaser is not likely to be useful on the aluminum head; the > remaining metal won't support the spark plug well enough. Got the tee shirt > on that, just with worn threads! you got unlucky. if done right, the chaser works perfectly - it depends on whether it was started where the original threads started or whether it cuts a whole new thread - /then/ you don't have much supporting metal and the helicoil is essential. if the head's already off, you can chase from the piston side as the crossing hardly ever gets all the way to the bottom of the hole. use a plug from the piston side first too to force as much of the old thread back into shape as well. > > Helicoils work superbly in aluminum heads, and the head doesn't have to come > off. Some people (including the pros where I used to take my cylinder heads > in Phoenix) advocate not worrying about the aluminum shavings; they blow out > when the engine is started. More commonly, people put the engine on the > beginning of the compression stroke for that cylinder and squirt a bunch of > shaving cream into the cylinder. They do the tap and helicoil thing and then > turn the crank until the shaving cream, with the shavings, is expelled > through the spark plug hole. I suppose they change the oil soon afterward > <8^P > > All in all, you may want to have a cylinder head shop do the work. Fewer > unknowns that way. > > Mike > > |
Re: Cross threaded Spark plug threads
Michael Pardee wrote:
> "Elliot Richmond" <xmrichmond@xaustin.xrr.xcom> wrote in message > news:acku72plod6ui9h7h1oagh4oehjf029ch5@4ax.com... > >>On 1 Jun 2006 13:34:31 -0700, "Cali89Honda" <netguyscott1@yahoo.com> >>wrote: >> >> >>>Has anyone ever ran into this situation >> >>Yes, several decades ago on an old Ford push rod V8. >> >> >>>and if so how did you solve the >>>problem. Someone I work with suggested I get a 14mm thread chaser >> >>The thread chaser worked great for me. >> >> >>>tried that and it wont catch either... cant repair any of the threads >>>if it wont screw in. Any help or comments would be appreciated. >> >>If you can't make it work, you are probably looking at a new or >>rebuilt head. I doubt that a Helicoil would work, but even then you >>are going to have to remove the head. >> >>Hope this helps >> >> > > A thread chaser is not likely to be useful on the aluminum head; the > remaining metal won't support the spark plug well enough. Got the tee shirt > on that, just with worn threads! you got unlucky. if done right, the chaser works perfectly - it depends on whether it was started where the original threads started or whether it cuts a whole new thread - /then/ you don't have much supporting metal and the helicoil is essential. if the head's already off, you can chase from the piston side as the crossing hardly ever gets all the way to the bottom of the hole. use a plug from the piston side first too to force as much of the old thread back into shape as well. > > Helicoils work superbly in aluminum heads, and the head doesn't have to come > off. Some people (including the pros where I used to take my cylinder heads > in Phoenix) advocate not worrying about the aluminum shavings; they blow out > when the engine is started. More commonly, people put the engine on the > beginning of the compression stroke for that cylinder and squirt a bunch of > shaving cream into the cylinder. They do the tap and helicoil thing and then > turn the crank until the shaving cream, with the shavings, is expelled > through the spark plug hole. I suppose they change the oil soon afterward > <8^P > > All in all, you may want to have a cylinder head shop do the work. Fewer > unknowns that way. > > Mike > > |
Re: Cross threaded Spark plug threads
Michael Pardee wrote:
> "Elliot Richmond" <xmrichmond@xaustin.xrr.xcom> wrote in message > news:acku72plod6ui9h7h1oagh4oehjf029ch5@4ax.com... > >>On 1 Jun 2006 13:34:31 -0700, "Cali89Honda" <netguyscott1@yahoo.com> >>wrote: >> >> >>>Has anyone ever ran into this situation >> >>Yes, several decades ago on an old Ford push rod V8. >> >> >>>and if so how did you solve the >>>problem. Someone I work with suggested I get a 14mm thread chaser >> >>The thread chaser worked great for me. >> >> >>>tried that and it wont catch either... cant repair any of the threads >>>if it wont screw in. Any help or comments would be appreciated. >> >>If you can't make it work, you are probably looking at a new or >>rebuilt head. I doubt that a Helicoil would work, but even then you >>are going to have to remove the head. >> >>Hope this helps >> >> > > A thread chaser is not likely to be useful on the aluminum head; the > remaining metal won't support the spark plug well enough. Got the tee shirt > on that, just with worn threads! you got unlucky. if done right, the chaser works perfectly - it depends on whether it was started where the original threads started or whether it cuts a whole new thread - /then/ you don't have much supporting metal and the helicoil is essential. if the head's already off, you can chase from the piston side as the crossing hardly ever gets all the way to the bottom of the hole. use a plug from the piston side first too to force as much of the old thread back into shape as well. > > Helicoils work superbly in aluminum heads, and the head doesn't have to come > off. Some people (including the pros where I used to take my cylinder heads > in Phoenix) advocate not worrying about the aluminum shavings; they blow out > when the engine is started. More commonly, people put the engine on the > beginning of the compression stroke for that cylinder and squirt a bunch of > shaving cream into the cylinder. They do the tap and helicoil thing and then > turn the crank until the shaving cream, with the shavings, is expelled > through the spark plug hole. I suppose they change the oil soon afterward > <8^P > > All in all, you may want to have a cylinder head shop do the work. Fewer > unknowns that way. > > Mike > > |
Re: Cross threaded Spark plug threads
"jim beam" <nospam@example.net> wrote in message
news:l_WdnSuLKOokTB3Z4p2dnA@speakeasy.net... > Michael Pardee wrote: >> A thread chaser is not likely to be useful on the aluminum head; the >> remaining metal won't support the spark plug well enough. Got the tee >> shirt on that, just with worn threads! > > you got unlucky. if done right, the chaser works perfectly - it depends > on whether it was started where the original threads started or whether it > cuts a whole new thread - /then/ you don't have much supporting metal and > the helicoil is essential. if the head's already off, you can chase from > the piston side as the crossing hardly ever gets all the way to the bottom > of the hole. use a plug from the piston side first too to force as much > of the old thread back into shape as well. > Not so much unlucky as I made a poor choice - it was in a Lotus with a Renault engine, and the threads were not even crossthreaded, just worn out. I wasn't even accelerating hard when I heard a POP and a sound like a lawnmower... the plug had probably been in for months at that point. Maybe a Honda head is more robust and not as sloppy. Mike |
Re: Cross threaded Spark plug threads
"jim beam" <nospam@example.net> wrote in message
news:l_WdnSuLKOokTB3Z4p2dnA@speakeasy.net... > Michael Pardee wrote: >> A thread chaser is not likely to be useful on the aluminum head; the >> remaining metal won't support the spark plug well enough. Got the tee >> shirt on that, just with worn threads! > > you got unlucky. if done right, the chaser works perfectly - it depends > on whether it was started where the original threads started or whether it > cuts a whole new thread - /then/ you don't have much supporting metal and > the helicoil is essential. if the head's already off, you can chase from > the piston side as the crossing hardly ever gets all the way to the bottom > of the hole. use a plug from the piston side first too to force as much > of the old thread back into shape as well. > Not so much unlucky as I made a poor choice - it was in a Lotus with a Renault engine, and the threads were not even crossthreaded, just worn out. I wasn't even accelerating hard when I heard a POP and a sound like a lawnmower... the plug had probably been in for months at that point. Maybe a Honda head is more robust and not as sloppy. Mike |
Re: Cross threaded Spark plug threads
"jim beam" <nospam@example.net> wrote in message
news:l_WdnSuLKOokTB3Z4p2dnA@speakeasy.net... > Michael Pardee wrote: >> A thread chaser is not likely to be useful on the aluminum head; the >> remaining metal won't support the spark plug well enough. Got the tee >> shirt on that, just with worn threads! > > you got unlucky. if done right, the chaser works perfectly - it depends > on whether it was started where the original threads started or whether it > cuts a whole new thread - /then/ you don't have much supporting metal and > the helicoil is essential. if the head's already off, you can chase from > the piston side as the crossing hardly ever gets all the way to the bottom > of the hole. use a plug from the piston side first too to force as much > of the old thread back into shape as well. > Not so much unlucky as I made a poor choice - it was in a Lotus with a Renault engine, and the threads were not even crossthreaded, just worn out. I wasn't even accelerating hard when I heard a POP and a sound like a lawnmower... the plug had probably been in for months at that point. Maybe a Honda head is more robust and not as sloppy. Mike |
Re: Cross threaded Spark plug threads
Michael Pardee wrote:
> "jim beam" <nospam@example.net> wrote in message > news:l_WdnSuLKOokTB3Z4p2dnA@speakeasy.net... > >>Michael Pardee wrote: >> >>>A thread chaser is not likely to be useful on the aluminum head; the >>>remaining metal won't support the spark plug well enough. Got the tee >>>shirt on that, just with worn threads! >> >>you got unlucky. if done right, the chaser works perfectly - it depends >>on whether it was started where the original threads started or whether it >>cuts a whole new thread - /then/ you don't have much supporting metal and >>the helicoil is essential. if the head's already off, you can chase from >>the piston side as the crossing hardly ever gets all the way to the bottom >>of the hole. use a plug from the piston side first too to force as much >>of the old thread back into shape as well. >> > > Not so much unlucky as I made a poor choice - it was in a Lotus with a > Renault engine, those are quite a good little engine! > and the threads were not even crossthreaded, just worn out. > I wasn't even accelerating hard when I heard a POP and a sound like a > lawnmower... the plug had probably been in for months at that point. > > Maybe a Honda head is more robust and not as sloppy. > > Mike > > i've seen this on a honda head - plug had apparently been loose forever. eventually the plug just pulled/wore out the last few threads, and then, as you say, loud chugging noises. as long as there's enough thread to hold the plug, it should be ok. the seal comes from the gasket/washer on the plug and bolts only need 3 threads to hold under most circumstances. |
Re: Cross threaded Spark plug threads
Michael Pardee wrote:
> "jim beam" <nospam@example.net> wrote in message > news:l_WdnSuLKOokTB3Z4p2dnA@speakeasy.net... > >>Michael Pardee wrote: >> >>>A thread chaser is not likely to be useful on the aluminum head; the >>>remaining metal won't support the spark plug well enough. Got the tee >>>shirt on that, just with worn threads! >> >>you got unlucky. if done right, the chaser works perfectly - it depends >>on whether it was started where the original threads started or whether it >>cuts a whole new thread - /then/ you don't have much supporting metal and >>the helicoil is essential. if the head's already off, you can chase from >>the piston side as the crossing hardly ever gets all the way to the bottom >>of the hole. use a plug from the piston side first too to force as much >>of the old thread back into shape as well. >> > > Not so much unlucky as I made a poor choice - it was in a Lotus with a > Renault engine, those are quite a good little engine! > and the threads were not even crossthreaded, just worn out. > I wasn't even accelerating hard when I heard a POP and a sound like a > lawnmower... the plug had probably been in for months at that point. > > Maybe a Honda head is more robust and not as sloppy. > > Mike > > i've seen this on a honda head - plug had apparently been loose forever. eventually the plug just pulled/wore out the last few threads, and then, as you say, loud chugging noises. as long as there's enough thread to hold the plug, it should be ok. the seal comes from the gasket/washer on the plug and bolts only need 3 threads to hold under most circumstances. |
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