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spark plug came loose
not sure what this means, but i had a spark plug come loose. i pulled off the airbox, etc... but i cant seem to get the spark plug to thread in. it makes a roation and 1/2, but then siezes and wont turn any more. A friend of mine said there is some kind of timing to doing the plugs, or a sequence or something?? any info would help! Also, this is the 2nd time this has happened within like 3000 miles. dont think it was the same plug though.
Also, where can i get a cheap manual for the 01 F4i? Thanks again, you guys are great!! |
RE: spark plug came loose
The plugs screw in like any other plug. The screwing in part isn't any different. If you are having trouble it may be because when the plug blew out it buggared up the last couple of threads.
STOP NOW. If it won't screw in with light pressure, then take it to a shop than can chase the threads with a tap. This will clean them up without having to drill/tap/rethread your cylinder head. I would think that just chasing may not require the removal of the head. If it needs to be re-tapped the head will need to come off and that's going to cost some bucks if you can't do it yourself. What do your plugs look like? If they keep backing out and look fine, then you are just not tightening them up enough. Check the plugs though because you may be getting detonation. That can somtimes cause plugs to back out. |
RE: spark plug came loose
Exactly!! Only thing I'd add is that unless you're running really crappy gas you shouldn't be getting detonation on a F4i -- I'd check the timing chain/cam sprockets to make sure it didn't jump.
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RE: spark plug came loose
ok, im new to this whole thing. what is detonation exactly? as for the gas thing, i only run premium (Shell or Chevron). How do i check the timing/cam? I think everything is fine. it was running great until all of a suddent the plug came out.
To answer your question, the plug looks fine. threads are good, and there is no real burning or anything out of the ordinary that i can see. What kind of shop can i take it to and get someone to chase the threads? I know i have a lot of questions, but i would really rather learn to do all this myself than just pay someone to do it. I mean, thats part of owning a sportbike right??? |
RE: spark plug came loose
Detonation is when the fuel ignites before it's supposed to. It's usually caused by excessive heat which can be a result from bad timing or bad air/fuel ratio. Other things can also cause detonation.
The plug threads would probably look fine because they're steel and the head is most likely aluminum. It may have steel inserts but I doubt it. On something as serious as the plug coming out I would take it to a dealer or a reputable shop in your area unless you are 100% confident in your skills. Chasing the threads my solve the problem but you'll need to blow out the cylinder and make absolutely certain there is no debris left in there or you run the risk of killing some valves or rings. Cam chain timing is explained in painful detail in the shop manual -- there are some floating around the net in PDF format that you can download if you have a broadband connection or you can buy one off e-bay from $5 to $50. |
RE: spark plug came loose
pssssssss....chain mang...you mean predetonation? we WANT detonation mang!
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RE: spark plug came loose
Detonation The fuel/air mixture is normally ignited slightly before the point of maximum compression to allow a small time for the flame-front of the burning fuel to expand throughout the mixture so that maximum pressure occurs at the optimum point. The flame-front moves at roughly 33.5 m/second (110 feet/second) during normal combustion. It is only when the remaining unburned mixture is heated and pressurized by the advancing flame front for a certain length of time that the detonation occurs. It is caused by an instantaneous ignition of the remaining fuel/air mixture in the form of an explosion. The cylinder pressure rises dramatically beyond design limits. If allowed to persist detonation will damage or destroy engine parts. Detonation can be prevented by: The use of a fuel with higher octane rating The addition of octane-increasing "lead," isooctane, or other fuel additives. Reduction of cylinder pressure by increasing the engine revolutions (lower gear), decreasing the manifold pressure (throttle opening) or reducing the load on the engine, or any combination. Reduction of charge (in-cylinder) temperatures (such as through cooling, water injection or compression ratio reduction). Retardation of spark plug ignition. Improved combustion chamber design that concentrates mixture near the spark plug and generates high turbulence to promote fast even burning. Use of a spark plug of colder heat range in cases where the spark plug insulator has become a source of pre-ignition leading to detonation. Correct ignition timing is essential for optimum engine performance and fuel efficiency. Modern automotive and small-boat engines have sensors that can detect knock and retard (delay) the ignition (spark plug firing) to prevent it, allowing engines to safely use petrol of below-design octane rating, with the consequence of reduced maximum power output and efficiency. A knock sensor consists of a small piezoelectric microphone, on the engine block, connected to the engine's ECU. Spectral analysis is used to detect the trademark frequency produced by detonation at various RPM. When detonation is detected the ignition timing is retarded, reducing the knocking and protecting the engine. See also Automatic Performance Control (APC). [edit] Pre-ignition Pre-ignition is a different phenomenon from detonation, explained above, and occurs when the air/fuel mixture in the cylinder (or even just entering the cylinder) ignites before the spark plug fires. Pre-ignition is caused by an ignition source other than the spark. Heat or hot spots can buildup in engine intake or cylinder components due to improper design, for example, spark plugs with heat range too hot for the conditions, or due to carbon deposits in the combustion chamber, or also due to overheating of the air/fuel mixture during compression. Pre-ignition and "dieseling" or "run on" are the same phenomenon, except in the latter case the engine continues to run after the ignition is shut off with a hot spot as an ignition source. Pre-ignition might cause rough running due to the advanced and erratic effective igniton timing and may cause noise if it leads to detonation. It may also cause "rumble" which is fast and premature but not detonating combustion. This heat buildup can only be prevented by eliminating the overheating (through redesign or cleaning) or the compression effects (by reducing the load on the engine or temperature of intake air). As such, if pre-ignition is allowed to continue for any length of time, power output and fuel economy is reduced and engine damage may result. Pre-ignition may lead to detonation and detonation may lead to pre-ignition or either may exist separately. |
RE: spark plug came loose
Toe-may-toe / toe-mah-toe :D
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RE: spark plug came loose
ok, this is getting taken care of, my neighbor is pulling the head off cause two of the seats were totally stripped. I have seen a few posts on here mentioning a "heli-coil"? what is that, and is that the best way to repair the seats? hope im getting the terms right. Thanks again for all your posts, you guys are awesome!
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RE: spark plug came loose
yikes...could be the plugs weren't torqued down, came loose then the pressure and detonation blew them out...
helicoil...basically, it's a sleeve (hollow tube) that goes into the hole, it's threaded on the outsdie and inside...outside threads allow it to thread into the head, inside ones allow the spark plug to thread in. yea helicoil them...or get new heads... |
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