Posted: 1/25/2010 2:36:51 PM EDT
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Ok
Just got a big farm truck. It has a 7.5 L. 460ci engine in it. I noticed that it had a ticking sound coming from the engine when you ACCELERATE. Just like any other engine/truck I had growing up. I have been running 87 oct I put in 93 oct today and notice a considerable less to very little at all ticking sound. Explain Please..... I have always been told - Lifters clattering ??? Is that really itand the better octain makes it better , how ??? |
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Quoted:
Ok Just got a big farm truck. It has a 7.5 L. 460ci engine in it. I noticed that it had a ticking sound coming from the engine when you ACCELERATE. Just like any other engine/truck I had growing up. I have been running 87 oct I put in 93 oct today and notice a considerable less to very little at all ticking sound. Explain Please..... I have always been told - Lifters clattering ??? Is that really itand the better octain makes it better , how ??? When was the last tune-up?.....and what year is it? Lifters usually make noise all the time, but can get worse as engine speed and load increase. Higher octane will help prevent what is called detonation, cylinder heat and pressure will sometimes ignite the lower octane fuels in the compression cycle....earlier than it is supposed to be ignited.....the noise is usually a clicking or clattering sound.....this was common in the late 70s and through the 80s before higher octane fuels and better engine/ignition management became more common. An engine that needs timing adjustment or has cooling issues can also knock. mm |
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Probably off the path with this one since it got quieter with higher octane fuel but check for exhaust leaks where the manifolds bolt to the heads and where the exhaust pipes/y pipe clamp/bolt to the manifolds.
A slower tick will usually be 1 cylinder leaking on the head and a fast to fluttery noise is usually at one of the manifold to pipe connections. The noise isn't coming from just one side is it? |
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It is a 97 f250
fuel injected 460. The way it comes through the firewall - it sounds as if it is in the middle of the engine ( but not sure) I am guessing it is tthe detonation. I am gonna do a tune up on it in mid march, but it is in great shape. Not a shimmy or a shake. idles, sounds, revs, everything is outstanding. I just notice a tinking sound like a chattering on acceleration. When not accelerating , it sounds fine and just like a newer truck. Heck - I get mid 10s in city, and mid 13s on hwy with the thing . 170,000 miles , standard tranny, crew cab, with 285/75-16" mud tires on it. So I can't complain - just wondering if this was / could be anything out of the ordinary |
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Quoted:
It is a 97 f250 fuel injected 460. The way it comes through the firewall - it sounds as if it is in the middle of the engine ( but not sure) I am guessing it is tthe detonation. I am gonna do a tune up on it in mid march, but it is in great shape. Not a shimmy or a shake. idles, sounds, revs, everything is outstanding. I just notice a tinking sound like a chattering on acceleration. When not accelerating , it sounds fine and just like a newer truck. Heck - I get mid 10s in city, and mid 13s on hwy with the thing . 170,000 miles , standard tranny, crew cab, with 285/75-16" mud tires on it. So I can't complain - just wondering if this was / could be anything out of the ordinary could also be an ignition wire arcing under load, won't see it happening at idle/low load. You can SOMETIMES spray the wires w/ a light soapy water and get it to arc under no load or while revving the engine @ the throttle cable. Since the octane change produced a change I would still bet on actual detonation. do the plugs/wires/timing and also check/change fuel filter as lean conditions will contribute to knock (via increased heat and volatility of a lean charge) If you are in the DFW area I can take a look at it with you sometime. eta: I would continue to run 93 until the detonation is taken care of. Even in a naturally aspirated engine, long term effects are nasty. |
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Quoted: Does it change with revs? Could be the lifters, they tend to get out of tune quite frequently in older or mis-used engines. There's a lot more info, but this is an example: http://www.buicks.net/shop/reference/noisy_valve_lifters.html If it has hydraulic lifters and push rods it could be one of them. If you have a large and long Phillips screwdriver you can do the poor mans stethoscope. Place the screwdriver in methodical places on the engine and put the round top of the screwdriver against your ear. You will be able to find the general location of the ticking as it gets louder. |
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+1. Your neighbors are sure to love the temporary cloud cover you will provide, to boot. |
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Hahahaha
SEAFOAM. I ran a can in my 2001 Suzuki Bandit 1200. You talk about ahuge smoke cloud...... WOW !! It seems to be running pretty darn well today and hardly if any knock noticable, even if I seem to try as hard as I can to listen from inside the car without A/C or Radio on while I drive. I wonder if it just needs that higher octain ? I am gonna run 91 or 93 in it depending on what I have at the pump I get to and see how it goes for a bit. Someone today at work said to pour a can of Marvels Mystery Oil in the tank and run it through the engine ..... You ever seen anything with that ? |
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Hahahaha SEAFOAM. I ran a can in my 2001 Suzuki Bandit 1200. You talk about ahuge smoke cloud...... WOW !! It seems to be running pretty darn well today and hardly if any knock noticable, even if I seem to try as hard as I can to listen from inside the car without A/C or Radio on while I drive. I wonder if it just needs that higher octain ? I am gonna run 91 or 93 in it depending on what I have at the pump I get to and see how it goes for a bit. Someone today at work said to pour a can of Marvels Mystery Oil in the tank and run it through the engine ..... You ever seen anything with that ? 
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Quoted:
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It is a 97 f250 fuel injected 460. The way it comes through the firewall - it sounds as if it is in the middle of the engine ( but not sure) I am guessing it is tthe detonation. I am gonna do a tune up on it in mid march, but it is in great shape. Not a shimmy or a shake. idles, sounds, revs, everything is outstanding. I just notice a tinking sound like a chattering on acceleration. When not accelerating , it sounds fine and just like a newer truck. Heck - I get mid 10s in city, and mid 13s on hwy with the thing . 170,000 miles , standard tranny, crew cab, with 285/75-16" mud tires on it. So I can't complain - just wondering if this was / could be anything out of the ordinary could also be an ignition wire arcing under load, won't see it happening at idle/low load. You can SOMETIMES spray the wires w/ a light soapy water and get it to arc under no load or while revving the engine @ the throttle cable. Since the octane change produced a change I would still bet on actual detonation. do the plugs/wires/timing and also check/change fuel filter as lean conditions will contribute to knock (via increased heat and volatility of a lean charge) If you are in the DFW area I can take a look at it with you sometime. eta: I would continue to run 93 until the detonation is taken care of. Even in a naturally aspirated engine, long term effects are nasty. I'm thinking detonation too, a lot of people don't realize that knock they are hearing can melt a hole in the top of the piston. |
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Quoted:
Quoted:
Quoted:
It is a 97 f250 fuel injected 460. The way it comes through the firewall - it sounds as if it is in the middle of the engine ( but not sure) I am guessing it is tthe detonation. I am gonna do a tune up on it in mid march, but it is in great shape. Not a shimmy or a shake. idles, sounds, revs, everything is outstanding. I just notice a tinking sound like a chattering on acceleration. When not accelerating , it sounds fine and just like a newer truck. Heck - I get mid 10s in city, and mid 13s on hwy with the thing . 170,000 miles , standard tranny, crew cab, with 285/75-16" mud tires on it. So I can't complain - just wondering if this was / could be anything out of the ordinary could also be an ignition wire arcing under load, won't see it happening at idle/low load. You can SOMETIMES spray the wires w/ a light soapy water and get it to arc under no load or while revving the engine @ the throttle cable. Since the octane change produced a change I would still bet on actual detonation. do the plugs/wires/timing and also check/change fuel filter as lean conditions will contribute to knock (via increased heat and volatility of a lean charge) If you are in the DFW area I can take a look at it with you sometime. eta: I would continue to run 93 until the detonation is taken care of. Even in a naturally aspirated engine, long term effects are nasty. I'm thinking detonation too, a lot of people don't realize that knock they are hearing can melt a hole in the top of the piston. I've got a knock induced paperweight of a piston holding files down on my toolbox. took about 3 seconds and it destroyed a quite expensive motor. looks like somebody literally beat the piss out of the piston for an hour with a sledgehammer. |
| Check that you don't have an air leak after the mass air sensor. Could be as simple as a loose intake tube. Be sure to also check vacuum lines and the PCV line and where they make connections. Small leaks will show up as detonation under acceleration. If there is a larger leak you would likely notice a rough, low idle in addition to the detonation under acceleration. |