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700/900 Series General Forum for the Volvo 740, 760, 780, 940, 960 & S/V90 cars |
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Nov 17th, 2017, 12:09 | #11 | |
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Nov 17th, 2017, 16:04 | #12 | |
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It will also help clean the piston rings allowing them to do what they should and improve compression and general running. There are a few other benefits but those aren't really relevant at the moment such as "Seal-Swell" which is an additive in most, if not all, ATFs that helps to revive and condition the various seals throughout the engine - you rarely if ever get an oil leak on an automatic gearbox unless there has been a problem internally. On cars with hydraulic tappets/lifters, it cleans and revives the hydraulic tappets as well. For example, the car i had between my last 740GLE and my current 760GLE was a Jeep XJ Cherokee 4.0 and when i first got it, that had at least 3 noisy lifters. When i say they were noisy, they sounded like i had at least three pile-drivers running under the bonnet when it was cold, not much better when it was hot either! First oil change a week or so into ownership and i used about 1.5L of ATF in the engine on top of the 5L of oil it had already taken - total capacity was just under 7L so it wasn't over-filled either! After a few hundred miles, that engine was quiet, cold or hot and pulled much more smoothly, quietly and more powerfully. Obviously you don't have hydraulic tappets so you won't get that benefit but when i got my 760, that was also noisy, particularly when cold, not as smooth as it should be either. That has had the ATF in the engine oil as well and it's like a different car now. That spark in the dizzy cap needs investigating! First there shouldn't be a gap that you can see through and secondly you need to try and find out where it's going - it's possible you've lost the carbon brush from the centre of the cap and you saw the spark jumping, if that is the case, i'm pretty sure you've found the problem.
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Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........ |
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Nov 18th, 2017, 16:33 | #13 | |
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The original cap was replaced by a Facet cap, but they looked exactly the same. On the picture I've marked the gap where I can see the spark through.
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Nov 18th, 2017, 21:17 | #14 |
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the blue spark you can see is to be expected - there is an airgap between the rotor terminal and the plug lead terminal and a spark generates across the gap.
If you are really worried about it, pull the cap off and look for thin, spiderweb like black lines on the inside of the cap. These are carbon tracking lines and indicate the spark is being lost to ground by tracking down these lines. The best technical running test is to get on a 'scope set to read the secondary ignition voltage and short each spark plug lead to ground while the engine is running. On the scope, you will see the voltage generated across the rotor/cap gap. It should be less than 5kv - typically 2-3kv. |
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Nov 18th, 2017, 23:05 | #15 |
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I forgot about that dimple in the cap, isn't there a flash-guard fitted on those dizzys?
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Nov 20th, 2017, 09:25 | #16 |
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