Engine knocking sound / cannot identify
#61
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I am back after some time.
Timing updated with OEM parts but the engine is still knocking. I will remove it for revision.
FYI both secondary tensioners were cracked but they still keep pressure. There is metal cylinder inside which keeps shape and pressure thus I expect that they worked...somehow. Primary tensioners were in a good shape. Primary guides cracked and blades scratched by chain. Some pictures will follow.
Timing updated with OEM parts but the engine is still knocking. I will remove it for revision.
FYI both secondary tensioners were cracked but they still keep pressure. There is metal cylinder inside which keeps shape and pressure thus I expect that they worked...somehow. Primary tensioners were in a good shape. Primary guides cracked and blades scratched by chain. Some pictures will follow.
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Don B (04-29-2024)
#63
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Don B: I have no idea why Jag mechanic told me that 5.0 Pulley bolt is weaker compared to 4.0 bolts. I think it was related to material quality but I have to ask him again to clarify that.
I have a question regarding torque spec from your table above. My engine has split locking ring thus I expect it should be torqued directly to 375 Nm and not via Stage 1 80 Nm and Stage 2 80 degrees? Am I right?
I have a question regarding torque spec from your table above. My engine has split locking ring thus I expect it should be torqued directly to 375 Nm and not via Stage 1 80 Nm and Stage 2 80 degrees? Am I right?
#64
Join Date: Feb 2014
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The torque table in the manual says 375 Nm, but the actual crank damper replacement procedure in the manual says 364 - 386 Nm. Either way you should be good at 375 Nm. Bear in mind that the SAE considers a torque wrench sufficiently accurate if it torques to within +/- 4% of spec.
I'm so glad you replaced those cracked tensioners - they were a ticking time bomb as too many have discovered the hard way.
I'm very sorry to hear that the engine is still knocking after all of your hard work. How frustrating! Do you have a mechanic's stethoscope to probe around the engine to see if you can better locate the area of the knock? A long socket extension or screwdrive can work also if held to your ear while probing various points on the engine, but they are more awkward to use and less maneuverable than a stethoscope. Most auto parts stores carry them, and Harbor Freight carries one that works well at a very low price.
Cheers,
Don
Last edited by Don B; 04-29-2024 at 09:35 PM.
#65
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Don B: replacing tensioners was quite fun but yes, I would prefer to have the engine done already!
Removing the engine is something I would prefer to avoid...![Smile](https://www.jaguarforums.com/forum/images/smilies/smile.gif)
I have a stethoscope but localization is a bit difficult this time. Knocking can be heard at many places at the top and also at the bottom of the engine etc. It is strongest at the thermostat tower and maybe oil pan. There is not much to inspect and the source is 99% connecting rod bearings as this is quite common problem if the engine is running without sufficient oil level or with very old oil. Once bearings become slightly worn it is progressing more and more and knocking is main symptome AFAIK.
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I have a stethoscope but localization is a bit difficult this time. Knocking can be heard at many places at the top and also at the bottom of the engine etc. It is strongest at the thermostat tower and maybe oil pan. There is not much to inspect and the source is 99% connecting rod bearings as this is quite common problem if the engine is running without sufficient oil level or with very old oil. Once bearings become slightly worn it is progressing more and more and knocking is main symptome AFAIK.
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