Mimosa Posted July 19, 2020 Report Share Posted July 19, 2020 Hello all, I've a TR6 1975 US model where I've renovated the engine i.e.; renovated crankshaft, new bearings, new pistons and rings, gas flowed and shaved head, new valves and new rocker shaft with bearings. The engine runs fantastic except when it gets warm a tapping noise starts over 2000 rpm under accelleration. The timing has been checked and the valve clearance. Any suggestions on what it could be? Quote Link to post Share on other sites
Tim D. Posted July 19, 2020 Report Share Posted July 19, 2020 I had a tapping sound that came from a loose alternator fan. Also from a loose front pulley Tim Quote Link to post Share on other sites
Mike C Posted July 19, 2020 Report Share Posted July 19, 2020 If you can get the noise with the car stationary, I'd reach for a mechanic's stethoscope to try and track it down. Quote Link to post Share on other sites
DaveN Posted July 19, 2020 Report Share Posted July 19, 2020 (edited) Broken piston ring... worst case! One other thing to try is get the engine hot, remove the rocker cover and with the engine idling slip a feeler gauge under each tappet in turn and see if the noise stops. Edited July 19, 2020 by DaveN Quote Link to post Share on other sites
Mimosa Posted July 20, 2020 Author Report Share Posted July 20, 2020 Thanks for the advice. Could it be the rocker shaft? Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 20, 2020 Report Share Posted July 20, 2020 20 hours ago, Mimosa said: Hello all, I've a TR6 1975 US model where I've renovated the engine i.e.; renovated crankshaft, new bearings, new pistons and rings, gas flowed and shaved head, new valves and new rocker shaft with bearings. The engine runs fantastic except when it gets warm a tapping noise starts over 2000 rpm under accelleration. The timing has been checked and the valve clearance. Any suggestions on what it could be? What fuel are you using? If you retard the ignition timing 3 - 5 degrees from where it is now does the noise go away? Cheers Peter W Quote Link to post Share on other sites
Mimosa Posted July 20, 2020 Author Report Share Posted July 20, 2020 I'll check it out, but according to a mechanic it is not originating from the ignition timing. Quote Link to post Share on other sites
Mike C Posted July 20, 2020 Report Share Posted July 20, 2020 Oil pressure/bearings OK? Engine mounts tight? No exhaust leaks? I assume the tapping noise is related to engine speed- it does not change with gear changes. Quote Link to post Share on other sites
SpitFireSIX Posted July 20, 2020 Report Share Posted July 20, 2020 "a tapping noise starts over 2000 rpm under acceleration." Sounds like pinging. Retard as advised to check. Quote Link to post Share on other sites
Mike C Posted July 20, 2020 Report Share Posted July 20, 2020 Does it get worse or disappear under 2000 RPM. Detonation pinging will get worse . Quote Link to post Share on other sites
Mimosa Posted July 20, 2020 Author Report Share Posted July 20, 2020 It is only above approx. 2000 rpm. and only when driving, not when you just rev the engine. Exhaust manifold has been checked. Quote Link to post Share on other sites
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