Clackety-clack

[Vetman]

I took my 75 L48 modified for a run yesterday and on returning home I noticed some tappet noise on the passenger bank. Today I removed the valve covers and spark plugs in order to adjust all the tappets. I turned the motor on the crankshaft pulley nut by spanner to each cylinder TDC based on firing order at 90deg apart. I found zero lash and added a 1/2 turn tightening to the adjustment nut. I used the starter motor to spin the engine and all ok. I replaced the spark plugs and leads and fired the engine. Very noisy and worrying, and a burning smell on the passenger side, so I switched off. I removed the passenger cover and checked the rockers and all seemed fine. I fired the engine again and the engine was quieter. I used a length of wood as a stethoscope to listen for unnatural noises but seemed ok. I switched off, replaced the cover, and removed the driver side cover to check and listen to this side. Starter motor dead. I connected the battery charger and tried again but still dead. Ho hum.
Any thoughts.

 

[stealthyflatfish]

Interesting, you stated starter motor dead, after cranking over on the starter motor a few times. Mine did that one day ( 1971 ) whilst fiddling with the timing and plugs etc, checked battery connections all ok, started checking cables further down towards the centre console and found a switch raped in insulation tape, took tape off and exposed the switch to reveal a thermal cut off switch which had gone open Circuit because the starter motor cable was very hot, so to stop the cable getting hotter and hotter the switch cuts out when it reaches a predetermined temperature. So I remade the connections and remounted the switch properly, but didn't re wrap the switch in insulation tape so it was open to air. Now I'm assuming that it's not a standard part, but thought it a good Idea to keep it as it stops the cables getting to hot. The only downside is you can't keep cranking and cranking the engine until the cable temperature drops, so just leave it for half hour then try again.

 

[Oneball]

I think your starter might have jammed so it was spinning with the engine and that was the noise and burning smell.

 

[Vetman]

I will loosen and re-tighten the battery post connections to see if that makes it happen.
I wondered if anyone had experienced initial engine noise after tappet adjustment. My worst fear was valve to piston contact but subsequent engine running seemed normal.

 

[Roscobbc]

Valve to piston contact won't happen unless timing chain has slipped a few teeth (very unlikely) - dialing-in the lifter pre-load sounds like a breeze to do (and generally works OK) - in my experience, and certainly with a hot cam is that it is something I have to repeat once or twice to make sure all clearances are the same and that the lifters are operating equally quiet. The longer it takes to do the bigger the chance of needing to adjust a few lifters again. Rather than use the 90 degree method I use this..........

Valve Adjustment Procedure - Century Performance Center, Inc.

Learning the proper valve adjustment procedure for V-type engine applications ensures a smooth-running, powerful, and reliable vehicle.

www.centuryperformance.com

 

[Vetman]

Thanks for the reply. I will try that method next time. Unfortunately at present I get no starter motor response when I turn the key. Not even a click. Sorting that problem is my next task. Just looking ahead and assuming I will have to replace the motor or solenoid or both, can I improve on the 1975 L48 standard equipment? Alternately, could there be another cause like the ignition or starter circuit? Is it fused?

 

[Vetman]

I think your starter might have jammed so it was spinning with the engine and that was the noise and burning smell.

You are correct I think. Today I checked for 12v at the power connection to the solenoid and also got 9.4v at the ignition connection on the solenoid with the key turned to start.
I then shorted the power connection to the motor connection just beneath. Big spark as expected but still made me jump. The car then started on the ignition key. This gave me a chance to listen for tappet noise following my earlier adjustments. Sounded ok. Took the car for a short drive with no issues. Oh joy.