Tappet Sound

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HusseinBM

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Hi Guys,
I completed restoring my E9 CSi 75 few months ago. A big thanks to Don as without him I wouldn't have managed to restore it. I am from Oman and I will write the full story of my car's restoration in another post. I have upgraded mine to M30B35 engine.
However, recently I hear something like tappet sound from the engine and also when I drive I feel that somehow it doesn't sound right. Anyone has any idea if the engine requires valve adjustment or could it be something else?
Any help would be much appreciated.
Regards,
Hussein
 
Do a valve adjustment and ensure your timing chain tensioner is working properly.
 
Remove the valve cover, check both oil bar bolts for tightness and adjust the valves to factory spec on a cold engine. With valve cover off- verify that the piston that provides the pressure to the timing chain tensioner is very firm against the tensioner.
Use a long screwdriver For this.
Also- with engine running- check that nothing is wobbling in the front of the engine.
If you take a video, can you hear the noise in the video?
 
Some rhythmic noise is both normal and practically unavoidable in a flat tappet-equipped reciprocating engine. Thus, checking valve lash is never a bad idea, especially when detecting an abnormal or unusual noise.

It is often difficult to differentiate between normal and abnormal without actually hearing the noise. Prior to removing the valve cover, it might be prudent to use a mechanic’s stethoscope or big screwdriver against the ear to localize the sound source. Is it toward the front or back of the valve train? Or, could it be lower and nearer the crankshaft or even emanating from one of your belt driven accessories, e.g., power steering or alternator? (Could a cooling fan blade tip be contacting the fan shroud?) A minor exhaust manifold leak due to a loose gasket could also be an overlooked “rhythmic” noise source, although it is typically described more like a knock rather than a tick. (Your tick might be someone else’s knock.) Depending upon the noise level, it is also quite possible, as suggested, that the oil spray bar is loose. Electronically triggered injectors ordinarily make a minor clicking noise, too. A vacuum leak where an injector tip fits into the manifold can sound like a squeak.

New parts go far in reducing the likelihood of problems, but absolute guarantees against imperfections and abnormal wear are rare. If your csi uses a traditional ignition distributor, consider that it too, contains parts that rotate which can make noise. A loose or bent plate (sandwiched between the distributor and the cylinder head)? Speaking of unlikely, since you mention hearing the noise “while driving,” a pebble or other foreign object wedged in a tire tread can make a rhythmic tick, tick, tick . . .


iu
Repair8.jpg




oil spray bar?
inv_014639_09.jpg




inv_014639_10.jpg


not a csi distributor, but note "plate" and imagine it is loose.
iu





1975_BMW_35CSLIMSA1.jpg




Alexander_Calder,_1975_BMW_3.0_CSL.jpg
 
Last edited:
Thanks a lot guys for your invaluable responses. It actually makes noise not only when moving but also when it is idle. The noise is high when the engine is cold but it goes down after some time. From my initial observation, the sound is from the front. I will see if I can take a video with some sound and post it later.
I really appreciate your feedback and will be back in touch soon.
Kind Regards,
Hussein
 
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