The 75 and ZT Owners Club Forums - KV6 engine rattle/grinding

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- - KV6 engine rattle/grinding - *not* inlet manifold? (https://www.the75andztclub.co.uk/forum/showthread.php?t=308535)

Quote:

Originally Posted by Teflon (Post 2842264)

New pistons and liners ...

Thanks Cliff. What was the mileage at the time and was a reason found for this rare condition?

Simon

Mileage was around 76K, so pretty low. Speaking with Russell and subsequently another ex MGR mechanic, I don't think the issue is as quite as rare as you may imagine, rather it simply goes undiagnosed, or mis-diagnosed. By no means common though.

As for the root cause, it's up for debate. Russell used to work for a main dealer some years back, and said the issue was quite common in low mileage 1.4 K series. One common factor was that the cars in question had all lead a very gentle life and been treated with "kid gloves" as they say - much as I treat mine (it rarely goes over 3K revs). Russells advice going forward was to let the engine work a bit every now and then. No driving like a loon, but just hold it in a low gear a little longer than normal once in a while to give it some excercise.

Interestingly, whilst I had a shed full of engine bits, I was finally able to check the pin holes in the cam covers. Both were perfectly clear - not sure why that should surprise me, but it did nonetheless :}.

Cliff

Quote:

Originally Posted by Teflon (Post 2842338)

Mileage was around 76K, so pretty low ... As for the root cause, it's up for debate.

Thanks for this Cliff. :}

Quote:

Originally Posted by Teflon (Post 2842338)

I was finally able to check the pin holes in the cam covers. Both were perfectly clear ...

Congratulations! Could it be down to diligent oil changing maybe?

Simon

Quote:

Originally Posted by Teflon (Post 2842173)

Here's what mine sounded like - more of a knocking than a grinding (noise starts at around the 18 second point):

The knock would only occur when the engine was stone cold, and only for a few seconds (1 minute max), after which all sounded fine. Opinions ranged from tappets, main bearings, idler / tensioner noise etc, however Russell used a long screwdriver as a stethoscope and correctly identified it as piston slap. He suggested the engine would probably out live me and was nothing to worry about at this stage, but being a picky so & so I wanted the noise gone, so he pulled the engine apart and sorted it :}.

It's worth mentioning, Russel is mobile and has been known to travel a fair distance for jobs. This week he is due to be in Liverpool (though I guess that plan may change with current restrictions). Having said that though, I guess a long trip just to listen and diagnose may not be the most economic approach.

Cliff

Dry tappets?

Quote:

Originally Posted by bl52krz (Post 2842570)

Dry tappets?

Nope, piston slap :}

https://live.staticflickr.com/65535/...84a46e83_b.jpg

Cliff

Quote:

Originally Posted by Teflon (Post 2842264)

New pistons and liners, plus new main bearings (it just made sense whilst everything was in bits), new gasket set, and a new clutch.

A lot of work, but it's nice and quiet now as it should be :}

Cliff

Very interesting post for me. I 'd have to fix a noise like that too. Useful to know.:bowdown:

Just a thought but the V6 has a low end induction "growl" which changes as the VIS balance valve opens and closes, between 1000 and 2000 revs approx. This could be mistaken for a grinding noise. (not to be confused with a definite ticking noise) :shrug: