Tap Tap Tap

Post by **Benjy** » Fri Jul 04, 2003 12:16 pm

I'm getting a (faily noisy) tapping noise from my engine, a std 1098.

I thought it was just the valve clearences, but checked & they're OK. The oil level seems to make little difference and it's definately tapping once per rev.

I'm suspecting a worn tappet, but have been told they only tend to go at very hight milages (mine's currently 57k), though the car ran for a while with the tappets badly adjusted. Is this likely to be the problem?

If not, where else should I look? I Don't really wan't to strip the engine if I don't have to!

Ben

Post by **Kevin** » Fri Jul 04, 2003 1:45 pm

Ben how did you check your valve clearances, as the rockers can wear with age and can give a false reading.
Have you confirmed the noise as coming from the rocker cover because the timing chain is also guilty of making a noise probably the most common cause of noise from the engine (if you go to a rally quite a few of the arriving cars will have a timing chain rattle)

Post by **Benjy** » Fri Jul 04, 2003 2:41 pm

Kevin,

Rockers were checked using feeler guage between rocker face & valve stem, with tapet on heel of cam (i.e. value fully shut). Is there another way?

I'm pretty sure the noise is coming from mid-engine somewhere and it's quite a distinctive "tap", I haven't investigated the timing chain though. Will look when my wife gets back!

One thing I forgot to mention - the noise disapears occasionally. Usually only for a few seconds, mostly on acceleration, but always re-appears when cruising. This doesn't always happen, so I guess that sounds more likely to be the timing chain?

Post by **Gareth** » Fri Jul 04, 2003 3:16 pm

You can use a micrometer designed for adjusting tappets, which works on a click principle. They should take away any possibility of a fase reading, although I've not tried one, as they're about £25...!

It could well be the timing chain, although mine never stops clattering. It's on the list, but some way down, as I'm not sure how to go about fitting one of those lovely duplex jobbies!

Post by **dennis** » Fri Jul 04, 2003 5:38 pm

hi
i had a simialar noise about 6 months ago, just like a slight clicking, done all the usual checks, still had the noise, ok i thought must be the timing chain.
about 1 week after that the starter pully shattered, so i would also check that.

Post by **grainger** » Fri Jul 04, 2003 6:54 pm

one way to check where the noise is coming from is the old trick with a long screwdriver held to your ear and then touch the other metal end onto the running engine, it works quite well ...

ps is your oil ok ?

cheers
grainger

Post by **Willie** » Sat Jul 05, 2003 4:34 pm

TIP, if you suspect a tappet is causing noise then run the
engine on tickover without the rocker cover on and then
slide a feeler guage between each rocker gap the noise
will instantly disappear when you try the faulty one!
(you will get a slight splatter of oil but nothing too bad).
The way to overcome the fact that your rockers may have
worn a grove where they contact the valve is to grind the
feeler guage so that it is slightly less wide than the valve
stem. You will now get a true reading.

Post by **Daddsie** » Sun Jul 06, 2003 12:28 pm

Great tip Willie, cheers

Post by **Benjy** » Thu Jul 10, 2003 9:55 am

Sorry it's been a while, I've had a lot of work on & no time to play!

Thank Willie, I have re-checked valve gaps with tip of feeler guage & reset a couple. Generally less noise, but still a distinct tap once per rev!

Tried your tip of inserting feeler guage to kill noise, but it didn't seem to make much difference. The noise has a habbit of dissappearing all by itself, just when you're looking for it, so tests were inconclusive, but I think it must be a tappet - I can't see anywhere else it could be coming from!

I don't suspect the timing chain anymore, there's no rattle from the front of the engine. In looking at the book, there's no tensioner on this, so does noise mean that it's worn & needs replacement (gears too?) ? If so, what are the advantages of a duplex chain?

Post by **Cam** » Thu Jul 10, 2003 11:04 am

If there is no tensioner and there's no rattle, then leave well alone! but if it rattles a lot then yes, it needs replacement. Usually it is just the chain that stretches, but if you want to be sure, then replace the sprockets too (you have to remove them anyway to take the chain off).

Duplex chains are stronger and less prone to stretching (useful when used with high lift cams).....but on a standard engine, I would not bother unless you have to replace the timing chain anyway!

Post by **dennis** » Thu Jul 10, 2003 7:58 pm

i would still be inclined to check your starter pulley for fractures, i had one that shattered

Post by **Willie** » Fri Jul 11, 2003 12:02 am

Ok Benjy you have eliminated the rocker assemblies as
the cause of your noise. I think the earlier suggestion
of using a long thin rod or screwdriver over the engine
could pin point the source( it is a good old dodge).