Miata engine noise under lifter ticking

[datsun40146]

I bought my 99' Mazda Miata about 2 months ago I guess. It has a 1.8 Liter four cylinder and a 5-speed transmission. I've put right around 800 miles on it, and I've been driving spiritedly for some of them. Anyway, I know all about lifter tick having grown up with manual lifters Datsun and VWs its not the problem here. I happened to turn off my radio today and I heard a slight repetitive sound similar to a ping or a knock is the best way I can describe it. I took two videos with my camcorder and one can hear the sound and the lifters clattering away in the background. Can anyone ID the noise? The car is not burning any oil or loosing any coolant that I can see. Its still have plenty of power, and it not using undue amounts of fuel. The car has right at 100K on the engine and all the maintenance has been done. I have a stack of records an inch and a half thick to prove all of them. Anyway the noise is present throughout the rev range. Here are the video. In the frist I vary the rpms.


In the second I hold them constant.


Please ignore the quality of the video, I was trying to get the sound captured.

 

[venomballistics]

hard to tell ... the modern gadget box of toys lacks a good sound recorder.
I think I hear a hint of a squeak to go with the knock which would have me gnawing my fingernails about a rod or cam bearing thats just gotten real expensive.
check oil after a 20 second run, and smear the dipstick on glass so you can look through it ... if you see iridescent floaters in there your in heap big trouble

 

[LVSteve]

The digitisation of the sound distorts it somewhat, but some of the noise sounds like a loose cam drive chain. I had a car in the UK where the chain tensioner ran out of travel and the chain thrashing about made a "chobolling" noise.

This is where I find out the Mazda uses a toothed rubber belt..

 

[randy g]

sounds like a timing chain

 

[wheelieguy]

Sounds like a trip to the local Mazda dealer is in order. Mazda Knoxville is great! They're the only people I let tinker with my NC MX5.

 

[Uncle Larry]

Sounds like it's time to get out the stethoscope and/or find a good indie shop that will go over everything thoroughly...it could be anything from a pulley bearing going bad to a pump bearing to (Heaven forbid) the start of a rod/crankshaft bearing headed South...
Hope you find out what it is.

 

[venomballistics]

The digitisation of the sound distorts it somewhat, but some of the noise sounds like a loose cam drive chain. I had a car in the UK where the chain tensioner ran out of travel and the chain thrashing about made a "chobolling" noise.

This is where I find out the Mazda uses a toothed rubber belt..

yup ... looked it up .. engine type code seems to be a "BP-4W" .. all of its ilk are belt drive DOHC

 

[mod34]

I am on my 6th Miata and have never had a problem with one, just bought 'em, drove 'em and sold 'em. To me they are almost like a pet, I can't be without one. In any case, the one I'm driving now has a born on date of 10/89 and had a pretty nasty valve tap when I bought it. The fact that the oil was let go until it was sludge didn't help a darn thing. The cure for your ills is to run 3 parts Castrol 20-50 to 1 part Marvel Mystery Oil and change it along with a new filter every 500 miles or so for 3 or 4 changes. Your tap will all but disappear. Keep in mind that there are 16 little, teeny, tiny holes in the lifters and it sometimes doesn't take much to make 'em sticky. Try it, I think you'll have great results.

 

[enfield]

Injectors tick also.

 

[p_jackson]

Wrong weight oil will cause problems

 

[7tenz]

Exhaust leak? Check for broken manifold studs and the gasket. Also check for some other simple things first.

 

[Bob R]

When I had a stuck lifter making that dreaded ticka-ticka noise in my Ford van I added and ran ran a quart of Marvel Mystery oil in it for about an hour then drained it. When I replaced the oil I used diesel engine oil, it has more detergent properties than regular oil. I ran that for about 500 miles, the tick went away and never came back. I then did normal oil changes with the regular oil I always used.

Another thing to look into is whether or not your particular model has any TSB's (technical service bulletins) that cover the tick. It may be something that Mazda did something about, such as changing oil weights.

bob