[rdye]

Did any of you notice any noises in the engine associated with the broken timing chain slipper referenced here?
http://www.sleeoffroad.com/technical/tz_time_chain.htm

I have a persistent internal noise in the front lower portion of the 1FZFE in my 1993 Land Cruiser. The noise is not present in cold weather at all and only starts after operating temps have been reached in warm and hot weather.
It sounds like pre-ignition under light loads and low speeds. At idle it is audible if you listen under the front of the engine and very noticeable with the old screwdriver to the ear trick. Again, when the engine is cool all you hear is the timing chain slinging oil. The engine has 151,000 miles on it and runs great. I would just love to get rid of the strange noise that a few of us 80 owners have and nobody seems to be able to resolve. This noise has been plaguing me for 2 years.

Recent work:
Tune up with oem parts and 1 degree cooler plugs
New fan clutch
Coolant system flush and fill
Professional decarb
Switched to 20w50 Amsoil 100% synthetic for the summer.

[knorrena]

No help from me yet - still to much of a newb; however, Whats a professional decarb?

Karl

[rdye]

I don't know too much about the process but I suspected I had a pre-ignition problem, possibly cause by carbon deposits, because the "pinging" noise would start after warm-up. So I thought I would try the de-carb since the 1FZFE is prone to carbon deposit problems.

They hook your car up to a machine that injects chemicals to soften and burn off carbon deposits in the intake system and combustion chambers. I haven't watched the process but I also had it done on a '92 3.0 V6 4Runner with tremendous improvement noticed in performance afterwards. It made absolutely no noticeable difference with the Land Cruiser. Cost was around $140as I recall.

I found some info on a Google search when I was researching the decarb process. I am sure a mechanic equipped with the machine could explain it to your satisfaction.

[IdahoDoug]

Rdye,

If your sound occurs at dead idle in Park, then it's not preignition pinging. If it's in the lower engine, another data point against that. What are you putting your screwdriver against to hear the sound?

DougM

[rdye]

Originally Posted by IdahoDoug

Rdye,

If your sound occurs at dead idle in Park, then it's not preignition pinging. If it's in the lower engine, another data point against that. What are you putting your screwdriver against to hear the sound?

DougM

I hear the noise when I place the screwdriver tip on the front of the shallow oil pan near the front of the engine. as I move towards the rear of the engine the sound lessons but is still clearly audible. The pan seems to amplify the noise. When I touch the pan with anything the noise is greatly reduced listening without the ear to the handle of the screwdriver. However, when I place my ear on the handle I hear a loud metal-slapping-metal sound that is irregular and off-beat to the revolution of the engine. It is a loud, irregular and tinny clattering when driving.

[landtank]

I'd pull the valve cover and take a look down the front of it. I think you can get a good line of sight along the timing chain.