Im guessing the heat from the engine expands the cylinders causing play ... Its not common on these 1uz engines though ... Only one other gs4 I have heard with anything along these lines

 

It's been running for nearly 5 years. But on that particular engine it's been running 2 years.

I haven't heard of a stock piston having piston slap. Since stock pistons are forged, the tolerances are tight and there isn't much expansion of the piston. Piston slap would occur more often when it is cold. As the piston heats up and expands, the "slap" should be much less. The cylinder walls do not expand to cause "slap"

 

Yeah I'm not an expert on engines but I understand what you are saying...

Since piston slap usually occurs when engines are cold , what in the hell is this ...I hope that hi98gs is right about the bracket. Well at least for my situation ...

 

I also forgot to ask , into your situation , when did the engine make the sound? Did it do it while car was in park or neutral ? Or just drive ?

 

It came on when the engine was running. But was louder when the rpm was going up. At idle, it was not really noticeable, but then again I don't have stock cams so the car sounds like a rumbly V8 so I couldn't really hear it.

 

Does it sound anything like the misadjusted cam lash issue? Makes your engine sound like a diesel.

 

Im sorry I've never heard of that issue... ANY insight on that from anyone else?

 

Update:


Dropped the car off to the mechanic yesterday.... He came to the conclusion that the engine was "Pinging"... based off of the fact that the sound was only happening when the car was warmed up and only on acceleration while in drive. It fit the description.

So since changing gas didn't work and several other options that should have solved the problem, He will have to go into the engine and look at the valves to see if there is any carbon build up which requires taking off the head.

We are also doing a full tune up and timing belt is also going to be done since I am not really sure if the previous owner did it or not.

This is going to be an expensive job and I hope it solves this... wish me luck fellas.

 

This will sound stupid but have you looked around for loose heat shield, maybe valve adjustment, dumb little things like that?

 

Checked for heat shield already... Havent checked valve adjustment... He will get to the bottom of it. I just left the car and told him to fix it

 

Any update on this? My 2000 LS 400 had a funny sound when I pulled in the driveway that my father heard....I had floored the car to like 85 down our street then slowed down and pulled into our driveway.....he said "it sounded like a truck"

Sounds similar.....any ideas?

 

Well i tamed down the issue by putting the highest quality of sunoco gas in my car.... The problem definitely has minimized since I changed gas. I hear the sound once in awhile but its rare... Sample different types of gas and see if it works.

 

BP gas is you problem or one of them. Use better gas!

On my car it sounds like the valve train is making alot more noise here lately. It is about time for another timing belt so I plan on having my valve lashing checked out.


Thicker oil could help.

 

After looking up the bearing clearances in the 1UZ-FE I wouldn't stray too far from 5W30 in winter and tops, 10W30 in summer, this is a very tight tolerance engine. Very very tight.

What is the oil pressure like? Adding a turbo takes out oil from the main oil gallery, so turbos would be more susceptible to a problem. With an engine with miles on it (any, not just turbo) the oil pressure needs to be monitored. If the oil pressure is dropping due to sloppy rod bearings or main bearings, then by all means, step up the oil weight till the oil pressure returns to normal.

Don't be afraid to run 15W40 or 20W50 in an old high mileage tired engine. It NEEDS it. But one that is still tight and tight bearing clearances, don't do it, you don't want to add the drag to the engine when cold.