Synthetic Oil Prep??? (1 Viewer)

[Jim_Chow]

I'm with Tinkerer. I'd never run a synthetic oil 10K mi here in So. AZ...way too much dust in the air. Sure, the OEM air filter gets most of it, but you know there's still some tiny particles that make it into the engine and aren't picked up by the oil filter. I'd look at your applications. If you drive lots of constant-speed highway miles and the air is clean (e.g., it rains often to flush the particulates out of the air, you live in the Pacific NW, etc.), you can push synthetics a long way. But if you take lots of short trips, temperatures are extreme, air is dusty, etc., you should adjust accordingly. I wouldn't blindly run it 10K mi just because it's a synthetic. I only run synthetic here in AZ due to the extreme heat. It gets changed out nominally around 5K mi.

 

[SWUtah]

How much of the valve gap over time is due to cam/bucket wear, and how much is due to valve seat/valve face wear? The former will cause them to get looser over time but the latter will cause them to get tighter & oil quality/change frequency won't affect that.

Since mine now has 100k on it & the dealer said that's when they recommend inspecting/setting the gap, I'm going to take the covers off mine just to see how it's doing. I won't necessarily go to the trouble of re-gapping it but it (unless it's way off) but it would be good peace of mind to know how it stands.

If it will make you feel better go for it but the 4.7 has shims just like the 4.5 used in the FZJ80 I checked mine at 100K and they were perfect. Never heard of any that needed adjustment at 100K.

 

[Tinkerer]

How much of the valve gap over time is due to cam/bucket wear, and how much is due to valve seat/valve face wear? The former will cause them to get looser over time but the latter will cause them to get tighter & oil quality/change frequency won't affect that.

Since mine now has 100k on it & the dealer said that's when they recommend inspecting/setting the gap, I'm going to take the covers off mine just to see how it's doing. I won't necessarily go to the trouble of re-gapping it but it (unless it's way off) but it would be good peace of mind to know how it stands.

Correct, regarding the fact that wear may cause either increased lash (clearance) or decreased lash, depending.

A little too much lash is not much of a problem. Insufficient (or negative) lash can lead to burned valves/seats.

Let us know what you find, if you decide to inspect yours.

 

[SWUtah]

Correct, regarding the fact that wear may cause either increased lash (clearance) or decreased lash, depending.

A little too much lash is not much of a problem. Insufficient (or negative) lash can lead to burned valves/seats.

Let us know what you find, if you decide to inspect yours.

That is what I learned, they don't get loose, they get tighter and can end up burning your valves if they get too tight. If you can hear them then you are OK it is when it gets quite that you end up having the problem. But I have never heard of anyone having a problem. But I would love to here how yours look after 100K miles

PS you adjust them with shims

 

[100 TD]

Thought I would mention this for information only, the Australian service book for V8 petrol engine says to "inspect" every 80.000 kms (50,000 miles). The note says "Inspect tappet noise and engine vibration at idle and adjust clearances if necessary."

The turbo diesel 100 series (1HD-FTE) states the valve clearance must be "adjusted" every 20,000 km or 12,000 miles..............what an absolute wank, they are just trying to keep their service departments in a cash flow positive status. By the way, they are adjustable., not shim.