[Delilah]

Quick general question if you don’t mind for you more engineering-minded people - When changing your oil and oil filter, does the first start-up (dry start) straight after cause any more wear/harm to the engine than a regular engine start?



Asking for a dumbass who changed his oil twice in a week due to putting the wrong oil in (don't ask) :-/




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[PACABADA]

The old oil is still inside the oil journals, oil pump, oil cooler and oil lines so I would say no.


Paul 03 ST4s, 15 675RX, 96 ZX11, 76 KZ900LTD B-1, 72 SL125

 

[Chuckracer]

Agreed, plus the film is still on the camshafts, etc. It's fine.

I really want to ask though.

 

[belter]

if i can i disable the ignition system, remove the plugs and crank it on the starter until it gets oil pressure. that way there's no pressure on the big ends until they have oil. cam lobe load is not reduced though, and later engines are still running cams against heads as the belt tension will push the oil out of the rh bearings i'd think.

but i don't know if oil pump speed has any bearing on how long it takes to fill the system with oil, then pressurise it. if it takes 100 revolutions (for instance) to get the oil up do you want to do it with no load at 250 rpm or idle load at 1,200 rpm. although the newer engines generally go straight to 1,800 - 2,00 rpm on cold start. if it still takes 100 revolutions to get the oil up then it's got 5 seconds or so of no pressure. maybe it takes less than 100 revolutions if it's doing 2,000 rpm. thoughts?

you can prefil spin on filters, but a pani has a cartridge so you can't do anything there. so every oil change it's going to get several seconds of no oil pressure. if they don't see it as an issue then it must be ok.

you can turn the engine over by hand and get the oil everywhere too. when i'm doing cam timing on a 4v i always start with the horizontal as that way you can usually get the rocker cover back on before it starts pissing oil out.

 

[Turbomart]

It's better to warm up a motor before draining oil and pre-fill oil filter before fitting if possible. Yes there is the possibility of increased wear but following these guidelines it's extremely low. Don't rev the engine after change until oil pressure comes up. I wouldn't sweat it too much tho, it's a bit like warming up a motor in the morning after oil has drained back to the sump overnight.