Originally Posted by oil_film_movies
Originally Posted by Shannow
Startup wear on cool/cold morning...again, how ?...0W isn't needed until quite a few 10s of degrees below zero...."cool" mornings, 10W, 15W, and 20W will not increase wear...with a PD pump, well into the pumpable range, they all get there at the same time.
No, VII only works at warm to hot temperatures, increases visc there. Remember 0w20 is made with thinner base oils than 5w20.
Also, there was a study showing that as long as startup visc is different, startup wear is different. That engineering study already refuted debunked remarks by you in another thread, yet there you go again. ...0w20 and 5w20 differ in visc below about room temperature as the VII becomes less effective.
From another thread, so we can use an actual engineering test set to settle the less wear at startup due to better lower viscosity argument:
Originally Posted by NGRhodes
Originally Posted by Ducked
Originally Posted by NGRhodes
http://www.emeraldinsight.com/doi/pdfplus/10.1108/00368790010352691
"This study has demonstrated a correlation between relative average cylinder liner wear rates at low engine start-up temperatures, base oil composition
and oil viscosity"
Emphasis mine.
So I have to pay 32 USD to read that and then if I'm convinced I have to buy "full synthetic SAE 5W40 grade oils based on Polyalphaolefin"", and a diesel truck.
Ooer! Just as well cold starts mean 10C here.
Engine Test procedure
"measurements were performed by AEA at
Harwell using a germanium spectrometer"
"Five cold/hot start engine test cycles were
run on each test oil"
"data measured for each of plotted as cumulative wear against each
appropriate cold start cycle"
"Differences greater than 10 per cent in the
relative average wear rate can be regarded as
significant. For each test oil, no additional
wear was detected after the five hot engine
start test phases."
Relative cold start wear rates (-21C) vs. CCS viscosities of test oils at -21C
Relative cold start wear rates (-21C) vs. scanning Brookfield (SB) viscosities of test oils at -21C
Relative cold start wear rates (-21C) vs. time (secs) for initial oil gallery pressure rise at -21C
Relative cold start wear rates ( -26C) vs. CCS viscosities of test oils at -26C