Appears lowered blowby with VSOT

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Feb 1, 2005
After playing around with VSOT, I have noticed that it seems to really work on engines with blowby. I have a 440 Mopar (actualy a couple) but one of them was a cheapo rebuild at 80K miles with new rings and bearings by the prior owner. I drove this car about 15K miles now, and learned to deal with its excess crankcase pressure. It basically had blowby past the piston rings when driven hard. Evidence of this was a near vacuum in the crankcase with the PCV at idle, but after hard driving the oil seperator on the PCV line would start filling and the oil dipstick would come out of the tube about a 1/4" and make a vent to relieve the pressure.

This engine has had changes with 10W30 Mobil 1 and Delo400 since I have owned it. About 2K miles ago I changed the oil and used a Witches brew of 5W20 and full bottle of VSOT making a ~30WT. Currently I have gone the last 1K miles without the seperator filling, nor the dipstick poping out. This car was also the one that gave the most dramatic mileage increase after VSOT.

3 cars I have seen the oil seperators clean out after VSOT now. I have used VSOT in a few other cars, but they didn't have oil seperators on the PCV so I can't include them here.

However the next new thing I found, the oil doesn't darken anymore like it used to. I mean at 4K miles on 2 of the cars its still pretty clear. Theory I am thinking is if the rings are giving blowby on a cold start, the oil naturally picks up more water (and reacts), if the rings are sealing better like I know mine are, then thats less water in the oil at cold start, and possibly might be the reason for the oil to stay clear longer.

I have seen quite a few others find oil consumption go down rather quickly after adding a full bottle (~10% of total) of VSOT. I am really starting to test this theory now and wonder if there are any other guinea pigs out there that might want to try this, or if anyone tried it already and found the same things (or not).
How much did you add?

Did you do a compressions test before and after?

Would be really cool to see and maybe the oil thickening might have increased compression a bit.
It was a full bottle in 5 quarts total or roughly 10% of total mixture.

Didn't do a compression test as wasn't expecting a difference like this. I do regret that now.

Oil was not thicker but actually thinner. I combined it with 5W20 to make a 30WT and that was after using Delo, so this comparision was right after using a 15W40.
I originally tried the VSOT for its friction modifiers to see if it would increase gas mileage, I was not expecting to find evidence of better ring sealing. So far I am on the fence about any gas mileage gains it may give from the friction modifiers. In my examples I cannot exclude the effect of the ring seal becoming better, which is why I cannot state that VSOT in and of itself gives better gas mileage. All 3 of my examples had evidence of bad prior ring seal that was shown with the PCV oil catch device.
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