Sick engine longevity Q

[-Nemesis-]

I'm after experienced opinions here please, not -non engine minded- peoples guesses thanks

The 1UZ in my 4Runner started compressing the crank case pretty heavily after 2 years of supercharging on a DIY tune. I don't think there's major damage, probably just flooged rings. After 5 min of running it will start pumping oily vapours out the PCV's and dip stick tube if stick is removed.

I hadn't started it for 3 months till the other day, when I did it turned over after only 2 starter motor revs. It idles fine, runs fine, drives fine, sounds fine etc... But it is compressing the oil.

My question is, if people have educated opinions; how long can I expect the engine to last?

My guess is that if I keep feeding it fresh oil frequently (thick stuff) it should soldier on. The only issue i can see is the exhaust gasses corrupting the oil and reducing it's lubrication. I will set up some sort of oil seperator for the PCV's etc...


Only asking because I was going to sell her, but am thinking of keeping for my daily/toy and can't afford a new engine yet (even though they're still only a grand.)

Other than oil breakdown and wear issues, what other issues are there i'm not thinking of (other than some random spectacular break down if the issue is a melted piston etc)?

[Thommo 73]

i spun a main and kept driving it for 12 hrs straight, by the end it was blowing alot of smoke and oil pissing out of every seal but it still idled purrrrfect as 1u's do, i would just check the pvc system and put a provent(oil catch can) on it

[oldmate]

Why don't you pull it down and replace the rings, who knows how much longer your supercharged, possibly flogged 1uz will last. You might find other problems anyway.

If it's a daily driver why would you run it knowing the engine is shonky?

Yes you can start doing more regular oil changes, but oil isn't cheap these days and you'll just be throwing money away. That's my opinion.

[-Nemesis-]

Why don't you pull it down and replace the rings, who knows how much longer your supercharged, possibly flogged 1uz will last. You might find other problems anyway.

When a replacement is < $1k it's not worth it

If it's a daily driver why would you run it knowing the engine is shonky?

Only asking because I was going to sell her, but am thinking of keeping for my daily/toy and can't afford a new engine yet (even though they're still only a grand.)

I'm talking about using it daily to go to work etc for a month or 3. Been trying to rack my brain what else could go wrong, so thought I would ask here.

[oldmate]

well it could go for a while yet if only the rings are worn. Then it will eventually loose compression to the point there will be no power, however you probably won't notice it until it's completely shot, because a sc 1uz has so much power anyway. At that point the bores could be done for too.

But since the rings are suspect, then you could well have suspect main or rod bearings, which could let go too.

You could drop the sump and check the rod bearings and mains if you can for a better indication. Same with the rings you could do a compression check now, and after a few thousand kays.

Honestly no one can say it will last x amount of time as there's just too many variables, but if it's still running smooth and making shitloads of power it's probably got a fair bit of life left yet, depending how you treat it anyway.

[-Nemesis-]

I should mention it is no longer supercharged, well at least it won't be by time I've got it running again (modding the LPG injection etc so suit NA atm)

[turbo gu]

I would do a leakdown test and compression test to see how bad the motor actually is first.

Is it using much oil?

If it is breathing heavily past the rings make sure the the pcv is as free as possible eg big breather on rocker covers to a catch can with aeither a good filter on

to or a big return back into the inlet of the motor to reduce the pressure.

If its only burning oil with no damage to pistons keep driving it till its starts to look like a stream train behind you

Running thicker oil will help,

I don't think it will fail on you that quickly IMHO

[coxy321]

i would just check the pvc system and put a provent(oil catch can) on it

x2

I think that contaminating the intake (TB, MAF etc) with oil vapour would cause the most dramas as far as running goes, but as long as you keep the oil up to it i can't see why it wouldn't keep going. I've had one or two cars with rediculous amounts of blow-by last for several years, one of which is still going 5 years later.

[Guy]

I had a camry that sound like it had the same sort of issues .. (nat caused by a supercharger unfortunately)

A grade or so hotter plugs to deal with the extra lube the pistons are now getting .. catch can to stop as much oil as possible getting into the intake to begin with and heavy oil.

I did about 10,000 ks like that .. was pretty gutless and it cost me about the same in oil as it did in petrol .. but it still ran like a champ the entire time.

[-Nemesis-]

I'll have to dig out a compression tester and see how bad it is I guess. I only really noticed originally as I had a filter on the throttle body side PCV valve. One day sitting at the lights I noticed smoke coming out of the bonnet on that side so I quickly pulled over thinking something was smoldering. Turned out it was that filter clogged with oil and blowing oily smoke (stunk).

I think the blow bye has significant pressure, but I did have fairly thin synthetic oil in it, will see tomorrow what it's like with the extra thick stuff. Makes me wonder how long it has been happening to an extent and limiting power output, I hadn't noticed a power dip at all.