A More Efficient Engine (Need help from some Toyota Experts)

[cRiPpLe_rOoStEr]

If it's just leaking oil, try to seal it with silicone. It's cheap but works effectively.

[serialk11r]

Early model 1ZZs are notorious for burning oil and destroying cats and such, because the oil passages are small, and the piston oil ring had a design flaw. My 1ZZ burns a quart every 1500 miles or so, and the previous owner + me combined have had to change out 4 O2 sensors probably because the soot from the oil destroyed them.

[jeff88]

Exactly. It burns oil, because the oil return holes are too small. The next gen Corolla has the updated pistons.

I have three options to fix the problem. Take the pistons out, drill bigger holes, replace or swap in the updated pistons or swap in aftermarket ones.

[XYZ]

Originally Posted by serialk11r

Early model 1ZZs are notorious for burning oil and destroying cats and such, because the oil passages are small, and the piston oil ring had a design flaw. My 1ZZ burns a quart every 1500 miles or so, and the previous owner + me combined have had to change out 4 O2 sensors probably because the soot from the oil destroyed them.

Do you REALLY think this engine did the described burning "a quart every 1500 miles or so" from the day when it was new?

Do you think that this is due to the design of the engine, or that it's due to its age (and/or possible abuse)?

[jeff88]

Originally Posted by XYZ

Do you REALLY think this engine did the described burning "a quart every 1500 miles or so" from the day when it was new?

Do you think that this is due to the design of the engine, or that it's due to its age (and/or possible abuse)?

It's not a new engine problem. It doesn't develop until after it turns 'high mileage'. A quart every 1500 miles is actually pretty good for this particular issue. I've heard of people who use a quart of oil a week.

It's a mix of design and improper maintenance/abuse. The design is the overriding problem in that the oil return holes are too small. But many people have not had an issue. These people usually are highly meticulous about their OCIs and so the gunk does not develop. They usually also are using synthetic oil, which is another way to keep the problem from developing. The people who forget about oil changes and use the 'thick' stuff are usually the ones with the problem.

[Flakbadger]

It sounds to me like you ought to deal with the oil burning issue and then stop worrying about it. Do some aero mods that are easy to undo and won't leave a scar, and call it good.

[serialk11r]

Originally Posted by XYZ

Do you REALLY think this engine did the described burning "a quart every 1500 miles or so" from the day when it was new?

Do you think that this is due to the design of the engine, or that it's due to its age (and/or possible abuse)?

Countless engines and cats have been destroyed like this since the car first came out. The first piece of advice given on a MR2 Spyder forum is "gut the precats" so that when they disintegrate the bores don't get destroyed. This is not just my car, it's a common early 1ZZ problem. Otherwise I wouldn't have said early 1ZZs are notorious for this issue.

[jeff88]

Originally Posted by Flakbadger

It sounds to me like you ought to deal with the oil burning issue and then stop worrying about it. Do some aero mods that are easy to undo and won't leave a scar, and call it good.

That's the basic plan. This exercise was intended to find an engine I could potentially swap in instead. I didn't want to do all the work of opening up the block and then find an engine I could swap in that is more efficient and possibly have more power.

I still have time until my friend's garage gets built (at which point, I will have a place to do it and an expert to help), so I have time to make a decision, but I am having a problem finding a good engine to swap. That was point of starting this thread, to get some ideas. It looks like the NZ engine would be my best option, but I don't want to do it, unless there is a fairly large increase in FE. (1MPG isn't going to be worth it, 10MPG is a different story.)