twowheeled New Reader
2/11/19 6:45 p.m.

I bought a junkyard toyota 1NZ-FXE for my prius that also came out of a prius. Since I had it sitting on the pallet I decided to do a leakdown before putting it in the car. I could not get a good reading in cylinders 1 & 4 at which point I gave up. I used wire in the spark plug hole to locate TDC, and cylinder 1 leaked big time out the exhaust valve, 4 leaked big time out of the intake. They both held around 40-50psi on 100psi source. I expected some leakage from the rings if it had been sitting for a long time, but not out of the valves. I wonder if my testing could be flawed, or if this engine could be crap? Should I bother to swap it into my car and try to run it?

The other thing I wasn't sure of was if the atkinson cycle would affect the intake valves opening, but TDC should be TDC. I rotated the crank 360 degrees, and could not get a reading that way (one set of valves open) Any advice?  

twowheeled New Reader
2/11/19 7:30 p.m.

Update: I tried again on cyl 2 and 3, same result. This time I'm sure its at TDC and the valves are shut, I pulled the IM off and there appears to be some sand/dirt inside. Does that look like wear on the intake tract from sucking dirt? Engine did not come with an airbox on it. 



TRoglodyte UltraDork
2/11/19 9:38 p.m.


Spray some lectra clean thru it and  let it runn. change the oil sooon.

dean1484 MegaDork
2/11/19 9:49 p.m.

So what is the toyota spec for the motor?  


Carl Heideman
Carl Heideman
2/12/19 11:10 a.m.

I've seen a lot of engines that have been stored give funny results on leakdown and compression tests until they've got a few miles (or at least heat cycles) on them.  Sitting for a few months with a few valves open often lets minor corrosion set in; running the engine gets them lapped in again.   They'll generally give better compression tests than leakdowns, so if you can put a starter on to check compression and they're not too far off, you probably don't have to worry too much.

devina Reader
2/12/19 12:22 p.m.

I have a similar question- can you somewhat accurately measure compression using a compression testor but turning the engine over to TDC with a ratchet and watching the gage (hopefully) move up??

rslifkin UltraDork
2/12/19 12:59 p.m.

In reply to devina :

No.  You'll show basically no compression turning it over that slowly.  You need a much faster cranking speed to get a good reading.  

Vigo UltimaDork
2/12/19 2:02 p.m.

I've seen the same thing of engines that have sat for a while failing leakdown and then running fine once installed. Probably has to do with surface rust on the valves and seats as Carl mentioned. 

twowheeled New Reader
2/12/19 5:33 p.m.

unfortunately I can't install a starter to turn the engine over, the prius uses the electric drive motor built into the transaxle for stop/start.  Current engine in the car with 270k miles and blown headgasket is leaking down around 10%. I guess I will bite the bullet and swap it in. 

codrus UltraDork
2/12/19 5:52 p.m.

How repeatable were the numbers?  I find that I often have to rock the engine forwards and backwards a bit to get the valves to seal properly on a leakdown test -- I think it's from small bits of carbon getting stuck between the valve and the seat.  Rocking the cam open when there's pressure in the cylinder will blow them out, then when you rock it back it'll often seal properly.


twowheeled New Reader
2/13/19 1:18 p.m.

I did rock it back and forth between TDC and shot WD-40 down the intake runners as well, didnt do anything at all for the leaks.

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