Supra Forums banner
1 - 12 of 12 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Hey guys looking to do a refresh with my 2jzgte
i want to replace my rings and bearings. I plan on doing all oem rings and bearings.

i know with bearings i need to match the number with the crank and rod

but in regards to rings..using the oem ones i still need to gap them?

i just want to do an oem refresh, had some leakdown issues i suspect rings because i has some air in the crank case cylinder 3 and 5 only i think it was...also need top do valve seals
 

·
Registered
Joined
·
46 Posts
If you use toyota OEM piston rings then you shouldn't gap them. They are intended to be used as is as they are sized correctly for a stock 2J.
It is more important to make sure that your bores are still straight and has no ovaling after 20+ years of use. If you bores arent straight then it dosent really matter what rings you put in, you will struggle to get a good seal.

I believe toyota once supplied 0.25/0.50 oversized rings for the 2JZ, not sure if they are still available or not. These would be required if you need to machine your bores slightly larger to get them straight again.
 

·
Registered
Joined
·
4,946 Posts
how much leak down did you have? ive never seen a 2j need a refresh like SBC or somelthing. if you do end up doing it i would still recommend checking the gaps. its just somethinng you should always do.
 

·
Super Moderator
Joined
·
11,715 Posts
how much leak down did you have? ive never seen a 2j need a refresh like SBC or somelthing. if you do end up doing it i would still recommend checking the gaps. its just somethinng you should always do.
Same. I've had 2JZ's apart with over 250k miles on the odo and the shortblock internals were just fine.

Assuming your car is near stock, If there's cylinder leakdown I'd suspect the valves/valve seats first and actual piston damage second. If you're on a standalone ECU or had some kind of event that made you feel like you may have hurt the engine, I'd pull the shortblock apart first to inspect for damage on the piston ring lands before ordering new rings, because you might need new pistons too.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
Same. I've had 2JZ's apart with over 250k miles on the odo and the shortblock internals were just fine.

Assuming your car is near stock, If there's cylinder leakdown I'd suspect the valves/valve seats first and actual piston damage second. If you're on a standalone ECU or had some kind of event that made you feel like you may have hurt the engine, I'd pull the shortblock apart first to inspect for damage on the piston ring lands before ordering new rings, because you might need new pistons too.
so yes all stock stock ecu with a precision 6266 12lbs of boost

i used a harbor freight leak down tool with my compressor. i only did a leak down because my compression numbers were wacky cylinder 1-6 125, 150, 165, 180, 140, 180 cold after sitting a while...oil helped compression come up...i will do another compression test cold then one hot

i do believe my my valve seals are bad i get smoke on start up especially cold

im hoping its just a valve issue and if so how can i go about figuring that out? alot of shops i try and talk to mention rings and rebuild and build the motor i just want top enjoy the car max 700hp if that ever and drive it on weekends or 3 days a week i wanted to avoid pulling if i didnt need to if my short block is okay i had some misfiring and on start up rpm is low but picks up when warm...cruising is has a little misfire but pulls hard

i want to give as much information as i can and whatever you need...i really hope and feel its not my block but i want to confirm and test more
 

·
Blue Thunder
Joined
·
3,760 Posts
With those numbers, it's time for some rings. As said before, very hard to damage a 2jz block.
 

·
Super Moderator
Joined
·
11,715 Posts
so yes all stock stock ecu with a precision 6266 12lbs of boost

i used a harbor freight leak down tool with my compressor. i only did a leak down because my compression numbers were wacky cylinder 1-6 125, 150, 165, 180, 140, 180 cold after sitting a while...oil helped compression come up...i will do another compression test cold then one hot

i do believe my my valve seals are bad i get smoke on start up especially cold

im hoping its just a valve issue and if so how can i go about figuring that out? alot of shops i try and talk to mention rings and rebuild and build the motor i just want top enjoy the car max 700hp if that ever and drive it on weekends or 3 days a week i wanted to avoid pulling if i didnt need to if my short block is okay i had some misfiring and on start up rpm is low but picks up when warm...cruising is has a little misfire but pulls hard

i want to give as much information as i can and whatever you need...i really hope and feel its not my block but i want to confirm and test more
JDM engine/ECU/injectors, or US spec?

How much did the compression come up when oil was added? If if was 10-15psi or less, might still just be valves. If it was greater than 20psi difference w/oil, likely have a damaged piston ring land or ring. Based on the spread of compression numbers I'd bet money on piston damage from detonation. Single turbos and stock ECU/fuel need to be carefully managed if it's going to survive.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #8 ·
JDM engine/ECU/injectors, or US spec?

How much did the compression come up when oil was added? If if was 10-15psi or less, might still just be valves. If it was greater than 20psi difference w/oil, likely have a damaged piston ring land or ring. Based on the spread of compression numbers I'd bet money on piston damage from detonation. Single turbos and stock ECU/fuel need to be carefully managed if it's going to survive.

JDM engine so the 440s and i think ecu is jdm

i dont remeber how much they came up i will redo my compression check this weekend and repost..i really hope its just valves :( or even HG
 

·
Registered
Joined
·
46 Posts
I just pulled apart a stock JDM motor today that according to owner ran like a dream at BPU level, but we noticed it sounded funny whilst cranking whilst doing some other work to car. Did a compression test and cylinder two was down, and chuffed a bit out the engine breathers. Engine still ran fairly well all things considered, but something wasnt right and on stripdown I found the following damage to piston 2.


Audio equipment Body jewelry Cable Gas Jewellery


OP, whilst you may not have damaged the block, its somewhat common to see factory pistons crack a ringland which can lead to compression issues. Hopefully this isn't your issue, but it's always a possibility with 25 year old components, bad tuning or shit luck. I'd be careful running a 6266 on a JDM ECU at 12psi, especially if you are running a FCD of some sort, definately get some det cans on there and check you don't have any det as it comes on boost.

Also don't bother compression or leakdown testing whilst engine is cold. In your scenario just get the motor warm then do both tests one after another and go from there. If you are doing leakdown test then dont put oil down the cylinders, you will be able to hear where your leaking is from valves, rings etc.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #10 ·
I just pulled apart a stock JDM motor today that according to owner ran like a dream at BPU level, but we noticed it sounded funny whilst cranking whilst doing some other work to car. Did a compression test and cylinder two was down, and chuffed a bit out the engine breathers. Engine still ran fairly well all things considered, but something wasnt right and on stripdown I found the following damage to piston 2.


View attachment 269005

OP, whilst you may not have damaged the block, its somewhat common to see factory pistons crack a ringland which can lead to compression issues. Hopefully this isn't your issue, but it's always a possibility with 25 year old components, bad tuning or shit luck. I'd be careful running a 6266 on a JDM ECU at 12psi, especially if you are running a FCD of some sort, definately get some det cans on there and check you don't have any det as it comes on boost.

Also don't bother compression or leakdown testing whilst engine is cold. In your scenario just get the motor warm then do both tests one after another and go from there. If you are doing leakdown test then dont put oil down the cylinders, you will be able to hear where your leaking is from valves, rings etc.

ok i will do the tests with engine at temp..is there a specific way to do a leakdown test? each piston needs to be at the top? not sure if i did the test correctly or not...when i did it i had cyl 1 at tdc then went to each on after the putting it at the top...i kept getting air through exhaust and intake...one cylinder i forgot which one i had air in crank case but i will redo tests and get those results back in here!! i do hope its not my piston and i haven't been driving it. just letting it chill while i figure this out
 

·
Registered
Joined
·
46 Posts
Easiest way to do the leakdown test is to following the engine firing order of the engine. 1-5-3-6-2-4

So start with TDC at Piston 1 as you can find that easily using crank pulley marking. After that move to cylinder 5 as this will be the next cylinder in the cycle that will be at the correct point in the engine cycle for all the valves to be shut as piston is at TDC on correct stroke. I normally use a long screwdriver to see when cylinder 5 piston is at TDC, then perform the test. Then move to cylinder 3, etc etc.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #12 ·
Easiest way to do the leakdown test is to following the engine firing order of the engine. 1-5-3-6-2-4

So start with TDC at Piston 1 as you can find that easily using crank pulley marking. After that move to cylinder 5 as this will be the next cylinder in the cycle that will be at the correct point in the engine cycle for all the valves to be shut as piston is at TDC on correct stroke. I normally use a long screwdriver to see when cylinder 5 piston is at TDC, then perform the test. Then move to cylinder 3, etc etc.
thank you so much i will get on all this!!!do you have an instagram? so i can take some vids and share results or noises
 
1 - 12 of 12 Posts
Top