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1/2 Na-T Project
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Discussion Starter · #1 · (Edited)
These were the compression test results:

Cyl 1: 180
Cyl 2: 180
Cyl 3: 60
Cyl 4:180
Cyl 5: 180
Cyl 6: 155

After the first test I tested all cylinders again and came up with the same results.
I tested cylinders 3 and 6 again after pouring a teaspoon of oil in the cylinder. The results were
Cyl 3: 65
Cyl 6: 175

Well I did a leakdown test on my car to see where the air was escaping from, so far I have only tested the 1st cylinder which came up as 180 psi compression and the 3rd cylinder which came up as 60 psi compression. The car wasn't warm so I am probably getting lower results then if it was. On the 1st cylinder the leakdown was right between the low and moderate area at 15% leakdown, there was a small amount of air coming out of the pcv system and oil dipstick, which is probably because the engine wasn't warm and there was no oil sealing around the rings. The 3rd cylinder was at 85% leakdown and I could feel alot of air coming out of the pcv system and the oil dipstick so it has to be a problem with the rings or piston. I still need to test the rest of the cylinders. Later.


I started prepping the engine to be pulled last night at 10:30 and worked until around 3:00am. I am just taking my time and taking lots of beer breaks :). This is the progress so far:

BTW I would like to thank Dr. J for his great write up on engine removal on MKIIItech.com. I removed my engine once previously to install a rebuilt engine and it took me forever. I didn't pull the ECU harness through the firewall and had to take the Intake mani and tons of other accessoreis off to make sure I had all the clips undone. I am sure it took me forever because of the learning curve but it seems like I will have the engine out with only about 8 or less hours of work. Here is the link...Dr. J's Engine Removal Thread

Before...


Took off Intake and IC Piping...


Pulled the fan and radiator...


Power Steering Pump Out of the Way...


Removed ECU Harness and Pulled out Through Firewall...


Removed Electrical Connectors Attached to body near the engine fuse box...
 

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1/2 Na-T Project
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987 Posts
Discussion Starter · #3 ·
profuse007 said:
whats up w/ the harness? scotchlok everywhere. those taps should be stay away from, especially goin to an ECU.

any special plan of rebuilding?
Yeah I know about the taps, I soldered most of the connections for my safc but couldn't get to a few safely so I used those, with the harness out I am going to solder everything and get it cleaned up...

About the rebuild, the engine is still under warranty through ATK, only has 20,000 miles on it, so I have to inspect it and see what went wrong and if they will still warranty it. If they do I will send this engine back and they will send me a new longblock, if not the car will sit for a bit while I save for the rebuild.
 

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1/2 Na-T Project
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Discussion Starter · #6 · (Edited)
NegativeGeForce said:
im thinking its a bad valve, but it can be anything. Good luck on the rebuild and such...keep us updated :bigthumb:

Doing a leakdown test pinpoints the cause of the problem, when you hear gases escaping through the pcv system and the oil dipstick you are loosing compression somehow between the piston and cylinder, so it is either the rings piston or cylinder wall that are fucked. If you hear air escaping through the intake manifold or exhaust it is a valve problem. Later.
 

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JT87NA said:
Doing a leakdown test pinpoints the cause of the problem, when you hear gases escaping through the pcv system and the oil dipstick you are loosing compression somehow between the piston and cylinder, so it is either the rings piston or cylinder wall that are fucked. If you hear air escaping through the intake or exhaust it is a valve problem. Later.
i didnt get a chance to read the whole thread...good points. Sounds like bad luck, good thing your engine is under warranty you should be back up and running shortly :bigthumb:
 

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1/2 Na-T Project
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Discussion Starter · #8 ·
Hopefully, if they don't warranty it I will just have to take my time. Later
 

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1/2 Na-T Project
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Discussion Starter · #9 ·
Did a little more work on prepping for engine removal today.
Progress Pics:

DP unbolted from Elbow:


Fuel Feed Line Seperated:

Note: You should use flare ended wrenches to remove the fuel lines. I didn't have metric wrenches but a 1/2 inch flare wrench and 3/4 flare wrench worked perfectly. Make sure you load up on the WD-40 before you try to break them loose, if that doesn't work get some PB Blaster or an equivalent penetrating oil.

Parts Removed:


Zip Locks are Key, Stick it in the bag label it and you are good to go
 

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usually when you hear it coming from the oil cap area, its the rings. in my case, it was cracked pistons. i had about 70psi in my dead cylinders. try to take it easy on it man. that's all i can say. sounds like you got some motor pulling excitment ahead of you. have fun, and good luck. my car just got done with its one month break from a cracked number 1 piston and a blown turbo. it feels good to be boosting a bar again with a bigger hairdryer!
 

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Discussion Starter · #12 ·
Juhanis said:
usually when you hear it coming from the oil cap area, its the rings. in my case, it was cracked pistons. i had about 70psi in my dead cylinders. try to take it easy on it man. that's all i can say. sounds like you got some motor pulling excitment ahead of you. have fun, and good luck. my car just got done with its one month break from a cracked number 1 piston and a blown turbo. it feels good to be boosting a bar again with a bigger hairdryer!

Did you do a full rebuild or just replace the cracked piston/pistons? Was there any damage to the cylinder wall? Thanks.
 

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i have probably less than 5k on a mild rebuild. then those pistons cracked. number 6 went out while racing a 450hp bpu mk4, i won 1 of 2 pulls. the 2nd pull is when the motor went. oh yeah it was at 20psi. the second, just took a dump while i was flooring it again on the freeway. and that was piston #1. in both cases the cylinder wall was perfect. both pistons cracked on the intake side at the ring lands. since i cant afford new ross racing pistons and a full rebuild again, i just put replacement pistons in. *i do not advise people to do this* this is my own car, and i weighed the risks before i did this. either way its hauling ass again @ 1bar with my new tial external wg. oh one more thing... you got to check those bore size numbers on the old pistons if you're gonna do this, you dont want to throw in off sized pistons. i matched everything perfectly before throwing it back in. compression tests have come back 160psi across the board doing this. so, it does work.
 

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1/2 Na-T Project
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Discussion Starter · #14 ·
Juhanis said:
i have probably less than 5k on a mild rebuild. then those pistons cracked. number 6 went out while racing a 450hp bpu mk4, i won 1 of 2 pulls. the 2nd pull is when the motor went. oh yeah it was at 20psi. the second, just took a dump while i was flooring it again on the freeway. and that was piston #1. in both cases the cylinder wall was perfect. both pistons cracked on the intake side at the ring lands. since i cant afford new ross racing pistons and a full rebuild again, i just put replacement pistons in. *i do not advise people to do this* this is my own car, and i weighed the risks before i did this. either way its hauling ass again @ 1bar with my new tial external wg. oh one more thing... you got to check those bore size numbers on the old pistons if you're gonna do this, you dont want to throw in off sized pistons. i matched everything perfectly before throwing it back in. compression tests have come back 160psi across the board doing this. so, it does work.

Good to hear it worked out for you, I guess I will have to weigh my options. This engine only has 20k on it after a full rebuild.
 

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it should, if you did everything right. you'll be alright.
 
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Just pulled my motor a couple days ago. Rebuilding my bottom end as i type. This thread is becoming useful for me :)
 

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Discussion Starter · #18 ·
WhiteKid said:
Just pulled my motor a couple days ago. Rebuilding my bottom end as i type. This thread is becoming useful for me :)

Cool, I try to help out other people by posting what I am doing step by step. I definately learn alot in the process also. Good luck with your rebuild.
 

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Discussion Starter · #19 ·
Well I got a new engine stand today since I don't want to borrow someones for however long it takes to rebuild or swap parts over to a new longblock if ATK warranties it. I have all the prep work done before I pull the motor, I honestly have to say it went 100 times easier then when I pulled it the first time, back then there was no Supraforums or Supramania just Sogi and Sonic...these boards are definately a huge help. I will be borrowing an engine hoist tomorrow from my previous employer, thank god I left on good terms :). Hopefully I will have time tomorrow to pull the engine. Later.

 
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JT87NA said:
See, thats what I need. I borrowed the engine lift from my buddies employer, now I need the stand so its easier for me to work on the bottom end and flip the block over whenever I feel needed. :) I think were basically at the same stage. Maybe we can help each other. Good luck :)
 
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