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Discussion Starter · #1 ·
I just had my lower end built by a good rebuilder. But I only ran the motor for a hundred miles or so. Since the new motor has been in there I had to change the rear main seal twice & now my front seal is leaking?
 

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You didn't take it back to them after the first RMS problem? IMO If I started having problems like that 100 miles into driving I would immediately be calling/showing up at the builders and taking things from there, not be on SF asking people who can't see whats going on and don't know what was done to the block....If your builder can't diagnose CW then you should have never brought it to them in the first place....

I hope if you figure out it IS CW you bring it back asap, as something happened during the build that either starved oil to the thrust bearings or the bearings were installed out of spec.
 

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Sounds like you have a problem with piston ring blowby and/or not enough crankcase ventilation. Assuming it is properly installed, the only way the rear main seal can be pushed out is due to excess crankcase pressure. Front seal can be due to excess crankcase and/or oil pressure. I doubt you could have enough crank walk to push the rear seal out without there being other issues like hard starting and grinding noises with the clutch actuated. Even then I am pretty sure there would not be enough displacement to push the rear seal out.
 

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Discussion Starter · #5 ·
It's a auto trans. And it starts fine, and runs great.
I had the motor built last year, drove it a little, then it went for a paint job. That took 5 months, got it back in the winter,so it sat for 2 more months. So the builder will tell me to go to hell. He also just built the bottom end I did the rest. Also I check blow by and crank case pressue is fine to.

Larry is there a way to do that test with a auto?
 

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There might have been a groove on the end of the crank. I've seen that with a few engines from just general wear. Its common enough where they make a sleeve that can slide over it and create a fresh surface for the bearing to seal on.

On my last motor build (not a 2J) I got lucky and had a spare crank as the machinist noticed it while they torqued everything down to take measurements.

Again, I don't know about the 2JZ engine (yet), but NAPA makes a fantastic product called "The right stuff" that is an AWESOME gasket maker. Its expensive but does one hell of a job. Maybe try cleaning up the seal surface really well and applying some of that stuff before placing the gasket.
 

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There might have been a groove on the end of the crank. I've seen that with a few engines from just general wear. Its common enough where they make a sleeve that can slide over it and create a fresh surface for the bearing to seal on.

On my last motor build (not a 2J) I got lucky and had a spare crank as the machinist noticed it while they torqued everything down to take measurements.

Again, I don't know about the 2JZ engine (yet), but NAPA makes a fantastic product called "The right stuff" that is an AWESOME gasket maker. Its expensive but does one hell of a job. Maybe try cleaning up the seal surface really well and applying some of that stuff before placing the gasket.
what?
 

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http://www.alliedbearings.com/mfg_prod/seals/cr_speedi/cr_speedisleeve_install.pdf

That is what I'm talking about.

If it was excessive blow by you could see the oil vapor coming out the breathers and through the dipstick tube. It would have to be a large amount of blowby to start popping new seals out.

FWIW, when I changed mine on my 2JZGTE I also put them in dry and they have been fine. Gasket came new from Toyota. Are you using OEM parts or some cheap ebay gasket kit shit? I bought one of those for my MX6 (KLv6) once and EVERY SINGLE gasket in that kit leaked...from the valve covers down to the main seals....garbage.
 

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You are going down the wrong troubleshooting path thinking crank walk. The chances of crank walk with a new build (new thrust washers) and an auto tranny in 100 miles is somewhere between minuscule and nonexistent. Even if you did develop crankwalk we are talking small displacement:
Standard thrust clearance:
0.020 - 0.220 mm (0.0008 - 0.0087 in.)
Maximum thrust clearance:
0.30 mm (0.0118 in.)
Even if the the back side of the rear main seal normally sat against an upset on the crank and crank walk was at double the maximum clearance (i.e. 0.0236") it would not push the rear main seal out. The rear main seal is about 1/4" deep and there is nothing behind it to push it out. Two things will cause the rear seal to blow out: wrong seal with too small outer diameter or too much crank case pressure. All engines have some blowby. Assuming you had the correct seal installed, you either have excessive blowby or you have inadequate crankcase ventilation or both.
BTW: when I rebuilt my engine this winter, I stupidly used a rear main seal I got from NAPA. It leaked like a sieve!!! The outer diameter was correct but the inner diameter was too large. Fortunately I noticed oil flowing out the tranny bell housing vent/drain when I was putting the engine and tranny back in the car. Lesson learned!!! Use only OEM parts.
 

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Discussion Starter · #11 ·
I used a oem seal, and did not put it in dry. Then I used a national seal & that worked better than the oem seal. Now I will be useing the oem seal & a new housing with new dowel pins, just to make sure it it centered on the block.
 

· Dr. Jeff Lange
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Since it's a new build: what was the thrust clearance when it was assembled?

If possible, check thrust clearance now? Still within spec?

Jeff
 
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