phunk

iTrader: (21)

I got my car running, and the rear main seal is leaking terribly. I took the trans out to look at it, and it is fine and dandy, other then that fact that I can see it is offset too low. There is less tension on the top of the seal then there is on the bottom.

The rear main seal housing is on dowel pins, so without machining, there is no installation error that could cause this misalignment.

Last year before I blew my headgaskets, I had the same problem. I went thru all the work (practically another engine rebuild project) to change it, and it was the same ****, leaking again. This year I am not even running the same block or crank, and same **** again, so I know its not a bad block / crank alignment, etc.

I have built engines for customers, and all their engines were totaly low miles, so I reused the rear main seal and housing. They did not leak. The only engine I have replaced them on is my own engine, and all 3 now have been no good. At this point, I am questioning if they are coming to me machined properly from nissan, since I can just barely see this misalignment by the naked eye, there is definatly a problem here.

Have any of you that have done build ups replaced the rear main seal and housing, and if so, have you had any problems?

XBS

iTrader: (29)

From what I understand charles it is a bit tricky to get the rear main seal to actually seal properly with out any leak. When nissan replaced my shortblock under warranty the rear main seal started to leak, we found this out when we took my tranny out to change the clutch and saw it was leaking.

I do not know how to fix this problem but Todd from Built Z motors.com has the "trick" down on how to fix the leak. I would contact him about this he should be able to help, hopefully he will respond to this thread. Good luck bro!

-George

Sharif@Forged

iTrader: (92)

Hey Charles....like we talked about yesterday...Honda Bond and 10 trial installs are your best bet. Also lube up the crank will some heavy grease, to easy the seating of the rear main on the crank.

IMHO, the rear main seal is a horrible design. The piano wire is super thin, and its seating groove is nearly non-existent. It is just way too easy for that cord to become dislodged on install. If you look at our front crank seal, its a more robust piano cord and seating groove, so that one never leaks.

Best of luck...I know its a huge pain.

phunk

iTrader: (21)

I have noticed that MicroSleeve has already released a sleeve kit for this engine. That must be saying something.

The MicroSleeves are sleeves that you press on the crankshaft to increase the OD just a little and form a tighter seal. I might have to pick up one of those.

GMZ

iTrader: (6)

I think John (USN HM 350) had this problem. Hall Nissan here replaced it under warranty

overZealous1

iTrader: (27)

i have had no probs with the crank part of the seal, but the half round seal can be tough to get in correctly. most engine stands don't allow the seal housing to be installed unless it is installed partly on the crank and dropped in on the end of the crank, atleast my stand is like that. i run a little sealant all the way across both sides of the half moon/lower block seal though.
btw, the last stock motor i pulled apart, had gobs of sealant everywhere. completely overdone on every wet seal. guess the guy on the assembly line that day was in a giving mood.

350zDCalb

iTrader: (21)

Hey Charles,


I have personally had two rear main seal leaks on my own motor, we had one of our first motors that went out have a rear main seal issue (we paid for all the parts and labor for that customer to get it fixed )

The BEST way to install the rear main seal is as follows:

do not install it when the motor is on the engine stand (the stand gets in the way and makes it difficult to symmetrically place the seal- so, we hang the motor from a cherry picker to put on the rear main, then put it back on the stand after we are positive that it is on correctly)

lots of lube

pull the dowel pins out of the block, as these also make placement of the seal difficult, after you are sure that you have the seal on properly (like Sharif said, try and test several times to ensure you dont push off the piano wire) , then you bolt the seal on with the 3 bolts, then tap the dowel pins back in...


now that I shared all of our secrets...buy some motors!!! (coming soon, pics of our new location)

-TODD

chimmike

iTrader: (7)

pics? Also, how do you get them dowel pins out? lol.

phunk

iTrader: (21)

i appreciate the feedback guys.

I spent a TON of special attention on it this time to ensure that it would not leak, and it did anyway. I am confident that the spring did not pop out, and I am also confident that the leak is unrelated to any of the areas with RTV. This is a problem with the seal sealing on the crankshaft itself.

Unfortunatly, I think my car is going to have to sit another year. I havent driven it since April of 2005 (well over a year ago). I really do not have the time to pull this engine back out in attempt to repair this seal that will just leak again. I only have about 2 months until winter comes, so I might as well just store the car now and worry about it sometime during winter, and that gives me times to decide what I want to really do with the car, as I have been thinking of just parting it out lately. Since I no longer run a full service shop, I dont have the the setup to be constantly rebuilding this very fragile engine. Doing this build in my garage at home was an absolute nightmare, and ill be damned if I ever want to do it again, let alone only days after having JUST finished it.

phunk

iTrader: (21)

I have a metric dowel pin extractor that has saved my *** many times.

Just like this one: http://buy1.snapon.com/catalog/item....re&dir=catalog

Only I think i paid like 75 bucks, snapon is an absolute ripoff.

That tool will pull the dowel right out without hurting it at all, only takes about 30 seconds to use and the dowel is ready to go right back in to where you want it. I used it plenty of times on this build since I changed blocks, but forget to order new dowels. Head alignment, oil pump, rear seal (pos), timing covers, etc.

failsafe306

iTrader: (38)

Aww come on, it's just a little leak

At least play with her a little and get some dyno numbers.

phunk

iTrader: (21)

alright, while i hate to admit it, i was wrong.

i stopped crying about it and i actually took the seal out. apparently, i messed up putting it in (regardless of special care taken), or it had a little tear before i put it on (maybe i messed it up playing with it).

what happened was, what started as a little tear was tearing more as i ran the engine. it was kinda like a fingernail that was halfway torn off... the crankshaft was pulling at the tear and making it get worse the more i drove.

At the moment I removed it, it had torn and pulled back about 2 inches.

My Bad.

At least im motivated to fix it now. Should be on the road again tomorrow... engine is hanging right now, crossmember bout ready to fall out.

AmyCroft

iTrader: (3)

Very odd, Good you found the problem.. Please tell us how to avoid this issue.

Cheers Amy -

Nealoc187

I haven't done a VQ35 rear main but I did a VQ30 rear main while the engine was in the car and it was a nightmare. I did get it installed and it didn't leak but I probably did 10-15 test installs just to make sure like others said, that I didn't rip the seal itself, that I didn't pop the piano wire out of it's half arsed groove, and that I didn't "fold" the lip of the seal over on the edge of the crank. Lube and perserverence is what it took. Glad you got it figured out.

hurahn

How can I tell if this is happening without a lift? When I park the car level it doesn't leak oil but if I park on an incline with the rear lower than the front I leak oil. How much would this be to fix? Good thing it's fall now cuz I almost want to say F' it. It seems like my car has low self esteem. She always has some annoying little issue with her. If she doesn't get her act together I'm going to threaten her with pictures of the GTR, Audi RS4 and Audi R8 and tell her she might get replaced by one of these.

350zDCalb

iTrader: (21)

do you have a jack? if there is oil coming out between where the transmission mates with the upper oil pan (motor) then chances are its a rear main seal problem....

I just put a rear main seal on today, but with a motor out of a car

-TODD

arizzee

iTrader: (28)

bringing this back to life...

after a few days at the track, I think my rear seal is finally done. Can this seal be replaced with the engine in the car or will it need to come out? Any words of wisdom are appreciated. thanks.

350zDCalb

iTrader: (21)

the tranny needs to obviously come out... the rear main seal CAN be replaced with the motor in the car, for sure...

to do it properly, the upper oil pan will need to be dropped, the easiest way to do this, and be able to rtv seal everything back up to prevent leaks in the improper re-installation of the upper oil pan, is by supporting the engine with an in-engine bay engine brace/lift... drop the subframe a few inches, pull the upper oil pan out, then pull off the old rear main seal

when installing the new rear main, pull the two dowels out of the block (the ones that fit into the RMS housing), lube the rear main up a ton, lube the outer diameter of the crank as well, carefully, keeping the RMS parallel to the block surface, slide it over the crank, re-do this a few times to ensure that your techinique is not knocking the spring out of the seal...once confident, install, put in 3 bolts in RMS housing, then tap the dowels in with a hammer, through the installed RMS, back into the block....

there you go

-TODD

arizzee

iTrader: (28)

Thanks for the info. Sounds doable but a total pain.

TurboTim

iTrader: (11)

We ran into this problem on a customers car and we found that the crank had a slight groove in it where the seal seats.The damn thing kept leaking before we figured it out so we used a scotchbrite around the perimeter and it hasn't leaked since.