Exhaust manifold leak !

[kjphilippona]

I have a manifold leak, replacing the gasket does not look too hard, only problem i have is the emissions pipe from the exhaust manifold to the intake manifold looks like it broke at one time and was welded. Is it possible to leave both connected and slide them off the studs far enough to replace the gasket ?

[FastWoman]

You're talking about the EGR?

I suspect you'd have a very hard time cleaning up the mating surfaces without pulling the manifold completely. Besides that, you could easily have a stud snap on you, if your car is as crusty and rusty as you've suggested. In that case you'd probably need to pull off the manifold anyway to remove the stud and possibly helicoil.

I could be wrong, of course. I've never pulled an exhaust manifold on a car. I've only done boats, which of course are crustier beasts anyway.

[kjphilippona]

Thanks, i'll pull the intake off and then soak the nuts to the exhaust manifold with pb-blaster of a few days and cross my fingers.

[ZCurves]

I have tackled this problem a couple of times here are my suggestions:

FIRST - Order ALL of the Studs, Nuts, Washers, Spacers and Gaskets from Nissan or Whomever BEFORE you begin this work, this way you will have them on hand for the job.

Soak all nuts/bolts on intake/Exhaust with WD-40 the night before, then soak again right before you attempt. Start by disconnecting the EGR piping FIRST, use a giant Cresent Wrench or Jumbo Crows Foot for this. You will need an Mechanic's Mirror and a couple of long 3/8" extensions so that you can see and remove the nuts that are UNDER the intake. Sounds like a pain, but if your are patient it will come out fine. There is a bolt under a little cover in the center of the intake -get that one first!

Now once the intake is off and you should inspect the exhaust for leaks cracks, etc. If you were thinking of a Header -now is the time to do it.

NEVER EVER go to all of this labor without replacing ALL of the intake and exhaust studs! If you have a broken stud(most likely #6 near the firewall), then you can try to chisel it out with a small chisel and a hammer. Just back the stud out by tapping with the chisel - believe me it will come out (Lefty = Loosey). If the stud is broken off way back in the head, then it is Helicoil time! (Drilling out takes some skill to stay level and not drift into the softer aluminum). Stop here and have a good drink.

Reassemble by locking two nuts together on each stud and torqueing it in. Be sure to coat all of the threads with Anti-Cease compound as you reassemble everything. PM me if you have any other questions, I can give you my phone # if you need.

Best of Luck,

Andrew (ZCurves)

[kjphilippona]

Thanks, have you ever removed the exhaust manifold without breaking any studs ? Is it possible to get studs, washers and nut from a hardware store ? what size's do i need ? A seller on ebay wants $50 for the exhaust hardware, that sounds steep to me.

[zmadnez]

I use the Manifold nuts and bolt kit @ MSA ($16.95) and lots of anti-cease silver stuff.

http://www.thezstore.com/page/TZS/PROD/15-8080

[kjphilippona]

Will i also need the 6 spacers ?

[zmadnez]

If you're referring to the extra thick washers as spacers; yes I did use them on the bolts that overlaps the intake manifold and header.

[ZCurves]

Looks like youre on the right track! :laugh: To answer your earlier question, I have broken some of the studs off but if you use lots of WD-40 you should be fine. More than likely what will happen is that you will back the entire stud out of the head when you are loosening the nuts (but that's ok because you should be replacing these anyway).

I have reused spacers in the past if they were in good shape, but use new ones if they are available. $50 is too steep, unless of course they are stainless or have some other specialized feature. I would still go with the MSA kit that ZMadnez referenced earlier. Do not bother with a hardware store, those bolts are not designed for this application and may end up backing out from expansion/contraction.

If your exhaust manifold is ok and you are reusing it, it might be a good idea to clean it up with some High Temp coating or Calyx Coating from Eastwood before you re-assemble. Calyx is cheaper and would last longer, I used the High Temp coating on mine and it still looks nice too. Here is the link..http://search.eastwood.com/search?asug=&w=exhaust&p=Q&ts=custom

Anyway, time to get started!!

Andrew

Edited November 12, 2009 by ZCurves
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[Zedyone_kenobi]

Quick question I am about to start putting my intake and header back on my Z. I have cleaned everything, chased all the threads of the head with a tap and got them squeaky clean, and I am about ready to put the new MSA studs in the head.

Would it be better to use locktite on the studs versus anticease. I mean it would help hold them in, and you can always heat it up to remove the locktite. I have been debating this. I actually bought a tube of anticease to use, as its my normal mode of operation, but it would be nice to not have to worry about the studs backing out.

Also, the torque spec for the manifolds is 8-11 ft lbs. Can I assume both the stud into the head and nut on the stud is 8-11 ft lbs?

[kjphilippona]

I ordered the MSA kit last night along with the 6 spacers. A friend of mine at work suggested heating up the nut/studs, not red but hotter than what you get at operation temp and letting them cool then spray WD40 or PBblaster. Has anyone tried this, i was a little worried doing this with the head being aluminum.

[motorman7]

Maybe I missed it in the earlier posts, but did you try to remove the manifold nuts and they did not come off? I recently pulled the exhaust and intake manifold off of a 39 year old Z and a recently rebuilt Z. No problem with either one. Just used a good Craftsman 12mm socket with extension for most of the nuts and 12mm box end for those the socket couldn't reach. Wasn't that hard.

Rich