Gollum Posted June 18, 2009 Share Posted June 18, 2009 So I've had my 75' with a L28ET for well over a year now, and it's had a nasty exhaust leak since the day I bought it. About 6 months ago I replaced the gasket and swapped to a different intake (turbo)... to no avail When recalling the whole thing I realized that the manifold was a PITA to get on because getting the downpipe to fit on nicely while mating to the head was more than a challenge. So I figured my exhaust pipe must be pulling on the turbo enough to not be allowing a good seal... Still leaks. I didn't let the gasket burn in yet, and I tried stacking gaskets. Still same as always. I've confirmed that the leak is at the bottom of the center 3 and 4 cylinders. Am I just having issues getting my gasket lined up right with the manifold? I was thinking before that maybe just letting everything hang on the studs and then bolting it up was letting it hang too low, so last time I taped up the gasket to the valve cover with a bit of tension and put a jack under the turbo to help get the manifold higher up on the ports... And like I said, still not sealing. The leak is DEFINITELY coming from the bottom between 3 and 4. ANY AND ANY Help would be GREATLY appreciated. Hopefully some of you guys with lots of turbo L series engines can help me figure this one out. Quote Link to comment Share on other sites More sharing options...
soullessjdog Posted June 18, 2009 Share Posted June 18, 2009 i have the same problem on my number 6 cylinder i cant even find out why i have went though 3 gaskets because that small leak eventually burns a hole in the gasket. Quote Link to comment Share on other sites More sharing options...
hughdogz Posted June 18, 2009 Share Posted June 18, 2009 Are you guys using Nissan OEM "graphfoil" gaskets or Fail-Pro type ones? Quote Link to comment Share on other sites More sharing options...
Noddle Posted June 18, 2009 Share Posted June 18, 2009 Take it off and get the manifold machined (gasket area) if it's not straight or pitted (rusty) Nigel Quote Link to comment Share on other sites More sharing options...
Gollum Posted June 18, 2009 Author Share Posted June 18, 2009 I've been using the run of the mill fail-pro gaskets. I haven't checked my manifold for straigtness because it seems so perfect, and I've talked to the guy who did the swap, who has no reason to lie, who says that he never had a leak with it, and this was less than 4 years ago, possibly less than 3. I'm going to try to cut just the center section out of an old gasket and see if that'll hold. If not I guess I'm going to start checking how straight all my surgfaces really are and if they're good then I'll be buying a nissan OEM replacement. Quote Link to comment Share on other sites More sharing options...
woldson Posted June 19, 2009 Share Posted June 19, 2009 I wanted to mention stuff not being "flat", just did not have the heart to say it...... Good luck my friend;) Quote Link to comment Share on other sites More sharing options...
jeffp Posted June 21, 2009 Share Posted June 21, 2009 Dump the FelPro gaskets. they are not going to seal for you. I used one one time and it was leaking in short order. I went to the Nissan gasket, NO MORE PROBLEMS! Also it is in you best interest to surface the manifold if it is pitted, rusted, and more then likely it is warped. You do that and I can assure you many happy days motoring. Quote Link to comment Share on other sites More sharing options...
Stationwagonguy Posted June 23, 2009 Share Posted June 23, 2009 Out of curiousity, how are you tightening the gaskets down? Are you overtorquing them maybe? My friend was having a similar problem with gaskets on his RB, he was just overtorquing them and tightening them in a willy-nilly sequence. Quote Link to comment Share on other sites More sharing options...
Challenger Posted June 23, 2009 Share Posted June 23, 2009 I had a blowout on the top of number 6. This was using the gasket I got from shucks. I assume their fel-pros? Have you made sure all of the spacer/washers are tight? Quote Link to comment Share on other sites More sharing options...
drift_inertia Posted June 23, 2009 Share Posted June 23, 2009 before you have the manifold machined flat, you can always lay a flat metal file acrocss the manifold and run it back until you see fresh clean metal to get it flater then it is in an attempt to get it to seal better. I had to do it on both of my intake manifolds because they woerent sealing right. Quote Link to comment Share on other sites More sharing options...
eec564 Posted June 23, 2009 Share Posted June 23, 2009 Absolutely check the flatness and evenness of the entire manifold with a good straight edge. Also check the thickness of the exhaust manifold's flange relative to the intake manifold's flange. If the exhaust manifold has had material removed, and the intake has not, the common bolts (namely the cupped washers) may not be applying proper pressure to the exhaust manifold. Stacking gaskets wouldn't help in this case, as you'd be raising both manifolds off the head. Checker/Schucks/Kragen (and now O'Reilly's) do use Fel Pro gaskets. They aren't known for their quality, and love to make gaskets that fit many years of vehicles by hybridizing the differences between them. Also, what changed that now you want to elimate our Early-Nathanial-Warning-System? Quote Link to comment Share on other sites More sharing options...
thrustnut Posted June 23, 2009 Share Posted June 23, 2009 I had the same problem. Have you checked your torque after the engine is warm? I did mine last time and was amazed. ALL of my hardware was loose. I also tired an old muscle car fix for crappy fitting headers that my Dad told me about. I got a can of roof sealant from Ace and coated both sides of the gasket. No leaks so far, I will check torque again this weekend. Quote Link to comment Share on other sites More sharing options...
Gollum Posted June 24, 2009 Author Share Posted June 24, 2009 I've tried low torque (20 lbs) and high torque (40 lbs) and I've always gone in the service manual suggestion, from center outwards. I've tried two different intake manifolds, so I don't think that's the problem, plus it's leaking on the cylinders that don't share. And the leak shows immediately, so the engine isn't even warm before I get a chance to recheck torque. I should have an update to see if my jerry rig works sometime tomorrow or thursday. If it's no good I'm going to have it checked my a machine shop and drop the money for a nissan gasket. Quote Link to comment Share on other sites More sharing options...
eec564 Posted June 24, 2009 Share Posted June 24, 2009 Maybe your head is pitted. Or more likely, while flat, the exhaust manifold has a slight amount of torque on it, that is to say it's a bit twisted. If you don't a three-foot straight edge to check things out, a large carpenter's square works surprisingly well, for surprisingly cheap. Quote Link to comment Share on other sites More sharing options...
Gollum Posted June 26, 2009 Author Share Posted June 26, 2009 Well it's still leaking. I tried adding gasket material to the section that's leaking, didn't work. I just finished assembling it after buying the nissan OEM gasket (which is MUCH nicer I must say, though three times the price), and I torqued it to the factory specs (which seem absurdly low to me), and assembled it all with high tack gasket sealant (aka copper spray). Still leaks. I guess I'll be looking for a machine shop with a decent quote. Quote Link to comment Share on other sites More sharing options...
woldson Posted June 26, 2009 Share Posted June 26, 2009 Bummer...... Quote Link to comment Share on other sites More sharing options...
rossman Posted June 26, 2009 Share Posted June 26, 2009 I don't think it's a big deal to have it trued up on a belt sander. The problem I've had is finding someone with a belt sander long enough ~24.5 inches. Quote Link to comment Share on other sites More sharing options...
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