Matt K Posted May 29, 2008 Share Posted May 29, 2008 I recently finished swapping a newer '78 L28 into my '73 240Z, which previously ran an L26 with triple Weber carbs. I swapped the Cannon intake/Weber setup onto the L28 & after installing it found a horrendous vacuum leak around the first two manifold runners. I could hear it & sprayed some brake cleaner around the manifold flange & found the leak. I couldn't use the L28 intake/exhaust gasket with the Cannon intake (bolt pattern was wrong) so used the L26 gasket instead, along with a light coat of high temp RTV to help seal it. To make a long story short, it isn't sealing for some reason. I'm going to try to seal it with some RTV, and see what happens. Do I need to use the EFI L28 gasket & drill the holes correctly for my gasket? What is the correct way to do this? Also, do I need to plug off the huge crankcase breather tube? Quote Link to comment Share on other sites More sharing options...
Silent Posted May 29, 2008 Share Posted May 29, 2008 leave the crank case breather alone. pul everything back off. make sure everything is flat, and nice and shiney without any silicone goo anywhere on the mating surfaces. put a new intake/exhaust gasket on it. Quote Link to comment Share on other sites More sharing options...
Matt K Posted May 29, 2008 Author Share Posted May 29, 2008 leave the crank case breather alone. pul everything back off. make sure everything is flat, and nice and shiney without any silicone goo anywhere on the mating surfaces. put a new intake/exhaust gasket on it. But if there's (god forbid) any warpage, then I might have the same issue again...would using two standard gaskets stacked together work OK? Quote Link to comment Share on other sites More sharing options...
jimzdat Posted May 29, 2008 Share Posted May 29, 2008 Stock L28 head? IIRC, the manifold for the carbs isn't going to seal right due to the reliefs cut into the head for the injectors - but I could be wrong? Quote Link to comment Share on other sites More sharing options...
Matt K Posted May 30, 2008 Author Share Posted May 30, 2008 Stock L28 head? IIRC, the manifold for the carbs isn't going to seal right due to the reliefs cut into the head for the injectors - but I could be wrong? Damn. I hope that isn't the case. There has to be a better solution, as I'm sure that many others have used carb intakes on L28's.... Quote Link to comment Share on other sites More sharing options...
Matt K Posted May 31, 2008 Author Share Posted May 31, 2008 Well, we were ALL wrong! When I ordered my MSA Header, I told them I was running triple Webers on a Cannon intake manifold with a 78 N42 motor...The Header flange seems to be too thick to seal the intake manifold, by approximately 2mm. I will dig out my micrometer & measure the thickness of both. Looks like I will have to mill the header flange in order to use it. SO, I will have to run the stock 240Z exhaust manifold on the L28 in order to be able to run it currently, AND I'll have to replace it all, spend more money to fix MSA's product to fit my application. I am NOT happy, especially after spending the extra cash for the Jet-Hot coated system, with matching twice pipes...which ALSO don't fit & need to be modified by an exhaust shop to work... Quote Link to comment Share on other sites More sharing options...
Babalouie Posted June 21, 2008 Share Posted June 21, 2008 Did you work it all out in the end? I've been trying to diagnose an issue on my engine and I think I have the same problem...if you look closely the intake flange is thinner and the washer on the nut is slightly cocked... Quote Link to comment Share on other sites More sharing options...
Matt K Posted June 22, 2008 Author Share Posted June 22, 2008 Sort of...I used washers cut in half & bonded together with JB Weld to use as shims for the intake manifold. Need to have them rebuilt & tuned... Quote Link to comment Share on other sites More sharing options...
Babalouie Posted June 22, 2008 Share Posted June 22, 2008 Mine is the same...maybe 1.5mm in it....you can see the bridge washer is not sitting flat behind the nut in the pic above but the pic below is a bit clearer Quote Link to comment Share on other sites More sharing options...
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