NismoZ Posted February 25, 2010 Share Posted February 25, 2010 (edited) Ok I got this problem I recently bought a triple set up and everything seemed fine. I went to install the setup yesterday only to find out I got a vacuum leak I cannot seem to fix. So I pulled everything back off to have a look, I placed a couple of straight edges on the manifold to see if that was the problem, turns out it isn't straight. Since this is my first time messing with triples and a aftermarket manifold Im going to need some advice..I mean is this the norm for triple manifolds? So here are some pics of what im talking about, they will be larger than life so you can see what is going on. Im hoping a resurface will do the trick but Im afraid it will need so much material removed that it will no longer be able to be bolted up with the exhaust washers. So with that said i need somebody who can tell me if this can be fixed. Big Thanks in advance Edited February 25, 2010 by NismoZ Quote Link to comment Share on other sites More sharing options...
Derek Posted February 25, 2010 Share Posted February 25, 2010 It looks to me like the front manifold is bent outward. Is the level sitting flat against the back two? If that's the case I would adjust the casting a bit. If you go that path I can give you a few pointers about working with cast aluminum. Derek Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted February 25, 2010 Share Posted February 25, 2010 Yeah, that thing is toast...you should buy a cannon manifold and send that piece of junk to me . Yeah, you should be able to get it machined level, then file the manifold washers as needed. Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 26, 2010 Share Posted February 26, 2010 MACHINED? Get yourself a big belt sander, steady yourself, and lay it on gently. A reference jig helps... Or on your layout table, rubber cement down some 80 grit sandpapaper, and start with the 'figure 8 lapping' motion, it will be flat soon enough. Is this a new manifold you bought, or secondhand? If new, I'd simply call Gary at TWM, but without seeing the gasket face on the manifold, I can't tell what has been done to it previously. Those manifolds are machined AFTER casting, and should be flat. I can't imagine what would do that kind of warpage short of someone taking my first suggestion with the belt sander and not being very careful... Quote Link to comment Share on other sites More sharing options...
NismoZ Posted February 26, 2010 Author Share Posted February 26, 2010 (edited) Yea I was like WTH when I looked at it with the straight, I ended up belt sanding it today and it is nice and flat now. It was way warped for being a new manifold. I did buy it second hand from a fellow Z member that stated it was a new unit but you never know. btw thanks for the replys guys, Im going to give it a go again and see how it all turns out. Edited February 26, 2010 by NismoZ Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted February 26, 2010 Share Posted February 26, 2010 Good job getting them flat, and good luck getting those Dellortos tuned Quote Link to comment Share on other sites More sharing options...
NismoZ Posted February 26, 2010 Author Share Posted February 26, 2010 (edited) Good job getting them flat, and good luck getting those Dellortos tuned Thanks.. Now all I need to do is make or have made some washers with a .125 of an inch step so it can be snugged up.. then I can get to the tuning. I hope that step is less of a hassle. I was thinking about using a filed washer but at .155in Im not sure if I could trust it, what are the thoughts on that? Edited February 26, 2010 by NismoZ Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted February 26, 2010 Share Posted February 26, 2010 Thanks.. Now all I need to do is make or have made some washers with a .125 of an inch step so it can be snugged up.. then I can get to the tuning. I hope that step is less of a hassle. I was thinking about using a filed washer but at .155in Im not sure if I could trust it, what are the thoughts on that? Here is what I did... Quote Link to comment Share on other sites More sharing options...
NismoZ Posted February 26, 2010 Author Share Posted February 26, 2010 (edited) Here is what I did... Damn that step looks HUGE... so you ran those with no issues huh? are they the oem pieces? Edited February 26, 2010 by NismoZ Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 26, 2010 Share Posted February 26, 2010 Argh! Someone else who bought a cheap header with the el-cheapo flange. Good luck with that. See my comments on triples in the other post regarding these washers. Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted February 26, 2010 Share Posted February 26, 2010 Damn that step looks HUGE... so you ran those with no issues huh? are they the oem pieces? Yep, running them on my car right now...Cannon Manifold / Pacesetter Header. If you notice...some of them are cut square as well. It is a "VERY" custom fit. Recomendation from Dave Rebello to use that header instead of the Nissan Comp. It has equal lenght runners, actually fits the car nice, and flows almost as well as the Nissan Comp unit. Quote Link to comment Share on other sites More sharing options...
NismoZ Posted February 26, 2010 Author Share Posted February 26, 2010 See my comments on triples in the other post regarding these washers. Tony I don't think I noticed your post on the washers..what post are you referring to? Quote Link to comment Share on other sites More sharing options...
NismoZ Posted February 26, 2010 Author Share Posted February 26, 2010 Yep, running them on my car right now...Cannon Manifold / Pacesetter Header. If you notice...some of them are cut square as well. It is a "VERY" custom fit. Recomendation from Dave Rebello to use that header instead of the Nissan Comp. It has equal lenght runners, actually fits the car nice, and flows almost as well as the Nissan Comp unit. Ok glad to here that, I wasnt sure if the washers would give after being filed so thin but I guess it should be ok then. That header flange looks thin what is its thickness? Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted February 26, 2010 Share Posted February 26, 2010 Dont know the thickness off the top of my head, but it is the same thickness as the factory 280z manifold....I have been grinding theese washers down for z-cars for years...either to mate up a Carb intake with an FI header or a FI intake with a carb header...the key is to get the washer to lay flat against both surfaces to avoid the manifold studs from bending and warping from the pressure and heat. Quote Link to comment Share on other sites More sharing options...
NismoZ Posted February 27, 2010 Author Share Posted February 27, 2010 I have a question is the carb body with the vacuum advance suppose to have more vacuum than the other carbs? I have the emission type carbs with the idle bypass and no matter what I do I cannot get one part of the throttle body to sync with the others (the one with vacuum advance nipple) it always has higher vacuum reading. Also what causes the carbs to backfire? car seems to still be running ruff or missing. I tried spraying carb cleaner where there could be vacuum leaks but got no results... Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted February 27, 2010 Share Posted February 27, 2010 I have a question is the carb body with the vacuum advance suppose to have more vacuum than the other carbs? I have the emission type carbs with the idle bypass and no matter what I do I cannot get one part of the throttle body to sync with the others (the one with vacuum advance nipple) it always has higher vacuum reading. Also what causes the carbs to backfire? car seems to still be running ruff or missing. I tried spraying carb cleaner where there could be vacuum leaks but got no results... Post a picture of the carbs...I am curious as to which Dellortos you have...do you have the Speedpro Book "How to Build & Power Tune Weber & Dellorto DCOE & DHLA Carburettors". if not I would suggest you get it. Are you trying to pull vacuum off of some port for your dizzy? I would recomend against it...just plug all the vacuum ports...but do get the tuning book, very usefull.....but remember...fuel quality has changed dramatically since these books were written Quote Link to comment Share on other sites More sharing options...
NismoZ Posted February 27, 2010 Author Share Posted February 27, 2010 (edited) Post a picture of the carbs...I am curious as to which Dellortos you have...do you have the Speedpro Book "How to Build & Power Tune Weber & Dellorto DCOE & DHLA Carburettors". if not I would suggest you get it. Are you trying to pull vacuum off of some port for your dizzy? I would recomend against it...just plug all the vacuum ports...but do get the tuning book, very usefull.....but remember...fuel quality has changed dramatically since these books were written Yea I just got the speed pro book.. I have the DHLA N carbs, I do have the the vacuum advance plugged, didn't plan on using it. Here are some pics, the side with the blue cap is the one that is flowing more than all the others. Edited February 27, 2010 by NismoZ Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted February 27, 2010 Share Posted February 27, 2010 Make sure all your vacuum port plugs are TIGHT...the 6 grey ones and the blue one...use zip ties if you have to Quote Link to comment Share on other sites More sharing options...
NismoZ Posted February 27, 2010 Author Share Posted February 27, 2010 (edited) Make sure all your vacuum port plugs are TIGHT...the 6 grey ones and the blue one...use zip ties if you have to What grey vacuum port plugs are you speaking of? the ones for color tune right next to the progression hole plugs? I have tried to get these flowing evenly but every single one flows more or less than the other even on the same carb. Its like the butterfly's are not equal on the same carb is this normal? These are second hand so Im not sure if it me or a problem with the carbs. They are all opening at the same time more or less, I have got the linkages all the same length so im kinds stumped. Edited February 28, 2010 by NismoZ Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 28, 2010 Share Posted February 28, 2010 (edited) That header flange is NOT the same thickness as the stock intake flange! If it were, you wouldn't have to grind a step in the washer!!! The EFI and the Carb flanges are THE SAME thickness. You can swap EFI onto a head with a carburetted exhaust manifold withotu changing the washers... because of this! Cannon may not be casing proper thickness, but Nissan Flanges are damned consistent on their height installed. The stock flange is close to 12-15mm thick (REGARDLESS OF EFI OR CARB!), what you have there is maybe 8-10mm thick at tops. Hence the need to grind the washers. Look at the proximity of the weld to the edge where it clamps as well---if the washer is on the weld bead it will be hard to clamp, or fit the nut on it. Pacesetter does NOT (as far as I know) use the proper thickness flange on their headers---never has. Typical American Produced header flange, used the same thickness as they did on the SBC. Some of them would have tabs of scrap welded on top from punch press operations which made the flange 1/2 thick, but placement was iffy... Clamp with flanged bolts to keep decent press on the bottom of the intake manifold. Using stock nuts and lockwashers you will run the risk of bending the cut down items. Regardless of how long you have been doing it, it's a result of someone manufacturing the header flange too thin---a correctly manufactured flange (such as on a Trust, Greddy, or now MSA) will the identical in thickness to the stock cast iron manifold, and will not need alterations to the washer to 'make it fit'... IMHO, this is a step you should not have to do. For what they charge for the headers, they can put the proper flange on it! Others do, and have done so for over 35 years now! Edited February 28, 2010 by Tony D Quote Link to comment Share on other sites More sharing options...
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