Datsun Roadster Parts from Rallye Enterprises, Ltd. |
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EXHAUST MANIFOLD *68-70 2000 This manifold attaches to the front pipe via a 3 bolt flange, which is an improvement over the 67 clamp that struggled to hold the manifold and front pipe together. Original manifolds are designed to fit and keep engine compartment heat to a minimum and cut noise. By their nature they are quieter than a header. These manifolds are very efficient flow wise, which is very unusual in an original equipment manifold. You may notice a dent or two in the above picture. Over the years we have had a number of people order these and then call thinking we sent a damaged part. Each one of those dents is put there when the part is manufactured and is there for a reason, to add clearance against another part of the car or provide the ability to remove a nut or fitting on the intake manifold. Nissan designed this complicated piece to combine the benefits of a header and a manifold. Unless you are using an equal length set of headers that dumps out the wheel well, which is only really workable on a full race car, a header won't offer noticeable gains over a stock manifold. Typically a production manifold on a car is a cramped part with lots of 90 degree bends. Here is one part that Nissan really did its homework on! |
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Making it Live Longer...Manifolds do crack, but not necessarily any quicker than headers burn out. These manifolds suffered greatly because lazy mechanics and/or owners "forgot" to reinstall the brace that runs from the front of the manifold to the engine mount bracket. This brace serves two purposes. One is to lessen stress on the manifold that is generated by the engine jumping around with the exhaust system firmly mounted. With the brace in place, the forces that are trying to bend the manifold are reduced greatly because the leverage is reduced. The brace also helps the manifold gasket to live longer as the constant motion of the engine in relationship to the exhaust system tends to eventually crush the manifold gasket. Unless the manifold is snugged down the gasket will eventually fail. The 2000 usually lets you know this by the presence of coolant staining on the side of the engine block below and behind the carbs. Keeping your engine properly tuned up will also increase gasket and manifold life. An engine that jumps around at idle is very stressful on the exhaust system in general, the manifold, the gasket, and even the engine mounts. The above described stresses can also be lessened by installing a section of "flex" tubing just to the rear of your front pipe's mounting flange. This is not the lightweight low quality flex tubing popular in the 60's for "modificiations" it is a webbed tubing that is used as original equipment many cars. Your exhaust shop can fabricate this for you. (When I get a minute I'll make some more "ready to install" replacements.) This also applies to headers. The headers have no provision for a lower brace so the flex tubing is very helpful. |
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