Randalla Posted October 6, 2010 Share Posted October 6, 2010 I have a 1971 240-Z with the original engine in it. I bought the car knowing it had a blown head gasket, intending to pull the head and fix it. After pulling the valve cover, I'm now suspecting the engine sat for years because of the scaly rust I see on the cam, timing chain and gear. I have not yet pulled the head or oil pan but expect to see a similar condition when I do. Two questions. First, has anyone successfully resurected an engine like this without a complete disassembly and rebuild. Second, I have located a low mileage, running, fuel injected N42 engine with N47 head that I could swap in but I'd like to convert it to SU carburetors. I've read that the N47 head is not be tapped for them. Is anyone here currently running this combination that can advise re: feasibility? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted October 7, 2010 Administrators Share Posted October 7, 2010 All US market L6 heads are drilled and tapped to accept factory carb intakes, from the first '240-Z up to and through the last L6 powered '83 280-ZX and '84 810/Maxima. Have even installed the early SU's on a Z car N47 and Maxima N47 head, bolts right no, no mods. Now if you want to install a factory EFI intake on an L6, it must be a '75 or newer head, Z or 810/Maxima. It wont bolt on to the '70-'74 heads, unless you drill and tap it and have the injector slots machined. Where did you read that the N47 head is not tapped for the carb intakes? Quote Link to comment Share on other sites More sharing options...
blue72 Posted October 7, 2010 Share Posted October 7, 2010 Please select your answer to the following question carefully: Can you drill two holes in an intake / exhaust gasket for a Nissan L6 engine? a: Yes b: No If you answered 'a' to the above question then you too can bolt a set of SU carburetors to your engine that was originally fuel injected! Quote Link to comment Share on other sites More sharing options...
280-ZeD Posted October 14, 2010 Share Posted October 14, 2010 Al 6 holes must be drilled I have been workin on this tonight LOL... just posted a comparo pic of my cifford 4bbl intake 2 mins ago vs n47 efi, and yes the head on my 78 z is driled and tapped just verified it 2 hours ago lol Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 15, 2010 Share Posted October 15, 2010 "Now if you want to install a factory EFI intake on an L6, it must be a '75 or newer head, Z or 810/Maxima. It wont bolt on to the '70-'74 heads, unless you drill and tap it and have the injector slots machined." 75 or newer US MARKET head! I have an unmolested N42 from a 77 Nissan Cedric that does NOT have the EFI bolt pattern, or notches! And I pulled the engine myself (30C 95% R/H bought for 2 50# bags of Rice and a Half Gallon of Whiskey) from the Cedric where I was able to review the service records of the vehicle. It was all original, unmolested, 42,000 Km Automatic! Another thing to watch for when using carbs on an EFI head is that some of those large EFI bolt holes seem to have been tapped a bit too exuberantly, and bored a tad deep---resulting in a terribly pesky oil leak that will have you scratching your head as to how the hell you can seal your valve cover to stop it...but you won't! It's coming from the *(&%*&%$ intake manifold bolt hole! RTV works wonders in this instance. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted October 15, 2010 Administrators Share Posted October 15, 2010 "Now if you want to install a factory EFI intake on an L6, it must be a '75 or newer head, Z or 810/Maxima. It wont bolt on to the '70-'74 heads, unless you drill and tap it and have the injector slots machined." 75 or newer US MARKET head! I have an unmolested N42 from a 77 Nissan Cedric that does NOT have the EFI bolt pattern, or notches! And I pulled the engine myself (30C 95% R/H bought for 2 50# bags of Rice and a Half Gallon of Whiskey) from the Cedric where I was able to review the service records of the vehicle. It was all original, unmolested, 42,000 Km Automatic! Another thing to watch for when using carbs on an EFI head is that some of those large EFI bolt holes seem to have been tapped a bit too exuberantly, and bored a tad deep---resulting in a terribly pesky oil leak that will have you scratching your head as to how the hell you can seal your valve cover to stop it...but you won't! It's coming from the *(&%*&%$ intake manifold bolt hole! RTV works wonders in this instance. Oops... Thanks for catching that Tony. I recall getting bit on that a few years back with the welded chamber N42 race head we built documented in the "Custom Cylinder head building.. What’s involved…" thread. Turned out to be a JDM N42, no EFI intake bolt holes or injector slots. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 16, 2010 Share Posted October 16, 2010 They are out there, especially in So Cal where K. Watanabe and other JDM suppliers flooded the market with $200 used engines in the mid 90's. Here you never know what it's going to get. Dismissively passing a Maxima station wagon in the junkyard some years ago (due to the probability stats saying L24E) my eye caught 'Y70' on the head. Car had a JDM Transplant L20E! Wouldn't have ever expected THAT here in the USA either! There is strange stuff out there. Nissan didn't export to just the North American Market as some would try and make you believe (Channelling Alan T now... ) Quote Link to comment Share on other sites More sharing options...
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