pshojo Posted February 10, 2013 Report Share Posted February 10, 2013 Intrigues being w body, anyone ever swap out the 3.5 for DOHC? Especially since it did come in Wbody? I've been wondering how similar head designs are? There is guy local has 3.5 with engine harness and engine with 30k miles for $300 Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted February 10, 2013 Report Share Posted February 10, 2013 3.5 is essentially a 6 cyl Northstar, 90 degree engine. Nothing in common with the 3.4 DOHC other than being a DOHC V6. Quote Link to comment Share on other sites More sharing options...
jman093 Posted February 13, 2013 Report Share Posted February 13, 2013 3.5 is essentially a 6 cyl Northstar, 90 degree engine. Yeah, I've always heard the LX5 was Northstar based, but I personally don't believe it. I've spent time looking for any sign of Northstar in LX5's at work and there is literally nothing in common with these engines, outside of the fact that they are both 90 degree DOHC layouts. The block is a completely different design ground up that doesn't even share bore centering, the heads, valvetrain, and accessories are all completely unique too. Even something that you could think would be easily adaptable like the igntion system is all unique too. And all that out-in-left-field stuff on the Northstar like the starter under the intake manifold, the water pump on the back of the block with its own belt is all conventional on an LX5. I think you'd probably find more similarity between the LX5 and a Ford engine than a Northstar. The most important difference, however, between a Northstar and the LX5 is that a LX5 is actually really reliable. Gosh, those Northstars were garbage. To the OP, you'd better be really confident in your mechanical skills to pull off a swap like that, and even if you can, it's a terrible idea, even to any of us fond of the LQ1. Quote Link to comment Share on other sites More sharing options...
pshojo Posted February 13, 2013 Author Report Share Posted February 13, 2013 I was thinking since the stats on HP and so forth seemed close, it would be nice to keep a DOHC motor in the car if it goes. Sounds like complete different beast. So the 3.5 DOHC is totally different than 3.4 DOHC, and 3.5 DOHC is diff beast from North Star. Mmm. Is the 4.0 better than 4.6 Nirthstar,? Quote Link to comment Share on other sites More sharing options...
jman093 Posted February 13, 2013 Report Share Posted February 13, 2013 I was thinking since the stats on HP and so forth seemed close, it would be nice to keep a DOHC motor in the car if it goes. Sounds like complete different beast. So the 3.5 DOHC is totally different than 3.4 DOHC, and 3.5 DOHC is diff beast from North Star. Mmm. Is the 4.0 better than 4.6 Nirthstar,? The 4.0 and 4.6 are the exact same engine. Only the displacement differs. All the problems that plague the 4.6 plague the 4.0. Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted February 15, 2013 Report Share Posted February 15, 2013 The LQ1 has nothing in common with the "Shortstar" LX5 (3.5). They're different degree engines based off totally different engines altogether (2.8 and 4.0 respectively). The LX5 itself was engineered from the ground up. They didn't do what they did with the LQ1 and adapt it to be a DOHC engine. As such, it doesn't have any issues the Northstar nor the Olds related engine had. It's supposed to be a lot more reliable than a V8 Northstar and less troublesome to maintain than an LQ1. The L47 (4.0 engine) is closely related to the Northstar. IT has a smaller bore and from what I've read up it was also cheapened out to reduce weight. I'd avoid Northstar and get a "Shortstar" instead. Quote Link to comment Share on other sites More sharing options...
pshojo Posted February 15, 2013 Author Report Share Posted February 15, 2013 Is 3.5 good engine? What issues plaque it? Reliable? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 15, 2013 Report Share Posted February 15, 2013 almost every 3.5 car i see on craigslist claims to have an overheating engine/bad headgasket... otherwise, i really don't see any other failures. also, i really don't see anything about the 4.0 being cheapened... it's literally a small bore 4.6. Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted February 15, 2013 Report Share Posted February 15, 2013 ^^^ To me using plastic on an engine is going cheap. I feel that way since plastic has a tendency to wear out quicker. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 15, 2013 Report Share Posted February 15, 2013 where on the 4.0 is there plastic where there is not plastic on the 4.6? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 15, 2013 Report Share Posted February 15, 2013 here is a TSB from GM... i removed the pics to save space. http://i.imgur.com/wGv3KmX.png http://i.imgur.com/K6Zkdd8.png the "info" on wikipedia... is mostly incorrect. the only truth to it that i remember is that the 4.0 is slightly heavier due to the debore. it's within a pound or two i think... i would have to check factory info to confirm it though. the heads and cams are different too. Quote Link to comment Share on other sites More sharing options...
AWeb80 Posted February 16, 2013 Report Share Posted February 16, 2013 I have a 01 Aurora with the 3.5 and love the engine. It totes this 4k lb car (without me) around just fine....but in normal GM fashsion, it's bolted to a shitty trans. I still get 28mpg at 65 and over 30 at 55. Not bad for a HUGE car. Quote Link to comment Share on other sites More sharing options...
alec_b Posted February 20, 2013 Report Share Posted February 20, 2013 The only two difference between a 4.6 Cadillac N* and a 4.0 Oldsmobile N* are the bore and cams. That is ALL. Keep in mind there's 2 different Cadillac versions of the engine. Vin "Y" and vin "9". The vin "Y" is rated at 275 HP/295-300 ft/lbs of torque. The vin "9" is rated at 300 HP/ 275 ft/lbs of torque. The ONLY difference in these engines is the cams. Nothing else. Period. To make the Oldsmobile N*, they debored the 4.6 block then installed the hotter cams from the vin "9" N*. There was only 1 version of the 4.0 made. The only thing that changed was the ignition system in 2001, same as when the Cadillac changed to a direct ignition system instead of plug wires with separate coils/module. Quote Link to comment Share on other sites More sharing options...
nelson480 Posted February 20, 2013 Report Share Posted February 20, 2013 Burns oil, leaks oil, blows head gaskets, coolant crossover gaskets fail... northstar was way more reliable than LX5, I'm from an aurora forum and hear about woes from everyone that has one of those engines. Stay away I advise you Quote Link to comment Share on other sites More sharing options...
pshojo Posted February 28, 2013 Author Report Share Posted February 28, 2013 Thanks Quote Link to comment Share on other sites More sharing options...
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