white4d96 Posted March 27, 2011 Report Share Posted March 27, 2011 The junkyard motor in my '96 is getting on the tired side. Top end's basically gone, has an intermittent vac leak I think is related to the LIM gaskets, etc etc. I don't want to have my car down for weeks while I rebuild it, BUT I have the original motor from the car still. It would have to be completely rebuilt, but I am more than willing to do this. The motor was torn apart pretty good when I got the car, but I was told it was showing symptoms of a failed oil pump, which IIRC could be symptomatic of cam failure? At any rate there was also coolant in the oil which said LIM failure to me. At any rate I will have to tear her down to be sure what is good and bad. Since I'm going to have it all apart, I was playing with the idea of doing some mild work to it. Most of it would depend on what the bores looked like. If they are still decent I will probably just hone them, but if they are scored or ovaled I am entertaining the idea of punching it out some. If I do that I plan on getting 3500 heads and LIM, and a large port UIM. If I can't bore it out enough to do that I will use the stock heads and the later intake. (or should I get later heads as well?) Either way I will be trying my hand at porting the heads and intake out. The possibility of the cam being broken is leading me to look at an upgraded cam. Anyone ever used the Milzy stage I cam? It says it can be used with stock valvetrain and PCM (although I would probably be upgrading the lifters and springs at the very least.) As far as the exhaust goes I am undecided. I may try porting the manifolds or I may try my hand at making some logs. Thoughts? My biggest issue though is emissions. I have to pass an OBD2 plug-in test every 2 years. I am already expecting to need a tune, but would using a tuner cause the emissions computer to not be able to read the PCM somehow? I haven't used a tuner before so I have no idea how this works. At any rate even if I just do a stock rebuild this will be a months-long project. I will basically just order a part a week until I have everything, and work on it on the weekends or maybe early morning after work. Quote Link to comment Share on other sites More sharing options...
White93z34 Posted March 27, 2011 Report Share Posted March 27, 2011 A stock 3400 would be a better starting point and in the end way cheaper then rebuilding a 3100, its virtually bolt in on top of that. Quote Link to comment Share on other sites More sharing options...
AL Posted March 27, 2011 Report Share Posted March 27, 2011 It would cost you way more to rebuild your 3100 than it would to get a junkyard low mile 3400 and swap it in... Do the intake gaskets on the 3400 while its out of the car, or even head gaskets if you want and swap it in Quote Link to comment Share on other sites More sharing options...
white4d96 Posted March 27, 2011 Author Report Share Posted March 27, 2011 (edited) That's not a bad idea... I read somewhere that the 3400 and 3100 heads are the same, is this true? Or are the smallport heads different? Whichever way I go, I would want to rebuild the valvetrain and maybe try some porting. I just figured I could try porting the 3100 stuff I have since I have it; if i muck up I'm out nothing, ya know? Although I could still practice with them I suppose. Edited March 27, 2011 by white4d96 Quote Link to comment Share on other sites More sharing options...
White93z34 Posted March 27, 2011 Report Share Posted March 27, 2011 If anything it would be the late "largeport" 3100/3400 heads/intakes that are the same, not the smallport 3100 like you have. Quote Link to comment Share on other sites More sharing options...
white4d96 Posted March 27, 2011 Author Report Share Posted March 27, 2011 Makes sense to me. Did the 3400's have the same issue with the lifters getting weak/noisy over time like the 3100's? Quote Link to comment Share on other sites More sharing options...
tornado_735 Posted March 27, 2011 Report Share Posted March 27, 2011 Yeah, I was in the same boat as you. I wanted to just rebuild my 3100, but you might as well go full bore (no pun intended) and swap in a 3400. I'm either doing that or a 3500. 3500 is more work, but definitely worth it. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted March 27, 2011 Report Share Posted March 27, 2011 3500 heads on a 3100 block = no happen, the combustion chamber overlaps something important, can't remember what ATM... work on 3400s though, since they have a larger bore. but it's cheaper just to go full 3500 at that point, more power, potential and efficiency at the same time as well. Quote Link to comment Share on other sites More sharing options...
white4d96 Posted March 27, 2011 Author Report Share Posted March 27, 2011 Idk, part of me just wants to build it to be reliable, but part of me is saying "while I'm in there..." Quote Link to comment Share on other sites More sharing options...
tornado_735 Posted March 27, 2011 Report Share Posted March 27, 2011 "while I'm in there..." Might as well dude. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted March 27, 2011 Report Share Posted March 27, 2011 3500 is likely more reliable than other 3x00s since the redesigned LIM doesn't have coolant running through it the way the 3100/3400 intakes do. Quote Link to comment Share on other sites More sharing options...
white4d96 Posted March 27, 2011 Author Report Share Posted March 27, 2011 True. I don't know though, I gotta figure out if I can make anything work with emissions testing. I don't know if I would be able to swap engines or not. Quote Link to comment Share on other sites More sharing options...
WhatTheFehl Posted March 27, 2011 Report Share Posted March 27, 2011 Paging BXX... I don't know, personally I'd love to see a well documented 3500 swap, but that's just me. Quote Link to comment Share on other sites More sharing options...
white4d96 Posted March 27, 2011 Author Report Share Posted March 27, 2011 I can't get 3500's locally for less than $700. 3400's I can find at Pick N Pull where they'll only charge me like $300. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted March 27, 2011 Report Share Posted March 27, 2011 yeah, there's some workarounds for the OBD2 testing, basically the PCM is set to have all required OBD2 tests as "passed" regardless if they're done, failed or passed. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted March 27, 2011 Report Share Posted March 27, 2011 I can't get 3500's locally for less than $700. 3400's I can find at Pick N Pull where they'll only charge me like $300. what exact vehicle are you using for a search? i assume you're looking for a LX9, right? http://en.wikipedia.org/wiki/GM_High_Value_engine#LX9 2005–2006 Buick Terraza/Chevrolet Uplander/Pontiac Montana/Saturn Relay 2004–2006 Chevrolet Malibu/Chevrolet Malibu Maxx 2005–2006 Pontiac G6 Sedan / Coupe 2006–2007 Buick Rendezvous 2006 Pontiac G6 GT Convertible Quote Link to comment Share on other sites More sharing options...
white4d96 Posted March 27, 2011 Author Report Share Posted March 27, 2011 But there isn't a way for them to tell that it's been tampered with? Quote Link to comment Share on other sites More sharing options...
white4d96 Posted March 27, 2011 Author Report Share Posted March 27, 2011 Of the local salvage yards, only one caters to late models, and they are full service and stupidly priced. Quote Link to comment Share on other sites More sharing options...
BXX Posted March 27, 2011 Report Share Posted March 27, 2011 A 3500 is your best bet. I got mine for uber cheap wif 59K on the clock. Robert, the LX9 DOES have coolant running through the UIM, but im yet to see a documented failure. Only the 3500 and 3900s found the the Impala/MC and vans (basically the VVT engines) have no coolant going through the LIM. White, I can bench flash a PCM for ya. It would be a 97 Lumina PCM (96 isnt supported with HP Tuners). Drive to Lorain, Oh. Ill sell ya my LX9 for $300. I also have some items needed for the swap as well I can let do for a small discount.. Lord knows when I will ever get around to putting it in my Vert. It was going in my Banana but I scrapped it last week since I discovered the rust was too severe for me to make a project car out of. Well hell, a quick search on http://www.car-part.com turned up a 04 LX9 with 87K on the clock for $185 at Advantage Auto Parts in Milwaukee. LKQ in Hustisford has a shitload with varying mileage for $350. IIRC LKQ gives a 1 year warrenty on their engines as well. They dont sell junk. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted March 27, 2011 Report Share Posted March 27, 2011 ah, yeah, i guess it is only the gen4 660s without coolant in the LIM, i thought the non-VVT started the trend. good to know the gaskets have held up in the 11 years they've been in existance though. Quote Link to comment Share on other sites More sharing options...
Jonpro03 Posted March 27, 2011 Report Share Posted March 27, 2011 I can't get 3500's locally for less than $700. 3400's I can find at Pick N Pull where they'll only charge me like $300. WHAT?! There's a 3500 local that's $150. Drive your ass down here and pick it up. Quote Link to comment Share on other sites More sharing options...
white4d96 Posted March 28, 2011 Author Report Share Posted March 28, 2011 I don't know if I really want to go that far into this, or if I can afford it. I'm looking to spend 12-1500 total and want to at least do all new valvesprings and rockers (maybe the rest of the headwork as well, but I haven't looked into it too far yet.) I will do all the assembly work myself, but will have to have the machine work done. Gaskets are also a given, and I would like to have it be as simple and bolt-in as possible. My main concerns with the 3500 are the crank trigger thingy you guys have, and what work needs to be done to make it work in place of a 3100. I'll admit I haven't looked into it all that much but from what I've seen from you and Bxx it looks really intensive. That being said I may just do it. I gotta sit down and figure out what I want here. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted March 28, 2011 Report Share Posted March 28, 2011 half of Jon's issues came from him wanting to run it on a megasquirt using the 58X reluctor wheel. Quote Link to comment Share on other sites More sharing options...
Jonpro03 Posted March 28, 2011 Report Share Posted March 28, 2011 half of Jon's issues came from him running it on a megasquirt using the 24X reluctor wheel. Fixed! Yea dude, just use the 3100 ICM and coils with an external trigger. Just install the external trigger and move the wire from the crank sensor on the back of the block to the external sensor. If you want the cheapest install, grab a 3400 UIM and TB. Then switch the rod out on the throttle body so it hooks up with no modifications to throttle linkage. Plus all of your 3100 accessories bolt up. The lower engine mount bolts right on, and the driver side dogbone. The passenger side won't bolt on, but you can modify it to fit (or not use it like me.) Quote Link to comment Share on other sites More sharing options...
BXX Posted March 28, 2011 Report Share Posted March 28, 2011 Yeah, the other engine mount bracket just needs simple grinding on it. A basic 3500 swap can be done for well under $1000. And its pretty much bolt in. For the PCM, I can send ya a 97 Lumina PCM ready to do with 3500 tune on it. And there is nothing intensive aboot a 3500 swap. The crank trigger kit bolts right on, and your 3100 harmonic balancer gets slapped on along with the second crank sensor. Only other minor hurdle is the coolant temp sensor, but I heard there are adapter fittings out there for like $20. You would be stupid IMHO to dump $1200 into a 3100 and be left with 155-160hp. Stock LX9 is ~200hp. Quote Link to comment Share on other sites More sharing options...
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