View Full Version : For those of you who've successfully rebuilt a northstar engine. . .

01-28-11, 04:39 AM
Would like to know what made you successful. Did you insert the bottom end. I would assume retorquing the bolts on the bottom end would have the same effect as retorquing the heads back into the block. Has anyone ever considered big serts Or studs in the bottom end?

01-28-11, 08:38 AM
I have used custom machined bolts in the bottom end with a slightly larger thread. The low torque of the main bolts would allow timeserts to be used without any problems. You have to be careful when modifiying the bottom end because bolt diameter is critical for the main bearings. Oil is fed past 12 of the 20 main bolts. If you increase the bolt diameter you reduce oil flow to the main bearings and crank journals. These are four bolt mains, and some may think "if one snaps, that's ok, there's still plenty of bolts holding -" well if it's one of those 12 and if the bolt is not even torqued properly (loose), oil pressure will be lost. If any one of those bolts strips or snaps, the whole bottom end is coming apart again-

I believe I will soon have a stud kit out for the bottom end, standard and oversize thread (nobody wants to redrill and tap ALL of these holes unless they absolutely have to). I just finished the Toyota 2.4L stud kit and it will be on the market within 2 weeks. It worked flawlessly. With studs and nuts, you won't be pulling those M10x1.5 threads out- at least not as easily.

01-28-11, 03:42 PM
Exactly what I had in mind. I want to have a machine shop drill out all holes (head and bottom end) and reassemble with a better threaded bolt. I'm loosing faith in northstars and GM altogether. i've never really had a quality gm product that was up to the standards of toyota. It seems many gm products are plagued by squeeks, rattles, and whining noises. I had a 2002 grand prix gtp bought brand new. Paid a lot for it when I bought it. The car whined from the first day (alternator whine). Took it back to dealer several times, they never fixed it. I finally got rid of it after 105000 miles and bought a used lexus sc400. Best car I ever owned since the toyota camry I had before the grand prix. Gave that up for my mustang (another horror story in itself).

01-28-11, 10:24 PM
Micah, about Toyota: - there's a lot of complaints arising on the 2.4L 2AZFE and get this: Toyota made the mistake of using M11x1.5 head bolts long after the problem was already discovered on the Northstar. 2002-2007 they used the M11x1.5 bolts. It's bad enough to make a mistake and have to learn from it like GM did with the Northstar head bolts; it's even worse if another manufacturer has made the same huge mistake afterward; years later. GM went to M11x2.0 in late '03/04, Toyota didn't correct their mistake until '07. The local Toyota dealer is now aware of the fix I have and want information so that the next time the problem arises in their shop; they'll have the solution.

When the time comes that you want a good Northstar for your '99 we'll set something up and it will be the last one you'll have to install.

01-28-11, 11:00 PM
That sounds like a plan to me. I understand what you mean by that. I guess I'm just picky. I hate squeeks, rattles or any noises of any kind. I like a nice comfy quiet ride. (thats what I like about the sts, sports but without sacrificing the comfort and capacity). I'd very much like to make sure I get another engine that will be reliable. I'm kinda on a budget tho, so this time instead of nickel and diming and spending a thousand here and a thousand there, I'm going to wait until I have enough money to just get one that's all done with a warranty. It's limping along as is but at the cost of peace of mind. Thanks for being there and talking to me about it so many times.