Streetwiseguy
Streetwiseguy UltimaDork
11/22/17 5:35 p.m.

My 04 Sentra has the destructo-cat, which has me burning a liter of oil about every 500 miles.  It runs fine, but I'd like to sell the thing.  I just put a bid on a crashed 06 Altima 2.5.  Did the Altima engines have the same cat problems?  Did Nissan ever actually fix the problem?  Am I going to winch an Altima that is missing most of the drivers side of the car onto my trailer, bring it home, swap engines and discover that I would have been better off watching late night TV?

Opti
Opti HalfDork
11/23/17 2:56 p.m.

Nissan makes really E36 M3ty cats and they all die. Ive replaced fewer 3.5 cats but lots of 2.5 4.0 and 5.6s, im pretty sure they never fixed it, unless its something they just did in the last few years.

Carson
Carson Dork
11/23/17 3:58 p.m.

I think it was ‘07+ that the pre-cat issue and butterfly valve screws were fixed, or at least, made better. 

Streetwiseguy
Streetwiseguy UltimaDork
11/23/17 4:15 p.m.

I think I can make enough money off the remaining parts to make the purchase of the wreck a profit.  If the trunk isn't full of half empty oil jugs, I will swap it and see whether I'm a complete idiot, or just a halfwit.  I sure can't see anybody buying it to repair, and it doesn't look like it would have damaged the engine.

May not get the car at the lowball bid I made on it, anyway.

Streetwiseguy
Streetwiseguy UltimaDork
11/23/17 4:24 p.m.

Fascinating damage.  We've been discussing just exactly how you can hit something massive enough to shear the side of the car off, but not so solidly that the car bounces away.

kazoospec
kazoospec SuperDork
11/23/17 6:53 p.m.

After you swap the engines, put in an aftermarket header, loctite the butterfly screws and the major problems with the QR are solved.  It's still never going to be a "bulletproof" motor, but those two fixes at least bump it up to basically reliable.  P.S. - you'll get a nice little power bump out of the whole thing.  You might even end up wanting to keep it. 

 

I had this one on my old Spec V:

el cheapo header that actually isn't too bad . . .

 

mad_machine
mad_machine MegaDork
11/23/17 8:07 p.m.
Streetwiseguy said:

Fascinating damage.  We've been discussing just exactly how you can hit something massive enough to shear the side of the car off, but not so solidly that the car bounces away.

I saw a car that grazed the rear carriage of a semi. The wheels ripped all the sheetmetal off of the car, but did not harm the structure

Streetwiseguy
Streetwiseguy UltimaDork
11/23/17 9:29 p.m.
kazoospec said:

After you swap the engines, put in an aftermarket header, loctite the butterfly screws and the major problems with the QR are solved.  It's still never going to be a "bulletproof" motor, but those two fixes at least bump it up to basically reliable.  P.S. - you'll get a nice little power bump out of the whole thing.  You might even end up wanting to keep it. 

 

I had this one on my old Spec V:

el cheapo header that actually isn't too bad . . .

 

It already has a $100 stainless ebay header.  Its almost hilarious when you search "Sentra header" but are looking for an SR20 unit.

Run_Away
Run_Away HalfDork
11/23/17 11:29 p.m.

Nissan claims it was "fixed" by a series of ECM software flashes that try to prolong the life of the cat. The later the car, the better chance it has of not burning oil. It's also driving style related I think. My parents have an 04 Sentra SE-R with 140kms that doesn't burn a drop. We also have a customer at work with 470kms on a 03 Altima QR25 that's still going strong on the original engine (and I think the cat too).

 

Or you could do what I did and swap a VQ35! I'll send you all the wiring pinouts needed (mine is also an 04, although late production) and make you a sweet deal on 2J Racing Mounts....devil

fanfoy
fanfoy Dork
11/24/17 6:59 a.m.

The first gen QR25 were only really reliable in 2006. They sent to a diferent ECU and finally used a wide-band O2 sensor to control the mixture well enough not to kill the pre-cat. It's the un-burned fuel that kills the pre-cat. The butterfly issues were fixed by 2006 too. 

The 2nd gen QR25 (which is a very different engine) doesn't have any of those problems, but you can't swap it into your Sentra (easily)

But like Run_Away wrote, the driving style has a lot of influence on the longevity of those engine. Cars with the automatic transmission don't seem to have any problems.

eebasist
eebasist Reader
11/24/17 9:35 p.m.

In reply to fanfoy :

Cars with autos don't have the issues as the Auto doesn't engine brake. This vintage engine and the Toyota MRS both had failing precats that sucked debris into the engine with manual transmissions but not autos

if i may ask, how much did you pay for that Altima?

Streetwiseguy
Streetwiseguy UltimaDork
11/25/17 7:04 a.m.
eebasist said:

In reply to fanfoy :

Cars with autos don't have the issues as the Auto doesn't engine brake. This vintage engine and the Toyota MRS both had failing precats that sucked debris into the engine with manual transmissions but not autos

if i may ask, how much did you pay for that Altima?

Haven't got it yet.  Bids close on Wednesday.  It's in a small town compound, 120 miles away from major centers, so I'm hoping I can get it for the value of the tail lights.

Knurled.
Knurled. MegaDork
11/25/17 8:10 a.m.
eebasist said:

In reply to fanfoy :

Cars with autos don't have the issues as the Auto doesn't engine brake.

So, from what I understand, this is mostly a problem of trying to make modern emissions controls function well with archaic driving styles.

 

I've only ever seen the QR25 installed in Rogues.  I've seen a whole lot of failed oil cooler gaskets, alternator clutches, and air conditioning compressor clutch bearings, but never yet a bad cat.  Until this thread, I didn't know Nissan ever paired this engine with a manual trans.  Is it as spitefully anti-drivable as a manual trans QG18(?) engined Sentra?  Lift the throttle to shift and the engine actually revs up for a moment?

 

Streetwiseguy
Streetwiseguy UltimaDork
11/25/17 10:27 a.m.
Knurled. said:
eebasist said:

In reply to fanfoy :

Cars with autos don't have the issues as the Auto doesn't engine brake.

So, from what I understand, this is mostly a problem of trying to make modern emissions controls function well with archaic driving styles.

 

I've only ever seen the QR25 installed in Rogues.  I've seen a whole lot of failed oil cooler gaskets, alternator clutches, and air conditioning compressor clutch bearings, but never yet a bad cat.  Until this thread, I didn't know Nissan ever paired this engine with a manual trans.  Is it as spitefully anti-drivable as a manual trans QG18(?) engined Sentra?  Lift the throttle to shift and the engine actually revs up for a moment?

 

Spec V B15 Sentra with Brembo brakes makes for a fabulous little car.  Six speed, LSD, quick, really good handling.  If it weren't for the oil burning situation, they would be way, way up on the list of great little sedans.

The throttle thing is typical to every manual shift car built for the last few decades.  I don't even notice anymore.

Streetwiseguy
Streetwiseguy UltimaDork
12/15/17 3:31 p.m.

So, the new Altima motor in the Sentra works just fine.  300 km, and the oil level is still where it was to begin with.  Before, it would have been approaching half a liter down by now.

$250 for the Altima, a tank of gas, and a few hours of wrenching.  I can now, in good conscience, ask an extra $1500 for the car.  Whether I get the extra dough or not is yet to be seen.  Watching for a gently crashed Altima that needs the right side doors now.

 

Run_Away
Run_Away HalfDork
12/15/17 8:28 p.m.

I don't know what scrap is at now, but I got $220 CAD for the shell of my altima (sans engine) when I parted my donor out. I'm assuming it's lower now since you only paid $250 for it.

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