Engine Rebuild - Questions

[Whaleboy]

So last month I threw rod #2 on my engine in the VX (they never explained why). After digging up all my oil change receipts, it was covered under warranty. However, this is a Carmax warranty - as it was bought used so a "remanufactured" short block from Isuzu was put in.

After a month and one week, I just got my VX back (THANK GOD). However, it appears its really sluggish in the performance dept. now. I noticed this when it didn't seem to have as much pep taking off from a light then before. It doesn't feel like a sporty engine anymore, it feels like a run-of-the-mill SUV.

So yesterday evening I decided to test it, it took the damn thing like almost 9 and a half seconds to reach 0-60, which wasn't right at all.

so my questions are - this is a stock VX, except the elbow is removed. And is still removed after all the engine work - which makes me wonder if thats the reason why it seems to be performing so slow? Would this factor in to anything - them not noticing the elbow has been removed when adjusting the timing, etc? not that I can imagine it makes any big difference..

Should I not expect the engine to perform as before after a remanufactured shortblock from Isuzu has been put into the car by the techs at the Isuzu Dealership?

Is there some kinda break-in process I wasn't informed about?

And if it really isn't performing as it did before, how exactly do I explain to the guys at Carmax this "yeah, I floored it - and it just don't move like it did"?

Should I take it somewhere else to verify the engine isn't performing up to snuff? and how is that checked anyways?

I dunno, maybe I've just been driving rental cars for too long... But even when I first purchased the car 2 years ago, it handled like a sports car.. Now after the shop, it handles like a soccer moms SUV...

[Inaba]

~9 sec from 0 - 60 is about right for stock.

It may be the "service syndrom" you are experiencing... your car feels better (or in your case worse) when you get it back from service, even if nothing was really done to affect performance.

That really blows that they put a remanufacturered one in your VX, though... but what can you do.

Without putting your VX on a dyno before the work and then after the work, there's no real way to "prove" it's behaving differently. However, putting it on a dyno and checking if bhp or actual HP is up to specs might be something you could do... if you don't know anyone that can do this, a performance shop will probably charge you $100 - $200 to run tests on it. It may be worth it to you, and especially if you can show that it tests out substantially below the "advertised" specs.

I'd be more interested in knowing why you've thrown a rod twice? That seems kinda strange, unless you are red lining the sucker

[Whaleboy]

I've never thrown a rod before, this was my first. I was saying it was rod #2, thats what the dealership told me.

I read on the other board, Road & Track rated the VX as 8.8 sec - stock. But I seem to be getting around 9 and a half now. I gotta try it again tonight.

Maybe it is all in my head - sure seems sluggish to me. Anybody still wanna help me with some of the questions please?

[AlaskaVX]

There is some type of break in proccess for new engines, but some people say to drive it how you would normally, some say to break it in slow, and others have their own technique for breaking it in (running certain gears for so long then swithching) Honestly I have no clue what the correct way to break an engine in, hell I don't even know what a re-manufactured engine is! Is it just a rebuilt one from someone else that blew a rod too?

I can't imagine that the elbow has anything to do with it, I would almost put my bet on you getting used to the rental car. Cars I believe FEEL faster since your all low to the ground and whatnot.

Anyway enough with my nonsense rambling, leave it to the gurus.

[Hotsauce]

Do check that they didn't give you a 3.2 instead of 3.5.

Since you only got a new shortblock(block,pistons,rods,crank) it is possible that the cam timing is off also.



John C.

[VX1]

I blew a rod in one of those MR2 Spyders a couple of years ago. When they rebuilt the engine, I felt the same way, like they didn't build it to the same tolerances; felt about 15 horses were missing. It blew again a couple of months later, because they didn't address the real issue for the first failure, oil starvation due to sludge.

It does sound like you're so close to stock performance anyway, you'd surely be wasting breath trying to convince the mechanics that you are a .2 second off specs. Another thing, it is warmer these days, and that'll definitely take .2 off your time and more.

I would just watch your oil very carefully over the next few months. Change it often (your "new" engine will contain more metal shavings and junk in it for a while), and make sure your oil doesn't smell burnt or feel thick.

Other than that, there's plenty of performance mods out there that'll get you back in the game. You found one, the elbow, but there's also the PV muffler, smaller wheels, K&N filter, weight savings, etc...

Scott Swett

[VehiX]

Do some real tests like check for a loose vacume line, gap in your spark plugs, fuel grade, intake manifold leaks, compression test, you know things like that

These can all contribute to sluggish performance.

It's pretty rare some one puts an entire motor back together correctly on the first try even if you have been doing it for years!!!



What have you been driving in the mean time while your VX was getting worked on? Something with a bigger motor and more pep? this could also make the VX feel sluggish to you after getting use to the spare/rental car after a while.

Take it back to the dealer that performed the work and explain your concerns to them. You might be surprised what you find if indeed there is something wrong.

just food for thought