ROCK AUTO 4.0 MOTORS

Does anyone know if the Rockauto 4.0 motors are good?

Well.., I've bought a few items from Rock Auto, and have been satisfied. However, they do sell a wide spectrum of different manufactured, or re-manufactured parts, etc. Many have also been satisfied, and often when a superior part is mentioned.., lol, and by the time I get to R.A.'s site.., they have seemed to have flown off of the shelves there.

That said, I was curious about your request so I clicked on my OPERA home page Rock Auto icon, went there to see what was offered for my year. There was only one long block available; FAMOUS BRAND Part # DA23 (LONG BLOCK), Reman In-Line Head Cast # 2686; Crank Cast # 453; Block Cast # 535, 665; All Blocks Line Honed, Block & Heads 100% Surfaced, Chrome or Moly Rings, Complete Installation Gaskets; SIM Tested for Compression, Leaks, Noises & Oil Pressure. NO MENTION of the brands of parts employed.., which could be a cause to pause...

Checking around it has been said that those engines come from Mexico. You might 'google' the time required to gain a thumbs up, or down.

The one thing I noticed is that they seem to not paint 'em, lol. It would appear that they have been cleaned out externally.., and hopefully internally.

Perhaps Rock Auto prefers to 'hide' the actual company, (if different than the rather oblique name given), in order to 'make a sale'.

One thing that makes sense is to have a local machine shop experienced in engine rebuilding to accomplish the task. Local, personal touch, rather than dealing with far off places, and the costs involved.

Many just go to a salvage yard...

Let us know what you find out.

I'm not big on salvage yards. I can't see buying a motor with 100,000 miles on it and you never know what's gonna go wrong with it.

You can get nice engines from salvage, I've bought a couple and been very happy with them. Just inspect them thoroughly, check the oil level and color, the oil filter condition, the coolant color and smell, is it covered in rust and mud from being outside or is it dry and clean from being in the garage, check the exhaust manifold for abuse, is the distributor broken (means it was in a front-end wreck or the yard abused it), just common sense stuff. These engines are pretty simple to swap so its not even that big of a deal if you end up with a lemon anyway (relative to others that are very difficult).

But obviously you don't want a 2000-2001 motor with the infamous 0331 head.

Based on my more recent experiences with Rock auto, I'd be worried they'd ship me the wrong engine.

Find a local builder, stock spec 4.0's aren't expensive when I've looked in to them

A friend bought a D34 from Rock Auto a couple years ago. It was an ATK rebuild. He called and talked with someone from ATK to see how they deal with the 0331 head. Supposedly, each one is magnafluxed. If cracks are found, the head is rejected. Time will tell.
Two things about the rebuilt, it doesn't have the power the stock engine did and the oil pressure is right at the lower limits.
One would hope for more for $1800.

Rebuilts always seem to be a crap shoot.

Everything is a crap shoot. I've known people to pay good money for a rebuilt only for it to be worse than than the one they took out. Likewise for junk yard engines. You do pay a premium for a mechanics labor and part but if the rebuilt engine fails, they have to pay the labor and do it again. All in all, I'd see what you can find locally and if you see something that seems good, try it.

md21722 said:

Everything is a crap shoot. I've known people to pay good money for a rebuilt only for it to be worse than than the one they took out. Likewise for junk yard engines. You do pay a premium for a mechanics labor and part but if the rebuilt engine fails, they have to pay the labor and do it again. All in all, I'd see what you can find locally and if you see something that seems good, try it.

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Just to play devils advocate, a friend of mine was torn on buying a rebuild or having a local shop rebuild a motor(not and XJ). He went with the local rebuild at a reputable well established shop. He was promised a fast turn around but kept in mind they are a busy shop and likely to expect delays. Well, the took several Months longer than promised. He started stopping by the shop a few times a week just to check in and see what the problem was. Every time they had some excuse or the other about why his motor was pushed to the low end of the priority list or why the needed to order something and it wasn't their fault it was taking so long. I also suggested that he not prepay, that may have been the problem.

Can't say that will be everyones experience or there is a clear right or wrong choice. However, the appeal of ordering a rebuilt motor and having it theoretically just show up at your door within a set timeline is nice. Compared to a being at the mercy of a busy shop to get your project done when promised...

I'd go with a salvage engine. Or better yet, one from craigslist that is still in the vehicle. Often you can hear them run, pull the oil cap and look down in there, etc. I'd rather buy a 100k mile engine built by the factory that runs decent for a couple hundred bucks than a crap shoot rebuild. You can get lower mileage good running used 4.0 engines for 300-600 around here that are still in the Jeep. Do all the seals while it is out of the vehicle, slap it in and go for another 200k.

jeepkid03 said:

I'd go with a salvage engine. Or better yet, one from craigslist that is still in the vehicle. Often you can hear them run, pull the oil cap and look down in there, etc. I'd rather buy a 100k mile engine built by the factory that runs decent for a couple hundred bucks than a crap shoot rebuild. You can get lower mileage good running used 4.0 engines for 300-600 around here that are still in the Jeep. Do all the seals while it is out of the vehicle, slap it in and go for another 200k.

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This. The last several motors I sold had around 200k on them but I waited till you could come listen to it before pulling it and they were 250 bucks. Not hard to find around here.