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rsteinmetz70112
03/03/2011, 08:29 AM
I know the engine used in the VX has a history of problems including premature failure and high oil use. I have read that there are some theories about the cause.

It appears that many engines were replaced under warranty, presumably these would have been new factory engines with whatever flaws were in the original engines.

It appears that many engines were replaced with used engines from a variety of sources which again would have had the same inherent problems.

It appears that many engines were rebuilt or repaired by a variety of local shops.

I saw a comment the other day that assumed that rebuilt engines would not have these same issues.

I wonder if it is true that an engine remanufactured by an engine specialist who tears the whole thing down and replaces major parts to spec would provide a better engine that OEM.

Does anyone have any experience along these lines?

circmand
03/03/2011, 12:43 PM
the VX engine is the same one as in the Trooper. As far as I have seen there has been no documented engine problem on the 3.5. Sure several people have had engine problems. Most seem to stem from a failure to check the oil or just plain abuse. Of course you blow an engine you are going to complain but if you do not blow an engine you are not likely to post hey I havent had a probem everything is okay

vt_maverick
03/03/2011, 12:56 PM
the VX engine is the same one as in the Trooper. As far as I have seen there has been no documented engine problem on the 3.5. Sure several people have had engine problems. Most seem to stem from a failure to check the oil or just plain abuse. Of course you blow an engine you are going to complain but if you do not blow an engine you are not likely to post hey I havent had a probem everything is okay

I'd say above average oil consumption is a very well documented problem with the 3.5 in the VX, Trooper, and Axiom (including the direct injection, one-year only version that I own). I've owned a Nissan/Infiniti, Honda, Ford/Mercury, Chrysler/Dodge, Chevy, and even a Jeep and never had oil consumption issues anywhere near as bad as with the Isuzu 3.5 engine. Now those cars all had much worse issues in other areas, but none were at the same level of oil consumption.

True, aggressive oil checking/maintenance can help stave off an engine failure. But just because the engine never fails doesn't mean that it is without design flaws.

circmand
03/03/2011, 01:36 PM
I'd say above average oil consumption is a very well documented problem with the 3.5 in the VX, Trooper, and Axiom (including the direct injection, one-year only version that I own). I've owned a Nissan/Infiniti, Honda, Ford/Mercury, Chrysler/Dodge, Chevy, and even a Jeep and never had oil consumption issues anywhere near as bad as with the Isuzu 3.5 engine. Now those cars all had much worse issues in other areas, but none were at the same level of oil consumption.

True, aggressive oil checking/maintenance can help stave off an engine failure. But just because the engine never fails doesn't mean that it is without design flaws.

But 1 quart per 3000 miles hardly classifies as excessive. Too many people just start the car and go and have totally ignore maintainance. There are tons of specialty cars that have more oil consumption and other unique maintainance requirements that if not followed result in catastrophic failure. Just about any real sports car for an example. Wile I agree it can be a design that could be improved upon I do not think it rises to the point of design failure otherwise a recall would have been done.

vxfocus
03/03/2011, 06:45 PM
i gotta put a quart a week in.i think that is execessive

Y33TREKker
03/03/2011, 07:03 PM
...I do not think it rises to the point of design failure otherwise a recall would have been done.
But the fact that a recall was never done doesn't mean there wasn't a design flaw either, so that's a circular discussion.

Either way. :badhorse:

Kona-Vs
03/03/2011, 07:16 PM
I've heard it said here that the 2000 and 2001 engines have less of an oil issue so what did Isuzu change in the engine after 99?

jmayer40
03/04/2011, 03:27 AM
I read that it's an oil relief problem on the piston's oil ring. I'm debating on... if i buy new pistons, will they have more holes...plus anyone know how long to rebuild engine? been awhile for me, last time I did it was on a 79 ford truck. Kinda miss the old quad carbs..

Buffy
03/04/2011, 05:22 AM
I spoke with Jerry Lemond about the issues with the 3.5 and how I could fix it when I rebuilt my motor. He said that Isuzu came out with a modified piston that basically had 4 additional holes drilled into the oil groove of the piston. I had to have my block bored .020 over which meant I had to have aftermarket pistons since Isuzu does not make oversized pistons. My new pistons did NOT have the additional holes in them but Jerry informed me how to modify the pistons which I passed on to the machine shop. Jerry told me to break the motor in and put about 400 to 500 miles on the motor to seat the rings. Then switch to 5W40 synthetic Rotella diesel oil. That is what I've done and no usage to this point. Of course I only have a few thousand miles on my build too so only time will tell.

Personally I've been skeptical on some of the high volume builders. I've read some real horror stories on quality issues and warranty claims. I've never had any personal experience with any of them though. But since I plan on keeping my VX I rebuilt mine using all (minus pistons) Isuzu parts. I worked with Merlin and asked where would he reccommend an aftermarket part vs an OEM part. He was very honest about what parts I could go aftermarket and where it was better to get from him. Ball joints and other suspension stuff I got through Rock Auto and saves a substantial amount of money.

rsteinmetz70112
03/04/2011, 06:10 AM
I don't consider the VX a specialty car in the same class as a high performance or limited production sports car, since it is basically a different body over the mass market Trooper.

I consider 1 quart of oil every 3,000 miles excessive when the manufacturers recommend oil change interval is more than twice that. I have never owned a car that used that much oil, including some cantankerous British cars and a 1974 Chevy Vega.

It seems that excessive oil consumption is a likely cause or contributor of premature engine failure.

I wonder whether the problems are the result of design flaws or poor quality control. Design flaws likely would not be fixed by rebuilding but quality control issues (like excessive tolerances) could be corrected by a rebuild.

samneil2000
03/04/2011, 06:37 AM
I seem to remember someone posting a picture of a piston and the oil rings were stuck in the grove instead of being freely moving about so that they could seal against the cylinder bore. I think I remember seeing that, and it could be one of many problems that are leading to the oil consumption. Again, I would think a reman would address most of not all of these issues. I mean, if they're using this engine in airplanes, I'm sure they have pretty strict quality controls for those, right? More dependence on 100% performance. Can't have an engine lock up at 5,000 feet. :o

vt_maverick
03/04/2011, 08:43 PM
... While I agree it can be a design that could be improved upon I do not think it rises to the point of design failure otherwise a recall would have been done.


But the fact that a recall was never done doesn't mean there wasn't a design flaw either, so that's a circular discussion.

+1 - This is one of my favorite quotes from the movie Fight Club:


A new car built by my company leaves somewhere traveling at 60 mph. The rear differential locks up. The car crashes and burns with everyone trapped inside. Now, should we initiate a recall? Take the number of vehicles in the field, A, multiply by the probable rate of failure, B, multiply by the average out-of-court settlement, C. A times B times C equals X. If X is less than the cost of a recall, we don't do one.

Gussie2000
03/07/2011, 08:52 PM
The 3.5L in our VX,troopers and rodeos were the 1rst of its generation so flaws are more likely to happen,

The true fact is that isuzu never admitted the issues,instead they issue an bulletin saying that one quart per every 1000 miles is just fine.

Has anyone ever read and/or heard vehicules from other car manufacturers back in the late '90 that had the same amount of oil consumption as "normal" ?

circmand
03/07/2011, 09:31 PM
The 3.5L in our VX,troopers and rodeos were the 1rst of its generation so flaws are more likely to happen,

The true fact is that isuzu never admitted the issues,instead they issue an bulletin saying that one quart per every 1000 miles is just fine.

Has anyone ever read and/or heard vehicules from other car manufacturers back in the late '90 that had the same amount of oil consumption as "normal" ?

I never came close to that it is more like 1 quart for a little over 3000 miles. I have not seen or heard of the bulletin you spoke of is it here on site? Of course I guess we can search the many vehicles made for similar consumption.

circmand
03/07/2011, 09:43 PM
"When the oil level goes down, it has either been burned inside the engine or it has leaked past a gasket or seal, says Jim Kerr. Determining how the oil disappears when there are no external leaks may seem complicated but it is really very simple, he says.

Some engines use more oil than others, but how much is too much? Leaf through the repair manuals of several auto manufacturers and you will find a variety of specifications. One states that the engine should use no more than 1 quart (.946 litres) of oil in 3200 km. Another states a litre in 500 km. This wide range of specifications challenges anyone to determine what is excessive. A lot has to do with the design of engine, the application, the oil viscosity and how it is operated."

Now I am no expert on KM but I beleive it is 6/10ths of a mile. Now a liter in 500 km is more than 1 quart per 300 miles. More in the article state more commercial engines have more consumption due to less tight seals. I wonder if Isuzus commercial truck experience has allowed them to be a bit more liberal than others?

VXR
03/07/2011, 10:15 PM
I wonder if Isuzus commercial truck experience has allowed them to be a bit more liberal than others?

Now that is a good question:yesb:

VXdoc
03/07/2011, 11:50 PM
This Usually Depends On The Local Shop. If They Are Good And Reputable Then Maybe They Did A Good Job. And If Not, Your Guess Is As Good As Mine. Typically All Engines Opperate On The Same Basic Principle Unless It Is Based Off Of The Wankle Set Up. More Commonly Known As The Rotary Engine. A Good Mechanic Can Pretty Much Rebuild Anything Well As Long As They Have The Specs. As To The Replacement By Other Simaliar Engine's That Very Well Could Be Depending On The Year Of Replacement. In That Case Maybe They Debugged All The Flaws In Those Unlike In Previous Models. It's All Speculation Really.

Anthony

TheGanzman
03/08/2011, 04:27 PM
Has anyone ever read and/or heard vehicules from other car manufacturers back in the late '90 that had the same amount of oil consumption as "normal" ?

Yes - Porsche; and now we're talking about "precision Teutonic engineering"...