racer

I know that the early 2.5L cars had some engine problems. My assumption is that many of the motors that were replaced were due to "slipped sleeve" issues.

So. How did "Porsche" make the "replacement" motors? Were/are they the same design? Did they change the cylinder designs? Is there less chance of the "replacement" motor failing like the original?

Since I am looking at Boxsters and some of them have replacement motors, are they therefore "less prone" to failure given a redesign?

85percent

from my understanding, the "replacement motors" are just new. period. i don't think they're remanufactured or anything. but if they are, then yes I'm sure they're much better than the original pieces of s**t that porsche tried to slide by its' customers.

99firehawk

THEY ARE REMANUFACTURED,,THE CASES ARE REBUILD NEW LININGS AND ALL NEW PARTS, NEW BEARINGS ECT, EVEN THE HARNESS AND ELECTRICAL PARTS ARE NEW OR REBUILT

racer

So.. are they still "sleeved" cylinders prone to the same problem as the original motors or are they improved? What did they change (if anything)?

99firehawk

Porsce motors have been sleeevd for years, I havent seen any dropped sleeves on any motors buil since 99 ish

GoGo In SoFla

Got a new (not remanufactured) 04S build on my 2000S in the Spring of 2005...2 year unlimited warranty. Original developed a crack in the block at 119,000. I currently have 167,000.
A newer remanufactured unit would have newer upgrades than a remanufactured engine installed a few years ago, so the more recent the implant the better...Remanufactured are warranteed the same as new...

Macster

Not exactly.

The cylinder starts as an insert that during the casting process becomes infused (if everything works right) with molten aluminum.

Subsequent finishing brings the cylinder bore to size and removes the softer aluminum from between the harder insert matrix material (something with lots of silicon).

It is this hard surface (with proper oiling with clean oil) that accounts for the Porsche engine's long wearing cylinders.

Early engine production had problems getting the alum. to flow into these inserts fully and as a result some early engines had porosity problems.

Because sufficient engine factory output was deemed critical to meet the pretty strong demand for the Boxster, these engines were sleeved: The original cylinders were bored out and a then metal (probably iron) sleeve was pressed into place. I expect different pistons and maybe different rings were used in order to be compatible with the sleeve material differences.

The problem is the Boxster engine is not quite as rigid as it could be, and the base material not quite able to securely retain the sleeves and some worked loose with the result the engine was toast.

Sincerely,

Macster.

Tool Pants

Macster has stated what I always understood to be the (excuse the pun) case.

The crankcase is cast with a piston/cylinder sleeve that is 25% silicon and 75% air. This sleeve burns away with the molten metal. What is left is a cylinder wall impregnated/infused with silicon. This is good.

With this method, called LOKASIL, you can end up with a porous cylinder. This is bad, and you have a substandard case.

Porsche had the vendor reworked these cases.

The cylinder(s) were bored out and a metal liner/sleeve (whatever you want to call it) was pressed in, which eliminated the porous issue for that cylinder. But, the sleeve must not move when the piston rings try to push the sleeve up and down. The sleeve cannot be pushed up because it is secured from moving up by the head. To keep the sleeve from being pulled down it has a "lip" on the top of the sleeve.

If this lip fractures, then the piston rings will pull the sleeve down and away from the head as there is no longer anything to keep the sleeve from moving down into the case.

When this happens the piston ring(s) get caught on the top of the sleeve. Then, when the piston ring(s) pull the sleeve down into the case, you have and engine failure.

The above is what little I know about the "sleeve" issue.