[928uk] Item number: 300662692370

[Paul R. Smith]

First the actual differences:
GTS pistons are forged, therefore expand less than the block with heat, 
so have more hot clearance than the previous cast pistons.
The early GTS pistons did not have oil drain holes from behind the oil 
ring to inside the piston. Ones with drain holes became available at 
some time, but not sure if these were ever fitted to a car on the 
assembly line. (This is the easiest mod to make, if the pistons are out.)
GTS pistons are shorter.

All three of the above will contribute to higher oil consumption. The 
extra consumption can come about in two ways, one is from oil being left 
on the bores after the piston moves down, the other is from extra 
blow-by of combustion gasses pushing oil around the breather system into 
the intake manifold.

The liners that I know were fitted to some replacement engines (I don't 
know if they were ever fitted on the production line), were also an 
aluminium alloy, I suspect that they were similar to the alusil of the 
block, but with different proportions.

I suspect that the biggest influence affecting the actual oil 
consumption rate of similar GTSs is the type of transmission and type of 
driver. A manual with an enthusiastic driver is likely to spend more 
time at higher revs, and the rate of blow-by breathing goes up 
drastically at higher revs. The idea that how the engine was run in also 
holds water as incompletely bedded in rings will also promote heavy 
breathing.

Smiffy

On 13/02/2012 08:52, andy wrote:
> Did porsche make any mods to the engine to solve the problem in its
> short life? I ask because i do not have that problem. It does 1,350
> miles per litre. Why would the problem be inconsistent? I am an engineer
> by profession . Machining is consistent. Components are manufactured to
> tolerances.materials " should be to the required standards with
> certificates of conformity" Love to hear your theories.
>
> Andy ( not really 928 educated despite having owned it for 10 years)
>
>
>
>
>     ========================================
>     Message Received: Feb 12 2012, 07:10 PM
>     From: "Paul"
>     To: "andy"
>     Cc: "David Morgan" , 928uk at lists.928.org.uk
>     Subject: Re: [928uk] Item number: 300662692370
>
>     There is undeniably a fundamental design flaw with the GTS pistons.
>     This may not affect every car, possibly because of individual
>     differences in the way that engines were run in, but it is certainly
>     there. The use of sleeves to fix the issue was not only unreliable,
>     but negated one of the best aspects of 928 engine design: the Alusil
>     bores that mean that even 200k mile plus engines have virtual no
>     bore wear.
>
>
>     Paul
>
>     87 S4 Manual
>
>     On 12 February 2012 18:55, andy <andrews at letham56.fsnet.co.uk
>     <mailto:andrews at letham56.fsnet.co.uk>> wrote:
>
>         Beautiful car. Seller a bit unkind to GTS model. Perhaps he has
>         not seen the article dedicated to GTS in March 911 & Porsche
>         world. They say GTS is the ultimate of the marque. Lovely one in
>         that article for £20k. At 108,000 miles it looks wonderful. He
>         says they burn oil well thats not universally true. If you had
>         the money which one would you buy?
>
>         Andy Smith
>
>         GTS manual (totally smitten by it)
>
>
>
>
>             ========================================
>             Message Received: Feb 11 2012, 11:45 AM
>             From: "David Morgan"
>             To: 928uk at lists.928.org.uk <mailto:928uk at lists.928.org.uk>
>             Cc:
>             Subject: [928uk] Item number: 300662692370
>
>
>
>             All,Check this beauty out on ebay.Dave MorganGuards Red GT
>
>
>
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