Gregg K

Woah! I repeat, Woah! It's early. I do that when the caffeine hasn't totally permiated my arteries.



Doug, where is this written?- Did I miss this in the owners manual?

Porsche state that up to 1.5 litres/1000 kms is "acceptable"

MikeN

These figures are in the little 928 Spec Book and service manuals.

Jim bailey - 928 International

When Porsche decided to make the 5 liter engine into a 5.4 liter for the GTS . They used the same 100 mm cylinder bore BUT decided to move the piston farther . Since the piston can not go any higher (hits the head) it must go lower on the down stroke . The crankshaft is also in the way at the bottom so they used a much shorter piston and moved the wrist pin higher in the piston . This crowds together the rings.......in addition the oil scraper rings which on all other 928 pistons have holes behind them to drain oil back into the underside of the piston are not drilled all the way through ! The GTS engines were , are , and will be "oil burners" compared to all the earlier 928 engines . One GTS in the U K was recently reported to be getting it's third engine compliments of Porsche , the owner must be a very good negotiator . All the "werkswagon" factory executive cars were said to have been fitted with NEW engines prior to being sold to the public . I know of one GTS (Texas) which on a long trip was run so low on oil that it ruined the engine , spun a main and cracked the block (the low oil level float warning does not always work and only checks with the engine not running ). It is very important to check the OIL every time you fillup with gasoline if you drive a GTS and note that by the time you reach the recommended 15,000 oil change interval you will have nearly "changed " the oil simply by ADDING oil ! It has been said that Porsche designed the GTS piston to "hold more oil" on the piston cylinder interface to preserve the block knowing that they would not have spare blocks in the future . That seems odd when you realize that there are S-4 engines with 200,000 ; 300,000 miles and more which have not worn out their blocks and consume far less oil than a GTS . I have been told that in the past Porsche would replace the engine while the car was covered by warranty when oil consumption exceed about one quart per 500 miles when the owner pressed the issue . There was a piston redesign in the GTS in 1993 were they "reinforced the piston skirts" that was probably to try to keep the short piston square in the cylinder . The additional side loading of the longer stroke crank makes the short piston want to tip sideways the skirts try to keep it straight . The only fix for the oil consumption involves a complete rebuild of the engine that is probably a minimum $ 10,000 exercise .

sweanders

Uhm.. This got me thinking.. Where on the engine can I check if it's a GT or GTS engine?

MikeN

Just below the thermostat housing there is a small raised metal surface with the engine designation code. Usually has to be cleaned off to read, but this should be a good indication of what engine you have unless someone did something VERY "funny" with the car in the past.

sweanders

Mike, do you have a pic that shows exactly.. I'll run out and check.

MikeN

Sorry, no pic......but look below the thermo housing from the left hand side, you should be able to spot it......

sweanders

Went out and checked in the dark and rain.. Will check it later when I get the car in the garage.

Anyone who has the different engine number available?

John Speake

Relax Anders, I think this only applied to the GTS Werkswagens.

Jim is 100% right on this one. Some GTS's are OK, but a very high proportion do develop an oil burning habit.

Yes, the UK guy did push hard for his "new" engine...............

sweanders

I was just going to check since I have information about my car getting a new or rebuilt engine after those two years as a company car.

John Speake

Yes, I realised the reason for your concern...............

However it would seem very unlikely they rebuild a GT engine with the special GTS pistons............

The only way you can check for sure is to ask the factory how they rebuilt your engine.

MikeN

Hmmmmm, can you stick a GTS engine in a GT without much modification if any??.......would that decrease or increase the value of a GT???

LarryM

Do a search on GTS oil consumption and read the thread from Marc at Devek. It's a detailed pre and post rebuild infromation on the block conserving forged pistons.
Jim's right, live with it or rebuild it. I'm living with it myself. I just clear its throat, so to speak once a week.

LM

Jim bailey - 928 International

the GTS engine is a direct drop in to any 87-95 including the GT ....however GTS camshafts are basicaly standard S-4 nothing special so the Hot ticket would be Gt cams in the GTS engine .

Fastest928

Stroker engine burn no oil, and have a HUGE stroke compared to S4 or GTS engines.

The oil consummation is due to piston oil ring oil return holes not being drilled out.

This was intentional by porsche, and as a factory rep noted, will assist in increasing the longevity of the block, as no more blocks ware to be maufactured.

I built two GTS engines with drilled out holes, each a little different, and both are using virtually no oil with interval checks around 3000 miles.

My opinion: add oil, it is cheaper. BUT, if you want to maximize power, rebuild it with proper drainback.....we have seen over 330 rwhp from a purely stock rebuild with some head casting cleanup....a gain of up to 50 rwhp just int eh rebuilt itself if done right.

Marc
DEVEK