John Veninger

Can the earlier GTS pistons have oil holes drilled to lessen oil consumption or did the newer pistons have other changes besides oil holes?
Anyone have a picture of the newer pistons with th holes drilled?

Vilhuer

Did any GTS pistons have oil holes drilled all the way through from factory? I thought '93 model year change was just to add strength in skirt area and number 1 (top) piston ring change. By the way, what is correct procedure to drill the holes? All or only some of them and how large drill?

Imo000

I don’t know the answer to your question, but you need some oil consumption to keep the rings lubricated.

Jim bailey - 928 International

The drain back holes behind the oil scrapper rings are blind on GTS pistons they do not allow excess oil to flow inside the piston. I recall that Marc Thomas mentioned drilling half of them all the way into the hollow center of the piston others have drilled all of them so they are just like early pistons.

John Veninger

So let me get the facts here.
No GTS factory pistons had holes drilled.
Devek has had good results with drilling have of the holes.

So what did the factory do to the early GTS engines they "fixed" for customers who were complaining about high oil consumption? What was done in the 94/95 engines to reduce some of the consumption, tighter rings?

Vilhuer

February '88 and newer S4 piston holes are totally different thing. They are at bottom of skirts pointing straight down where as GTS holes are under oil rings pointing sideways.

Lango

I had Marc Thomas / DEVEK drilling holes in my GTS pistons prior to assembling the engine. I have a few photos of them too if anyone is interested.

John Veninger

Yes, I'm trying to help out a GTS owner.
Send them to john928@yahoo.com

Thanks!

Fastest928

After years of discussions with AG, and arguments on ""longevity", we received a late rebuailt factory short block and guess what ... they drilled out the holes!

Finially ...

Marc

John Veninger

Thanks everyone for the info!

RyanPerrella

John, did you ever get these pics?

Could you post them?

The guy in the UK mentioned he had a 95/96 replacement GTS engine and confirmed that half the holes (4 of them were drilled) he also stated that there was NO oil consumption.

How if this mod done. Is it as simple as putting the piston under a drill press and having at it 4 times ?

GregBBRD

I've drilled all the holes on the ones I've done. They all work great.

Charley B

My oil consumption on the GTS went from a quart every 400 to 500 miles, to almost nil after about 60,000 miles.

John Veninger

Can't remember, that was 3 years ago!

RyanPerrella

Greg,

I assume this is just something you can do quite easily?

Any idea on cost? I imagine a couple hundred?

I would still love a pic of a GTS piston, ive never seen one. But in the end im sure they LOOK just the same as the S4 GT pistons.