928GTSM

At $1488.00 a set I have no intention of ordering 3 sets on a wing and a prayer, sorry but it's not economicaly viable. Is it possible to measure the end gap prior to install and if so does anybody know what size gap I should be aiming for? If I can use the measurement out of the box as a reference I could attempt to ask that they only send me those rings with a gap less than.......whatever the gap should be , just a thought.

6.0-928S

I used Total Seal Gapless & file fit 'em.

Hammer

Koenig928

Is there anything wrong with current rings in your motor?

Reason I ask, I went through the same thing several years ago when I replaced GTS rings in the Koenig engine during rebuild. From my situation, I did not find a significant difference in end gap between the old and new rings (from Porsche).

Unless you've got another issue going on with the cylinder walls/pistons, the rings just don't wear out very quickly. Not sure what you're trying to achieve, but you could just reuse the current rings if there's nothing wrong with them, especially when assessing the cost of new rings from Porsche, but of course it's your engine and your money. Just a suggestion.

I think the WSMs have the end gap spec., but not sure. I do have end gap measurments at home from the rebuild, I can dig them out if it'll help.

I do think the biggest improvement you can make to your GTS pistons is drill out the oil return holes. That should significantly reduce your oil consumption (as it did in my case).

Vilhuer

You need to put them into block one by one and measure. Well, any correct size round hole will do but try to find for example pipe which has same diameter within 1/100th of mm as your block.

Vilhuer

And that engine is running without problems, for how long?

928mac

I second this as it is what I would do in your case.

I have taken parts to a engine race shop and asked them to fit parts for me as I do not have any special equipment.
Make sure to tell them that it is an alumasil block and may require a larger gap (I don't know) I would look up the factory spec and take that to them.

I always, always dubble check any work I have done

RyanPerrella

Alusil block

You dont need any special equipment to measure ring gap. You put the ring inside the cleaned out cylinder bore and you can measure the gap with a feeler gauge

Point is, that part production is not up to spec's so if the word on the street from those in the know is that the gap's are less than ideal, then lets think they are less than ideal.

I would think a used original ring would be better than a new ring with too much of a gap.

If your tearing down a GTS, I guess you could just reuse rings, it sucks to not replace them, but you usually replace rings because they are just cheap and its a WYIT job. But when rings cost $1500 a set then its no longer cheap and no longer is a WYIT job.

Perhaps your best bet is to clean the pistons up of carbon, drill out the blind holes, reuse the original rings and reinstall with the R2 rods (do not reuse R1 rods whatsoever)

Charley B

R2 rods

RyanPerrella

Thanks Charley

928GTSM

All I'm trying to achieve is a reduction in oil consumption and to eliminate the puff of smoke I get out of the back when coming back on the throttle from the overun. To the best of my knowledge there's nothing wrong with the rings that are in there but I was told I should replace them as a matter of course. Now I'm being told I should replace the con rods as well!
I had no intention of removing the rods from the crank but if the original rods, which have given no problem so far, need replacing as well then this is going to get really expensive.
I was going to do the rings while I'd got the pistons out to drill, replace the main bearings and do the ubiquitous intake refresh while I'd got the engine out. TB & water pump if needs be but I hadn't planned on a set of rods as well, what's wrong with the original rods?

ptuomov

The GTS engine is a disaster, which is furthermore expensive to fix. For example, why did they go to wider rings when everyone else in the world went to narrower rings at that point in time?

A hot-rodded GTS engine is nice, though. If you are going to take the engine out and open it, you should do all the obvious hot-rodding items the same time.

What do I mean by hot rodding? Here are some items, others more experienced and knowledgeable may want to add to the topic:
- Have the intake manifold ported for balanced flow and gasket matched
- Add a spacer on the throttle linkage side
- Have the heads ported and gasket matched
- Install larger intake valves
- Drop in new cams. For example, S3 cams modded to fit the heads. No issues, and cheaper than fully new cams, if you buy a set from someone on the list.
- Lightweight lifter and racing chain package
- Mod the crank case breathing system with breathers in all cam cover ports, a baffle system in the chimney, etc.
- Drill the pistons holes. If the piston rings and the bore are not worn, just install the old rings. Just my opinion. If you really need new rings, you are likely SOL.
- You need new rods if your rods say 1R, but if they say 2R you're fine. One can get cheap aftermarket rods for this, I have an extra set, for example. I don't know what new Porsche rods cost.
- Web drilling the crankshaft and partially grooving the center main bearings is a good idea as well
- Oil pan spacer helps, and some sort of baffling, windage screen, etc. is probably a good idea. New starter motor probably as well.
- Add headers. I don't think it's that critical to have exactly equal length headers, diameter and average length are a bigger deal.
- A new exhaust is nice.
- Sharktuner 2 and lots of dyno time, preferrably on a load dyno

Caveat emptor warning here, I haven't ever hot rodded a GTS engine or actually done those things myself. So don't rely on anything above. Think of it as a set of leads, and then find more info from others.

Vilhuer

They can bend to S shape or snap to pieces. Some have used them while factory says they should be replaced.

In your case I would first try this before any engine work:
http://www.928gt.com/ps-40579-321-92...cvs-93-95.aspx

ROG100

A couple of us in DFW with smoking GTS's fitted DR's "Sharkvent" and have no more issues with smoke.
Our oil consumption also reduced - about 30% to 40%.
As Erkka points out try that before doing any tear down.
Roger

RyanPerrella

I would be replacing rod bearing 100 times before going to the mains. As in, the Rod bearings can show wear, the mains, not so much.

dr bob

I see a conflict between "...had no intention of removing the rods from the crank..." and "...I was going to do the rings while I'd got the pistons out to drill, replace the main bearings.." Steps leading up to the second sentence include the removal of the rods from the crank. It's the only way to get the pistons out for drilling and new rings fitted, or to get the crank out for replacement of the main bearings. At least the oil rings come off for the drain holes.

Rings tend to suffer from loss of tension as they age, so putting used rings back into an engine that you are going in to for oil consumption problems is likely a poor decision. Putting used rings into a different bore or in a rotated position that was different from where they were originally seated is a crapshoot at best. Lots of reasons to look for a set of new rings, IMHO.