By GregBBRD
Well what I do know about this is that when then coat the softer metals they use chrome nitride. Now chrome nitride is now common in Nascar on the Ti valves. They use it on the seat area and when the Ti valve was specified for the Zo6 Corvette the whole valve was done. The DLC for the valve is the next optional step.

So when they do the pistons they first chrome nitride the piston to provide a stabile surface. As I mentioned it is in an experimental stage at the company I spoke to. So from what I have read and explained to me is as long as the surface is stabile the DLC will stay on anything. The big question is, is the aluminum stabile? As I noted in testing lead to an impressive 2% gain in power and much lower wear on the piston in a race engine. I suspect they are using it in F1 to get by the limited engine rule.

The chrome nitride is quite stabile I have been told and it will be interesting if this is what Mahle or KS used., I realize on of he factory options was Ferrostan, an iron coating. The coatings are expensive but long lasting and what I have now been informed of is the recycling of parts, that is the stripping of the worn DLC and surface refinishing if necessary and then new DLC on say a tappet or wrist pin. Then reuse the part.

The price isn't too bad, I was quoted 10 pounds for a 38 mm tappet and that is all over, not just the contact face. I think the cam was 100 pounds.

We all know race engines wear more quickly due to extreme forces but the wear is definitely reduced, as such longer life and it should pay for itself, of course if you don't rev the engine so hard of course the wear is less too. Everything it seems has a trade off.

Greg

 

Gentlemen...
What does DLC stand for?
And what kinda of material is it made of?
Does it go well with Alusil blocks?
Cheers. Michael

 

DLC is diamond like carbon, yes it is hard like diamonds, please do a search on it, F1, Nascar and LeMans engines would not be able to complete a race without it these days, so it is pretty important coating, it reduces friction quite dramatically. As to its relationship to Alusil, well that is the $64,000 dollar question, it should be great but every theory needs an experiment.

Greg

 

It is a lot. All seem to go through rings on those cylinders where end gap was too large. Have to see how it changes when engine is properly run in. Before that I'll need to fix what appears to be wide band lambda problem.

 

On my engine build, I have decided to go with the Woessners. I spoke with Chris White today and he claims to have a letter from BMW endorsing the skirt coating used by Wossner to run in BMW alusil engines. I'm going to give it a go and if it failes, then I guess I'll over bore and build the 5.4L down the road. ( If I don't hang myself first ) I'll be sure to keep the board informed as to the progress and let you know how it goes. If it works well, it should be a good option for us 928 folks. The 951 guys have already started using them with no failures that I can find so far.

 

Thx for the explanation of the meaning DLC!
Pretty state of the art technology I gather...
And I also have come to think that Woessner is the way to go. I contacted them a few months ago and they seemed very professional and eager to serve.
Maybe better to leave German coating technology to Germans..?!==)
They must know what they are doing.
And the 944 guys have proven it to be true.
This Forum is awesome...!
I am so thankful for all your input.
Cheers.

 

Michael, takk for sist! Du gir heldigvis aldri opp 928 hører jeg!

IF your block is damaged and the pistons are ok, how about using a S4 block instead? There were a thread on the differences here, I think the conclusions were that the GTS block had som ventilation holes between cylinders, but it might be cheaper to have this done to a S4 block than to spend a lot of money on boring the GTS block and using some custom pistons that might ruin your block again...