AyrtonSenna

Hi everybody
Some of you know that I've planned my engine build with ZZP girdled 2.1 forged block with wisecos, carrillo, SFI turbo balancer, ZZP neutral balance shaft, ZZP head/cam combo and stage 2 tranny.
My only doubt is concerning the valves. I've heard that inconel valves work better than stock. What are the advantages? Are the .5mm oversized better than stock size if ran with the ZZP stage 1 cams of the head/cam combo? Anyone of you have the Supertech inconel?
Thank you all in advance
Christian

black67

iTrader: (1)

Inconel can take the heat much better stock valves. It is an extremely hard metal (work hardens) that is hard to machine. It is used in areas where heat is excessive. You will not see creep in the material due to heat. Stainless valves will grow and move with excessive heat, where Inco will stay at its original size.

Inco is an expensive material to use, due to machining problems, the raw material process, and specialized tooling just to make it.

I do not have them in any of my cars, but we do use it at work. The machinist have to be specialized for it.

Have you looked into any sodium filled valves? For my older car I have Manley Extreme Valves for it, they are sodium filled stainless. This helps with the heat.

jmesl8er

It is badass ****, we machine generator parts made out of it for GE. 13' diameter rings, it can handle immense heat for very long periods of time. 1.5 million dollars per ring

blackbird

I'd have to double-check but I believe the stock exhaust side valves in the LNF are sodium filled Inconel valves. As already mentioned, that alloy works well for the higher temps that exhaust valves are subject to in turbocharged applications when exhaust back-pressure is high. Inconel alloy (primarily composed of nickel and chromium vice iron-based steel alloys) is also used for the turbine wheels in most conventional turbochargers although titanium-aluminide (TiAl) with the proper heat treatment and other lighter materials are becoming more common in higher-end turbochargers. Exhaust valves that are sodium filled have a hollow stem with a sodium material that liquefies under extreme heat and provides better heat transference capabilities to move heat from the head of the valve into the cylinder head for dissipation.

Certain alloys of stainless steel may work okay for exhaust valves in naturally aspirated engines or some turbocharged applications if you have low back-pressure and keep EGTs (exhaust gas temps) down but for most conventional turbocharged applications they are best left to the intake side if you're seeking a long service life.

AyrtonSenna

Supertech makes them in stock size or .5mm oversized. Wonder which ones I should get

KangolRiot

I ended up getting the stock sized ones.

AyrtonSenna

Pretty much I made my mind up. The problem is that ZZP is not giving me any info because they want me to get their combo the way it is, meanwhile I want to add the inconels. That's the only thing I want to change in their all motor build. They are encouraging me to drop these valves, but for sure the stock size inconel must still work fine with their combo, since the size is just the same as the valves in the combo. Just they are not telling me if the oversized ones will work ok with their stage 1 camshaft.

KangolRiot

I don’t know much about the oversized ones, but the guy building my car told me to stick with the stock size so I did. With those valves I also have zzp’s 78lb valve springs/retainers and there stage 2 turbo grind cams

blackbird

If you're building the valvetrain and head I'd suggest listening to someone reputable such as a porter or builder that has worked a lot with the Ecotec heads and knows your goals. Bigger isn't always better when it comes to valve size and they should generally be matched to the flow characteristics of the head and for the intended application and use (forced induction, high compression naturally aspirated, etc.). For example, going too large on the exhaust side might allow for more potential flow but harm velocity too much and/or not be well matched to the intake side.

With that said a 0.5 mm oversize valve isn't a significant increase in size in most cases. Depending on the head it may require new valve seats though which is more machining, work, and expense. Also there's more to a valve's design than the size of the valve's head. The taper of the stem and backside of the head could have a significantly bigger difference than a very small change in size.


As for trying to substitute a different brand or material valve in the same size as what ZZP is suggesting perhaps they are only comfortable recommended parts they have tested. If I were running an aftermarket company and had proven parts that I had personal experience with and were trying to sell you a significant amount of other components that I'd matched together, what happens if one of the components you decided to substitute in place of my suggestion failed prematurely, due to a manufacturing defect, or caused an issue with one of the other parts? While some people might accept this and move on there are a lot of other people who will complain or try to say the failure occurred due to something else, maybe even trying to say it wasn't the part that was substituted in but due to the other upgrade parts.

It's common sense to many but there's a lot of people who don't have much of that and don't like being accountable for their own decisions. If ZZP is busy right now perhaps try to follow up and express your concerns or if you're sure you want to run something else call and be prepared to order on the spot if they'll remove them from the package you're looking at buying, just don't expect the highest level of support if there's a valvetrain related failure down the road. Also spend some time looking at the quality of the parts you're thinking of substituting and see if anyone has had issues in this or other applications. It might be good to compare other characteristics such as weight differences as well between the two parts, especially if you plan to rev the engine out or may be close to the limit of the valve springs.

AyrtonSenna

Zooomer PMd me today saying that the .5mm inconel Supertech valves should work fine with their head/cam combo, so I guess I will get them

SKY888

I was about to say .......... .5mm supertech valves should work fine for their head/cam combo.

not too big compared to stock.


and yeah, I agree with the guys here.......INCONEL valves trump over the ss valves


I am using .5mm supertech valves with my ported head (non zzp)........... but will probably be using ZZP stage 1 cams....

so we'll see what happens

Malaclypse

iTrader: (1)

The stock exhaust valves are indeed sodium filled inconel steel valves. The intake side are stainless steel.

I'd say inconel valves on the intake side would be total overkill because the exhaust valves are the ones that see the majority of the heat as far as the valvetrain is concerned. It will make a negligeable difference in both longevity and power output.

Same with .5mm oversize. Sure it'll give you a larger margin to work with on the valve face when you're doing your 45 degree cut... but the stainless is going to work just fine. That extra. 5mm is just extra area for the air to flow around on its way into the cylinder. Now if we were talking several mm of difference it'd be a totally different story. You could then machine the heads and seats to match and would end up with an overall better flowing head. Larger valves on stock seats would be a total waste of money.

AyrtonSenna

In fact, if I've read the description correctly, the Supertech kit has stainless steel intake valves and the inconel valves for the exhaust. They are not all 16 of them inconel.
What do you think of the Ferrea 1mm oversized? They are not inconel but a little bigger, 1mm against .5mm.