Anyone with engine builds? Random questions, who you've used for machine work, etc.

I think the ringlands fail because of the ridiculously small OEM ring gap (that works fine for the 270 HP it was designed for). That's my theory anyway on why some have had problems. If you keep the combustion temps down with a bit less timing and perhaps methanol injection, you should be fine with 400 WHP long-term and the stock pistons that you're coating. Better yet, open up the ring gaps a bit more from the OEM specs when you rebuild.

I am a bit puzzled though why you would go to that time/expense and not replace the pistons while you're in there. A 400WHP goal may turn into a 500WHP goal in the future (ah, the problems with boost) and you'd wish you changed pistons.

davidsk said:

They wouldn't say who they used for machining, or offer any help to anyone not having them do the full engine build. I would be all for paying them money for the wrist pin conversion, balancing, etc, but they won't have any part of it. I'm not the only person that's had this experience. Nothing against them, but they aren't willing to help a person in my situation. Which is why I've started to look elsewhere. I understand not wanting to be held liable for anything.


Maybe I should elaborate, don't seem to be help for a DIY engine build as too much money and liability/reputation is possibly at stake.

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I know at one time, Portflow used to do the SOS heads. Not sure who they use now. Endyn is also popular, as are a few others.

If you are just doing simple stuff, then any local reputable machine shop can take care of the block and heads.

Dave

Mac Attack said:

I know at one time, Portflow used to do the SOS heads. Not sure who they use now. Endyn is also popular, as are a few others.

If you are just doing simple stuff, then any local reputable machine shop can take care of the block and heads.

Dave

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Block and heads aren't the issue, bushing titanium rods is. No one here is either willing to or competent enough in it. I wasn't really wanting to go to a full aftermarket rotating assembly, as my goals don't really require it.

davidsk said:

Block and heads aren't the issue, bushing titanium rods is. No one here is either willing to or competent enough in it. I wasn't really wanting to go to a full aftermarket rotating assembly, as my goals don't really require it.

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I betcha if you had the titanium rods in hand and talked to Shad at D.A. He'd probably have them done for you if sent in.

davidsk said:

Block and heads aren't the issue, bushing titanium rods is. No one here is either willing to or competent enough in it. I wasn't really wanting to go to a full aftermarket rotating assembly, as my goals don't really require it.

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Ah, so that's your issue.

For my engine build (there's a thread on here somewhere), I didn't want to weaken the OEM titanium small rod ends by boring and then bushing for the full floating wrist pins (I'm pushing their limits). I ended up sending my wrist pins to Calico coatings in NC so they could diamond-like-carbon (DLC) coat them. I think I paid about $250 for the six pins around 5 years ago, so it's probably not much more than a machinist would charge for the conversion anyways. Then, the small rod ends just need a slight hone and you are good to go.

DLC coatings are robust if prepared and coated correctly. High-performance OEM manufacturers do this now commonly.

Just out of curiosity, what state are you located in?

Mac Attack said:

Ah, so that's your issue.

For my engine build (there's a thread on here somewhere), I didn't want to weaken the OEM titanium small rod ends by boring and then bushing for the full floating wrist pins (I'm pushing their limits). I ended up sending my wrist pins to Calico coatings in NC so they could diamond-like-carbon (DLC) coat them. I think I paid about $250 for the six pins around 5 years ago, so it's probably not much more than a machinist would charge for the conversion anyways. Then, the small rod ends just need a slight hone and you are good to go.

DLC coatings are robust if prepared and coated correctly. High-performance OEM manufacturers do this now commonly.

Just out of curiosity, what state are you located in?

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That's actually not a bad idea. I'm in Oklahoma. And I've thought about calling DA to ask some general questions. By the looks of the FB page, I'm not sure whether I'd even get anyone on the phone as busy as it looks.

davidsk said:

That's actually not a bad idea. I'm in Oklahoma. And I've thought about calling DA to ask some general questions. By the looks of the FB page, I'm not sure whether I'd even get anyone on the phone as busy as it looks.

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I'm not sure if you're talking about Jinks suggestion or what I had done, so I'll throw out two more NSX experts you could try to talk with:
Autowave (CA) and Applied Motorsports (CA). I highly recommend each.

Obviously, a lot of work is subcontracted out for these engine rebuilds. The NSX experts dis-assemble, supply the parts and the specs to the machinists or specialty shops, and then re-assemble. Rightfully-so, there's some markup involved for their efforts and knowledge, but for those of us that have some mechanical skills, knowledge, and are looking to learn more, it can be a bit frustrating.

DLC coatings on piston wrist pins for normal engine rebuilds is rare. Even then, I haven't heard of anyone else do it for the C-series engines. As such, if you suggest it to others they will probably dismiss the idea and say it is unproven, unreliable, or too expensive. Well, I've been at 550WHP on a custom twin-turbo build for a few years and about 7500 miles without any problems. I have a Canton oil filter cartridge that makes it easy for inspecting what's been filtered in my oil, and there have been zero indications of any DLC flakes. Calico coatings assured me it would be fine for my application and it has so far. You'd think they would know :wink:

Good luck on your build.

My mild build was sort of documented here:
http://www.nsxprime.com/forum/showthread.php/154927-Semi-DIY-Mild-Engine-Build-for-FI

I'm not sure what happened to the pictures, and I eventually stopped updating it since I was the only one posting in it... but there may be a few good tidbits of info or at least some good links to other interesting info.

Dave

Mac Attack said:

I think the ringlands fail because of the ridiculously small OEM ring gap (that works fine for the 270 HP it was designed for). That's my theory anyway on why some have had problems. If you keep the combustion temps down with a bit less timing and perhaps methanol injection, you should be fine with 400 WHP long-term and the stock pistons that you're coating. Better yet, open up the ring gaps a bit more from the OEM specs when you rebuild.

I am a bit puzzled though why you would go to that time/expense and not replace the pistons while you're in there. A 400WHP goal may turn into a 500WHP goal in the future (ah, the problems with boost) and you'd wish you changed pistons.

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If I have to rebuild down the road then so be it. For now we decided to do a refresh and coating the pistons has shown a lot of good success with other platforms. I'm curious how it will do in a boosted NSX and there is only one way to find out. Also keep in mind I don't have any problems with the oem pistons at the moment. I could have just bought new pistons, but the cost was very low to coat and I personally wanted to see what happens. It will stay at 400whp with pulled timing up top and slightly rich on e85 throughout the tune. If it holds out at the track then I will be very happy and if not then I will throw in some custom pistons and turn up the boost a little.

jones83 said:

If I have to rebuild down the road then so be it. For now we decided to do a refresh and coating the pistons has shown a lot of good success with other platforms. I'm curious how it will do in a boosted NSX and there is only one way to find out. Also keep in mind I don't have any problems with the oem pistons at the moment. I could have just bought new pistons, but the cost was very low to coat and I personally wanted to see what happens. It will stay at 400whp with pulled timing up top and slightly rich on e85 throughout the tune. If it holds out at the track then I will be very happy and if not then I will throw in some custom pistons and turn up the boost a little.

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The coatings will help and I think you'll be fine with the tune and methanol... probably even a long life at 500WHP. Using new OEM rings? What are you planning to do as far as ring gaps? Err on the larger side of OEM specs (0.016" top, 0.020" second)?

I did the same skirt and dome coatings on my Wiseco pistons after dimpling them. After 7500 miles at 550WHP, I did a boroscope check and the combustion chamber looks like when I built it. Water/methanol injection helps keep everything looking new anyways.

Yes, we are going with the larger side of OEM specs for ring gap. I am still unsure if I will go with meth injection or not. I have the W2A intercooler, coated pistons, e85, and I will be monitoring IAT and EGT. If I need it then I will use it, but not interested in that avenue at the moment. At least not until I run some summer track days and get an idea of the extreme temps I will see.

Good luck...

I know you don't agree, but I appreciate it all the same. I'll be documenting what happens regardless of the outcome.

I truly hope it proves to be enough for your intended use. For being as far into the build as you are, with the engine completely apart, I personally feel the $ is better spent going toward a stronger piston than trying to improve the factory one. Fingers crossed.

Any updates on this?

I had Benson do my sleeves but I had Ramey Racing out of Virginia Beach do my line bore with my SOS main caps. Ramey was going to do the full bottom end for me but I had already committed to Benson by then. Both shops did GREAT work. Ramey currently holds the recond for fastest FWD car so he knows his way around a honda, he as also done many nsx builds.

My current set up
Benson sleeves 93mm
Cp pistons (WPC treated)
Cp upgraded wrist pins (WPC treated)
Carrillo rods
SOS Main caps
Arp head and main studs
Cometic head gaskets
Re-build oem heads (WPC treated valves)
SOS oil pump
new oem gaskets