B16B and B18CR Internals

[spetz]

Hi guys,

Can someone tell me if there is something special about the pistons/rods of these 2 engines?
ie, are the forged?
From memory they are just cast pieces, so what allows them to rev to almost 9,000rpm?

And, would for example, a D16 bottom end be able to rev to those rpm?

Please note this is just a question out of curiosity.

[mocchi]

weight, chromoly coating on side skirts, oil holes in base of piston.
not sure what else. most likely different material in terms of silicon content. not sure higher or lower.
http://www.ff-squad.com/tech/temp/pistons.htm

i think the difference is not just on the pistons, also with the crankshaft, cshaft main bearings, con rods and conrod bolts.

[dougie_504]

I think it's the rods that are more important mate, because if they sh!t themselves they fling out through the wall of the block lol.

If you upgrade your valvetrain you could easily get a D16 to 8,000 RPM, but 9,000 RPM I'm not sure on stock lower internals, nor do I think you'd be making any decent power by that stage. Would plateau earlier than that unless you're running a really tough camshaft profile, and by that stage you should have gone B-series or K-series anyway.

[spetz]

So they are not even forged items, then what would a B16B or B18CR be able to rev safely on forged pistons/rods? Not taking into account valve-train, crank, rod bolts etc, just the rods/pistons themselves?

Again, I am not interested in doing any of this, I am just curious to know.

[vtecing]

B16B and B18C pistons are what Honda call forged, similar to STi pistons etc.. This pistons dont have so much to do with the engine reving to 9,000rpm as the crank shaft does. The tyre r crank shaft has been sepcially designed to rev up to 9,000rpm with the addition of 8 weights to make it completely balanced. The whole engine is balance from factory. I was reading an interview somewhere that if they found a valve or a rod that was 0.1 grams weight difference they would throw it in the bin. The head also plays a part in how the engine is able to rev that high. Larger cam profile, bigger ports, thinner valves etc...

This is why it is ridiculous that people think they can put high profile cams in their road cars and rev them up to 9,000prm without opening the block. Sure, the engine will rev that high, but for how long?

[spetz]

And what would actual forged (say Wiseco or CP pistons) be able to rev to ignoring all other aspects? ie, the forged rod/piston safe limit?

Of what I understand though it seems that with most cars the redline/revlimit is more governed by the valve-train than the bottom end. Ie, the valve springs being unable to cope with more rpm and getting valve float

[vtecing]

every part of the motor is relevant, even the diff. You cant just pick out one specific part and say this will make your engine spin faster. The cam profiles and size of your valves are what limits the amount of air/fuel entering the motor, but unless you upgrade everything else your going to have an engine that doesnt perform well and is unreliable. It annoys me that Honda sped millions on R&D and then some kid in his shed thinks he can do a better job.

[spetz]

Yes I am aware that everything else needs changing too, but I was more curious about the pistons and rods, on the assumption everything else was taken care of as well

[vtecing]

They will rev to exactly 23,050rpm before they explode

[mocchi]

They will rev to exactly 23,050rpm before they explode

you got data to back that up?

[90LAN]

butt dyno he feels the vibrations of the revolutions lol

[dougie_504]

They will rev to exactly 23,050rpm before they explode

Serious or talking BS? Pistons or rings?

I'm sure you'll snap a rod before 23,000 RPM lols.

[chiupowing]

Other the crankshaft rod and piston, the stoke is and other main factor.
For B series
Bore and Stroke : 81.0 x 77.4mm
For D series
Bore and Stroke : 75 × 90 mm
Just for example F1 the rules on engine limit bore to a maximum of 98 mm , consequently stroke has to be 39.7 mm they rev up to 18000rmp+
means even all internal are balance, the short stoke will allow higher rev.....

[mocchi]

Serious or talking BS? Pistons or rings?

I'm sure you'll snap a rod before 23,000 RPM lols.

http://t2.gstatic.com/images?q=tbn:ANd9GcQ7ZYN-ABMs1j0oSANSi9cCtX9EDnugdfOXiayW1DyVEAfDCBHX

[vtecing]

lol dude, you cannot determine how fast a piston can move before it fails. Every motor is different. A piston in a v8 super car might last 'X' number of kms.. and a piston in a top fuel drag car migh only last 'Y' number of kms, spinning at the same revolutions. How much boost are you running, what fuel are you using, how much compression are you running, how many kms has the engine travelled etc etc etc....