3.0 vs. 3.2 valvetrain differences?

[L_RAO]

Can someone confirm the following for me?

1. The 3.2L has different valvesprings than the 3.0L? If "yes", is it simply a case of dual vs. single valvesprings?

2. The 3.2L has bigger intake valves than the 3.0L? If "yes", is it 36.0 mm (3.2L) vs. ??? (3.0L).

 

[BATMANs]

Can someone confirm the following for me?

1. The 3.2L has different valvesprings than the 3.0L? If "yes", is it simply a case of dual vs. single valvesprings?

2. The 3.2L has bigger intake valves than the 3.0L? If "yes", is it 36.0 mm (3.2L) vs. ??? (3.0L).

1. My 3.0 has dual springs and I think the spring rate was low in the 90's which is great for keeping the parasitic power lose down.

2. Yes the 3.2 is larger it's on SOS site

 

[L_RAO]

Excellent. Thank you.

So, my next question, per the old DAL Motorsports site, it was recommended to go to the largest intake valve possible, which would be a +1 mm on the 3.2L (so, 37 mm).

Has anyone gone from the 35 mm intake valve to a 37 mm intake valve on a 3.0L?

 

[BATMANs]

Excellent. Thank you.

So, my next question, per the old DAL Motorsports site, it was recommended to go to the largest intake valve possible, which would be a +1 mm on the 3.2L (so, 37 mm).

Has anyone gone from the 35 mm intake valve to a 37 mm intake valve on a 3.0L?

i explored that and was advised against it for 2 reasons:

1. greater mass/weight of the larger valves
2. I would need to bore and go with the Darton sleeves to do it right so there is reasonable valve to cylinder wall clearance.

 

[Mac Attack]

Excellent. Thank you.

So, my next question, per the old DAL Motorsports site, it was recommended to go to the largest intake valve possible, which would be a +1 mm on the 3.2L (so, 37 mm).

Has anyone gone from the 35 mm intake valve to a 37 mm intake valve on a 3.0L?

I think he was advocating using the 3.2L valves in the 3.0L heads. Unfortunately, I don't think anything was published how his other test worked out of using larger valves than the 36mm ones:
http://ojas.net/nsx/mirror/dal#Heads

As Batmans and I were discussing in another thread, if you do the common overbore to 90.5mm, the larger 36mm diameter valves are only 0.25mm closer to the cylinder wall than OEM. That being said, I have no plans to go to 36mm valves on my rebuild right now:
http://www.nsxprime.com/forum/showpost.php?p=1500576&postcount=10

 

[Speedy93]

I have 3.2l intake valves, in my 3.0 block. Bored to about 3.1l

 

[L_RAO]

I have 3.2l intake valves, in my 3.0 block. Bored to about 3.1l

Care to share the rest of your setup, esp. valvetrain?

Thanks.

 

[Speedy93]

Care to share the rest of your setup, esp. valvetrain?

Thanks.

Car has pretty much everything Comptech made,(used to be their r&d car) plus rc 550 injectors AEM fic JE forged pistons, thats most of the basics

 

[L_RAO]

Car has pretty much everything Comptech made,(used to be their r&d car) plus rc 550 injectors AEM fic JE forged pistons, thats most of the basics

Pretty cool car to own!

 

[whrdnsx]

Does anyone know if the Vtec rockers are the same from other Honda Engines?
I need a complete set to build some C30A heads but they are stupid expensive from the Dealer.

 

[L_RAO]

whrdnsx: They are close, but I'm not sure if they're interchangeable.

Part numbers are definitely different.

I have a set of B-series rocker arms sitting in my garage. If you can take some measurements/dimension of the C- rocker arms, we can compare notes.

 

[whrdnsx]

Ok, have the heads off & rockers out.

Can someone take some measurements of the B series rockers?

 

[A.S. Motorsport]

Head design is very similar to B-Series,
Not sure on the interchange, I do know head bolts are.

Maybe I can take a look for you in Japan? should be cheaper.

 

[L_RAO]

Ok, have the heads off & rockers out.

Can someone take some measurements of the B series rockers?

Can you take pictures with your caliper so I know exactly what dimensions you are measuring? I'll try to match them picture for picture.

I have a set of B-series and K-series rocker arms in my garage right now.

 

[whrdnsx]

Can you take pictures with your caliper so I know exactly what dimensions you are measuring? I'll try to match them picture for picture.

I have a set of B-series and K-series rocker arms in my garage right now.

Ok, i'll take some pics with some measurements tomorrow.

 

[austrian type-R]

The C30 engine has dual valve springs on the intake side and only a single spring on the xhaust side. Does the C32 has stronger springs? It has also only a single spring on the exhaust side?

 

[L_RAO]

The C32 also has a dual valve spring (intake) and a single valve spring (exhaust).

 

[whrdnsx]

Here's some measurements of the NSX rockers to compare with B series.