A friend of mine wanted to see some pics, so I figured I would just post them for all to see.

What you see here are close up shots of the assembled valvetrain of a J37A2 head (2010 RL). This and the TL SH-AWD have full VTEC (intake AND exhaust). Enjoy!

 

wow impressive! Thanks for sharing

 

It always amazes me whenever I see the inside of an engine. It boggles my mind to think that somebody somewhere had to detail and draw out each angle and contour of every mechanical surface and part. All while maintaining calculated specifications and tolerances to design a well oiled machine(no pun). Engineer porn is the best kind of art!

 

Yeah, I know what you mean. It's a work of art.

 

I have no idea what I'm looking at but it's awesome.

 

I have some pics I can contribute to this thread as well.

 

exhaust port looks different, larger and shaped?

 

Can these heads swap onto J32A3 blocks?

 

^ how are you going to control the new vtec system? There vtec on both intake and exhaust?

 

The exhaust port is actually smaller. Probably to make better torque at lower RPMs with higher RPM flow being accommodated by a different CAM profile.

Yes, these heads should be able to directly bolt onto a J32A3.

VTEC is controlled by a single solenoid exactly like the J32A3, J35A8, etc.

 

hmmm

 

That's correct. All added exhaust VTEC changes were made inside the head itself. Primarily in the valvetrain and it's associated components. There are rumors, however, of weak valvetrain components in these heads. May be a good idea to have some sort of hardening or shot peening done to the rockers if anyone plans on a performance build with these heads. Especially motors that will be seeing regular high rpm revs.

 

Very nice pics. I have the 2010 MDX heads (NOT installed) and would be interested to compare them to these to see the difference of the I/E VTEC.

 

OK Robert, where did you here these rumors from?

 

i want those heads

 

Lets not focus on the negatives here buddy. Didn't mean to upset the charisma in your thread. Lol.

Here's some more badass pics to reintroduce the goodness this thread brought! Got both of the castings ready for use. The front one just needs to be reassembled but I'm waiting on the camshaft as the original showed some signs of wear. One of the heads are brand new out of the box and the other is from a used j37a2 I purchased solely for the heads themselves. The used casting (front) has been cleaned extensively, crack checked, resurfaced and had all valves/springs checked for proper specs.

 

Sweet! Perhaps some pics of the valvetrain components individually layed out would enhance this thread even more.

 

Any seat pressure check?

 

Valve size/lift?
And all on a SOHC... porn

 

Was cleaning up my j37a2/j37a4 head and prepping it for use then remembered Eric (OP) requesting some pics of the rockers. I managed a few with my iPhone and they came out pretty decent considering.

Here's the two of the four exhaust rockers. The other two exhaust rockers are identical to these.





The intake rocker and cam follower. There are only two pieces from the intake side. This is because the actual rocker has a split end design that can depress both intake valves at once when riding the primary or secondary lobe of the cam. Took a few more pics of these rockers due to the design complexity. This was the first ever variable valve lift design on both intake and exhaust from a SOHC head the world has seen. Honda engineers are truly the best in the world.







The next pic was simply to show how Honda uses pressurized oil to lock rockers. The cylindrical shaped steel lock is actuated into another rocker (usually the "VTEC" rocker) next to this primary rocker. You can see the small orifice in the bottom of the cavity where the lock sits where the oil is fed through. Although nearly all VTEC systems use this method, this one is both intricate and simple all at once.



Oil for the VTEC system (as well as the valvetrain) is fed up from the block into the end cap shown here by a small port on the right. Then it's directed out of the two dime size holes which obviously then feed the two hollow rocker shafts. The shafts are ingeniously dual purposed in holding the rockers themselves as feed oil for the VTEC system and valvetrain lubrication. The shafts have very tiny holes that perfectly lineup behind each VTEC rocker to feed them pressurized oil. As a matter of fact, both shafts are held in a specifically "clocked" position by machined indentions for the top mounting bolts of the rocker bridge. Again, a typical thing for Honda to do on their heads.

 

Epic groovyness.

 

dam i want that entire setup on my car, zdx engine swap in my tl. 6 speed trans too.

 

k series twin cam goodness, in a sohc beast! i believe baby jesus helped in the design of this!

 

NEED MOAR PIX!

 

What is the size of the roller on each. Can you mic those to compare to see if they are any larger than the ones on the other heads?

 

My wife drives the zdx n vtec is loud. N i mean loud

 

Don't temp me. .. I'm willing to put my tl as a guinea pig... if it direct fits.

 

Also. I need the part numbers for heads. Also the head gaskets... which I'm guessing I'd have to use the 3.7. What about the timing belt. That's that big question. And then also get valve covers. Plus maybe nee coil packs if they're longer... Damn me. .. I'm teasing myself now. ..

 

The cam belt is the same. The head covers are different, the coils are different, the intake runners are different and the exhaust port / manifold mounting is different. But the J-pipe mounting is the same. There are many online Honda/Acura parts websites that list part numbers, so you can do your own research.

 

Well thanks for the help... I just wanted to make sure I get everything right.

 

Hey Eric, what's the word on the install of this motor? You running the a8 ecm with FlashPro or what?

 

Is the J37A1 from the MDX intake and exhaust VTEC as well, or just the RL and SH-AWD TL and ZDX?

 

Only the j37a2 (09+ RL) and j37a4 (09+ TL AWD) engine codes carry the VTEC on the exhaust and intake. All other j37 variants from the MDX (j37a1) and ZDX (j37a5) are intake VTEC only. What's funny is how much smaller the cams are (intake lobes) in the a2/a4's yet they ONLY make 5 additional horsepower. Hmm, can you say DE-tuned!?

 

J37 still waiting. I did finally remove the J35 this past weekend. Have to work out some other issues before the J37 goes in.

 

damn you for getting me interested in all of this!!!

 

Justn, I know you said you are doing MDX heads in a different thread. Any reason you didn't go with the RL heads? I understand if it's something you got cheap or had lying around, but if buying new, why not go with the 2 or 4 heads? You'd really be like, "VTEC just kicked in, yo!" lol

 

Robert(yungone501) sold me the used MDX heads(J37a1). I dont think he had any of the newer engines available or he would have mentioned it to me.

plus, I wasnt even really thinking about upgrading until my friend so happened to over-rev the car. i was hastily making decisions and my first choice from Robert was 3.5 heads until I woke up sunday morning and was like....wait, i wont be happy with the 3.5 heads.

but this thread has got me thinking about the future and if i so happen to over-rev again, I know which route to take.

 

We have an accord on v6p with the j37a1 head already. I have a tls head with 09 camshaft in my j30a5.

You guys will probably have better luck with the j37 heads since you have the displacement and compression to fully utilize it.

From the look of your heads Honda increase the valve size in the new engine correct?

 

Not sure what's going on here sir but you should REALLY make a thread here on Azine with this car. I know you have a few others out there but this forum is where the traffic is.

Nobody let this guy fool you, Eric is one of the quiet automotive/engine masterminds that just sit back and watch from his garage full of badass j-series parts and custom electronics.

I've got my EYE on you...

I've got several other pairs of newer style tumble port heads sitting on a shelf at the shop. The thing is that the MDX heads are IMO far more appropriate for the pre-j35z engines in regards to versatility in camshaft selection and valvetrain compatibility with the 3G TL 3.2/3.5 engines. When the later j35zX heads were designed, they were given different cam/valvetrain designs that, although were a much less complex, took away the ability to use a standard j-series camshaft from say Bisi. This and so many of them include VCM related components and parts that must be removed and converted back to a non-VCM system unless they are from the Accord 3.5 6MT (AT heads had VCM) or the 4G TL 3.5 engine.

The 07-09 MDX heads were given the best of both worlds with their traditionally placed cam journals, tumble port design, stronger and lighter valves/springs, and enlarged cooling jackets. Basically the j35a8 heads with much better port design. The j35a8 heads are better for higher revving large displacement engines because the ports don't induce turbulence which agitates airflow at higher velocities.

All 3.7's have 36/30's.

 

i bet you get tired repeating the info.
Thanks buddy!

and I do agree, this thread is where its at!!!