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JDM H23A Vtec Blue Top Mystery Motor, True Facts, Questions?

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Old 07-21-2008, 03:53 AM
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Default Re: (vinuneuro)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vinuneuro &raquo;</TD></TR><TR><TD CLASS="quote">Well for one thing, the H23a crank has drill holes in the counterweights from balancing, like the H22 and unlike the H23a1. I'd really like to see one out of the block to see if it's structurally any different than an H23a1 crank. I've read a few archived posts that say that it looks more like an H22 crank, but the pictures were down.

Are you sure about the nut-less con rods? The only other Honda engines to use a such a design are the F20b and F20/22c. That's a pretty extreme engineering measure to reduce weight. I mean the H23a only revs about 500rpm farther than the H23a1.</TD></TR></TABLE>

the f23a also uses the same rod bolt. i think when honda started using 55mm mains they switched to the threaded rod and bolt.
great thread . can you measure the rod width?
Old 07-21-2008, 10:12 AM
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Default Re: (alterdcreations)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by alterdcreations &raquo;</TD></TR><TR><TD CLASS="quote">

the f23a also uses the same rod bolt. i think when honda started using 55mm mains they switched to the threaded rod and bolt.
great thread . can you measure the rod width?</TD></TR></TABLE>

What'r you talking about? The only other Honda engines I'm aware of that use nut-less rods are the F20b and S2k engines. This can be easily confirmed by looking at the parts catalogs.

Has there ever been a discussion on why Honda switched to 55mm main journals? It was around the same time, they went to open deck. What are the pros/cons?
Old 07-21-2008, 12:21 PM
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Default Re: (PirateMcFred)

Hmm, didn't realize the K's use that design too.

Any thoughts on the 50 v. 55mm mains?
Old 07-21-2008, 12:36 PM
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Default Re: (vinuneuro)

Here are some of my crank pix televator:

H23A1 Crank:







H22A Crank:


Old 07-21-2008, 12:40 PM
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Default Re: (ESP.net)

It's hard to tell from the pics. Are the H22 counterweights any larger in size?
Old 07-21-2008, 01:01 PM
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Default Re: (vinuneuro)

It's been a while since I took those pictures. But yes I believe the H22A crank has larger counter weighs and weighed a bit more if I remember right. I guess I could crack open another jdm h22 short I have that spun...
Old 07-21-2008, 01:19 PM
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Default Re: (ESP.net)

The differences in counterweight sizes are still pretty much undetectable to the eye. Hmm....Are you completely dismantling the H23A VTEC eventually?
Old 07-21-2008, 01:30 PM
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Default Re: (Televator)

Nope don't plan on another rebuild too soon... just waiting for my clutch to get here and ill run down and get a oil pan gasket and pickup gasket and I'll button her up. I'll measure the Rod width before I button her up. So if anyone wants some measurements or another picture now is the time...
Old 07-21-2008, 01:49 PM
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Default Re: (ESP.net)

I understand. At least it's a lot further than what I've seen on my H23A block. Thanks for sharing with us.

I wanna tear into mine, but I gotta relocate my storage items before I start making a mess again.
Old 07-21-2008, 05:42 PM
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Default Re: (PirateMcFred)

Pirate... think I could get away with type s cams on the blue top piston to valve clearance enough if it has a H23 type reliefs? As well as running the stock valve springs and retainers
Old 07-21-2008, 06:07 PM
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Default Re: (PirateMcFred)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PirateMcFred &raquo;</TD></TR><TR><TD CLASS="quote">I'd bet your engine on it. You can do some drastic things to stock motors. Type-S cams really aren't that aggressive anyway.</TD></TR></TABLE>

True makes me wonder if the $400 investment for a few ponies would be really worth it... have to think it over tonight before I get ancy and throw on the TB.


Modified by ESP.net at 7:12 PM 7/21/2008
Old 07-22-2008, 07:33 AM
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Default Re: (ESP.net)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PirateMcFred &raquo;</TD></TR><TR><TD CLASS="quote">Altered, I would be careful of assuming that the H23A rod bolts are the same as the F23's. The F23 and the K20A3 (2002-2005 Civic Si) have 8mm rod bolts and the K24s and high-output K20s with "real" i-VTEC have 9mm. Both bolt styles use a 12-point 10mm to torque them.</TD></TR></TABLE>
correct.
same "style"....sizes may vary
Old 07-22-2008, 08:06 AM
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Default Re: (alterdcreations)

I am still stumped why this h23avtec AUTO has a 65.5mm throttle body ID on the outside. Tappers obviously to about 63mm is my guess on the insided... Kinda makes me wonder if the TB is same as Euro R/Type S maybe it has Type S cams? hmmmmmmm
Old 07-22-2008, 08:36 AM
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Default Re: (ESP.net)

I'd imagine it could also be the simple demand from the larger stroke combined with relatively high revs (for a 2.3). I wonder if the head ports are anything special...
Old 07-22-2008, 08:49 AM
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Default Re: (Televator)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Televator &raquo;</TD></TR><TR><TD CLASS="quote">I'd imagine it could also be the simple demand from the larger stroke combined with relatively high revs (for a 2.3). I wonder if the head ports are anything special... </TD></TR></TABLE>

That is the only thing that makes sense... The Throttle Body numbers read PCBX HF-1

The injector size and postion also appear to be the same as the Euro R

Definetly not Type S/Euro R cams like we thought...

The casting number on the Blue Top Cams:
Int: F
Exh: H

JDM H22A OBD1:
Int: L
Exh: L


Modified by ESP.net at 10:00 AM 7/22/2008
Old 07-22-2008, 09:35 AM
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Default Re: (ESP.net)

The cams could be specific to the motor. If the pistons are specific the cams would not be a stretch either. Just look at the B series and its wide array of cams that were engine specific.
Old 07-22-2008, 09:45 AM
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Default Re: (Televator)

I am still debating back and fourth if I should invest in some Type S cams just to have something lil more on it... However the engine is already getting a Euro R manifold and 68mm TB both are on there way... decisions

The few typical dyno numbers I have seen with this H23A Vtec Blue Top with basic bolt ons have been...

184whp 162 trq
190whp xxx trq

Shitty way to say it but id moreless kinda think the cams are JDM H22's


Modified by ESP.net at 10:52 AM 7/22/2008
Old 07-22-2008, 10:16 AM
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Default Re: (ESP.net)

Ah that's a toughy...Even though it's a blue top, the compression is lower in this motor. To say the gains would be anything really substantial is difficult, unless you actually try it.
Old 07-22-2008, 12:18 PM
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Default Re: (Televator)

great thread!

weve done several of the blue top h23 swaps here. weve seen variations on the pistons and cams...probably between the the SiR and ive heard that it was actually used in the prelude at one point in japan. I have no been able to confirm it one way or another tho. too many people saying too many things.

i do know that the 5th gen Jei had with the blue top came automatic...no manual option since it came out of the accord. it had the regular jdm h22 cams. the pistons seemed to be slightly higher compression than the USDM and had floating wrist pins. on our dyno it put down 185whp out of the box. the car reved to about 7500 rpms. 55mm mains and no oil squirters. i know most of that has been covered in the thread already...just trying to reiterate.

another blue top we had here we installed the type-s cams with no valve to piston issues...and with some tuning the car hit 204whp. with the cams and an SMSP header.

the third motor had a complete type-s head. which made me think of the rumor that went around that the blue top was an H23 with type-s head.

the TB is tapperd down to a 62mm. why the bottle neck? im not sure...but honda does things for a reason.

youve got a great motor. i LOVED driving the 5th gen with that motor stock.
Old 07-22-2008, 12:31 PM
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Default Re: (BlacktraxGirl)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BlacktraxGirl &raquo;</TD></TR><TR><TD CLASS="quote">great thread!

weve done several of the blue top h23 swaps here. weve seen variations on the pistons and cams...probably between the the SiR and ive heard that it was actually used in the prelude at one point in japan. I have no been able to confirm it one way or another tho. too many people saying too many things.

i do know that the 5th gen Jei had with the blue top came automatic...no manual option since it came out of the accord. it had the regular jdm h22 cams. the pistons seemed to be slightly higher compression than the USDM and had floating wrist pins. on our dyno it put down 185whp out of the box. the car reved to about 7500 rpms. 55mm mains and no oil squirters. i know most of that has been covered in the thread already...just trying to reiterate.

another blue top we had here we installed the type-s cams with no valve to piston issues...and with some tuning the car hit 204whp. with the cams and an SMSP header.

the third motor had a complete type-s head. which made me think of the rumor that went around that the blue top was an H23 with type-s head.

the TB is tapperd down to a 62mm. why the bottle neck? im not sure...but honda does things for a reason.

youve got a great motor. i LOVED driving the 5th gen with that motor stock.
</TD></TR></TABLE>

Yeah saw the ad and the dyno numbers

Hmm yeah mine was an Auto, PDE head (Euro R/Type S same casting) but with P13 cam tops etc., I am doubtful if it has the type s cams in it, being auto and the castings of H and F on the cams. But as long as there not milder then the JDM H22A 5 spd cams I am happy...

But as you mentioned Prelude and Accord might of had this H23A Vtec engine it's possible tiger the place I got then engine from does say it's from a 97+ Prelude not Accord so could there be type s cams in it... who knows... my mic's are just a hair to short from reaching over the cam tops and measuring the lobes...
Old 07-22-2008, 01:43 PM
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Default Re: (ESP.net)

"S" cams are fairly blue.
Old 07-22-2008, 02:41 PM
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<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by A Blue Lude &raquo;</TD></TR><TR><TD CLASS="quote">"S" cams are fairly blue.
</TD></TR></TABLE>

That's funny that you mentioned that... these (H23A Vtec Blue Top) appear to be blue tint as well... next to my JDM H22 cams. Hmm...

You know for a fact they are blue tint and they are only to the Euro R and Type S?

Old 07-22-2008, 02:57 PM
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Default Re: (ESP.net)

Blue tint? Isn't that a higher magnesium content in an attempt to make a lighter cam? I know in the 90s' some companies were looking into magnesium cams. I've seen the patent docs. I suppose it could be something else giving them that color though.


Modified by Televator at 4:03 PM 7/22/2008
Old 07-22-2008, 04:25 PM
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Default Re: (Televator)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ESP.net &raquo;</TD></TR><TR><TD CLASS="quote">

That's funny that you mentioned that... these (H23A Vtec Blue Top) appear to be blue tint as well... next to my JDM H22 cams. Hmm...

You know for a fact they are blue tint and they are only to the Euro R and Type S?

</TD></TR></TABLE>

id take those out and measure the lobes....but from what i see those are type-s cams! thats very distinctly blue. and yes type-s cams are noticably blue i have a few sets laying here and i run those in my stock a4 engine

no harm in measuring them to make sure!

the accord SiR engine we had here.... the one with the type-s head...was auto since they didnt have a manual for that car in those years. What also makes it harder is that we dont know for sure becaue over there they were doing crazy things before we even thought about it so who knows that the owner of the car the engine came out of did?!

i emailed my friend in japan to see if he could dig for some better info than the old a$$ flyers from japan on the prelude and the avail options....hopefully find something. I know there was a prelude SiR.

Old 07-23-2008, 07:35 AM
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Default Re: (PirateMcFred)

???
does this block have iron sleeves like the f20b of is it frm like the standard h22/23?


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