ESP.net

JDM H23A Vtec Blue Top:

H23A VTEC
Accord Sir Wagon (CH9) (JDM)
197hp@6800/163tq@5300
notes: 10.6:1 CR, open deck likely regular JDM H22a head. 95mm stroke
Auto Tranny stock

Auto versions redlines at 6200 rpm

From the differenct Engine Importers there appears to be a Auto version and a 5 spd???

I am also curious if there would be an internal differences from the Auto version and 5 spd version, such as cams being less agressive on the Auto, injector size etc.?



__________________________________ Update 6/17/2011 ____________________


Thought I would go over the basics of this engine since all information is fact and documented now. Since I have been looking part numbers up on Euro EPC.

All H23AVtec Blue Tops came out of either SIR Station Wagon CH9 chassis code 2WD and 4WD model was CL2. Both were Auotmatics. 2WD got the same Prelude 97-01 Triptronic Auto transmission

H23AVtec Blue Top Head Facts:
1998 and 1999 head castings are P13 (H22)
1998 and 1999 Intake Manifolds will read PGMFI on the plenum
IACV will be on front of plenum like a P13 (H22)
2000 and 2001 head castings are PDE (H22 Euro R/Type S)
PDE heads have different valve *Seat Angle* than P13. PDE went to 45* from P13 60* was said to be better for performance
PDE head has a factory port clean up job like the ITR and CTR heads. Smoother casting, less pit noticed intake runners.
2000 and 2001 Intake Manifolds will have no PGMFI on the pleunum and will be smooth
2000 and 2001 will have IACV on back of plenum

The biggest question was cams, When I spec'd mine out they did not seem to be as agressive as the Type S/Euro R/F20B MT cams. PDE head.

The Fact is after comparing part #'s the Cams in 2WD and 4WD P13/PDE models are the same that are in the SIR OBD2 JDM H22 5 spd/Auto. As we all know and part #'s show over seas Auto and 5 spd JDM H22 cams are the same no difference.

Valves: Are the same as the JDM OBD2 H22 (P13)
Valve Springs: Are the same as the JDM OBD2 H22 (P13)
Retainers: Same as the Euro R/F20B Auto and MT

All H23A Vtec Blue Tops cam with a larger Throttle Body then a normal JDM H22 OBD1/2. My measurements showed it was 65mm on inside (meets intake) and outisde was 68mm
Throttle Body is same casting as ITR and S2000 which those gaskets will work on it.

Bottom End:
Open Deck, 55mm mains, H22 Auto tensioner, 95mm stroke 10.6-1 compression, No squirters.
Alternator Only crank pulley, same part as Euro R/F20B since both are electric PS not belt.
H22A4 98-01 Prelude Oil Pump, Water Pump, Timing Belt, Balancer Belt, Head Gasket, Intake Manifold Gasket and Exhaust Manifold Gasket.

H22A4 98-01 Main Bearings/Thrust
H23A1/F22 Rod Bearings

All H22A4 head parts are swappable to the Blue Top H23.

Swap driver side engine bracket for 92+ Prelude H and bolts in like H

I am still looking into it but I believe the Blue Top H23 has a larger oil pan then a typical H22 92-96. Which sucks far as replacement.

Other neat info: F20B Blue Top MT shares same Valve Springs/Retainers/Cams as the Euro R
F20B Blue Top Auto version shares same Valve Springs/Retainers/Cams as the JDM H22 OBD2 SIR and H23A Vtec Blue Top

Televator

iTrader: (1)

I've never seen a stock manual version...got links?

B18 Piston

i just got h23vtec for my Lude. Doing the swap right now!

ESP.net

These 2 questions probably the most impotant questions about this mystery motor:

Auto H23A Vtec Blue Top cams identical to the JDM H22A 5 spd far as specs?

As we all know usdm h23 crank and rods with jdm h22 piston will sit .020 out of the hole.

H23A Blue Top has a 10.6-1 compression same as JDM H22A, so in order to get this compression identical as the JDM H22A, is the wrist pin in different location? (different piston) or shorter rod in order to have the piston in the hole like normal?

Last question I am curious about is if this bottom end uses oil squirters?

mgags7

They're guessing just like you are, so don't trust what the website says. Oil squirters can be installed.

I believe the pistons were probably one-off for this engine, with a shorter compression height than normal h22 pistons.

vinuneuro

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">They're guessing just like you are, so don't trust what the website says. Oil squirters can be installed.

I believe the pistons were probably one-off for this engine, with a shorter compression height than normal h22 pistons.</TD></TR></TABLE>

In the H23a1 blocks, are the oil squirter galley's there but blocked off?

I'd imagine the H23vtec would have them since the squirters are there to manage heat, and the H23a and H22's make the same power.

Has anyone seen the H23a crank? I wonder if/how different it is from an H23a1 crank. The the H23a doesn't rev much higher.

mgags7

Right, as far as I know you can install squirters in every H block.

ESP.net

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">They're guessing just like you are, so don't trust what the website says. Oil squirters can be installed.

I believe the pistons were probably one-off for this engine, with a shorter compression height than normal h22 pistons.</TD></TR></TABLE>

Hmm, I am thinking the rods are different and the piston is the same as the JDM H22A hince 10.6-1 compression. I will let you guys know on the squirters if they are in. Just ordered a JDM H23A Vtec Blue Top. Definetly not taking the engine apart but will peek under the pan.

Only reason I would doubt the squirters not being in is because of the amount of RPM a auto would be using redline is 6200. I think squirters are more for the cast piston in higher RPM's.

Correct squirters can be added in any H block

vinuneuro

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

Hmm, I am thinking the rods are different and the piston is the same as the JDM H22A hince 10.6-1 compression. I will let you guys know on the squirters if they are in. Just ordered a JDM H23A Vtec Blue Top. Definetly not taking the engine apart but will peek under the pan.</TD></TR></TABLE>

It's easier to make a new piston. They probably just increased the dome volume of the H23 pistons.

ESP.net

That makes sense to me

ESP.net

Found some juicy info. on this JDM H23A Vtec Blue Top







1. 55mm mains
2. no squiters
3. counterweights similar the h22a4
4. p13 head
5. open deck
6. high compression
7. and it has a auto tensioner on the timing belt

Center to Center of Rod is "CLOSE" to 5 9/16

So it looks like it is more like a H23 typical rod length?




Modified by ESP.net at 3:14 PM 7/11/2008

vinuneuro

That's pretty interesting. The skirts of those pistons are different than the other H series pistons around the pin area. Any word on the compression height?

Def seems like H23 rods.

ESP.net

Anyone have a picture of the top of a factory H23A1 usdm piston?

So it appears that the piston wrist pin location maybe different in order to get the piston in cylinder hole instead of out.

Here are 2 pictures of a typical JDM H22A Piston and Rod (P13Z) 10.6-1





From the looks of the above picture sure looks like that dome is no where near a 10.6-1 dome piston?

10-1 USDM H22A4 piston just for dome reference...





Modified by ESP.net at 4:33 PM 7/11/2008

Televator

iTrader: (1)

LOL, those pics look familiar. Yup, that's from the PP thread were me and a couple of dudes dragged out all the misunderstood info as far as we knew and found answerers the best we could. I tried to see if the guy could get a more accurate measurement of the C to C on the rods. I believe his measurement is off and his method for measuring was crude, which gave him an H22-like rod length. He provided a great service documenting the tear down with pics like that though. I agree with Matt on the different pistons.

Here's the thread: http://www.preludepower.com/fo...age=3

If 2lude4u were still around, I'm sure he'd have some insight on the block he sold me.

I've also got an assortment of pics and info on the H23A VTEC and non-VTECin my photo bucket that I've linked in my sig...


Modified by Televator at 5:50 PM 7/11/2008

ESP.net

Yea that's where I got the pix... it did in fact have a lot of un solved facts on the engine which was very helpful... so we all agree the pistons are different? and the rods are typical length H23A1's? but is the compression actually 10.6-1?

ESP.net

Yes that pic is yours Pirate...

What do you think is going on with the JDM H23A Vtec Blue Top far as piston? Think it's a different pin location? We all agree the piston obviously sits in the hole .008 like a normal H

ESP.net

The Mystery Motor...

Just for giggles on the Mystery H's check out the Rod on the right, has an oil orfice in it and is visible lot larger however came from a JDM H22A with JDM H22A pistons. I ran it in my JDM H22.

The rod on the left is a typical H22A rod, I think the rod on the right is from the 91-93 JDM H22A period? Oil orfice could have something to do with. Or Honda possibly skimped to a skinner rod for cost?

Televator

iTrader: (1)

Hmmm these things are definetly worth looking into. The B-series still remains much more well documented than the H-series. Kind of an embarrassment considering that the H-series has become quite popular nowadays with a lot of Hondas. It would require constant update and review by several people with a wide range of motors to compare their findings. I feel so bad that I've put my H23A on the back burner for now. Not much I can really do with my tight work schedule. I'm working on a project for NOAA right now. That's right...like the government agency.

vlang29

i thought the h23a redline was more like 7000-7200?

fwiw, the zeal autowerks compression calculator indicates:

pistons
H22A 31.00mm comp height, 1.70cc dome
H23A 30.55mm comp height, 0.00cc dome
H23A1 30.55mm comp height, -10.5 dome

ESP.net

Auto is going to have a lower RPM which I believe on the cluster I saw was 6200 Accord SIR Auto H23A Vtec Blue Top. No Honda Auto's I believe go any higher then 6's on redline.

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">Honda's like any other big corporation that has a product with parts that come from several different manufaturers. The difference in rods could be one manufacturer's forging cut in a fashion that's slighlty different than another manufacturer that has different production process. Honda's not going to make their own stuff so they will award a contractor that can do the job for the lowest price. Honda's main concern is about having parts within their design spec and at a cheap price.

The difference in rods might also be a design iteration where later a better/cheaper material/design was used.

I remember that weird H22A rod thread and I don't suppose it matters if you're going to build an H22. Whichever factory rod you choose there's a much lighter aftermarket alternative that's better for high-revving applications.</TD></TR></TABLE>

I believe that 100%, Honda switched to another Co. to save money.

The Big Rod thread I did a few years back.

As far as balancing and using the heavier rod, since factory rod not a big deal till you start building on the platform. However I wouldnt mix match skinny rods with big rods thats a given.

ESP.net

Can we say safely that this JDM H23A Vtec Blue Top uses a normal H22A timing belt?

Televator

iTrader: (1)

The furthest my info has gotten is that the HID equipped wagons were in fact the manual H23A equipped versions.


Edit: Nope wait......Here's something interesting I found on Wiki Japan. 2 SLIGHTLY different specs.....

* H23A (3 generation, SiR) DOHC 16-valve inline 4-cylinder VTEC 2258cc (× bore stroke: 87.0 × 95.0)

147kW(200PS)/6,800rpm　221N・m(22.5kg・m)/5,300rpm：FF 147kW (200PS) / 6800rpm 221N m (22.5kg m) / 5300rpm: FF
140kW(190PS)/6,800rpm　221N・m(22.5kg・m)/5,300rpm：4WD 140kW (190PS) / 6800rpm 221N m (22.5kg m) / 5300rpm: 4WD

Same Peak RPM, but 10 HP difference.


Translated link: http://www.google.com/translat...tl=en


Modified by Televator at 11:25 AM 7/14/2008

ESP.net

Hmmm few importers that do carry this engine say there is a manual version but I am not thinking so, thinking they just put on a H manual trans? Haven't found any info yet to prove the 5 spd other then importers.

4wd has less power hmm...

Televator

iTrader: (1)

Well I'd imagine that the manual versions are actually pretty rare considering the region and intended consumer for this car....