Aradin

I had to scrap the engine. It was no good after the #4 rod broke.

And no you shouldn't be revving it to 8500rpm. It was only designed for 6900rpm from the factory. Some people take it to 8000 without issue but that's more than I would do. I only revved mine to 7200.

It is worth rebuilding. They're very strong engines. Keep babying it. I recommend changing your oil more frequently and looking out for metal shavings in it. That's how mine started. After a few oil changes, if everything looks good, take it to get an appropriate tune and you should be fine.

bottomedout

Awesome. Thanks for the information.

Tight-R

I clearly felt the power loss around 7000-ish RPM with mine so I never shifted above 7200-ish. It's a great motor though, I would swap one into a higher mileage or bad motor prelude any day of the week over the H22. Not hating on the h22, but it's almost double the price. It's a lot "cleaner" if that makes any sense, but I am down with the cheaper/justasgood fix.

bottomedout

I've got mine in a ej6. Got a good deal on the whole swap. I'm hoping to baby mine through the summer and rebuild in the winter with a full wire tuck and maybe a shave as well

Bense

love my h23a vtec

Brent_vtec

I have a JDM h23 blue top paired with a tiptronic transmission in my 4th gen prelude, can a chipped ecu work on an automatic I really want to raise the redline from 6200 to 8000. I'm new to the Honda game excuse lack of knowledge

1991_crxsi

iTrader: (1)

Yes and no. Talk to your tuner.

mansour

lot of good info here on H23AV... im in process of building H2B on my crx since complete drive train of B series is all ready along with the QSD kit.

i got both options 99 and 00 available in same yard for same price, but not sure which to go for..
the 99 spec seems to be in a healthier condition compared to the 00 spec.. the 00 was proly run by an unhappy owner ... but i do know the 00 head has better valve angle than the 99 one! so imma bit confused.

any advice which of these 2 do i go for ?
i would be rebuilding the head soon; port polishing + new ST valves/springs/retainers + K series PRC manifold with H2K Skunk mani adapter (for better firewall clearance in crx) + KS balance shaft delete kit.

some pics of the are posted... any input is much appreciated.

1991_crxsi

iTrader: (1)

I have had both heads and have not noticed a difference on the dyno. Just go with the healthier engine.

ESP.net

X2 go with the healthier engine. Difference between PDE 00-01 and Non is PDE has 45 degree valve seat instead of a 60 normal h22. It also has slightly smoother casting in the intake runner. As well as the intake manifold gasket port nose are is a little bit more open and gasket matched. Due to has similar bottom intake/gasket as PDE Euro R.

P-Motorsports

FRESH JAPANESE ENGINE BUYING TIP!

WHEN SHOPPING FOR A BLUE TOP DOHC VTEC ENGINE:
(JUST MY EXPERIENCE NOT EVERYONE WILL HAVE THE SAME)

F20B- KNOWN FOR JUMPING TIMING AND WORN TIMING BELTS
H23A- KNOWN FOR BEING USED HARD EVEN WITH AUTO TRANS

TIMING SIDE FOR BOTH ENGINES IS A TRADE SECRET
REPLACEMENT PARTS THAT FIT AND "UPGRADE" THESE ENGINES
TO MAKE MORE EFFICIENT REQUIRES COMPONENTS FOR
A FEW OTHER SERIES OF HONDA ENGINES TO
MAKE A SYMPHONY OF VTEC THAT MOZART WOULD CHALLENGE

RACING IDEAS

IVE TALKED WITH ALOT OF DIFFERENT BUILDERS AND
EVERYBODY HAS THEIR OWN OPINION!

F20B- NITROUS AND E85

H23A- TURBO AND E85

DISCLAIMER!

I HAVE HEARD MANY STORIES OF BOTH JDM BLUETOP DOHCS

LITERALLY THROWING RODS LIKE ZEUS LIGHTNING RODS


BOTTOM LINE IS HAVING FUN AND NOT WORRIED ABOUT
WHAT THE OTHER GUY IS RUNNING AND IF ITS BETTER
YOU BUILD IT, YOU RUN IT!
CHEERS TO ALL WHO READ THIS RANT

Bense

What?

grushko

DO a leak down test on both, and choose the best one. I personally would go wth one that doesn't have PGMFI logo on the intake (aka pde head).

ISUBIEXI

Just wanted to add a note, my phearable.net H23AV baseline is extremely rich, if you go that route be careful.

Bense

Feel free to post a linnk to the .bin for the dyno tune that you paid $450 for

Bense

I forget. Didn't someone discover that the rod rod length is actually 141mm?
and that the piston compression height is ... ?

ISUBIEXI

Pherable was $139 to chip and program my ecu. "Phearable.net's basemaps are based off dyno proven fuel & timing maps" The tune definitely got the car running but I I'm not so sure the "dyno proven" results were for this specific engine.

I was a little concerned with the tune and that's why I got the Wideband. The wideband made it clear that the "premium" basemap was still just a stopgap until I could get an actual tune in the car. I'm going to attempt a street tune and when that turns into more than I can handle ill move on and get an actual dyno tune done. If I manage to get any exports of my tune I don't mind posting them.

Aradin

Yes. The rods are 141mm and also floating pin. Compression height is same as H22.

Lgalvez19

My h23 blue top came with a regular solenoid instead of a vtec solenoid. I was wondering if I can just slap on a vtec solenoid and would it work or would I have to go through tuning the ecu and so on?

snobordboy

Why would someone remove the vtec solenoid? Want to post a picture of what you are talking about?

In any case, if you are not using the original ecu for the engine, you should look at getting it tuned properly, especially since North American gas is different than Japanese gas specifications.

autoluder

Hey Guys, ESP.net.. I just got a P13 H23A Vtec Bluetop swap done.. and was wondering,

Whats the most respectable Redline/Fuel Cut off on a stock H23AV BT with bolt-ons used for road racing. I seem to keep damaging valves in these H22 heads, twice now.... prob not related to honda engineering cause first time was mis-shifts, second time was 7500-7700rpms in 4th gear on a higher speed road course high load with aftermarket PIP valves from the previous head rebuild. Exhaust valve broke off. So I'm thinking these heads need to be under 7500rpms, but with H23AV BT being designed with H22 valvetrain but designed around a Auto Trans with 6800rpms, was that because the auto trans cant handle higher RPMs ? I've see auto h22 dashes showing 7400 redline.... but the h23a1 auto and manual redline is 6500. Prob cause longer stroke of engine and non vtec head, non H23A internals, The H23AV from reading this thread has the shorter pistons so I'm assuming lighter in weight, lighter rods, and lighter crankshaft. So I assume this was to help it rev reliably to 67-6800? as apposed to 6500???

Despite concerns with longer stroke in H23A causing higher piston speeds, seems the bottom end was built up, but I see the valvetrain being the weak point, and maybe the rod bearings and rods due to horrible rod/stroke ratio of 1.48 and thinner rods.

Long story short, I guess when I get this tuned in the spring, was debating setting a hard Redline/Fuel Cut off between 7100-7400. thinking of setting it for 7300 right now..... my main concern right now is Valve Float.
Yes people have revved these H23A's to 8000. But after a few years and many miles if the valve springs get worn out, I would imagine valve float to be a concern? Or do you get a valve adjustment and re-torque things to accommodate wear?

What do you H23A vtec bluetop owners think? Do you road race yours? How many miles have you put on your motor and what average WOT RPM shifts has the motor seen?

snobordboy

Hi autoluder,
I would be more concerned about the condition of the valve guides, and strength of the valves in use. The head design is the same between the H23A bluetop, H22, and F20B, and there were variations that had factory redline closer to 7800 rpm. Many of use rev our cars with this head to 8-9K or more, but usually with upgraded cams and appropriate valvetrain.

The rpm limits that were used on the H23 had much more to do with the 95mm stroke crank, and bearing wear and oiling issues in that area of the engine, as well as piston heat, which is why the piston squirters were added.

With a head in proper spec, valves adjusted properly, and everything else in the engine good, I would have a stock H23A that has an actual tune, set in the 7500 rpm range, but it would be worthwhile to take a good look at a dyno chart, and the gearing and final drive, and see what you might be able to do to maximize your setup through all three areas.

autoluder

snobordboy, Thanks for the input,

So what happens with the valve guides? they can get worn out and the valves can bend, or the they can get loose and slide down causing the valves not to shut fully?

I was debating to install my h22a oil squirters on the H23A, but we couldn't get them off fast at the shop so ditched them. I've been reading that the h23a has oiling holes in the rods, i guess that gets the oil to the crankshaft bearings? don't know how the cylinder walls get oiled though. Also, some are saying with the piston hot on the top, but cooled from the bottom with squirters can create uneven wear or make the piston out of round? seems kinda far fetched. Other possible issues with oil squirters on the h23a is that they have to be bent out of the way to make clearance for the 95mm stroke, and hence making them less efficient. And lastly the oil squirters heat the oil?

So is it detrimental to install them, especially for me who will be road racing the car a couple times a year? Seeing constant high RPMs....I want to say the people with spun bearings or bent rods were turbo applications or over revved?

The the F20B I read has the intake valve springs on the exhaust side as well, (same Part#) since they are stiffer, to handle the RPMs.

I'm using stock final drive, with h22a intake manifold, IABs for lowend torque, and i have 66mm tb portmatched, and hytech header, and 2.5" catless catback, with hondata s300. On the H22a this setup made 199whp at 7200rpms losing 8whp by 7500. and 164.3wtq at 5300rpms. So I wouldn't imagine the H23A needing a higher redline anyways, my concern isn't so much the peak power, but how much spare RPMs i can afford when I'm running out of gears on the road course, Having a 5spd is kinda limiting, my hope is that with the great torque of the H23A, i can ride 4th gear through some mid speed turns, if i run out of 3rd gear too early, or like at NCM when i was running out of 4th gear, I don't think ill ever go back to that track as beautiful as it is, it was designed purely for corvettes, 3 high speed straights, with 2 of them going into fast sweepers.

Aradin

Oil squirters are not likely to be needed. The cylinder wall oiling is handled a little differently in this engine but it's definitely adequate. You can install them if you bend them out of the way so they don't contact the piston skirts but you may not notice much of a difference.

For the rev limit, the bottom end isn't going to be the limiting factor here so don't worry about it. Honda did an excellent job at over-engineering it for it's intended purpose. The only worry is that the valve reliefs on the factory H23A pistons are not adequate for any larger cam. They are not quite in the right spot nor deep enough. There have been multiple examples of P2V contact on the exhaust side when using bigger NA cams. If you stick with the stock cams, you should be fine to 7800+, assuming the rest of the valvetrain can handle that kind of RPM. A local guy took his to 7800 every day, and basically had no mercy on it for over a year. Constant long highway pulls racing down the local highway, etc. It eventually gave out due to a poor tune which lead to 2 ruined pistons. I had one boosted and I will say that these engines are not good candidates for forced induction applications but that's not your concern here. If you want peace of mind, throw in some valvesprings and you should be fine revving it to whatever you want.

Side note: You won't really need IABs with this engine, especially since you plan to be in the higher RPM range all the time. It makes plenty of usable torque below 4k and having the IABs in place is only going to hurt your peak power. You should gain around 10whp peak with a spacer in place of the IAB plate. It may be worth making that change.

autoluder

Aradin, good insights..

I think i still use the IABs for the low speed corners where i may fall out of vtec but dont want to downshift. And dont want to lose any lowend torque. But it would be nice to have a simpler set up and less parts to wear out or break, I always think about that IAB vacuum box and how i would ever replace it. My H23A came with the ports busted, i was hoping to have a back up. I may look into a Euro-R manifold, seems to be good middle ground. But the spacer like you said may be the easiest and fastest solution, i remember blacktrax selling these parts. Thanks reminding me! :-)