H22a1 VS H22a4
09-26-2008, 09:35 PM
#12
0.0 BAR
Thread Starter
Join Date: Jul 2007
Posts: 17
Re: H22a1 VS H22a4
Originally Posted by bigdaddyvtec
WRONG.
The reason I ask is becuase I have an H23 from a 4th gen prelude (92-96) and I want to put on a H22 Head, I would like to keep it simple and stay with the same Generation and keep it OBD 1 (ie: out of 4th gen also), however I can't find one locally, all I have found are H22a4, and no "a1's"
09-26-2008, 10:41 PM
#13
3.0 BAR
Join Date: Mar 2006
Posts: 5,631
Re: H22a1 VS H22a4
Originally Posted by StreetTuner
You seem to know the differences, you've just won't tell me!
The reason I ask is becuase I have an H23 from a 4th gen prelude (92-96) and I want to put on a H22 Head, I would like to keep it simple and stay with the same Generation and keep it OBD 1 (ie: out of 4th gen also), however I can't find one locally, all I have found are H22a4, and no "a1's"
The reason I ask is becuase I have an H23 from a 4th gen prelude (92-96) and I want to put on a H22 Head, I would like to keep it simple and stay with the same Generation and keep it OBD 1 (ie: out of 4th gen also), however I can't find one locally, all I have found are H22a4, and no "a1's"
09-27-2008, 12:04 AM
#15
3.0 BAR
Join Date: Mar 2006
Posts: 5,631
Re: H22a1 VS H22a4
You dont have to worry about the OBD1 II ---- the heads are the same.
ALthough I still dont know what car you are putting it in... I know this for sure.. (refer to the h22a as obd1 as well)
The H22A vs H22A4... Here we go:
The H22A is specifically a Japanese Domestic Market (JDM) engine.
Any H22A made and sold in Japan will bear the H22A designation on the block, and only be differentiated by the serial number. This includes engines that were used in every JAPANESE model of Prelude.
The H22A4 is SPECIFICALLY the engine used in the 1997-2001 Honda Preludes sold in North America.
The H22A4 has TWO variants: The base model block and the Type-SH block. The type SH block is machined to allow the proper fitting of the ATTS unit (Active Torque Transfer System) and the transmission. For swap purposes the H22A4[SH] is useless for anyone with a "normal" or non-SH block.
Basic Differences:
1) The H22A series of engines have higher compression ratios: 10.6:1 and 11:1. While the H22A4 series has a 10:1 compression ratio. All engines require 91 or better octane gas, and this is not negotiable if you have an H22A. Significant usage of non-premium fuel will eventually ruin your rings, no matter how much the ECU retards the timing.
2) The early H22A series engines have CLOSED DECK design, while the H22A4 engines have an OPEN DECK design. The closed deck means that aluminum is cast around the tops of the cylinders with coolant port openings, leaving block-to-cylinder bore contact at the TOP of the block. The H22A4 does not have this. Instead, the cylinder bores are ancored only at the bottom of the block, and the head gasket / cylinder head keep them ancored on the top. Mechanically, the closed deck design is stronger. However, the open deck design allows for superious cooling of the top part of the cylinder bores, thus reducing NOx emissions. Later H22A series blocks are exaclty the same as the H22A4 blocks.
3) Once again, early H22A series engines are different on the timing side of the engine, since the later model H22A and H22A4 engines are OBD2. This means that the oil pump housing must accomdate different sensors that the old OBD1 H22A's don't require.
4) The crank harmonic balancer bolt is smaller on the older H22A's.
5) The intake manifold is an older design on the older H22A's. ...and on the 11:1 version of the H22A (for the 5 Gen Type-S Prelude) the IM is ported and polished at the factory.
6) The Thermostat housing is different on the older H22A's.
7) The distributors are different on the older H22A's.
Most of the older H22A series engines used type A pistons, whereas the H22A4 pistons are the smaller tolerance type B pistons.
9) The older H22A series engines (lets just call them 4th Gen Prelude engines [92-96]) have different oil pans. (The H22A4 and later model H22A units are aluminum and have a transmission stiffener.)
Basically, it's a matter of the bolt on's and the electronic controls... but only when you are comparing a 4th Gen Prelude H22A JDM to a USDM H22A4.
ALthough I still dont know what car you are putting it in... I know this for sure.. (refer to the h22a as obd1 as well)
The H22A vs H22A4... Here we go:
The H22A is specifically a Japanese Domestic Market (JDM) engine.
Any H22A made and sold in Japan will bear the H22A designation on the block, and only be differentiated by the serial number. This includes engines that were used in every JAPANESE model of Prelude.
The H22A4 is SPECIFICALLY the engine used in the 1997-2001 Honda Preludes sold in North America.
The H22A4 has TWO variants: The base model block and the Type-SH block. The type SH block is machined to allow the proper fitting of the ATTS unit (Active Torque Transfer System) and the transmission. For swap purposes the H22A4[SH] is useless for anyone with a "normal" or non-SH block.
Basic Differences:
1) The H22A series of engines have higher compression ratios: 10.6:1 and 11:1. While the H22A4 series has a 10:1 compression ratio. All engines require 91 or better octane gas, and this is not negotiable if you have an H22A. Significant usage of non-premium fuel will eventually ruin your rings, no matter how much the ECU retards the timing.
2) The early H22A series engines have CLOSED DECK design, while the H22A4 engines have an OPEN DECK design. The closed deck means that aluminum is cast around the tops of the cylinders with coolant port openings, leaving block-to-cylinder bore contact at the TOP of the block. The H22A4 does not have this. Instead, the cylinder bores are ancored only at the bottom of the block, and the head gasket / cylinder head keep them ancored on the top. Mechanically, the closed deck design is stronger. However, the open deck design allows for superious cooling of the top part of the cylinder bores, thus reducing NOx emissions. Later H22A series blocks are exaclty the same as the H22A4 blocks.
3) Once again, early H22A series engines are different on the timing side of the engine, since the later model H22A and H22A4 engines are OBD2. This means that the oil pump housing must accomdate different sensors that the old OBD1 H22A's don't require.
4) The crank harmonic balancer bolt is smaller on the older H22A's.
5) The intake manifold is an older design on the older H22A's. ...and on the 11:1 version of the H22A (for the 5 Gen Type-S Prelude) the IM is ported and polished at the factory.
6) The Thermostat housing is different on the older H22A's.
7) The distributors are different on the older H22A's.
Most of the older H22A series engines used type A pistons, whereas the H22A4 pistons are the smaller tolerance type B pistons.9) The older H22A series engines (lets just call them 4th Gen Prelude engines [92-96]) have different oil pans. (The H22A4 and later model H22A units are aluminum and have a transmission stiffener.)
Basically, it's a matter of the bolt on's and the electronic controls... but only when you are comparing a 4th Gen Prelude H22A JDM to a USDM H22A4.
09-27-2008, 04:08 AM
#16
0.0 BAR
Thread Starter
Join Date: Jul 2007
Posts: 17
Re: H22a1 VS H22a4
I drive a 1995 Honda Prelude SI.
The SI has the stock DOHC NON - vtec H23a1 with 160 HP and compression at 9.8:1.
I'm thinking about possibly changing the head in order to be vtec'd :P
I originally wanted the 4th gen (92-96) VTEC model that came with the H22a1 , however do to my budget and luck I was not able to find any H22a1's
as a result, time has passed and I have about $300 dollars extra to buy a head, I have searched locally and I have yet to find any H22a1 heads, however I have found about three H22a4 heads, as mentioned, and they all are from $225 to $300.
However before I do something stupid I'm TRYING to find out as much as I can about my situation and possible head swap. I don't want to buy the H22a4 head and find out a made a HUGE mistake.
so the general gist is: will the H23a1 from my 95 work with an H22a4 Head out of a 97-01, and if it does work will it even run good? Because, hell it can work but it might not run strong.
from guys on a prelude forum (not so many members so they take FOREVER to reply so I came here) they have told me that the H23a1 with the H22a1 head all coming from 4th gens works good. They have yet to give me good info on the H23a1 with an a4 head compatibility.
BTW: thanks for the write up, most info I have found so far!
The SI has the stock DOHC NON - vtec H23a1 with 160 HP and compression at 9.8:1.
I'm thinking about possibly changing the head in order to be vtec'd :P
I originally wanted the 4th gen (92-96) VTEC model that came with the H22a1 , however do to my budget and luck I was not able to find any H22a1's
as a result, time has passed and I have about $300 dollars extra to buy a head, I have searched locally and I have yet to find any H22a1 heads, however I have found about three H22a4 heads, as mentioned, and they all are from $225 to $300.
However before I do something stupid I'm TRYING to find out as much as I can about my situation and possible head swap. I don't want to buy the H22a4 head and find out a made a HUGE mistake.
so the general gist is: will the H23a1 from my 95 work with an H22a4 Head out of a 97-01, and if it does work will it even run good? Because, hell it can work but it might not run strong.
from guys on a prelude forum (not so many members so they take FOREVER to reply so I came here) they have told me that the H23a1 with the H22a1 head all coming from 4th gens works good. They have yet to give me good info on the H23a1 with an a4 head compatibility.
BTW: thanks for the write up, most info I have found so far!
09-27-2008, 04:25 PM
#18
1.0 BAR
Join Date: Nov 2006
Location: Orlando, FL
Posts: 283
Re: H22a1 VS H22a4
I guess i'm wrong about the LMA's according to bigdaddyvtec...
but he talked about all differences in the block.....but left 1 huge issue out.....the main journal size (92-96/97 = 50mm and 98+ = 55mm)
but then again the original poster was talkin about the heads...not the bottom end
OP...if u do use and a4 head...as far as distributors go....just use ur distributor off ur h23
Regardless which head u pick up....its going to fit.... U just have to use an OBD1 distributor (which ur h23 has ON IT) and depending on what year your prelude is....u might already have vtec solenoid wiring and the only thing u'd have to do as far as wiring is connect the VTEC pressure switch to a wire that's already in the engine bay, and ground the sensor.
You also need the H22 head bolts and lower timing gear, water pump, water pipe and a few other things. But u probably already know all that.
I'm sorry buddy but if that's all u know about the h23vtec hybrid...u have alot of reading to do. And what prelude forums are you on? because them not knowing or takin forever to tell u the a4 and a1 heads are BASICALLY the same would be a concern.
but he talked about all differences in the block.....but left 1 huge issue out.....the main journal size (92-96/97 = 50mm and 98+ = 55mm)
but then again the original poster was talkin about the heads...not the bottom end
OP...if u do use and a4 head...as far as distributors go....just use ur distributor off ur h23
Regardless which head u pick up....its going to fit.... U just have to use an OBD1 distributor (which ur h23 has ON IT) and depending on what year your prelude is....u might already have vtec solenoid wiring and the only thing u'd have to do as far as wiring is connect the VTEC pressure switch to a wire that's already in the engine bay, and ground the sensor.
You also need the H22 head bolts and lower timing gear, water pump, water pipe and a few other things. But u probably already know all that.
I'm sorry buddy but if that's all u know about the h23vtec hybrid...u have alot of reading to do. And what prelude forums are you on? because them not knowing or takin forever to tell u the a4 and a1 heads are BASICALLY the same would be a concern.
