EJ25D and EJ22 compatibility

yes.

not the intake manifold though.

I have a set of pristine rebuilt '96 25d heads with HLA. They were done by a shop that specializes in heads with a cut and grind, deck shave, seals, and wash. PM me for more info.

'96 DOHC heads have the largest intake ports and are ideal for running a high boost application.

ALL the timing components are swappable if you are using 25D heads.

And tytek.. I have a set of 96 2.5 HLA heads as well. I used to think that they'd be great for boost applications as well; but the more I learn, the more I think not. Especially since they apparently won't actually fit on a EJ22.

ALL the timing components are swappable if you are using 25D heads.

 

And tytek.. I have a set of 96 2.5 HLA heads as well. I used to think that they'd be great for boost applications as well; but the more I learn, the more I think not. Especially since they apparently won't actually fit on a EJ22.

They need to be used with the EJ255 or 257 and applied to pre AVCS builds. Like an RSTI, for example. There are bunch of guys running those heads on the RS site.

Best poor man boost builds are the following:

97-99 25D heads on an EJ22 block.

96 25D heads on a 97-99+ EJ25 block.

They need to be used with the EJ255 or 257 and applied to pre AVCS builds. Like an RSTI, for example. There are bunch of guys running those heads on the RS site.

True. I was speaking along the lines of 2.2/2.5 build. Either way, I'd rather use the 97-99 EJ25D heads. They have a better quench design, you can rev them higher, and they're just as good after some porting. I'm not saying they wouldn't work, I'm just saying the non-HLA head is a better start.

97-99 25D heads on an EJ22 block.

i wouldnt do this, it'll just cause more detonation than anything

i wouldnt do this, it'll just cause more detonation than anything

What? Pre or post detonation? They'd lower the compression ratio quite a bit... I see no possibility of predetonation with that compression level.

idk what i was reading..

I have a set of 96 2.5 HLA heads as well. I used to think that they'd be great for boost applications as well; but the more I learn, the more I think not. Especially since they apparently won't actually fit on a EJ22.

but +1 to this.. i vote for the high comp. build, grind cams, etc.... easy and effective

Is the oil pump, alternator, timing components (obviously not the belt), and all the other external drive systems from an EJ25D compatible with an EJ22?

Everything that you have mentioned is perfectly compatible with the EJ22.

There have been some instances where I've seen the same accessories on both engines.

True. I was speaking along the lines of 2.2/2.5 build. Either way, I'd rather use the 97-99 EJ25D heads. They have a better quench design, you can rev them higher, and they're just as good after some porting. I'm not saying they wouldn't work, I'm just saying the non-HLA head is a better start.

The 96 25D heads are better suited for TQ due to the wider intake ports & the VERY small exhaust ports. The quench chambers are suited prefectly for the 2.5 bore. These heads would be perfect for a smoothly running engine. Smoothness contributes heavily to reliability & response.

i wouldnt do this, it'll just cause more detonation than anything

I'm running a DOHC EJ22E with 9.4:1 CR.

It isn't even close to detonation but produces more power than the SOHC EJ22E in the midrange while low-end is a little lacking but not as much as before the tune-up with the 0 resistance plugs/wires & maintenance.

The 96 25D heads are better suited for TQ due to the wider intake ports & the VERY small exhaust ports. The quench chambers are suited prefectly for the 2.5 bore. These heads would be perfectly for a smoothly running engine. Smoothness contributes heavily to reliability & response.

Yes, the design from the factory is better suited to lower end torque on a stock motor. I'm not disagreeing. Especially since I am ALL about low end torque, to the point of obsession almost. But, there really is just not enough of a difference to warrant getting a set of HLA heads and putting them atop a lower end that already has the cloverleaf heads that are already ported and matched to the ported intake manifold. Yes, the chambers obviously fit a 2.5 bore, but they chamber has a different design. The cloverleaf design is just better, and creates less volume in the chamber when compressed. Thus, compression is increased (especially with a Cometic 0.027" head gasket) and not only low end torque in increased, but the whole power band raises.

I've pondered over which head would be best for a boosted or NA build. I used to be all for the HLA since they used a hydraulic lifter. But, you can't rev them as high as the solid lifer heads. Currently, his motor is designed to have a bit a peaky power band. But that's nothing that some cams can't fix. Since we're not talking about that much of a difference in power and not even that much of a difference in the low end, I see no point to spending money on another set of heads. The cost to benefit ratio is just not worth it to me. If his heads weren't already ported, and we weren't talking about high compression and cams and such, I would be all for the HLA's.

Just what I would do, is all.

Thus, compression is increased (especially with a Cometic 0.027" head gasket) and not only low end torque in increased, but the whole power band raises.

Your statement about the 97-99 heads is true.

I guess it would depend on your intentions for either pair of heads.

96 25D HLA heads for the smoothness/quickness of response or the 97-99 heads for a slightly longer powerband for touring/long distance traveling. The 97-99 25D heads on my 22E come to life after about 2500rpm & the power is carried all the way to redline.

96 25D HLA heads for the smoothness/quickness of response or the 97-99 heads for a slightly longer powerband for touring/long distance traveling. The 97-99 25D heads on my 22E come to life after about 2500rpm & the power is carried all the way to redline.

So is it as simple as just swapping the heads and new gaskets? I'm trying to get to know this stuff and would love to do this! Most of my driving is highway and plenty of 25's at the junkyard.

So is it as simple as just swapping the heads and new gaskets? I'm trying to get to know this stuff and would love to do this! Most of my driving is highway and plenty of 25's at the junkyard.

To create a DOHC EJ22, you need the following:

25D heads (97-99).

25D oil pan & dipstick.

25D black coolant passage line for the driver side head.

25D intake manifold.

25D ECU.

EJ22 shortblock.

EJ22 head gaskets (MLS, thin-.050-, & for the 222).

Anywhere north of 2500-3000rpm will be a vault of eagerness & mpg.

Ordering a head gasket thin enough will get you VERY close to 10:1.

^+port the heads and IM and grind the cams for torque, 2.5" exhaust and rear diff bushings and lock kit

You'll probably have a power no different from a regular 25D or 253, which is a NICE welcome! Whenever I have an opportunity, I am going to port my intake w/manifold & have them match the intake spacers to get more air in.

Ok so a little more work that I was anticipating but you make it sound so worth it, I just may have to start collecting parts

It's only seems harder than it actually is.

Get 2 engines (25D & 22E) & take what you need from both.

At the end of everything, you should have a DOHC EJ22 & a SOHC 25D.

See, I don't have to port the intake on my Honda... I can just swap an Acura TL's 3.2 or 3.5 intake manifold. I could even go as far as swapping a set of TL heads as well! Just a thought of randomness for you guys

Just keep a lookout for that transmission.

Hondamatics aren't the best trannies out there.

IF you have an auto, that is!

Just keep a lookout for that transmission.

Hondamatics aren't the best trannies out there.

IF you have an auto, that is!

No worries! I have a 6MT I wouldn't have bought it if it was an automatic!