[nharv88]

Does anyone know what the differences are between the H20a, H25a and H27a heads?

Port size (Intake and Exhaust)
Head cc
Cam Specs
Maximum lift without valve contact

While i was looking at parts last night I discovered that the valves are the same size for all 3 engines, this seems really weird to me that a 2L uses the sames valves as a 2.7L (78mm vs 88mm bore)
It makes me think that the heads may be the same, I just didn't think they would be. Whenever i try and do a search on here, nothing comes up about heads.

[nharv88]

has no one ever done any work/mods to a H Series engine? i have a feeling the engines are left bone stock in all suzuki 4x4s...

[Gwagensteve]

Mostly yes they are, for good reason.

[Gwagensteve]

Oh, except on Facebook, where apparently everyone is building a carby blow through turbo.

Fordem might be able to tell you if the part numbers are different, but that might be it for a comparison.

[nharv88]

Why is that? Are the internals weak? Ports too small? Crank can't handle more torque? The H25/H27 are tough little motors, I'm sure with cams, port, extractors, bump up CR a bit and E85 they would be an outstanding motor...

[nharv88]

Even without E85, 98 Octane would still perform well. i dont wanna go forced induction. used to drive a SQ625 around, and it felt like it could use some head/intake/exhaust mods to use it to its potential. just felt like it was choking...

[tanshi]

because we are wheelers not ricers! 4x4s are not race cars generally.

h27 are plenty powerful enough without work done to them.

[nharv88]

so by opening up the potential of a motor that makes you a ricer?

[tanshi]

my point is this is a 4x4 forum, we talk about more 4x4 related stuff. if your after gaining engine performance your not going to get as much (if any) info here as its just not what most people on here do.

I can tell you you wont find anything about building a h motor up on here.

[nharv88]

well where would i find info? Every search for H series motors takes me here or other 4x4 forums. PLENTY of info on building G Series though... I thought 4x4 was about torque and gearing. yet if you chase more torque by changing the amount of torque an engine makes vs simply making it rev harder all the time, you're some kind of weirdo... I'm not a huge fan of sitting on 4-4.5k for hours on end on the highway... I dont want to do extreme 4x4 tracks, just go fishing/camping. A vast majority of my driving (about 99%) is done on road, mainly highway...

[tanshi]

mate i have a race car im building with an h27 in it. ive searched this info to the ends of the earth.

you are chasing info that doesn't exist. no one mods them, and if they do they dont share the info as its stuff they have spent heaps of their hard earned on.

[nharv88]

So it's a simple case of, if you wanna know anything, go buy an engine and figure it out for yourself? Fair enough

I don't understand why no one mods them, they seem like stout motors that would love a tickle here and there to wake em up. I think a lot of people are missing out...

[Gwagensteve]

Mostly we place reliability, torque production and reliability above any other criteria. Typically we correct perceived inadequacies by correcting gearing or fitting a larger capacity engine in factory trim, because spending loads of money on narrowing the powerband is of little relevance to our use.

How were you planning to increase torque? Retard cam timing? Run smaller valves and ports? Increase stroke?

There was a workshop in the SE of Melbourne that did lots of work on a H20 in an (I think) clubman. Normal mods were done to increase HP (and the engine responded well) but as normal they aren't relevant goals for an off road car.

[BlueSuzy]

In 4wd's. If most people want more power, They change the exhaust or They change the whole motor. i.e. 3.8L/5L Because Commodore.



A stock motor is easy to replace and cheap.

A worked motor, Isn't.



Anything you do will be new to the H world. Fit the H27a and then see if you want more power.

[fordem]

Gwagensteve wrote:

Fordem might be able to tell you if the part numbers are different, but that might be it for a comparison.

I did look at the numbers but it's not that clear of a picture.

H20a heads - R - 11101-85FA1; L - 11103-85FA2
H25a heads - R - 11101-86FA0, 11101-86FA1, 11101-86FA2, 11101-86FA4; L - 11103-86FA0, 11103-86FA2, 11103-86FA4
H27a heads - R - 11101-86FA0, 11101-86FA1, 11101-86FA2, 11101-86FA4; L - 11103-86FA2, 11103-86FA4

What do the numbers mean?

The 11101 is a right side head, the 11103 is a left side head - the last five characters usually, but not always point to a vehicle type, but, it appears to relate to the vehicle the part was first used on, so some part numbers will point to a vehicle other than the one that part is being used on - pay close attention to the last digit, notice how it changes - the parts specialist at my local dealer, who, by the way, I have total faith in, tells me that this digit can be ignored - my personal belief is that this is a "supersession" indicator - an 86FA0 part would have been replaced, for whatever reason, by an 86FA1 part, so higher numbers may be more desirable - the higher numbers are also later production. Re-designed parts will usually have a change in the first half of the part number.

Note that I say may - parts are superseded for different reasons, there may have been a quality or defect issue, or, it may just be a change of supplier, for example instead of using struts from Monroe, KYB had a better price on the equivalent part.

When all is said and done - the H27a & H25a heads appear to be the same, the H20a heads are different - they may or may not be interchangeable.

One last thing - this comparison was E24 market only - vehicles built for Australia are generally, but not always E24 - there may be other differences if the other markets were included.

[nharv88]

cheers Fordem

[Joe]

There was a fella on here years ago that built a rally GV with a tweaked 2.5 i'll see if i can find the thread

[Joe]

250hp 2.5 unfortunately he hasn't logged on for close to two years

viewtopic.php?f=1&t=6097&hilit=DJ710

[fordem]

If you want to talk about high horsepower H series motors, Nobuhiro (Monster) Tajima of Pikes Peak fame runs a tuning shop...