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H22A7 cams in H22A

Engine/Gearbox questions and discussion
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H22A7 cams in H22A

Post by wurlycorner » Mon Feb 12, 2024 10:18 am

Drax wrote:
Mon Feb 12, 2024 9:04 am
JUN cams 37.47
The Shizzle

Spec for the jun cams is here:
https://www.junauto.co.jp/products/camshaft/h22.en.html

H22A2 cam specs (from the first 4g supplement manual):
H22StandardCams.JPG
H22A and H22A2 cam specs (from third 4g supplement - this confirms that A2 and A cams are the same!):
H22A2A_cam.JPG
This is from the yank 5th gen manual, which only refers to H22A4 engine model, but shows that the Type-S over there had different cam profiles (did it still carry the A4 designation on their engines???)
H22A4_Cam.JPG
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H22A7 cams in H22A

Post by Drax » Mon Feb 12, 2024 2:29 pm

ah there we go, nice one Iain! and see, told you i'd make a mistake somehow - ive just measured any cam, not thinking that the intake & exhaust cam are different thicknesses of course :facepalm:
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H22A7 cams in H22A

Post by LIE » Mon Feb 12, 2024 6:18 pm

Anyone has an account in accord typer site?
I tried to register but never received a verification link.

There are some topics related to metrics I’m looking for.
F.e. This:
http://www.accordr.org/index.php?/topic ... -vs-h22a7/

Maybe someone can peek for a7 specs?
If everything else fails, read the manual!


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H22A7 cams in H22A

Post by Drax » Wed Feb 14, 2024 9:14 am

i had a log in :thumbup:

Normal H22A vs. "Type-S" H22A7/8
Intake opening (BTDC)
15°..................15°
Intake closing (ABDC)
40°..................45°
Duration: 235°.... 240°

Exhaust opening (BBDC)
40°..................45°
Exhaust closing (ATDC)
15°..................15°
Duration: 235°.... 240°

Gross valve lift measured w/1.55 rocker ratio
Normal H22A vs. "Type-S" H22A
Intake:
(mm) SAE (mm) SAE
(11.5) 0.453"..........(12.2) 0.480"

Exhaust:
(mm) SAE (mm) SAE
(10.5) 0.413"..........(11.2) 0.441"

I've just measured the VTEC profiles on the H22A and H22A7 inlet cams I have, lift measured every 2 degrees (crank) at the valve with 0.15mm clearance:

H22A Max lift 11.27mm, duration @ 0.1mm 272 degrees, duration @ 1.0mm 236 degrees

H22A7 Max lift 12.03mm, duration @ 0.1mm 295 degrees, duration @ 1.0mm 248 degrees

--------------------------------
Skunk
-Pro 1-
Intake: 264 deg. duration, 12.6 lift
Exhaust 264 deg. duration, 11.9 lift
-------------------------------
I'd be taking on a bit much to explain here how cams work, I posted this really for the benefit of those that want to be able to make proper comparisons between the standard cam profiles and after market items.
Cam profiles are typically summarised by the headline figures of peak lift, duration and sometimes advised lift at TDC. Unfortunately, these values really don't tell you much at all. You could have 10 cam profiles all rated at 300 degrees and they could all be hugely different and well or ill suited to the rest of your spec!
The H22 engines have six cam profiles on each cylinder, three for the inlet side and three for the exhaust side (primary, secondary and VTEC). The valves follow the primary/secondary cam lobes together until the VTEC switch, then the valves follow the VTEC profiles. What I've done here is measure just the VTEC profiles, for the inlet valves on the H22A and H22A7.
The x-axis of the graph is crankshaft degrees relative to the peak of the cam lobes. The y-axis is valve lift (opening) in millimetres.

The VTEC H22A7 profile is pretty clever, it combines good flow potential with fairly harsh opening and closing to ensure minimal cylinder pressure loss. So essentially, any cam more severe than this is going to be a trade off of some kind in terms of:
Valve acceleration (needs stronger springs, so valve train wear and risk of breakage increases, power is lost too due to the extra effort in opening the valves).
Greater lift (as above and modification of the head and valvetrain required, expensive!)
Greater duration (basically moves the sweet spot further up the rev range, due to the loss of cylinder pressure during the slower induction cycle in the mid range, which can be countered to some extent with higher compression and careful induction and exhaust geometry tuning. Also, if the engine needs to rev higher to reach the sweet spot, other provisions have to be made to ensure it can withstand the higher stresses.)
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H22A7 cams in H22A

Post by vanzep » Wed Feb 14, 2024 6:23 pm

Great Info :thumbup: very helpful

I have a couple of sets of cams here but have forgotten what is what - they all have markings on them ie/ a letter or number
can these be used to help identify what are A7 & A8 cams.
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H22A7 cams in H22A

Post by Sailor » Sat Feb 17, 2024 9:22 pm

wurlycorner wrote:
Mon Feb 12, 2024 6:42 pm
@Sailor ?
I'm not sure what you're asking.

I think @Drax has given us the important info. He's pretty much taken all the good stuff off the ATR forum thread. At the same time, Andy at vtec Direct confirmed that JDM type S and Euro r and ATR cams have same profile.

The vtec 'step' is more pronounced than on, say, an a5, but it's not just the cam lift. It's also partly because it is, in stock form, set to come in and out at higher revs. If you think of the power uplift as a percentage, it would be easy to imagine even a very aggressive cam doing very little at low revs - and vice versa.
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H22A7 cams in H22A

Post by Sailor » Sat Feb 17, 2024 9:35 pm

vanzep wrote:
Wed Feb 14, 2024 6:23 pm
I have a couple of sets of cams here but have forgotten what is what - they all have markings on them ie/ a letter or number
can these be used to help identify what are A7 & A8 cams.
Most sources seem to fall back on the 'measure the lobes' advice. This of course doesn't allow for wear.
Have you tried asking someone like Russ at HondR. I've found him to be very knowledgeable - and relevant! Try 01235 530055.
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H22A7 cams in H22A

Post by wurlycorner » Sat Feb 17, 2024 10:09 pm

Sailor wrote:
Sat Feb 17, 2024 9:22 pm
I'm not sure what you're asking.
I tagged you before Drax jumped in. You were the only 'active' member on here that I could think of who might also have access to the ATR forum - didn't know Drax did too :D

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