jdm_rb20

As always, I have way more opportunity to search than to go outside and actually work on my project. Having a job, wife, and a toddler doesn't leave enough free time, so I search and ask questions when I can't find my answer....just trying to make sure I am ready to do some WORK when I have a day to go outside and put in a few hours.

Anyway, I have been playing with the calculator and self-educating myself via the "search" button, but I keep coming up short:

I NEEEEED to know the STOCK h22a and/or h22a1 p2v!! The crank, rods, and head are the same..only the piston is different, but that means it will have a different p2v!!!

The calculator shows me how much the piston of my ideal build will rise out, and OF COURSE i have read and been told to clay, so I WILL. However, I want to play with the numbers some more, and I don't know what to consider a SAFE clearance so I want to end up with the same safe clearance as a STOCK setup (or close to it).

snobordboy

I think you are getting ahead of yourself. Are you using aftermarket cams or adjustable cam gears, or decking the head or block a bunch?

With stock parts, even fairly aggressive you should be fine. I ran jdm pistons sticking out the hole .020, and jdm cams on stock gears, stock head gasket, and it was just dandy.

I know you have been linked to the Zeal compression calculator once before, but use it alot, and it will show you safe combos that you can run, and obviously claying before final assembly will verify safety of the build.

jdm_rb20

snobordboi, do you remember how much extra clearance you had? I can do some regression-math to get back to the stock clearance answer.

coincidentally, I am also expecting a "-.020" with the following setup, and one day I may upgrade the cams further:

H22a1 block
f22b crank & rods
JDM h22 pistons
JDM h22 cams
JDM h22 cam gears
OEM generic 3-layer head gasket (that comes in my rebuild kit)

so I would love to hear what your p2v clearance measurement was....especially because our setups are identical (-.020 and stock head with JDM cams/gears).

I have read that it is worth sacrificing a little compression (with a thicker headgasket) to make room for upgraded cams. I am not expecting a 10-second car, and I am not addicted to the idea of >11.x:1 compression if upgraded cams are gonna yield better performance in the longterm and save me some labor hours re-claying and switching headgaskets later. I just want it to be fun and faster than the stock ricers' bolt-ons..lol

How much hp am I really gonna be losing by using a thicker headgasket (.05") and dropping from 11.64:1 compression to 10.96:1 compression??

snobordboy

I didn't check it, since I was only planning to run that engine with stock cams. My new build has pistons with more dome, so it wont come out the same either.

jdm_rb20

I was hoping you would know the clearance..you seemed like my best bet. btw, I have read your "Deck height" thread a few times. Did you ever come to a conclusion about the question I asked above (sacrifice a little CR to make room for running a bigger cam)??

Was yours dyno-tuned and dyno-tested at 197 whp? I would love to get a copy of your basemap...hint hint..lol It would be a great start for me to get started.

snobordboy

Unfortunately I haven't really gotten to that point yet. I have both sets of rods, so that I can make the choice once I see how it all sits, but I still have to get my block honed, and get the crank, rods, and pistons balanced. I have the cams I am going to run on the way, and should be ordering my cam fixture kit this week, so maybe once I have that I can check P2V on the stock jdm H22 thats in my car currently.

Didn't do much tuning on my old setup, just fiddled with the neo while keeping an eye on my WOT air fuel on a crappy gauge to hope that I didn't lean out. I got my power figure from trap speed calculation, so it is really more accurate than a dyno.

jdm_rb20

Which block and parts were you using when you ran the motor mentioned above? I see your signature says -h23vtec- so i was hoping that you had already run the same motor I am building.

snobordboy

Standard H block, H23A1 crank and rods, JDM H22A pistons.
Full stock JDM H22A head.

I am changing it up from the H22A pistons to Type-s pistons, so I am going to measure with both the H23A1 rods, and H23A rods, which are .020 shorter, and use which ever is safe. I am upgrading the valvetrain and going to Pro1 cams as well, which is why I am actually measuring all of my clearances and making sure I have the correct clearances and range of adjustability when using the cam gears.

The last engine cost me 600 bucks, so I wasn't too concerned about it, but this one is costing alot more, and I plan to keep using the head when I build a block for boost next year.

jdm_rb20

Iirc, the h23 rods are the same length as the f22 rods I am going to use. If i understand everything correctly, the shorter rod is "safer" and will allow more room for valve-play and still have safer p2v......ya?

snobordboy

Exactly.

jdm_rb20

but is there a difference between h23a and h23a1 rod lengths? The calculator doesn't list them individually so I was thinking they are the same. (just trying to help)

jdm_rb20

I am going to check p2v the backyard way on my JDM h22a (thrown rod). I am going to put a piston at TDC, clay it and spin the cams one at a time and then measure. It won't give me an accurate v2v (because I am spinning cams at different times, instead of "in time" with each other or with the piston timing for that matter) but it will tell me the absolute closest that the stock JDM setup can come together.

NOTE: This is on a motor with a thrown rod and a disintegrated piston and possibly a bent valve or two, so I am not too concerned with screwing anything up.

snobordboy

The H23A rods are fairly rare, therefore not listed in the calculator. Both Rosko and John @ESP have measured them, and they are .020 shorter than the H23A1 rods.

mherkamp

^^^Now that IS interesting.

jdm_rb20

If all else remains the same, that means the H23A has a lower compression than the US H23A1? Makes me wonder if the H23A uses different pistons just like the H22A uses different (higher compression) pistons....