What about pct’s in a b17 with .050" mill off the deck 
:run:
13.36:1 with an unmilled head. Ouch.
Later,
BR
hasn’t it been said that the c-speed calc. is not accurate for the PCT pistons?
New information found!
I accidentally discovered something because my B18a has been acting sluggish and we are going on a run this weekend. I picked up a new set of spark plugs from Pepboys - NGK BCPR5ES-11.
The plugs that I had in the car were from the Honda dealer - NGK ZFR5F-11.
Check out the image below:
See the differences? No wonder my piston dome to spark plug depth was so shallow with the ZFR’s. It’s the wrong freaking plug!!! Also notice the shortness of the ZFR’s when it comes to the insulator. I’m guessing that my wires never actually seated therefore creating the performance issues I’ve been having.
Whew!
CTR pistons will work fine. I have a B-17 with head milled 20 thousanths, mugen thin head gasket and skunk 2 stage 2 cams. I clayed the motor and still had 20 thousanths clearance.
Thanks, I know there were others out there running a similar setup as this, but I’m learning new things as I go along with this build.
I think the spark plug finding is pretty significant. I was about to redo the whole build because of it.
sup archon let me shed some light into your problem, dont put in the ngk 5’s
ive seen this problem with other motors built with ctr pistons. they touch the top of the pistons. the hotter the plugs the longer they are. you should get 7’s or 6’s at the least and with a good ignition system you should be okay.
Thanks, the 5’s were for my 18A, I have a set of 6’s of the same design. I used the 5’s in the picture to show the size difference.
Thanks for the tip though 
no problem. the bcpr6e11,s should be cool, how about ngk iridiums? good luck
“An open mind is more useful than an open mouth.”
POWERLINE
I might pick up some Iridium plugs after I get everything situated. I don’t want to spend $6/plug while I’m still tuning. Do you think that’s apropiate?
Just run the coppers. I wouldn’t even bother with the iridiums or platinums. Continue running the NGK BKR6E-11 or BKR6ES-11. Your engine will be happier. I’ve been running copper plugs in my high compression motors for years.
damn duy that’s scary having the wrong plugs in there, did you ever get that tranny debacle solved? :uhoh:
sup anthony 
hey dan, how often do you change your plugs since you run coppers, every 6 months or is it like every 4 months? i need to change my plugs in the gsr and am torn between getting some iridiums or just running coppers, she’s just a daily driver that every so often will be taken out for some mountain runs. :manual: tia
yuri
After seeing this, and thinking long and hard…
I’m the one that gave you those plugs. Those are the NGK’s that run in the 92 up cars… I was told they work , and work good, I even had them in mine for a long time. Little did I know how (not close) they were in size. So I apoligize for that, and am very happy you figured it out without any serious building issues.
:sad:
ttys,
Scott
I mentioned no names 
No worries Scott, we’re all learning new things everyday
Thanks for the advice Dan, I’ll look for a set of those.
I change my plugs every other oil change, so every 6000 miles. They are never bad, but it keeps my baby running in tip top condition.
Duy, if you can’t find any let me know. The local shop stocks them.
sup yuri! (mav3rick478)
sup Archon , lets just say that if you get iridiums it wont really be much of a power increase. but, it will last longer than using conventional spark plugs, iridium is much stronger (you wont have to change it every other oil change) less maintanence. if you are serious about building a good set up, why not invest in your baby right. ive been using copper plugs in high compression motors for years also. and my buddy and i, we are currently building a b20vtec with JE pistons,12.5:1 compression. we also have another project as RS machine is finishing,a B18 sleaved and bored 2.2l @ 15:1 compression and guess what we are using iridiums. if you believe you are putting the best parts in your motor why stop with spark plugs.
what set up are you using in terms of cams and valve train?
“An open mind is more useful than an open mouth.”
POWERLINE
The tranny issue has not been resolved. I won’t see it. I’m almost sure of it.
The only thing stronger on an iridium plug is the electrode, and it just won’t wear as fast. The ceramic is made out of the same material, so if it detonates it will break just as easily. No matter what plug you run, if you run too rich you can foul out either. $50 on plugs is not what I consider a wise investment. If anything replacing your plugs every 6000-12,000 miles is just a good way to ensure your car is running properly. Plug inspection, and maybe do a compression test while they are out. Coppers are still the way to go. Iridiums, platinums, etc, are a gimmick, and the public is buying. Someone posted that they saw a 1.1hp increase on the dyno with the iridiums. Well, there’s more variance run to run using the same setup than that.
yah that import builder dyno was done on my friend’s High compression SOHC. its true, hp gains will vary. and $50 for one hp isn’t worth it, might well just change your oil.
i posted that
where i posted that
what i posted
denso iridium vs. bosch platinum #4227
sorry G2 guru i didnt mean to get you riled up, but every body is entitled to their opinions.