rebuilding my GSR long block.
head has been completely cleaned up valves and seats have been grinded.


and for the block:
Honing .25 over..and came up on CTR pistons for a really good price.

wanted to know if it was all bad running high compression pistons with stock GSR valve train.
with stock rod and main bolts..

just wanted to know now bfore re assembling.

 

no its not a bad idea running high compression pistons with stock valvetrain as long as the rev range is kept at 8000 rpm, but CTR pistons are very high compression in a gsr motor and you live in california.. you planning on tuning your car on 91 octane? you're looking to be around the 12 range. Why not jdm p30's or jdm ITR pistons?

 

I agree jdm itr's would be better of a choice IMO!

the ctr piston to valve clearence with a gsr head is tight!

 

yeah i heard with cam gears you can't go more then 2-3 degrees

 

The motor is gonna be tuned forsure.
Using CTR pistons bcuz it was a steal of a deal.

 

A word to the wise.... you never buy pistons "bcuz it was a steal of a deal" that's how you end up spending money for nothing with disappointing results. You plan out your build to accomplish a certain goal, by researching other builds and carefully selecting the part combinations that will help you achieve the goal(s). Then when you come across a good deal on one of your desired parts, you buy it. Not only will you save money, but you'll know what you're going to end up with when your done.

 

WAY TO RESEARCH YOUR BUILD, MAN!

https://honda-tech.com/forums/all-motor-naturally-aspirated-44/can-i-run-pct-ctr-pistons-p72-gsr-head-2498047/

Might be a good idea to read that thread before you put this together!

 

who sells thick head gasket?

 

you should be fine.. im running a c1 block ctr piston and a gs-r head... on pro 1 cams... just bring your car to modacar for tuning cause they are the **** in the bay area. alot of people would not do this build for a d/d but i don't know why. i have over 20k on my build.. and many other of my friends have similar set up that are tune to run 91 oct that runs some decent numbers with the build... low 13 to high 12.

 

They don't do it because you have to pull so much timing to get it to keep it from detonating on 91, that you really lose power. They don't do it b/c you can make MORE POWER running less compression and more timing.

Get it, now?

 

Wait, you got the block bored first, then bought pistons? What are you piston to wall clearances?

 

I still say oversized itr's is the way to go!

 

i didnt hone or buy pistons yet.

i see that theres an argument about using CTR pistons. and i read an article about some guy knocking one of his valves out but he was using Skunk2 Stage 2 Cams.

im gonna be running stock gsr's...so wouldnt it not open as far??

 

You obviously didn't read the thread I linked you to.....

Good Plan...DON'T listen to what 2 of THE most experienced builders on here have to say about that combination....just listen for the answer you want and RUN with it!

 

as far as i'm concerned, everything i have ever read about using ctr pistons in anything but a b16 is a touchy subject. some guys get away with it fine, others dont.

i just know, personally, that i would never go over 12:1 in my motor in a daily driver. we have crap gas in california.

p.s. that head looks amazing. almost brand new.

 

If I were you I would use an ls crank and rods,with 0.25 over itr pistons, acl bearings, arp rod bolts and head studs and your done for the bottom end! simple and reliable yet better performing than stock!

 

Cometic makes thicker gaskets if your dead set on the CTR's, but chew on this. The CTR piston is designed to work in stock form with a B16 combustion chamber, right?

Why?

My guess is, because the CTR piston yields a taller compression height over the other B-series pistons, and because its working with a recessed quench area of the B16 combustion chamber unlike the GSR which it was never intended. Not saying it cant be done or isnt possible but look here,






B16 /GSR

Valve clearance is another concern but this is what you need to check for, especially if the block & or head has been machined. My $.02, I'd use another piston just so you dont have to compensate by using a thicker gasket.

Like everybody here is saying you can make HP other ways.

 

can be done, plenty have. compression will be high so you'll have to back off the timing. then it's why not just go with jdm itr pistons and run full timing

 

You and DC_Legacy reiterate the points I was trying to get across.

Short of it is that you'd be better off running something with a lower compression height (B16, ITR) with the GSR head. Compression won't be so crazy (which really isn't the main issue, here) which will allow you to run full timing without crazy octane. i.e. you'll make more power with a lesser CR and more timing than vice versa.

 

^^^Sorry, I was mearly agreeing with your advice not trying to repeat it.

 

My bad man I didn't read the responses.

 

Listen to this guy, he is spot on.

 

What about CTR pistons in a B18c5 98spec ITR motor? Will this have the same clearance problem? Is this a good mod? What would be the estimated compression ratio? Are one layer HG good for reliability? The car will be my daily driver. Please give opinions.

 

The ITR has a Pr3 casting so the combustion chamber is better tailored (for clearance) with these pistons as used with the B16B. All in all if I choose these pistons I'd check the clearance's reguardless for blueprinting a motor.

IMO if you want to bump the compression alittle, you could use a thinner gasket or mill the head & use flatface valve's rather then swapping the pistons for CTR's.

 

What kind of compression ratio can i expect using a 1 layer hg on a stock itr motor?