I've spent the past hour searching, but got nothing more than a few results that weren't really what I was looking for... Here's my scenario...

I'm in the planning stage of my rebuild of my B18C, after dropping a valve and shattering a piston....

I'm running all Skunk2 on the top end, with stage 2 cams, so I'm planning on beefing up the bottom end... When the motor blew, it developed some deep scratches on the cylinder wall, so I know I'm going to need to bore the motor, but I'm really not sure where to begin when deciding on what internals to run. I've read that people run CTR pistons without a problem, but others have...

Here's what I need to know... How big should I go? I'd love to bore to 2.0L, but I don't think that's feasible at this time, since I'm probably not going to be able to afford to sleeve it, unless absolutely necessary..

I'd like to stay pretty close to stock, but increase displacement a little, so what's everyone got for advice? Should I just run slightly bigger pistons? Can I use stock GSR rods? I really don't know what to do, and my car's been out of commission since Easter... Help me make my decisions so maybe I can get my car back on the road before I have to take it back off for the winter! Thanks!!!

 

Greetings Mate

I'm hope i'm not too late but I'll try to give the best advice I can. Probably what caused you to blow your piston was the Stage 2 cams without proper upgrade to the managment and the valves/valvesprings. Alot of things can cause inproper combustion, perhaps better sparkplugs, ...have it checked out.
Personally I wouldn't overbore your engine as it is one of the best engines out there along with BMW's 6 cylinder. Coming from personal expirience working at a performance magazine, overbored engines are not best when it comes to beutifully balanced engines, like Honda's DOHC 4 bangers. Overboring is usually applied to engines that are destined to be turbocharged to fight turbo-lag. But if you are completly bought on doing the modifications you have in mind, ask JE to customize pistons a millimeter or 2 larger than the factory ones to give you the new engine displacement you want. Also check out for a new and lighter crank shaft (i.e. Spoon), and aftermarket connecting rods.

Hope I helped, but the best thing is to get advice from a licenced mechanic who knows what he/she is doing.

Good Luck mate

(:

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote"> Probably what caused you to blow your piston was the Stage 2 cams without proper upgrade to the managment and the valves/valvesprings.</TD></TR></TABLE>

The entire top end was upgraded. Cams, valves, springs, retainers, locks etc..

 

Need help ASAP... Anyone?

 

Wow... Thanks for the help guys...

 

to up the displacement slightly u can use an ls crank and rods and use .25 over itr pistons

 

I can get .40 over type r pistons, you will increase displacement and make more power. I would reccomend staying with a cast piston. the problem with forged pistons is that there good. but heavy for one thing, and also they consume alot of oil due to piston to wall clearence. you cant get tighter clearences then with factory style cast pistons. you dont have to go all crazy to achieve some good solid performance. just dont try and over do it. you might get in over your head. just my 2 cents. pm me if you need help on your project. later

max-

 

If money is a huge issue then my best suggestion without resleeving your block to 84-85mm would be to light the crank and balance at a good machine shop. Shot peen your stock rods and get some arp rod bolts. If you still want .25 over pistons thats not a bad idea but raise the compression ratio to 11.5:1 or 12:1 with new pistons. CTR's wouldn't be a bad idea. Since you have your head internals covered with good cams to work well with the higher compression ratio you should see some nice results but if the head hasn't seen any port or polish work now is the time to get it done. With all this work done make sure it breaths well on a budget. ITR intake manifold, larger throttle body (RC eng. does a great job boring them out to 65mm) and dc jdm 4-1 header. If you have no kind of engine managment, with the great results people get from hondata, go with the base s200 from hondata and head to a dyno after the new build is broken in. Good luck

 

I've read alot about people running CTR pistons in their B18C's, but have heard that there can be piston-to-valve issues because of the dome on the CTR? Is this true? Since I'm running new springs and valves, is that really an issue?

Also, I guess I need a little bit of an explanation... I need to bore the motor to get rid of some serious score marks on the #1 cylinder.. If I bore it .25 over, then CTR pistons will fit? How's that work? Does the CTR motor have a shorter stroke, and that's why it's .2 liters smaller than my GSR? Are the pistons in the CTR bigger than my GSR?? I'm learning all of this (the hard and expensive way), so forgive the noob question...

 

Also, can I use stock GSR rods on CTR pistons??

 

you can get standard size or .25 o/s pistons and you can use them on GSR rods.

 

Yes a true CTR motor has a shorter stroke, and also you can use ctr pistons on stock gsr rods. Ctr pistons will work in a bored .25 block you just need ctr pistons that are .25 over. That is a factory, or in this case a jdm factory size piston offered in case such a thing is needed like in your case. It is possible to have piston to valve slap with high compression pistons with short valve reliefs ( the indention on a piston shaped like a half moon) slightly larger valve reliefs will help prevent that mess, but can also happen with larger cams (larger lift and duration) and over reving. Best thing, actually what you need to have done is clay your motor for piston to valve clearance. Check with your engine builder on this matter or http://www.theoldone.com for more info.

 

I'll check that site out when I get home from work... Right now, I'm late... LOL

Anyone else have 2 cents???

 

i would just go with jdm itr pistons for the reliability issues. with a gsr head the comp ratio will be around 11.4:1 you can go with the ctr pistons but you will have well over 12:1 and will need some very good tuning.

the jdm itr pistons come in .25 over also.

 

I've got the valvetrain to take advantage of higher compression, so I think I want to go the CTR route... I have to make some decisions fast... The 89 Prelude I'm driving now just isn't the same... lol

 

ttt with another question... What kind of valves should I go with... I've got a full set of Skunk2's in there, but one broke, and this is why I've got to rebuild the motor...

Running higher compression, I'll need something stronger, but what??? Any ideas??

 

Update time... I broke down and made my decision... Went with oversized CTR pistons, and shot peened GSR rods with ARP bolts...

Now I just need to search and find my new GSR head, and I'll be set, and MAYBE, the car will be running by the end of the summer!!! It's been out of commission since Easter weekend...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C_EJ8 &raquo;</TD></TR><TR><TD CLASS="quote">
How big should I go? max bore on stock sleeves is 82mm

Can I use stock GSR rods? yes, for added security you could polish the rods, and have them fluxed
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with the cams you have I'd go about 12:1 compression. I was planning a similiar build not too long ago. I was going to run CTR +.25 pistons with a B16 head. I've got a JUN III valvetrain so it really would have ripped.. But alas the project is no more. HTH!!

 

Should i get a new GSR head or should I throw a B16 head on there?? I need a new one, just not sure of the pros & cons of each...

 

ttt

 

Use the GSR head and you'll have higher quench effectiveness, while making the compression you're looking for with a lower (kinder to the combustion flame-front) dome....netting more "mechanical octane", and more power.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Woofer &raquo;</TD></TR><TR><TD CLASS="quote">Use the GSR head and you'll have higher quench effectiveness, while making the compression you're looking for with a lower (kinder to the combustion flame-front) dome....netting more "mechanical octane", and more power.
</TD></TR></TABLE>

agreeded... I was going to weld a re-shape the quench areas... that takes $$. You could just toss the GSR head on there and be ahead of the game. I like to tinker

 

Just ordered my GSR head... What type of valves should I put in there? I tried Skunk2's, and one broke, and that's why I'm in this mess....

Any suggestions??

 

Probably should have thought about this earlier, before I agreed to buy the head, but does it matter the year of the head, as long as it's still a GSR? I've got a 94 GSR block, and I just bought a '98 head... Shouldn't be any problems, right? A GSR is a GSR, right?? *nervous laugh*

 

It won't matter as long as the head's from a 94, or newer engine. Heads on the 92-93 B17 (GSR'S) are B16 castings.
The valves you use should depend on the size and the operating range you plan for the engine. Keep in mind that building a "killer" engine requires that each and every part be part of a larger planned "system".