b18c head

[tinkerbell]

in regards to fitting CTR pistons into your b18c block/B16a head combo.. I have a b18c2 block and pistons ready to be fitted but people keep talking about clearances and how I need to check them to avoid piston meeting Valve = engine death senerio... My Queston is - If I go ahead and fit them (of course with new rods/bearings) will this actually happen, where is the safe limit for high comp Pistons or do U need to be running Bspec or C spec camshafts for piston to meet valve = engine blow up?? Anyone know what the go is cause im stumped..

can you 'clay' the clearances yourself?

it is fairly easy and will give you peace of mind:

place blutac in the valve reliefs and put a used head gasket on:



swap the VTEC pistons in the rocker arms over so that one valve is in VTEC all the time (you can do just one cylinder)



then put the head on, torque it to specs, put the cams in and put the timing belt on:



crank the crankshaft around a few times (so that the piston beign 'clayed' is at TDC at least 2 or 3 times) and then remove teh head and see what happend:



then you can measure with a metal rule how much clearance you have:



if you are using adjustable cam gears, set them to full advance for the intake and full retard for the exhaust, (but if you are quite fearful of piston to valve contact, start at maybe half advance and work your way to full advnance (or vica versa)...)

[tinkerbell]

BTW - it is said that you need ~35 thou of an inch clearance... or ~0.75mm ...

[spardikis]

Thanks tinkerbell that was a great pic up on claying and will do that once i have the pistons/rods in place, was just wondering if there was anything I coud do before I actually install them, you see when i first started that project i was like whoo hoo ctr pistons"rushofbloodtohead" and brought them, then did some more research... dumdom...so now im wonderin if i should sell them and get some forgirs or ITR pistons or is it safe to stick with them... im sure it will be fine though??????

[tinkerbell]

my instinct says will be fine, as it *sounds* like you are simply building a factory CTR spec engine,

ie same block, same head, same pistons, same cams... just different crank and rods...

but logically, why would this matter if the deck height (as Illegal has already said) is the same

[spardikis]

that is what I thought and what my boy's in NZ think is fine as welll, but every "internet bandit" that I had spoken to in the past just said nah cant be done u have to check the clearances.. I just needed some peace of mind - Initially it will just be CTR spec, but ill be using eagle rods and there is a good possiblity that ill run some skunky's or toda B specs. The other thing being u dont want to go and buy the gear and then not be able to use it!!

[Illegal]

I got it in mine with no problems! My cam gears are set also (not at zero) and I have skunk 2 stage 2 cams and again, no worries

[dsp26]

OK.. gonna bump this with a slightly irrelevant question...

LS/VTEC option has fallen back in my radar... it seems the the difference between B16a2(1595cc) and B18A/B(1834cc) is 239cc therefore 14.98% increase in displacement and therefore under the NSW modification 15% rule therefore no engineering required...

I will be using a GE kit instead of tapping block/head etc for oil lines so thats covered....

I am aware this block won't rev past 8krpm too great due to bore/stroke ratio but what is unclear in my research is what i need to change.

Just rods/bearings? or is there anything else i should while i'm there...

According to this:
http://www.angelfire.com/dc/lsvtec/lsvtec2a.html

my resulting CR will be 11.7:1 if i transfer my pistons over which i think would work well with Skunk2S2/TodaB/etc spec'd camshafts....

my other options are to use non oem "Stage 1" type spec cams like Skunk1s/TodaA and lower rev limit to 8000-ish..... according to my dyno my b16 cams already start dipping around 7,800rpm anyway....

OR

does anyone have a B18C2 shortblock so i can be done with this quicker


OVERALL, the plan is to buy a B20Z block for my mrs GSI teg and i take the B18B and everyones happy...

[fatboyz39]

If you search around the forums, tu88y had a LS/vtec which pumped out 116kw atw. Nothing special was in the motor, b16a pistons, p72 head, ITR cams, stock manifold, ITR JDM 4-1 headers, ECU and tune.

[dsp26]

If you search around the forums, tu88y had a LS/vtec which pumped out 116kw atw. Nothing special was in the motor, b16a pistons, p72 head, ITR cams, stock manifold, ITR JDM 4-1 headers, ECU and tune.

got most of that already minus the block and ecu.. hoping i can run the jdm p30 rom fine.

the bit i wanted clarified was the rods... naturally with internet posts theres misguided info.

the rod part, my researc lead me to believe that:
- Rods are weak and can't handle 8krpm+
OR
- like the crvtec b20 frank, it was the rod bolts that was holding it back due to the 1.54 R/S ratio that made the oem ones bend...

so which is it? i need to replace rods or just the bolts?

i don't mind not being able to rev past 8krpm as the purpose for this is lowend power anyway...

will look for tu88ys thread in the meantime... thanks

[tinkerbell]

do the rod bolts.

[aramiK]

I've also heard that the b18c2 head works better then the b18cr head for worked engines - IE , engines with work done to the block.. and cams etc for the head.

Is this correct?

[dsp26]

do the rod bolts.

Thanks, all i needed