I’m sorry if this subject has been brought up before but I’ve searched a few sites and can’t seem to find an answer. I was wondering if anyone here knows if b16a pistons (pr3) will fit on b18a rods? I have a budget LS/Vtec project going and thought this would be a cheap way to raise compression…TIA…
yes they will fit. actually all b series pistons will fit. But if you use itr, ctr or even gsr pistons you’ll have to have the rods shaved 1mm on each side. If you don’t want to have to pay for the rods to be shaved then you need to use:
-pr3 (89-91 b16a) pistons
-p30 (92+ b16a) pistons
-p61 (b17a) pistons
here is some more piston info for you: http://tiiite.b16a.com/pistons.htm
thanks man! That’s exactly what I needed to know. also, you wouldn’t happen to know how to remove the pistons from the rods do you? the b16a pistons are still attached to the rods and of course I would need to removed the LS pistons off of the LS rods. I think i’m gonna have to take it to a machine shop and have them do it, but if there’s a way to do it yourself that would be great too.
sorry, i’m not to versed on specifics yet. I’m planning on a rebuild of a b17a, so after that i’ll know, but as of now i’m still in the dark.
but i’ve heard that you have to have the pistons “pressed” onto the rods–so i’d assume a machine shop needs to do that. Just take everything to them and they’ll add that into the price (I ssume you’ll be having the block honed/decked, internals balanced, and rods shot peened).
yes I do intend to have the block hone/decked, rods shot peened, crankbalanced, etc… just don’t have the money to do it all at once so I’ll have to do it in stages.
I’ll probably just take everything to the machine shop to have it done…good luck on your rebuild and thanks again for the reply.
i’d definitely suggest having it all done at the same time. chances are that they will charge you less if you just bring them the block and all internals and tell them to:
-bore/hone
-deck
-balance (crank, pistons, rods, flywheel, clutch)
-shot peen rods (shave if needed for other pistons)
-press on new pistons
-and re-assemble if you are having them do that
good luck with your ls/vtec. when you said “budget” i was worried you were gonna skimp on a lot of stuff, but it sounds like you’re going the right stuff. only thing you haven’t mentioned as of yet is arp rod bolts–but i’m sure thats in the plans as well.
yup, i was gonna buy arp bolts as well. i know i’ll have to buy all new bolts (rod bolts, head bolts, etc…). i’m a strong believer of doing it right the first time. plus i’ve seen too many people that blew their motor because of reusing parts and taking short cuts. it will probably take me awhile to save up enough to do everything. thats what i really ment by budget.
oh have you heard of z10 block girdle? i’ve been to their site but can’t seem to figure out what it is for.
yeah, i’ve heard its a good upgrade for ls/vtec and crvtec. I think it stops some sort of extra flex when the engine revs high.
i heard something about non vtec blocks showing more wear on certain rod bearings—meaning that the strain of all the rotation isn’t evenly distributed. The b16a and b17a blocks don’t have the block girdle because they have really good rod stroke ratio’s and i think thats why they don’t need it. Non vtecs don’t rev that high so they don’t have them either. But b18c engines have a block girdle. The rod/stroke ratio isn’t as good as the b16a or b17a, and they still rev high----I think this is the reason why honda put a block girdle on them.
sorry, thats kinda confusing, i just don’t know enough about them. but definitely worth looking into. But depending on your setup it might not be necessary.
that actually clears up a lot. i had no idea that the b18c has a block girdle. it does make sense to have a block girdle for ls/vtec because of the rod/stoke ratio. i will definitely look in to it. maybe i should stop by their shop someday, i believe they are located in arizona.
Originally posted by 91IntegGS
yeah, i’ve heard its a good upgrade for ls/vtec and crvtec.
Good for the LS/VTEC setup, but it won’t work in a B20-VTEC setup… different diameter in pistons (81mm vs. 84mm). With PR3 pistons in a LS/VTEC motor, that’ll yield you 11.7:1 compression. With a SiR tranny, that is a very quick setup with CTR cams and a Mugen chipped ECU. PR3 pistons in a B18A alone is around 10.8:1 compression… still very good for all motor, and I might actually do that for a sleeper effect.
wow!..I didn’t think a pr3 piston in an ls/vtec running a b16a head would yeild an 11.7:1 compression, thats awsome! Will I have any problems running that kind of compression on 91 octane gas?? I use to be able to get 92 but for some reason everyone (gas stations) is selling 91 now.
I have ITR cams already and hopefully this weekend I’ll have my ECU chipped with the mugen program.
Is the necessity for balancing the rotating assembly only for when the engine is going to be revved higher than stock? So all the previously minor jiggies will be more prevalent? Or is it done because the assembly is older and worn and it could become out of balance (i assume Honda would balance things originally).
Also, shotpeening the rods is for strength forsure. Would brand newish rods need it (for an all motor, lower cr, moderately revved ls/vtec setup)? Or is it just somthing good for older rods (or big turbos etc.)? thanks
d
You would think that honda balanced everything from the factory, but then again you have to consider that b18a motors were never meant to rev to 8k or beyond let alone an ls/vtec. Why take the chance of having something go wrong when you can do it right the first time. unless you have an unlimited amount of resources to keep rebuilding your motor, I would highly recommend balancing and strengthening the bottom end. but what do I know, I’m still working on my setup right 
everything I plan on doing (shot peening, balance crank, etc…) is for reliability purposes. And also the fact that these parts are old with high miles… Even if I don’t ever plan on revving to 8k, which I intend to, it’s just piece of mind that I know the motor was built right. The last thing I want is for my car to blow up on me in the middle of the arizona desert where it gets 100+ degrees daily in the summer.
The b16a head I have was actually donated to me from a friend that blow a rod in his ls/vtec. He was just driving home on the highway doing about 80mph then all the sudden his car turns off. cost him a couple hundred bucks to tow it home. After taking the engine apart, it was apparent that whoever did the setup just swapped the b18a head with a b16a head without doing anything to the bottom end.
just my 2cents…
hmmm. thanks for the response. Part of the reason for my question was because the LS engine that i have a line on has almost no miles on it. Its been sitting in an automotive technical schools parking lot for 12 years with just parking lot miles on it.
d
Use ITR bearings. They’ll last longer.
The Z10 block girdle is a great idea. Keeps the main bearing caps nice and strong and generally just reinforces the block.
azboy
Any idea how high you’re friend revved his engine? The strongest recommendation i’ve seen yet is the arp rod bolts. If the stock ones are the weakest link for high revs, maybe one of those broke.
d
my friend was aways trying to race people with his car, but at the time when his motor blow he was driving normally. I’m pretty sure the rod bolt was the problem cus we were able to push the #3 piston down with our hand, but then again I didn’t really stick around to see. I just took the head off and left 
to be honest, I don’t know if you really need to balance the crank or shot peen the rods for ls/vtec, I’m new to this myself. Its up to you if you wanna do that or not and of course money is always an issue. But I would definitely replace the rod and head bolts with arp.