vtec block, non-vtec head - compatability questions..

i have a vtec block, and a b20 head… got the dowel pins to work together (drilled out the holes on the head to work with the existing holes in the block…

then did a test fit with all head bolts, all of them thread in, and can be tightened…

questions are about head bolts, gaskets, sensors, and how things can work with another…

the block only has a few sensors on it that i saw.

crank positioning sensor, knock sensor, and one other sensor… forgot what it was…

but on my LS, there were 4 or so sensors back there… i just wanted to know if there were other spots available to run the sensors at, or if i can run without them, or what would work.

headgasket - i would have to use a itr headgasket? or would any dohc vtec headgasket work?

headbolts - can i use the LS headbolts?

and would i have to run higher octane fuel? it would, im guessing… bump compression going from stock LS compression, 9 something, to itr pistons… not sure what it would add up to, havent checked on c-speed yet.

and as for the timing belt, i installed a LS water pump, and hoping that i can just run a LS belt with the setup, it should work… right?

thanks.

-tegboi

kev i think the bore on the b20 is bigger, so the chamber in the b20 head will be bigger than the cylinder in the b18 block. might run into valve clearance issues. as for the belt, i think the vtec head is taller, so you probably ok with the LS belt. thats all i can think of right now…the knock of course will just be left alone.

humm… ok, i’ll do some measurements later on today.

but shouldnt it be okay? since people run b16 heads with LS blocks? so the chamber is smaller… so then cant they do the opposite also?

but valve clearance is something i didnt think about yet… dam… i guess i’ll have to clay test it…

very curious on the result that come from this ‘crazy’ hybrid.

I always considered putting something together from misc. spare parts not being used for anything else…

B16 blocks, b18/b20 heads… :up:

im gonna put it together today… minus a new headgasket… just to see how things will work…

gotta take a trip later on though to pick up the water tube that goes behind the block from my old house… then i can see where things go from there…

I think the combustion chamber is the same on the b20 head and b18 head are all the same…?

headgasket
which one could/should i use?

b16a2 & b18c5 & b18c1 headgasket part numbers are different…

anyone know?

thanks

whats up ken. sup kev ic youre up to some tricks again hehe. any vtec head gasket will work. ive compared the b16 and b18c’s. they are identical. you will also need to tap and plug the vtec oil return on the vtec block so you wont have an oil leak. speaking of crazy hybrids my buddies put together a 91 d16 single cam with a zc dohc head and turbo’d it. no joke.

A bit concerned here… you havn’t mentioned for sure what block you are using. If you are useing the B18c block then you should be fine but if you are using the B16/17 block like you mentioned in one of your posts about if you can do it one way then why not the other, Then you have a problem. The B16 has a shorter deck hieght and therefore uses a shorter belt than the B18/20 so you can not use an L/S belt on a B16 block with a B20 head. Never heard of a B16 without VTEC and don’t know if a VTEC belt will fit an L/S head.

As for the combustion chamber the P75 head is the same no matter what block it is on and the chamber is sized for the B18b pistons. The B20 pistons that are in fact larger do not reach out of the block so the overlap from head to block makes no diff.

b18c block
LS timing belt will work with ls water pump.

pretested already

vtec oil return? huh??

Hmmmmm…no its not. The head is a p75 head, just like the b18, same chamber and everything.

Ben

I might be way off on this one but wouldn’t the oil controll plug be wrong for the B18c block? Are they different? If the LS has a smaller “Jet” (think carbs for a second) than the VTEC block you may want to install a LS oil controll plug.

:shrug:

:bawl:

more and more problems… thinking i should just some how, somewhere find a cheapo b16a head so it just goes all together…

kevin when doing an lsvtec where you plug the vtec oil return with a 1/8 plug
you should know where its located the small hole by the head stud thread/hole
in your case its the same hole but its on the block where you have to plug.

never mind ill tell you where its at on the other post

umm… update?
it works, daily driver, still pretty fast… higher compression 10.6:1
no oil leaks, colant leaks, or anything that i’ve seen. doesnt burn so much oil. something is still wrong, when i WOT, there’s a little bit of blue smoke out the tail pipe. so iunno, could be valve guides again. but nothing very bad. it runs. im happy.

kind of embarassed when i dyno’d my car though, was at racetune’s bbq, and my girlfriend won a raffle, so in front of about 70 people watched my car dyno in at 114 @ 111.

114 hp
111 lb. tq

bad sh*tty numbers, many problems, and major tune up is needed. but whatever. frank (owner of racetune) says that with everything tuned correctly, fuel done right, major tune up… he can probrably pull 150hp out of it.

but whatever, im goin boost… :giggle:

what up kev, we finnally met up lol. you almost fooled me with with your b18c5 block but we’ll just keep that between us. pretty nice set up tho, cant wait to see how you do with a turbo. didnt know you just started at race tune. good luck with that.
do you think frank might rent me his dynapacks for a day? ill stop by to talk to frank. we have about 10 cars on our team in need of dyno tuning.

www.EFI101.com
ems tuning services available

i dont know about renting it out… haha, it’s his personal stuff…

it’s almost like a…

“you value your life, as i value my tools” kinda thing…

u can ask him though…

right now, im in-between on things from turbo and vtec… if i use a vtec head with my setup, it’ll bring out the life in the block… and show what numbers it really has…

but for turbo, i’ll still be running a weird setup with it…

i might go vtec…

Go vtec turbo. The well breathing vtec head, coupled with boost, makes for three separate moments of acceleration:

  1. Initial launch
  2. Vtec crossover
  3. Turbo spool

BTW Kevin, I’m still at a loss as to why you’d choose a lower displacment block (b18c), with a less efficient breathing head (b20). Don’t ussually people go the other route? (I.e., bigger displacement block, with a better breathing head? Such as B20 block, with B18c head.)

Anycase, I hear you about the oil-burning/smoking problem. I’ve got clouds of smoke coming out my exhaust. I’m pulling apart my engine with Mr. HybridCRX this monday, and I just ordered SRP rings tonight.

yes go vtec turbo, hondata i hope. as for frank. if you put it that way im notsure if i want to ask. he’s the only one around with dyna packs. im looking for more part throttle accuracy. god willing ill be able to get my own dyna packs in 05. they are already calling us about financing one.

www.EFI101.com
ems tuning services available