sscivicsi

THe build:

darton sleeved y8 block
cp 9:1 pistons 75.5 bore
eagle rods

y8 head
.5mm oversize valves
dual valve springs
comp cam

we had a stock cam in it and were running it for about 200 miles and it would kick vtec with no issues.

took the stock cam out for the comp cam and now it WILL NOT engage vtec..

I took the girdle back off to make sure none of the pins for the rockers fell out (for the secondary vtec rockers) and all of the rocker pns were snug as a bug in a rug in there place!

next i was thinking bad thoughts and thought i had low oil pressure.
hooked a gauge up and it has 25 psi hot at idle and 75 psi hot wide open throttle
then i thought i could be the wiring or the vtec solenoid (tested the sloeniod on my buddys car, works) wiring is fine too aswell as my ecu. (running neptune)

WHAT CAN IT BE!!!

furious94ls

How do you know it's not engaging?

beecee18

whoa thats RAD!

Dc4LsTeG

iTrader: (7)

x2...what can you rev to?

hatch22ajdm

first thing to do is see if the vtec is working just because you can hear it dont mean its not working, second make sure you have oil preasure, hook up a oil preasure gauge and check, third if you ripped apart the cylinder head did you make sure that the "O" ring in the center of the block was their or aligned good or worm out, you always replace them ALL THE TIME, just to be on the safe side you dont want to work double over a small mistake like that

hatch22ajdm

oh yea make sure you installed the cam girdel (what holds the cam to the head) correct. and do u have a check engine light and have you swaped ECU's with a car that also has vtec just to make sure its not your ECU

alwaysbroken

There is no check engine light. We've used my computer and my tuners master computer. The first dyno session we took it over 7200 rpms and no vtec. This time just over 6000 still no vtec so we pulled it off the dyno.

furious94ls

It wouldn't rev that high if VTEC wasn't activating. Are you going by "sound" thinking it's not working? Or are you losing a lot of power on the dyno after it hits a certain RPM? With a good tune, you really shouldn't hear the VTEC crossover.

alwaysbroken

According to the dyno graph there's no crossover. It's making about 80 less go then it did before with this cam. It's now making less power then the stock cam with same boost level.

sscivicsi

well it only made 257whp! with the stock cam AND vtec it made over 350!!

sscivicsi

sohc y8 doesnt have a oring on the girdle OR in the center of the block when the head is off.
when we swapped the cam all we did was remove the girdle, NOT the entire head.

grumblemarc

iTrader: (4)

What part of this are you having difficulty with?

I think either your tuner needs to step his game up, you need to get a better cam or you put the stock one back in the head.

sscivicsi

my tuner?

fremontcivic

iTrader: (1)

I was just wondering what kinda cam is it? different cams will make a noticeable difference with the vtec? are you sure you bought a vtec cam?

hatch22ajdm

have you tried swaping the vtec solenoid?

BitcDwg11

Hmmmmm

alwaysbroken

I've tried many different vtec selinoids. We can engage vtec manually. And yes it's a vtec cam. It's the same cam I ran in the same head last yrs setup (105300) made over 420 with it. Ran a stock cam to break in new motor and vtec worked. Old cam no vtec

furious94ls

The same thing everyone else is having difficulty with. We are trying to figure out if VTEC is/is not activating.

As for your comment, the only part that would help the OP is putting the stock cam back in the head. BUT he want's to know why VTEC isn't activating with THIS cam, so we are trying to diagnose it.

Do you have any useful information? Or would you rather teach his tuner, or pick out a "better" cam for him?

HondaPartsHero

The non VTEC cam won't fit in the VTEC head so I highly doubt it's this


https://honda-tech.com/forums/hybrid-engine-swaps-18/%5Bfaq%5D-%22my-vtec-doesnt-work%22-1812135/

apexi_rsx

your not going to gain any power without a new tune. you can always hook a voltmeter to the solenoid wire by the ecu and ground the other and watch for the voltage to turn on as it engages. also if u have a oil pressure gauge watch the oil pressure suddenly rise to almost 100psi near 5-5.5k the pressure will vary between fresh oil or weight or oil and/or port an shimmed oil pump.

hatch22ajdm

So what happends when you manually engage vtec does it kick on or still nothing ?

grumblemarc

iTrader: (4)

Again, did you re-tune for the new cam? I don't remember you answering that. I don't remember if you answered the question of how high can you rev the engine to. I don't remember you saying if you actually retuned (whomever is doing it). If you can rev PAST the VTEC engagement point, and not throw codes, then there's nothing wrong with it. What ARE your gauges reading when VTEC is supposed to kick in? Really, this is a little beyond the scope a general tech forum. Sounds like you need to have posted this in either Engine Management or one of the racing sections.

Post up screens of your Neptune maps.

purgat0ry

iTrader: (3)

Agreed, nowhere did it mention it was tuned after something as drastic as a cam change.

OP, if you didn't get that engine re-tuned, for lack of better terms you just created a ticking time bomb waiting to blow up your hard earned money and time.

ZackPP1990

Tune or go boom.

jbpnoman

If you blow it up, make sure you post videos. We all love to see fireworks, especially from people who ask questions and then don't take advice.