Honda LS / Vetec head

[cboggs]

I have an LS / Vetec head conversion, ..
( Vetec head on non-vetec bottem end )

We checked valve to valve clearance when it was built, ..
but it now has touched intake to exhaust valves two times.

It looks like the Vetec isn't engaging or all the vetec rocker pins
aren't engaging cause there are marks on the retainer where it
looks like it hit the center Vetec rocker. Seems to have good oil
pressure to the head but wasn't checked by me.

It's the only thing I can figure out, .. touched valves twice now, .. and
I can't find any other reason for it.
It has good valve train, .. Crower springs & retainers, .. Fererra valves, ..
stock ex, +.5mm intake, .. and checked valve to valve clearance in the engine
with the cams degreed in.

Anyone have this problem with Honda?

Curtis

[rpm]

What cams are you running?

[cboggs]

What cams are you running?

Skunk 2's, ..

but we degreed the cams in, .. left the pistons out and checked the
valve to valve clearence on the engine, .. as it was run.
Had plenty, ..

Curtis

[autorace]

How much valve to valve clearance did you have and what was the stem to guide clearance. When the head was ported were the guides shortened. I install checker springs and at overlap I find the closest point valve to valve, and then hold the valves towards each other and then measure it. I made a fixture so you don't need the engine block to do this. Did they all hit or was it just certain chambers? Make sure you lock the vtec when checking. I try to keep as much clearance as possible because checking at the closest point does not tell you what happens at a 13K over-rev. I don't like the crower retainers because you do have to grind the rocker. That is probably what is side loading the valve.

[cboggs]

Autorace,

Thanks for the reply.

The head was built with new valves, .. very good guide clearance, etc.
The guides where not cut down.

We did lock the Vetec when checking, .. I'll have to look at the notes for the
clearance but I remember it being plenty, ..
Customer claims there aren't any over-revs.

Perhaps you hit something we haven't checked, .. the retainers hitting the rocker.
There is evidence this is happening as there are some marks on the retainer.
I thought this may be caused by something else as they don't hit when rolled
over on the stand, .. but perhaps they do under dynamic conditions.

I was thinking that because this is an LS/Vetec conversion that there wasn't
enough oil pressure for the Vetec and all the rocker pins aren't locking.

Curtis