I have heard of people shaving down the outer rocker arms for use with some high lift cams in vtec motors to avoid hitting the retainers.

examples from TOO:






BUT have you ever heard of anyone having to shave down the middle rocker arm for clearance of retainers?

I will post pics later, but had to get busy with a dremel recently due to the middle rockers hitting my retainers.....

Here's the setup:

usdm itr motor
toda spec c camshafts
toda valve springs
portflow Ti retainers
toda gen 2 cam gears
power enterprise timing belt
i/h/e
rev limit set at 9500...
history of exactly two 9000 rpm misshifts that zinged it up to the 11k-12k rpm range for a second or so...
the rest of the motor is stock with the exception of mugen oil pan and has only 35000 miles on it since purchased brand new by yours truly.

 

ive seen rockers shaved but i just thought it was to reduce vavletrain weight....how much lift are u running?

 

12.5mm of lift.

 

is this a custom cam?

 

ive seen this done on a homies H22..he had some crower springs and retainers though..the cams where stock..

 

12.mm lift? any milling? headgasket thickness?

Ive heard of the retainer to arm clearance.. and i might have to do it with my cams, not too sure yet..

 

Did you degree the cams in during install?

I am running 12.7mm of lift on stock rocker pads and am not experiencing what you are with your rockers and retainers. How are your LMA's?

What was the install height of your valve springs when they were installed.

 

how much mm did you end off taking of the rocker arm?

 

Lift has nothing to do with it. When the valve is down the retainer comes nowhere near the rocker. That is like valve to piston clearence for high lift, the valve is at full lift when the piston is over half way down the bore, meaning you could run 38 mm of lift and not hit the piston. The prob. is valve and retainer height, they come close at .0000 valve adjustment. Some retainers sit higher than others, that is why you pay someone to check stuff.
By the way look at the first picture, how much lift is involved in that .0000000
Its called proper assembly, tall retainer to get correct spring height, check cl. to rocker arm.

 

just like i said stock cams and it was hitting..

 

One of the reasons spring retainers are slid up the valve is to increase the retainer to valve/guide seal distance , in order to be able to run real high lift cams.
lowering the guides in the head also improves this clearance.
spring pressure should always be checked and installed at adequate rates.
yes, the middle rocker can interfere in some situations, requring shaving on the sides.
checking each rocker with a small mirror in the exact location to be used makes for good sleeping!, not having to second guess yourself whether the rockers are clearing or not...simply the right thing to do.


Modified by PocketRockets Racing at 12:10 PM 8/11/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF &raquo;</TD></TR><TR><TD CLASS="quote">Lift has nothing to do with it. When the valve is down the retainer comes nowhere near the rocker. That is like valve to piston clearence for high lift, the valve is at full lift when the piston is over half way down the bore, meaning you could run 38 mm of lift and not hit the piston. The prob. is valve and retainer height, they come close at .0000 valve adjustment. Some retainers sit higher than others, that is why you pay someone to check stuff.
By the way look at the first picture, how much lift is involved in that .0000000
Its called proper assembly, tall retainer to get correct spring height, check cl. to rocker arm.</TD></TR></TABLE>

yea, listen to don. he's the man.

 

I put a good 25000 miles on those portflow retainers without any thinning... the chipping of the tops of them occurred recently... which is strange - within the last 2k miles or so.

Either that, or I somehow didn't notice it - which is highly unlikely. I am quite meticulous and check valve lash at every oil change.

They went in when I originally had spec b camshafts installed. Then I used some stock itr cams with them for a while, and then spec c camshafts... I'm pretty sure the lift of the vtec lobes does play a role - as it's moving the middle rocker/ lma and the corner of the middle rocker was hitting the Ti portflow retainers ever so slightly - causing little knicks around the upper outer portion of them.

I *did* notice that the rocket Ti retainers that I installed sit a little lower (about two hairs lower) on the valve with the keepers..... This would've prevented my problem in and of itself - but now I'm concerned about coil bind...

Rocket has assured me that his retainers will be fine with the toda valve springs and spec c's...

Is anyone else running this setup?

 

There is always the possibility, that after 25,000 miles the portflows pull the keepers down and get egg shaped like the Crowers. That would give you a higher installed height and possible touching the rocker.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF &raquo;</TD></TR><TR><TD CLASS="quote">There is always the possibility, that after 25,000 miles the portflows pull the keepers down and get egg shaped like the Crowers. That would give you a higher installed height and possible touching the rocker.</TD></TR></TABLE>


haha, you must have been reading my mind. I was just thinking of that possiblity - of the keepers sinking into the Ti over time and high rpm's...

The keepers didn't want to let go of the retainers. Mike and I were BEATING THE CRAP out of the portflow retainers to get them off and most of the keepers were almost welded into them?!

Don, you need to reply on my timing belt thread - it really has me stumped.

 

update: I got finished the other day, and uploaded pics in a new thread.

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