[6426yy]

I'm trying to finish up my BB 781 heads. I bought the guide cutter and seals, shim kit, and EV rotator eliminators.

I'm using all comp cams hardware.
Cam 4x4 extreme 270H
Springs 924-16
Locks 612-16
Retainers 714-14

Now my springs call for an installed height of 1.900"
On the Exhaust with the Spacers in place I get an installed height of 1.840"
and 1.850 on the Intakes.
All measurement are made with a spring mic.

I think the easy solution is to buy +.050 locks this would get me within about .010. Is this close enough?

Now on the seals, how far to I cut down the guides? Should I trim them off with a cut-off wheel or something first to gain additional clearance, or just let cutter cut them down?

from my rough measurements I get .540 from the seal to the bottom of the retainer which isn't enough I know. Granted I haven't cut the guide yet I just roughly measured the seal its self and subtracted that from the retainer to guide.

Sorry so long winded
Thanks in advance

 

[ericnova72]

Yes, .010" on the installed height will be close enough, but be aware that the +.050" locks might put you into a spring retainer to rocker arm body interference situation depending on what rockers you are using and the tip length of the valve.

Just use the seal cutter to cut down the guide, you need a .060" seal to retainer minimum clearance at max lift.

 

[6426yy]

ericnova72,

Thanks for the reply, so I can just use the cutter to cut the guide all the way down? .060 was what I was thinking but I figure if I decide to install larger valves and maybe a hydraulic roller someday I might as well get as much clearance as I can. Can I cut them down to the spring seat? This would be about an inch, I don't want to dull the damn thing it was kind of expensive. I was wondering if I could use a cut off wheel to shorten them first then use the cutter, would this work or should I not bother.

Thanks again.
Jesse

 

[6426yy]

Thanks F Bird,

Do most cutters shorten the guide also? I cut down one of the Exhausts today and the cutter doesn't seem to want to cut the guide shorter. It has the third carbide that is higher that the first two.
Am I missing something?

It is a Howards cutter

HRS-92045

 

[Plaintoast]

Most of those style cutters are designed to reduce the ID
of the guide, and put a chamfer on the top of the guide. They
are not designed to cut the spring pocket, or reduce guide height.

 

[6426yy]

So, is there a cutter available to shorten the guide it's self? Or is there another way to cut it down?

 

[Plaintoast]

I normally use a counter bore with appropriate pilot, but I do it in a seat and guide machine, I don't know how it would work to do that with a hand drill. Maybe if you had a drill press and could put the head at the proper angle you could get it to work.