More lift from stock cam

[X Factor]

I was cleaning the garage today. as I dusted off my dohc heads and over heads. an idea poped into my head. to have cams made the $ would not be worth the HP. but how else would I get more lift from the stock cams?
What if i would have the cam carrier decked. If we start at .370 for lift, why not cut the bottom of the carrier 30 or 40 thou, to make lift .400 or .410 . now I can have the cams reground so my valves will fully seal
the cams will have to be cut(the lifters and cams are in contact all of the time)

someone tell me why this will not work?

[ryan.hess]

Sounds good to me... As long as you realize you're cutting on a radius, and not milling something that's flat... I heard somewhere that hydraulic lifters can adjust quite a bit, so just grinding the flats of the cams down by (insert amount here), I would think, would give you what you want... Since the hydraulic lifters would pump up to compensate... But I'm specifically thinking of northstar lifters, don't know if the 3.4's are any different...

[Lyle's GTP]

I thought of this too, but I was told by the guys at work that I was nuts. Made sense to me though. Try it let us know.

Lyle

[RacerX11]

It won't work. To change the lift of the cam, you need to have it re-ground with a new lobe profile. The valve lift is determined by the difference between the height of the lope and the height of the base circle. You are only changing the lifter preload, or lash.

Your line of thinking is the same one that says changing the rod length will change the stroke of an engine.

Marty

[Lyle's GTP]

Your line of thinking is the same one that says changing the rod length will change the stroke of an engine

Well that's just crazy talk. But now I gave it more thought, and you're right, the deck height won't do it.

Lyle

[RacerX11]

Well that's just crazy talk.

That is exactly my point.

Marty

[X Factor]

Marty , how much valve lash dose the 3.4 have?
yes the only thing that will increase stroke is the crank.
bring the base circle closer to the head
rethink this and please reply. or am I still nuts

[RacerX11]

I don't know how much lash it has. I don't need to rethink it. Milling the heads or cam carriers, or doing anything else to effectively change the lash or lifter preload, will have no noticable affect on valve lift. If you mill it enough, you will end up keeping the valves off their seat when the cam is on the base circle. This is bad.

In your initial post, you said you don't have the money to get re-ground cams. You then mentioned that if you milled the carriers enough, you would "have the cams reground so my valves will fully seal; the cams will have to be cut(the lifters and cams are in contact all of the time)"

You answered your own question already..to change the valve lift, you need to change the cam itself.

Marty

[Streetrodder83]

They will have 0 lash. A hydraulic lifter is meant to take up the play in the valve train. A hydraulic lifter is set by preload.

[pocket-rocket]

Leave the cam carrier alone, and have the cams reground. Then get lifter shims to take up the extra space that was removed from the cam. This has already been discussed before, but not tried.