The Right Cams...

les holt wrote:

I take it that the 650 buckets just aren't up to the task, because thats just what I was going to do If I put this thing back together

A lot of guys run them in their drag bikes. Over time, they'll give up and take the cam lobe out as well.

I tried GPz11 buckets once to save some coins.... mistake. I ended up buying the good buckets [that I always put in everyone else's motors] and another set of cams.

If you want the strongest you can get, seat your head up properly and get the PM or APE that are .117" thick.

Stock are .100" thick. You loose roughly 9 shim sizes with the thicker performance buckets so you either have to setup the valves for them or order smaller base circle cams.


Here's a photo of a valve shim with magic marker on it that shows the lobe wipe pattern. It's how close the lobe touches the shim out near the edge that the issue of spitting shims is all about.

From a post I did a couple of years ago.

n the past, I've never bothered too much with shim spit worries. Since Branden spit one out of his motor with mild street cams, I decided to take an opportunity today to test a few things.

This test is only to see how easy it would be to dislodge a shim. It's not intended for anything else but that.

I had a perfect candidate on the bench, 81 J that I was degreeing cams in. So here's what I experimented with.

Head assembled with light springs [won't really matter for this test though].

Opened up the exhaust valve to about .150" lift. Just far enough to expose the leading edge of the shim so I could touch it with something.

Took the Kawasaki shim removal tool, reached down in there to the leading edge of the shim and just pushed on that edge a little.... Shim would pop right out with amazing ease. And I'm talking about pushing down on the front...not prying up on the rear like you would be during removal process....

Now you'd think the lobe would hold it down but in reality, it's not near the center of the shim enough to do so.

While I was setup, I figured I'd show you about using magic marker on the shim to inspect where the lobe rides. This is with a .390" net lift cam with 216* duration @.100" lift.

So it boils down to the material the buckets are made from or the treatment they go thru isn't up to the added spring pressures that ape or pm's are. Just as I have decided to go with sob so shall I on good buckets.
Thanks

PLUMMEN wrote:

the motor larrys refering to has 2x4s for cam lobes if its the engine im thinking of which is a lot differant than a set of cams in the .410 range.
if youre just turning high rpms occasionally without a huge amount of lift with cams requiring bigblock chevelle coil springs to keep valves from bouncing id say youll be fine.
im guessing the 650 buckets are made from same material as 900-1000 style

Actually, they are 8x Andrews which are .410 lift.

I've seen a few used sets over the last couple of years and not a good lobe on any of them. On the flip side, I've seen a few sets of Megacycle cams too. Each one in great condition.

Anyone interested, I have a brand new set of Web 109 that I will let go for $350. They belong to a friend of mine that could use the cash right now so holler if anybody want's them. If anyone wants to run the risk, I'll throw in a set of Kaw OEM S.O.B buckets with the cams....

Did Web Cams discontinue their .410 lift cams?

i was thinking of that worn out bigblock motor you were talking about Larry! :laugh:

So anyways.. the consensus is what? The Cam Motion Z4 cams at .420 are OK (like the manufacturer says) for shim over, but its really at your own risk and I should stick below about .400?

Andrews 3x is being re-manufactured by PSP and they are pushed pretty heavy on eBay. Are these cams any good? They claim that they can be used shim on top, but I have the feeling this is kind of a grey area in regards to shim spitting.

Also, I'm looking at some camchain wear issues with cams in this range. I already have Liska rollers everywhere and the APE tensioner. How long can I expect out of my camchain with some really hot cams. I can deal with 5k between engine teardowns (typically every winter).


-Dave

They have a lot of TDC overlap timing Best suited for motors 1075 and larger. The bigger the better. IMO, smart move when running that grind is S.O.B.

Anyone twisting their motor to 10K continuously should go S.O.B with any cams.

larrycavan wrote:

They have a lot of TDC overlap timing Best suited for motors 1075 and larger. The bigger the better. IMO, smart move when running that grind is S.O.B.

Anyone twisting their motor to 10K continuously should go S.O.B with any cams.

larry for clarification,are you actually saying that high lift,high rpm engines should use shim over bucket?
or shim under bucket?

leon

s.o.b shim on bottem

Which are an SOB to deal with. :laugh: PLUMMEN wrote:

s.o.b shim on bottem

PLUMMEN wrote:

s.o.b shim on bottem

always heard it was
shim on bucket (s.o.b.)
shim under bucket (s.u.b.)

i hate when people use acronyms.
it is to easy to get confused and counts too much on expecting people to have previous knowledge.
it is fine if everybody is on the same page.
which is very seldom on internet forums.
i work for a toyota forklift dealership and the japanese use acronyms for damn near everything,
dont mean i like it tho .

leon

Can
Hear
Every
Valve
Rattle
On
Long
Extended
Trips

hows that Leon? :woohoo: