New Comp Cam ductile rollers

[JCotton]

CB,

How many of these cams have you installed? The new CC ones....

 

[Cheeseburger]

Originally posted by JCotton
CB,

How many of these cams have you installed? The new CC ones....

I have installed 4 of them using both methods.........(the pte shim button and the needle bearing cam button).
Both methods worked fine for me.

 

[Russ Merritt]

Originally posted by Cheeseburger
Here goes...........i just pulled my 4th ductile iron cam and it has ware marks right on the lobe where the edge of the lifter rides, you can catch the indentations with your finger nail!

That's why you can't use a regular spring loaded cam button. They want .004 end play and if you look closely as some of the valves are closing, the edge of the lifter is VERY close to an opposite lobe. My new motor had about .015 clearance on 2 lobes. Not sure why they make the lobes as fat as they do, it's not needed. I run a spring loaded button on my ATR billet cam as clearance wasn't an issue. I made sure to have as little play as possible on the ductile.

As for springs doubles aren't needed. They actually recommend single beehive springs # 26918 for all ductile turbo roller cams.

I'm going the Chuck L route on the race motor, BBC beehives.

 

[JCotton]

CB,

Not sure where you get your info from, but none of the spring numbers are in the CC catalog for the application the original post was about. What's the part number of the cam you are using? As for the correct number recommended by comp it is the beehive spring set-up, #26918-12, we have been using the Kmotion springs in place of those and have had no problems to date. It's true the roller cam button's may appear to work sometimes, but do they?Is the spring tension on the nose of the cam correct? Since our customers need to get it right the first time, I recommend the adj. button kit.

 

[Cheeseburger]

Originally posted by Russ Merritt
That's why you can't use a regular spring loaded cam button. They want .004 end play and if you look closely as some of the valves are closing, the edge of the lifter is VERY close to an opposite lobe. My new motor had about .015 clearance on 2 lobes. Not sure why they make the lobes as fat as they do, it's not needed. I run a spring loaded button on my ATR billet cam as clearance wasn't an issue. I made sure to have as little play as possible on the ductile.

As for springs doubles aren't needed. They actually recommend single beehive springs # 26918 for all ductile turbo roller cams.

I'm going the Chuck L route on the race motor, BBC beehives.

If thrust had anything to do with it then the marks on the lobe would not be in the exact same location,imo.(but they are).
The marks are from the edge of the roller and not the body of the lifter.
The remark about double springs came directly from a comp cam tech!
The front nose assemble has no bearing what so ever on the cam being worn from the edge of the roller lifter.

 

[Russ Merritt]

How many of the lobes are beat up? Are they all?

 

[Cheeseburger]

Originally posted by Russ Merritt
How many of the lobes are beat up? Are they all?

I would not call them "beat up", and not all lobes have the indentations.(i never counted them).
What it is...........is enough to catch the mark with your fingernail.
NOW..............on this particuler cam i had it custom ground to my specs(i used a more aggressive lobe)so maybe the material cannot handle it............but comp told me it is not an issue.

Jack, i looked up the springs, here is the info:

#986-16(984-975)
1.430 dia
132lbs@1.750
280lbs@1.250
1.150 coil bind.

It seems to me that judging from those numbers there is a concern for over the nose spring pressure because IMO it is on the low side.
Also it does not make sence to go through all the trouble to machine the heads etc when you could get a 1.250 with the same or more pressure.......however the larger diameter springs will probably hold up longer which is probably the idea.

 

[Russ Merritt]

Yea, 280 ain't even close for a roller. The BBC beehives are 155# closed 380# open. Did you use the new 885 roller lifters with your grind? They are recommended over the 853s for the turbo roller cams although they have worked well on a couple of engines I put em in. Not revin passed 6K.

I have 941s on my heads and they worked well for 2yrs now. Small cam, under .500 lift both valves.

 

[Cheeseburger]

Originally posted by Russ Merritt
Yea, 280 ain't even close for a roller. The BBC beehives are 155# closed 380# open. Did you use the new 885 roller lifters with your grind? They are recommended over the 853s for the turbo roller cams although they have worked well on a couple of engines I put em in. Not revin passed 6K.

I have 941s on my heads and they worked well for 2yrs now. Small cam, under .500 lift both valves.

To be honest i think i have the 853s????not sure they are marked speed pro and i got them from pte about 4-5 years ago.
What is the difference?
I rev my stock block motor to 6200 with 500 plus lift, I.M.H.O,you should replace your springs every season after what i have seen.
Or at least varify your pressures.

 

[frankg]

So you guys are saying you are having problems with the beehive springs losing tension over time??? Just wanted to get this straight. Thanks,Frank

 

[Russ Merritt]

http://compcams.com/Technical/Catalogs/106-03/HTML/282-289.asp

No on the springs, who said that?