Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   General Q & A (https://www.offshoreonly.com/forums/general-q-20/)
-   -   Cam and valvetrain longevity....??? low duration high lift... (https://www.offshoreonly.com/forums/general-q/341258-cam-valvetrain-longevity-low-duration-high-lift.html)

Full Force 11-05-2016 07:08 AM

Myself and all us locals been using cam motion for years, Never seen an issue... Not saying that it can't happen and I am not sure future direction yet, but at least they stepped up and offered, what was issue with yours besides spec? Never ran you can't blame cam motion... People think they don't do BBC stuff much but they do, for many years but focused more on Ford and LS due to high sales, they do a lot of cams for BBC though, this info came from others besides can motion.

Originally Posted by Black Baja (Post 4497753)
I will not use anymore Cam Motion cams fact is they are junk. I have a 55mm cam here brand new and it's not going in any of my motors nor could I in good conscience sell it. I did let Bob spec that cam and of course it's to small 267/277 @.050 for a 6,800 rpm 632 nah never going to happen it would be luck to make it past 6,000. I honestly don't know how he comes up with these numbers. It's only about 20* off on the intake and 30* off on the exhaust.


sutphen 30 11-05-2016 07:32 AM


Originally Posted by 14 apache (Post 4497709)
[ATTACH=CONFIG]561227[/ATTACH]

Anyone see something odd here?

said it back in the beginning.

vintage chromoly 11-05-2016 07:36 AM


Originally Posted by sutphen 30 (Post 4497757)
said it back in the beginning.

Are you guys looking at the dark line on the far side of the pattern being indicative of the lifter bores not being perpendicular to the lobe?

If so, do you guys think it's the bores not being "square" to the cam journels or do you guys think the cam has a slight taper to it?

Also, pretty cool that cam motion is offering to pay for two cams!
Slippery slope for them, as tbis could open up a cam of worms with other bob cam customers wanting the same.

Full Force 11-05-2016 07:44 AM

Talking to a few last night, if bores were the issue I would be digging all around especially on the nose...

MILD THUNDER 11-05-2016 08:22 AM

What are the thoughts, on using a .700 wheel lifter, on a cam of those specs?

Full Force 11-05-2016 08:26 AM

My fault lol


Originally Posted by MILD THUNDER (Post 4497767)
What are the thoughts, on using a .700 wheel lifter, on a cam of those specs?


SB 11-05-2016 08:30 AM

A bigger wheel increases lifter acceleration rates. When using more agressive cams, always best to ask the cam grinder if changing to the larger wheel size is okay.

Black Baja 11-05-2016 08:35 AM


Originally Posted by MILD THUNDER (Post 4497767)
What are the thoughts, on using a .700 wheel lifter, on a cam of those specs?

I don't think the .700 wheel helps matters when you have an Inversed Radius lobe. The larger diameter wheel is better however I still don't think any of that is the issue. I think it all goes back to the finish on the cam. If you hold a Cam Motion cam next to any of its competitors it's plain as day that they are rough.

MILD THUNDER 11-05-2016 08:45 AM


Originally Posted by SB (Post 4497772)
A bigger wheel increases lifter acceleration rates. When using more agressive cams, always best to ask the cam grinder if changing to the larger wheel size is okay.

Isn't the reason to go to a larger body lifter, and accompanying larger diameter wheel, to allow more aggressive cam profile? While the larger wheel may accerlate the valve quicker off the seat, I think it can also slow it down over the nose.

Who's running .700 lifter wheels on big stuff?

I've always been told that if you run a cam, designed for an .810 wheel, and go to a .750 wheel, things may become more unstable quicker.

MILD THUNDER 11-05-2016 08:51 AM


Originally Posted by Black Baja (Post 4497775)
I don't think the .700 wheel helps matters when you have an Inversed Radius lobe. The larger diameter wheel is better however I still don't think any of that is the issue. I think it all goes back to the finish on the cam. If you hold a Cam Motion cam next to any of its competitors it's plain as day that they are rough.

I agree. It was more of a general question. Just seems like going up in a cam's aggressiveness, and down in lifter wheel diameter, is a lateral move. A basic old .350 lobe lift std diameter bbc cam, is quite a bit different shape than a .400 lobe lift std diameter bbc cam. They did it with solids forever with no issues, but I don't recall many solid roller lifters with .700 wheels, and they also had lash ramps in the lobe.


All times are GMT -5. The time now is 03:35 PM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.