Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   General Q & A (https://www.offshoreonly.com/forums/general-q-20/)
-   -   Roller Cam Bearings? (https://www.offshoreonly.com/forums/general-q/333220-roller-cam-bearings.html)

GLENAMY 242SS 12-22-2015 09:31 AM

Regarding cam questions it might be worth your time to contact somebody like Cam Motion in Baton Rouge, LA. They are a high end custom performance cam grinding company. (Truth be known I bet many of the custom cams on this site are ground by them). They are very knowledgeable and willing to spend time with you explaining the nuances of these cam aspects. Check out their web site and you get an idea of their pedigree.
Keep in mind that I personally don't know squat about anything but I can get it figured out.
Regarding 9,500 RPM, cam RPM is Engine RPM/2 (4750). My Harley Davidson uses roller rod bearings with dry sump oiling at 7,500 RPM (not a typo) and bearing failure is at the bottom of my concerns. Just saying.
And enough is always just the starting point for improvement.

horsepower1 12-22-2015 09:34 AM


Originally Posted by ham_r_down01 (Post 4387310)
The larger the bearing the bearing speed slows down yes....? I always was under the impression that was true. Slower bearing speed less heat, then higher rpm durability.

No, larger bearing means more surface area and more surface speed for the same RPM. I think the differences between cam journal diameters is moot (regarding heat) as compared to the gains in valve train stability, but we're also not turning 10K rpm here. PS and cup guys are also running 9 journal cams, so I don't think heat is the issue. Everything in an engine is a compromise and there is always a give and take to consider.

mike tkach 12-22-2015 09:37 AM

what is the intended use of the boat this engine is going in?i,m not being a smart azz,i am just curious as it looks like you are building a pro stock style engine.

Black Baja 12-22-2015 09:55 AM


Originally Posted by mike tkach (Post 4387317)
what is the intended use of the boat this engine is going in?i,m not being a smart azz,i am just curious as it looks like you are building a pro stock style engine.

Mike I don't really look at it like building a pro stock style engine. I look at it like modernizing a BBC. When I started all this I had I couple goals. Make as close to 1000hp N/A on pump gas as I could. Secondly get the boat over 100mph. And lastly beat up on the guys that I boat with. We are a pretty close bunch. Talk a lot of crap to each other you get my drift. So we will see what happens. This isn't some thrown together project. Each part of this build has been carefully looked at and at the end of the day I have a lot of confidence that it will turn out great.

Panther 12-22-2015 10:30 AM

Seeing how companies such as Isky are moving "away" from roller bearings in their lifters, I think I'll stick with regular bearings.

mike tkach 12-22-2015 05:16 PM


Originally Posted by Black Baja (Post 4387324)
Mike I don't really look at it like building a pro stock style engine. I look at it like modernizing a BBC. When I started all this I had I couple goals. Make as close to 1000hp N/A on pump gas as I could. Secondly get the boat over 100mph. And lastly beat up on the guys that I boat with. We are a pretty close bunch. Talk a lot of crap to each other you get my drift. So we will see what happens. This isn't some thrown together project. Each part of this build has been carefully looked at and at the end of the day I have a lot of confidence that it will turn out great.

ok,i understand now.you have set some goals and i hope you can get it done.looking forward to seeing progress on your build.i totally understand talking smack with the buddy,s.

MILD THUNDER 12-22-2015 06:04 PM


Originally Posted by Black Baja (Post 4387324)
Mike I don't really look at it like building a pro stock style engine. I look at it like modernizing a BBC. When I started all this I had I couple goals. Make as close to 1000hp N/A on pump gas as I could. Secondly get the boat over 100mph. And lastly beat up on the guys that I boat with. We are a pretty close bunch. Talk a lot of crap to each other you get my drift. So we will see what happens. This isn't some thrown together project. Each part of this build has been carefully looked at and at the end of the day I have a lot of confidence that it will turn out great.

Is there really any reasoning on how most of us do things? We are all nuts. :bong:

I think a good start to finish build thread on your piece would be in order when completed.

KAOSS 12-23-2015 10:14 AM

Plain babbitt cam bearings in my experience are junk above 750 hp with a SOLID ROLLER cam . When a plain babbitt or conventional non roller bearing fails you will see a loss in oil pressure above 5000.00 worsening exponentially. If you don't catch it in seconds you will cause rapid oil starvation and boom
Goes your 35000.00 1000 hp motor. It's insurance and if I were to go racing boats I would endure the maintenance required for abating solid roller cam demons. My boat has a hyd. Roller
I have no problems running 4800 for 70 miles non stop.
solid roller. Roller cam bearings ain't hard or expensive and you can turn the motor by hand and insure proper cam alignment under a load the bearing ain't tin like babbitt. If you intend 7500 + rpm and a 1000 hp don't be afraid if you don't know ask a real engine builder. Sure as **** I blown 6 540s in 4 years . My learning curve.

Black Baja 12-23-2015 10:35 AM


Originally Posted by KAOSS (Post 4387596)
Plain babbitt cam bearings in my experience are junk above 750 hp with a SOLID ROLLER cam . When a plain babbitt or conventional non roller bearing fails you will see a loss in oil pressure above 5000.00 worsening exponentially. If you don't catch it in seconds you will cause rapid oil starvation and boom
Goes your 35000.00 1000 hp motor. It's insurance and if I were to go racing boats I would endure the maintenance required for abating solid roller cam demons. My boat has a hyd. Roller
I have no problems running 4800 for 70 miles non stop.
solid roller. Roller cam bearings ain't hard or expensive and you can turn the motor by hand and insure proper cam alignment under a load the bearing ain't tin like babbitt. If you intend 7500 + rpm and a 1000 hp don't be afraid if you don't know ask a real engine builder. Sure as **** I blown 6 540s in 4 years . My learning curve.

This was never intended to be a Babbitt vs roller thread. At this point it's going to be roller. I'm sure there are plenty of solid roller experience that will discredit your post.

What I was trying to find out from the guys who have ran rollers is who's bearings is everyone using. Are there any to stay away from... That sort of thing.

But putting up a post saying your stuff blew up because it had a Babbitt bearing in it. I'm sorry but there has to be more to the story.

mike tkach 12-23-2015 06:37 PM


Originally Posted by KAOSS (Post 4387596)
Plain babbitt cam bearings in my experience are junk above 750 hp with a SOLID ROLLER cam . When a plain babbitt or conventional non roller bearing fails you will see a loss in oil pressure above 5000.00 worsening exponentially. If you don't catch it in seconds you will cause rapid oil starvation and boom
Goes your 35000.00 1000 hp motor. It's insurance and if I were to go racing boats I would endure the maintenance required for abating solid roller cam demons. My boat has a hyd. Roller
I have no problems running 4800 for 70 miles non stop.
solid roller. Roller cam bearings ain't hard or expensive and you can turn the motor by hand and insure proper cam alignment under a load the bearing ain't tin like babbitt. If you intend 7500 + rpm and a 1000 hp don't be afraid if you don't know ask a real engine builder. Sure as **** I blown 6 540s in 4 years . My learning curve.

how does an engine ^750 hp destroy cam bearings?i have never heard of that and have built plenty of engines way over 750 hp and solid roller cams with no failures.


All times are GMT -5. The time now is 03:47 AM.


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