bbc retrofit roller update

[weq92f]

Doing a cam swap on my BBC. Would like to get you all's opinion on the combination of parts...

BBC 1970 402 4-bolt block bored out .030 over ( .060 over 396 )
stock stroke
piston dome at 10 to 15cc
piston deck meets block deck at zero
#063 Cast Iron heads, stock valves, 102cc combustion chambers ( may mill a bit )
will be adding long tube headers, 2 3/4 inch tubes
dual plane Edel Performer II+ intake
1000 CFM MSD EFI TBI
will be adding a 1" carb spacer

700r/1800 stall/3.73 posi

compression is between 9:1 and 9.5:1

The cam we have chosen is the Comp xr276hr ( 224/239 Dur @.050, 110 LSA, 1900-5600 RPM: 410HP@5000, 467TQ@4000 ).

A close second was the comp xr270hr.

With this update, I'm looking for a gain in off the line performance ( may need more stall ) and mid range torque.

Fire away please. No parts have been purchased yet, well except for the rocker arms

-klb

[geezer#99]

Maybe you should call Chris and see what he recommends.
http://www.straubtechnologies.com/

[b454rat]

That’s a big cam for a small motor. Doubt you will have anything down low...

[weq92f]

Originally Posted by b454rat

That’s a big cam for a small motor. Doubt you will have anything down low...

It is the small big block, yes! This cam repeatedly comes up as an "great fit" using CamQuest6 with some conservative input parameters. It does call for intake, headers, stall and gears in the spec.

What would you recommend as an alternative, better cam for this pile of parts?

thanks,

-klb

[b454rat]

I should retract my statement as i don’t have really any experience with roller cams. I saw the 276 part, I had 274 or something similar flat tappet in a 468 and was a pretty nasty cam. So be even more so in a smaller motor.

[geezer#99]

It’s not always the duration that makes the cam nasty.
Wider lsa’s Will make it less lumpy.
Try a cam with 112 or 114 lsa in the smaller bbc.
An example of nasty idle is those created by the infamous thumper and motherthumpr cams which typically run lsa’s of 106 to 108 degrees.

[alsriv2]

Take a look at the Lunati series of cams. They have a good selection of various profiles that should work well for you and reasonably priced as well.
I put a 60211 roller in mine and it is working well. However, make sure you know all your specs. I gave my builder the wrong gear ratio (was told it was a 3.73 without verifying) and after the engine was built and installed, we discovered it was a 3.07 with a limited slip. My cam doesn't wake up until 2500 or more so what I am dealing with is an ok launch to highway speed, but an engine that wants to really go once I am at highway cruising speed... not exactly what I wanted, not the builders fault, but I will be changing the cam to one of the Lunati rollers that wake up at a much lower RPM. I am not going to change the rear end gears anytime soon as I love the 2600rpm at 70mph.

[Captainfab]

IMO that is too big of a cam for a street driven 402, especially with EFI. I doubt that you will ever get it to run right with that big of a cam with a 110* LSA. I don't know what cam you have now, but that cam will not give you good low end to mid range power. More like mid range to top end.

[Mike C]

I am not going FI on mine, but I just put together a pair of 427’s. First one I ran the Comp XN273hr which is 224/236@ .050 113 LSA and the second is the XM284hr which is 230/236 @ .050 112 LSA. I wanted extra exhaust duration to try and improve power through iron manifolds.

I know the marine cam is WAY too big for your motor, but for FI consider running the Comp smallest marine hr or the dedicated fi cam they offer. Both the xm and nX series have wider LSA which will help FI.

Marine cams in general are easier on valve springs and designed for a smooth idle.

[weq92f]

Originally Posted by Captainfab

IMO that is too big of a cam for a street driven 402, especially with EFI. I doubt that you will ever get it to run right with that big of a cam with a 110* LSA. I don't know what cam you have now, but that cam will not give you good low end to mid range power. More like mid range to top end.

This is what I want to avoid. I want quick throttle response and loads of bottom end torque. The outgoing flat tappet cam was bone stock or so mild that it was very close to stock anyhow. My guess is that it was ground close to 112/114 LSA, probably .45 lift and conservative duration.

What do you guys think of the xr270hr ( 218/224 Dur @.050, 110 LSA, 1600-5400 RPM: 383HP@5000, 453TQ@4000 ) with respect to my goals?

Note the same RPM peaks for HP/TQ as the 276 cam. The HP/TQ graph provided by COMP for these two cams both spin out 350 lbs of TQ at 1500 rpm. Is that just marketing or am I missing something?

Now I'm confused!

-klb

[Mike C]

The Comp TBI 266HR roller is 1000-5000 rpm 210/220 on 113 degree lsa. I would think using similar numbers would be good. Does the injection company make a cam recommendation? If so, I'd run that...

The smallest marine cam is the same lobe patterns as your cam you referenced above,218/224, but it's on 112 deg LSA. 1600-5400 there rpm range. That's by far as big as I would go I think and no narrower than 112.

[weq92f]

My EFI supplier ( MSD ) accepts LSA down to ( and maybe below ) 108 and durations out to 250. At least in the docco.

Quote:

"Camshaft Selection
There are three selections; Street/Stock, Mild and Performance. Select the cam that best suits your application.
Camshaft Selection
NOTE: If lobe separation angle (LSA) is less than 108° you may need to go to the next larger cam profile. If cam duration is longer than 250° the Atomic EFI will not be suitable for your application."

I'm now leaning more toward the 270 roller cam.

-klb

[Mike C]

Seems like it's hard to go wrong then. Pick the grind you like a burn up the credit card!

[funkatation]

Just be weary of the lifters you get. Mine were rebranded morels, and they sounded like a sewing machine. Kept getting all kinds of weird answers for fixes and they never quieted down. It drove me crazy I pulled the cam and lifters out and went with Isky.

['63GENIII]

Originally Posted by geezer#99

Maybe you should call Chris and see what he recommends.
http://www.straubtechnologies.com/

The Vortec that I have is running a CSI cam. Great throttle response and pulls like a train. Chris is a great guy to deal with too. Just try and catch him before race season gets hot and heavy.

Originally Posted by Captainfab

IMO that is too big of a cam for a street driven 402, especially with EFI. I doubt that you will ever get it to run right with that big of a cam with a 110* LSA. I don't know what cam you have now, but that cam will not give you good low end to mid range power. More like mid range to top end.

The '63 pulls hard off idle and drops off around 4k. I still need to get a live tune on the engine as I think the "start up" tune I have is leaving a lot on the table. Even with this mild tune, it goes real good.

Originally Posted by weq92f

This is what I want to avoid. I want quick throttle response and loads of bottom end torque. The outgoing flat tappet cam was bone stock or so mild that it was very close to stock anyhow. My guess is that it was ground close to 112/114 LSA, probably .45 lift and conservative duration.

What do you guys think of the xr270hr ( 218/224 Dur @.050, 110 LSA, 1600-5400 RPM: 383HP@5000, 453TQ@4000 ) with respect to my goals?

Note the same RPM peaks for HP/TQ as the 276 cam. The HP/TQ graph provided by COMP for these two cams both spin out 350 lbs of TQ at 1500 rpm. Is that just marketing or am I missing something?

Now I'm confused!

-klb

I know we are running different stroke / bore combos but Id give Chris a call. Im at a 109 LSA, port injected with slightly larger than stock injectors. It can sound a little choppy (I think) at times and comes off idle like a bat out of hell. Ill dig through my receipts and try and find the cam card and get you the lift / duration. Its a pretty mild sounding cam but I don't think Id want anything else for what Im doing with the truck.

Originally Posted by funkatation

Just be weary of the lifters you get. Mine were rebranded morels, and they sounded like a sewing machine. Kept getting all kinds of weird answers for fixes and they never quieted down. It drove me crazy I pulled the cam and lifters out and went with Isky.

I have the Morels as well. They do make noise. My "guess" is that it's the tie bar between the lifters. The original lifters were very quiet but they had the dog bone alignment bars that were not attached to the lifters. The noise initially bothered me but Ive gotten used to it. Could be the Comp Magnum roller tips too. Sounds like the solids on my Singer .....I mean Shovelhead

[weq92f]

I'll be using COMP 854-16 roller lifters ( part of their full roller kit ).

I'v read so many accounts of noise related to these XE/XR ( roller ) cam kits. My machine shop warned me of some noise from the lifter "arms" that attach pairs of them to keep the roller tips properly aligned with the cam lobes. This is something I'm willing to accept for the benefits of the roller. I don't want the dreaded sewing machine clatter that has been reported.

If the geometry of the valve train is correct, all the components are correct, clearances are proper and it's all installed right, there's no reason for the rest of the components to make any more noise than a non-roller setup. That is, aside from the harder/faster action of the valves.

In many cases, these online forum discussions of noisy retrofit roller setups were resolved by a combination of proper lash adjustment ( sometimes a full turn after 0 lash, sometimes only a quarter turn ), run time and/or faulty lifters/rockers. Most of the discussions were from earlier times like circa 2006 through 2010 for example.

Another thing I noticed was that most of the excessive noise Extreme Energy threads I looked through ( random sample from google ) were on small blocks. May not even matter.

-klb

[funkatation]

Mine were installed last year and it drove me nuts. I was told the lash, the weight of the oil, it needed more miles. None of it fixed it. Hydraulic rollers are supposed to be quieter than flat tappets. I haven’t run the engine with the new lifters (they are Johnson ones) but I think a lot of it had to do with how the bbc oiling system works. These Johnson ones are said to do better with less oil. I was told to run lighter oil with the morels, which went against my engine builders recommendations for the rest of the engine.

[weq92f]

I'm committed now. The expensive bits have been ordered ( xr270hr along with the comp recommended lifters, springs and a set of pro magnum roller rockers ).

-klb

[weq92f]

Had to lean the grill out about an inch and a half to get the cam out!

Before that, I discovered that a PO had tapped out one of the front main pulley bolts to 7/16 ( the next larger size ). That ended up costing me about 100 bucks because I had to modify the puller I borrowed from AutoZone ( 30 bucks ) and purchase a new balancer ( 70 bucks ) because there's just no way I'm putting the F'd up one back on there!

The front cam bearing looks a bit worn but I'm going to assemble the top end back together without replacing the bearings and hope for the best! If I have problems, guess I'll have to pull the block out and freshen it as well then.

-klb

[Mike C]

Looking forward to hearing how it runs! That should be a good cam for your combo I think.

[weq92f]

Life threw me a curve ball about mid January so I've put all this on hold for a while. Back on it not though. Got the block all cleaned up and ready for assembly.


-klb

[Mike C]

It has a way of doing that...

Will be watching to see how it comes together.

[weq92f]

some pics...

[weq92f]

My PVC press

[weq92f]

And the button...