bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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.

Re: bbc retrofit roller update
 

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.

Re: bbc retrofit roller update
 

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.

Re: bbc retrofit roller update
 

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.

Re: bbc retrofit roller update
 

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.

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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.

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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.

Re: bbc retrofit roller update
 

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.

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.


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.


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:lol:

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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.

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

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

Re: bbc retrofit roller update
 

It has a way of doing that...

Will be watching to see how it comes together.

Re: bbc retrofit roller update
 

some pics...

Re: bbc retrofit roller update
 

My PVC press

Re: bbc retrofit roller update
 

And the button...

Re: bbc retrofit roller update
 

My front cover did not make contact with the button. My button measures nearly an inch so it's the biggest one available and it sits nearly flush with the sprocket edge so no loss there.

After much tossing around I finally decided not to spend more cash and just modify my cover to make it work. Beat the crap out of it with big hammer until it made contact with the button then slowly beat it back out until I managed to get the clearance to .006 on the dial with the cover and gasket torqued down.

I may yet do a new cover down the road if this one ends up making noise or causing timing fluctuations. My guess right now is that it will be fine. Moving on.




-klb

Re: bbc retrofit roller update
 

Did you use some sort of thrust bearing/washer on the cam gear? You may not have to, but on mine I ran the Summit billet 9 keyway double roller chain with Torrington bearing to protect the block. The 3/4" big block thrust button worked fine on that setup.

The Comp kit came with a cam sprocket that did not have bearing or bushing so I guess they don't think it required, but I felt better about long term reliability with it.

Re: bbc retrofit roller update
 

My timing set from Comp didn't allow for a bushing or bearing between the cam sprocket and the block. I did quite a lot of reading on the subject and decided in the end that this setup should do OK without. That is, as long as I get the thrust clearance correct rather than just jamming the cam hard against the back stop with the front cover.

Re: bbc retrofit roller update
 

Decided to drop the oil pan to replace the gasket...

Bad idea...

Not enough room to drop it all the way...

So now I own a 2 ton engine hoist!



-klb

Re: bbc retrofit roller update
 

Got the pan removed finally and found that most of the bolts had been way over tightened which has bent the pan up pretty bad. Can't imagine how this thing wasn't leaking far worse than it was. The worst of the damage measured 1/8 inch of bolt hole bending up toward the block due to over tight bolt. Most of the damaged bolt holes measured just under 1/8 inch.

Good thing I took it off!

-klb

Re: bbc retrofit roller update
 

Some people seem to think that if tight is good enough, then REALLY tight is even better. Quite often that is when problems occur.

Re: bbc retrofit roller update
 

Progress...

I used the one piece fel-pro gasket, attached it to the pan with some plastic coated wire. Then got the pan up onto the block and just started two of the rear-most rail bolts. Climbed around to the top and situated the front gasket teets into the holes in the timing cover then secured the pan as tightly as possible against the gasket to hold in in place ( I used the wire again here ).

After making sure the gasket was properly in place along the rear main cap channel, each rail bolt was installed ( the wire was easily removed ) and then torqued in sequence beginning from the center working out toward the end caps. Only then would the two pan to front cover bolts reach. I torqued the rails to 60 in-lbs and the two cover bolts to 100 in-lbs.

Re: bbc retrofit roller update
 

Before I locked down the pan, I went to check the cam thrust clearance one last time. There was none. The cam was being held tight against the rear stop by the timing cover. This! This after my having spent a load of time and effort to create .006 of cam thrust clearance with that cover torqued down. I have no idea how this happened?

That cover is now on the left-over parts pile. I replaced it with a Cloyes quick-button two piece cover. This thing has a built in button that is adjustable with the cover installed. Done.

Placed a head up on there to check P/V clearance...

-klb

Re: bbc retrofit roller update
 

No P/V issues so...

Got the heads on there and torqued down. No way I could have done this alone with the engine in the truck. Good friend of mine came by and helped me get them safely over the fenders and on the block. Thanks Tom!

-klb

Re: bbc retrofit roller update
 

Adjusting these valves cold was an adventure. The rocker nut could be adjusted by hand down to zero lash and beyond. I could use my fingers to crank the rocker down and watch the plunger in the lifter just keep going down. If I wanted I could simply spin the rocker all the way to the bottom of the lifter I bet.

So, I had to decide to pick a spot and call it zero lash before the lifter starts getting depressed by the rocker bolt, then add my additional fractions of a turn and lock down the nut with the poly lock ( This while on the base circle ). Given these are roller lifters and the docco says no reason to pump-them-up, I'm just guessing at this first round of adjustment.

After the adjustment on all 16 and of course all the rotation and subsequent plunging of the push rods into the lifters ( dry ), those rockers whose lifters are on the base circle are loose now and well, just I'm not real happy about that! My thinking is that when the pressure comes up, those lifters will pump up and all that slack will be gone.

Any thoughts?

Moving forward...

BB is assembled and the headers installed. Should achieve startup today after we get the radiator installed, fans wired and the fuel lines plumbed up tight.

The headers fit real nice. Hedman 68198 for 67 BB Chevelle. Passenger side was the tightest as far as install and potential for interference, but the only issue was had to relocate the main battery lead to the starter to keep it off the tubes.

Driver side install was wide open and easy. The longer extension to the collector on this side meant the truck needed to be up higher on stands to gain a bit more clearance below but the header needed no help at all going up between the frame and engine into it's final resting spot. Plenty of room to install it without any issues or interference.

I think if a column shifter were in use for the transmission, this header might have issues with that. Mine is of the cable type so no worries there. The collector terminates about 9 inches from the transmission crossmember in my case on this truck so I don't have any issues there.

These headers sit right at frame level essentially so they are perfect for my lowered stance!

-klb

Re: bbc retrofit roller update
 

Started it up today... No O2 sensor so it's running in open loop and very rich... but it's running!!! Tuesday I'll get it to the exhaust shop to get the noise down and start tuning it.

Here's the link to the video...

https://youtu.be/7W148nXt60A


-klb

Re: bbc retrofit roller update
 

How do you like the 402/700r4 and 3.73 combo?

I have a mild 402/4l80e and a 3.08 that Im considering going to another gear.

You think the 1800 stall is right for you?

Build looks nice btw.

Re: bbc retrofit roller update
 

It is the right combo for me in terms of off-the-line gear and highway cruising. The stall I have is not enough. This cam update has done a lot in the way of improving this truck. I'm still tuning so can't really update fully on the cam update and what it has done to this engine, but the BBC=>700r=>3.73 definitely makes for a great combination IMO.

EDIT: It's not all roses. IMO the weak point of the 700r is the gear ratio jump between 1st and 2nd...
... for comparison have a look at this little chart showing gear ratios for popular transmissions. Note the 700
... has a 1.44 difference between 1st and 2nd gear where the 350 and 400 have only 1.0.
Trans.....gear ratios 1/2/3/4/..
700r4.....3.06/1.62/1.00/0.68
th400.....2.48/1.48/1.00
th350.....2.52/1.52/1.00
powrg.....1.76/1.00

and for fun...

6L80E.....4.03/2.36/1.53/1.15/0.85/0.67
8L90E.....4.56/2.97/2.08/1.69/1.27/1.00/0.85/0.65
10LXX.....4.70/2.99/2.15/1.80/1.52/1.28/1.00/0.85/0.69/0.64

Hth,

-klb

Re: bbc retrofit roller update
 

.
Drove the truck open headers and with no O2 sensor to the exhaust shop on Tuesday morning. It was about a 6 mile trip on two lane black top back roads, across and onto one main 6 lane for a bit to the shop. The truck made it all the way there but it was super loud and just a choppy slow drive. I was worried about so many things including, because I couldn't hear it, the valve train flying apart because it was mal- adjusted!

Pulled up there just fine though and had the shop install the 02 bung in the appropriate spot, reduce the 3" flanges to my 2.5" pipes and install an H pipe behind that.

With that, I was able to hear that I've got one, maybe two tapping rockers that ~may~ need attention. Maybe, but overall that initial adjustment was pretty good! Also very apparent was a massive single cylinder exhaust leak at the head on the passenger side.

Unfortunately something else became immediately obvious, somewhere near the front of the engine a noise indicated contact of a worrisome sort. The sound was cyclic as if spinning and encountering more, then less 'resistance' over and over again and varying with engine RPM. High pitch and scratchy sort of grinding sound.

Slow and easy drive back to the shop...

Tried to pinpoint the sound using a couple tricks but was not successful so I removed the belt and fired it up....bamb! the sound is gone!!!

I was real worried that my button troubles were about to come back, I was going to find that the sound was the cam sprocket eating the block.

Only thing I can find that has any sound at all when I spin it is the water pump so I'm going to swap that out tomorrow and we shall see. The idler, tensioner, alt and ps pump seem OK to me.

-klb

Re: bbc retrofit roller update
 

Thanks for your input. I think Ill look around the 2200-2400 rpm stall when I do mine. I don't really want to spend $1k so Ill probably look into a stock sized converter. I also don't know what cam is in my truck so its hard to judge whats needed.

I haven't put many miles on my build yet but the 3.08 and the 2.48 first gear makes for a long time before getting into second. Itll still bark the tires pretty nice though going into 2nd.