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More CAM ADVICE Please

Started by BDF, May 25, 2018, 06:49:07 PM

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BDF

I am wanting to re-cam an engine and am seeking advice/recommendations to minimize problems please.
The engine is fresh and I really don't want to pull the heads or tear down more than what is needed to accomplish the cam & valve train work.
I don't want to waste $$$ but will purchase quality parts to achieve the goal of reliable performance. Is that an oxymoron?

Car:
4000#  this is an around town & highway cruiser, NO drag racing but inevitable, excessive tire spin OK and expected.       
727 Auto (unknown but lower stall TC, 18-2000? willing to purchase new one to compliment ideal combination if needed)
No A/C but PS & PB
3.23 SG
235/55r17 tires, 27" tall
MUST run on 91 OCTANE

Engine:
'77 RB BLOCK
4.375 bore
4.375 forged crank
7.1 forged rods
Icon 10.25cr pistons
ARP rod & head bolts
Elgin heavy wall push rods (5/16?)
Cloyes 3-bolt billet timing set
Promaxx 210 runner x 84cc heads ('claimed' OTB flow = 256@ .400, 278@ .500, 294@ .600)
  heads had more bowl work & clean-up NOT ported, were cc'd, pushrod clearanced & intake port matched to
Performer RPM intake
Quick Fuel 780 vac sec carb
MSD 8546 dist, 6al, blaster 2 coil & firecore wires
1 7/8 x 36 x 3" headers to x-pipe & free flowing mufflers then 2 1/2" pipes to rear of car
Engine makes 630tq @ 3700 and 551 hp @ 5300 but has ROUGH idle characteristics & low (9" @ 900rpm vacuum)
I am satisfied with the long block but want to replace the following for known reliable parts and seek suggestions to replace the following:
Bullet Cam, is now 300* w/ .540 lift (thats all I know now, not much is it? To rough for me)
Bullet HYD FT Lifters
Springs (unknown, 'good to .600')
Engine has streetmaster ss roller tip rocker arms, adjustable, 1.6 ratio (replace with Crane ductile iron?)
I don't like the thought of them coming apart in my engine.
I would like an 'easy-on-valve-train' hyd FT BUT am open to solid FT as well.
I have Hydroboost waiting in the wings if needed, so that is an option if necessary.
I don't plan on spinning this past 6000rpm but would like it to stay together if it did...
And again, the thing must run on 91 octane, oh well!
I hope this is enough info to begin with so start spending my money, thanks!




BSB67

The rest of the cam specs would be nice.

Do you have a cylinder pressure numbers?

What do you like or want to keep as far as the it does well now?

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

BDF

Thank you for responding.
I don't have any more specs on existing cam is the problem. All I know is it is a Bullet hyd FT with 'about 300* dur. and .540 lift' and 1.6 ratio rocker arms. I've looked at the Bullet master lists online and there are a lot of similar spec cams but I can't figure out much more than the lobe lift & durations posted. I have the dyno print out & balance sheet and rudimentary parts list but I haven't had it in car yet. I've had the valve covers & oil pan off and everything looks great except the rocker arms  :eek2: I'm seeking advice because of 10.25 cr & 91 octane limits.  I know the intake valve timing events are critical to performance & don't want to 'hope' I got it right.
I've been reading ALL of the proven engine threads & more here & elsewhere and decided I should leave the cam selection to experts in the field to maximize the bang for the buck.
I realize that this is going about this completely backwards (engine build before cam) but I am comfortable with the build & the cost of upgrades to valve gear still won't put me in the hole for cost. I (think) I got a great deal still knowing I would spend more on it.
I was tempted to just install the hydroboost and run it like it is until I went on a drive that should have taken 1 hour but took 2. I don't want to suffer if/WHEN I get stuck in traffic with a long duration, rough idling cam.
I've been playingaround with the Wallace & Icon compression calculators but still only have what I feel is rudimentar knowledge for this sort of thing. I do not want to make a big mistake with the cam & supporting parts.
I have to sign off now, bad weather & the cell signal fails here. Also hurt my hand & it takes a long time to type & correct 1-2 mistakes for each word right now.
I will check back in a day or to & post some cams I had considered before thinking better of it on my own.
Thank you for your willingness to help.

Challenger340

On the original Dyno sheet you stated 551hp @ 5300 rpm, which is a product of the "rough" idle F.T. Camshaft events, including what's called the overlap event(port reversion) at lower rpm's present in that Cam grind. Unfortunately, given the rather small Heads for the large engine, the only way that indeed the 551hp was even present at 5,300 rpm, was in fact that the Cam was THAT large in Duration, including that overlap(port reversion = lumpy idle)
just say'in...
you can't "have your cake and eat it too" so to speak ?

Invariably, there is only so much you can do with a Camshaft, and generally speaking within static parameters, you typically don't gain anything somewhere, without sacrificing somewhere else ?

just say'in....
you have a large Engine with relatively small Cylinder Heads.  Although the current F.T. Camshaft, as I understand it is quite "lumpy" and hence you want more "streetable".... you must understand at the outset that a good portion of the 551hp @ 5300 rpm is a direct result of that Large F.T. Camshaft carrying the small Heads.
Reduce the Cam Lift, Duration, and shorten the Overlap events with a wider LSA to make things more "streetable", and you may expect to lose HP, and the Peak rpm where that HP occured. The Good News is that Higher/Flatter Torque can be expected with a smaller more "streetable" Cam, and really Torque is KING on the Street with the heavy car anyways.

IMO, before selecting another Camshaft, you should get a Degree Wheel and magnetic base dial indicator, start reading.... and plot the current Cam events as a starting point for best results moving forward.

The other option is to consider moving away from a F.T. Cam/Springs, etc., and start considering Roller style Camshafts which can provide more power versus Cam event size than the F.T. Cam.
Either way...
I would forget 6,000 rpm as a viable upper rpm limit with any Cam given the small Heads/Large Engine combo... and especially with a smaller Cam as you are intending..... ain't happenin !
Only wimps wear Bowties !

BDF

Thank you for the info Challenger340,
I understand (most of) & agree with everything you state.
I knew this would be a compromise when I got the engine with those heads & cam.
I'd be happy with 500 reliable hp which should be relatively easy to get with that many cu. in. even with those heads.

"Reduce the Cam Lift, Duration, and shorten the Overlap events with a wider LSA to make things more "streetable", and you may expect to lose HP, and the Peak rpm where that HP occured. The Good News is that Higher/Flatter Torque can be expected with a smaller more "streetable" Cam, and really Torque is KING on the Street with the heavy car anyways."

This is what I want to do, then got lost with to many choices/options.

I didn't mean to convey the idea I want to run the engine to 6k, but rather I want it to be built well enough (good parts) so that if it did get spun that fast that it wouldn't fly apart...I will be using a rev limiter.

As far as looking at roller cam profiles,
Are hyd roller lifters ok to 5-5500rpm w/out the lifter bores being bushed?
&
Are sollid roller (street only) oK to idle around for lenghty periods of time?
I do like the idea of a roller set up & am willing to pay the price.

I am not looking for a max hp build nor trying to eek everthing thing out of what I have but rather just put together as reasonably healthy & reliable engine as possible with what I have to work with in this case.
If I did go with a roller setup in this case what would be better, hyd or solid?
I don't mind checking/setting lash...

I have been looking cams like this:
Howards #CL721161-12 is a hyd FT with 235/245 @0.50 & .488 .488 w/ 1.5 or .520 .520 w 1.6 rocker ratio.
It is LSA 112 & centerline 108 
There are so many choices so close I bogged down & thought I would seek council.
I have a lot of cam recommendation requests out there & need to call Lunati back.
After reading all the engine builds here and elsewhere & seeing the suggestions & critiques I though I'd go ahead and ask here also.

I read on the Hughes site that when picking a stroker cam going 2 sizes up from the characteristics listed for a standard size engine is generally a good idea. I also just read that if confused to call them...
Thanks again for the response & wisdom!


XH29N0G

I have a question, that all of you are probably factoring in, but I don't know enough to be sure whether it is an issue (and I didn't see it noted above). 

If a smaller cam is used, won't something else have be done to keep the dynamic compression in a range where detonation doesn't become an issue? 10.25 static CR strikes me as in the middle of what people do, but still pretty high.

Apologies if I missed a comment about this on my read of what has already been posted.
Who in their right mind would say

"The science should not stand in the way of this."? 

Science is just observation and hypothesis.  Policy stands in the way.........

Or maybe it protects us. 

I suppose it depends on the specific case.....

BSB67

Quote from: BSB67 on May 25, 2018, 08:27:39 PM

Do you have a cylinder pressure numbers?


Don't know if you answered this question yet?  If you don't have the numbers, they will be easy enough to get and will help in giving advice.  Piston part number and any other build details like CD, head gasket and chamber volume would help verify the compression ratio.  Understand that with the more uncertainty in your current set up, the more uncertainty in the cam recommendations.  None of this precludes us from giving recommendations, but there is a bit more risk particularly on the ping avoidance/gas goal.  Generally speaking, I think the direction you are going is correct, smaller duration lobes, wider LSA.

Here are some observations and opinions.

You're not looking for max power and giving up some power to make the the car more docile at low speed is worth it.  I'm also sensing that ideally you are more of a close the hood and forget it kind of guy.  Is that is correct?  If so, you might want to stay away from solids.  Myself, I prefer solids, but they are noisier, harder on valve train parts, and do require some additional maintenance.  The higher lifts that usually come with hydraulic roller cams will help make more power over a hydraulic FT.  With that, consider a hydraulic roller.  This is just one man's opinion based on what I think I'm hearing you say.  You should get clear on this yourself first.

Nobody talks about cam overlarlap anymore.  I think we believe we've become too sophisticated to over simplify a cam in this regard.  And probably true in most cases, but for a street car where idle quality matters, it is still a worthwhile number to look at and consider.  Smaller duration lobes and larger lobe separation angle will result in a smaller overlap.  The factory hp cam overlap is 46° (advertised/seat timing).  My guess is your cam has an overlap >80°.  The smaller the overlap, the smother and better the idle quality is.  My opinion, target 60°, +/- 4°.  As I'm sure you know, larger duration has a higher hp making potential (generally speaking and within reason for the combination).  You can read about the effects of LSA, but again, generally speaking, lower LSA seems to make greater peak power, larger LSA broadens out and flattens the hp curve. Typically, the LSA ranges from 106° to 114°.   Bracket guys with high stall converters like 106 - 108°.  Street cars balancing idle quality and performance will compromise with 112-114°.

So now you can take these three cam specs, overlap, duration, and LSA and plug and play with some understanding of what you gain or give up as you change any one of them.

So here are some examples of how you can mix and match.  The first is the least aggressive Comp Cam lobe profiles to the most.  Lift with 1.6 rocker ratio.

1) Thumr 3026 lobes
291°/291° (235/235° @ 0.050) on 114° with 63° overlap.  Lift is 0.555

2) Extreme Energy lobes 3316/3317
288°/294° (236/242° @ 0.050) on 114° w/ 63° overlap.  Lift is 0.555

3) Magnum high lift 3111/3122 lobes
286°/290° (230/236° @ 0.050) on 114° w/ 60° overlap, lift 0.600

4) Extreme Energy 3194/3196
282°/288° (230/236° @ 0.050) on 112° w/ 61° overlap, lift 0.620


Personally, not too sure of the merits of larger exhaust valve duration on a big cu.in, low rpm, low compression heavy street car with good exhaust.  My guess these would all run fine, and the power difference would not be that large.









500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

BSB67

  And a couple of other comments:

1)  Just because your springs are good to "0.600" lift" does not mean that will work with all cams at and below that lift. 

2) You could probably gain some power back after the cam swap with a 950 hp style carb.   :Twocents:


500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

Challenger340

Quote from: XH29N0G on May 27, 2018, 06:11:37 AM
I have a question, that all of you are probably factoring in, but I don't know enough to be sure whether it is an issue (and I didn't see it noted above). 

If a smaller cam is used, won't something else have be done to keep the dynamic compression in a range where detonation doesn't become an issue? 10.25 static CR strikes me as in the middle of what people do, but still pretty high.

Apologies if I missed a comment about this on my read of what has already been posted.


That's exactly the point regarding my post about some "homework" is required before moving forward with any new and shorter ABDC Intake closing event Camshaft ?
A wider LSA and reduced scavenging efficiency can only compensate so much..... invariably with shorter lobes there will still be an rpm range where the VE is high and it would be nice to know we aren't exceeding the Fuel stability ?

Elevation, Heat Load, quench, current static pressure present, LOTS of factors needed for accurate assessment moving forward ?
especially...
since as I understand things a 3.23 Cogged rear with little to NO stall Converter ? is also contemplated ? Is that correct ?

I mean I all FOR that "stump pulling" Torque these big Wedges can deliver in these Heavy Cars.... just say'in, there can more to it in this case on a pre-built combo with many unknowns ? than simply use "this" ?



Only wimps wear Bowties !

BDF

Quote from: XH29N0G on May 27, 2018, 06:11:37 AM


If a smaller cam is used, won't something else have be done to keep the dynamic compression in a range where detonation doesn't become an issue? 10.25 static CR strikes me as in the middle of what people do, but still pretty high.



This is why I was asking.

Regarding the other comments & questions I haven't answered yet:

The engine is not in a car, it is on a build (not run) stand so I don't have cranking #'s.
Regarding springs 'are good to .600': that is the type of generic info I DO have. I thought that I stated that I want to replace the entire valve train (except timing set) including rocker arms with compatible, known parts.
I do not know QD. I did not want to have to pull heads because if I did they'd be off to the porter or be replaced. That stlll may happen, but I'd rather not at this time.
The pistons are Icon, all I saw on the bottom was 'Icon' and 'R120' BUT I don't know the Felpro head gasket # OR how much the block was decked so... :shruggy:   :brickwall:
The TC is low stall, but I stated I would/will purchase an appropriate one for whatever the build ends up being.
& lastly yes, I would prefer that this engine be low maintenance/dependable, not maximum build as I have plenty of other junk to occupy my time.
It isn't the mechanics/wrenching aspect of this but rather the science/physics of camshaftery.
I see how this is a can of worms with all the unkowns so I have engaged an engine builder to help me out and I will deliver the engine to him to explore/diagnose.

I thank you all for the replies & will post what I find out & decide to do/go with.  :cheers:

This was a good read on the subject:

http://victorylibrary.com/mopar/cam-tech-c.htm#factor

BDF

BTW:
I will be rebuilding the #'s engine for the Charger later and intend to do IT correctly to begin with.
My dad asked for a 'hot' 440 in '87 but I'm pretty sure he got the 1263s instead  ::)
The heads were 'surfaced' but the block was not molested at least.

PRH

My preference would be to use a solid flat tappet cam.

As long as you're pretty confident in the build spec of 10.25cr, I think there is enough info there to chose a cam.

I'd get rid of the speedmaster rockers....... I just don't trust Chinese rockers.
Since its a street car, I see no real advantage to running 1.6 rockers.
It's just extra wear and tear on the cam and lifters for a very minimal power gain.

I'd be looking at a cam in the low/mid-240's @.050, single pattern or minimal split, 112lsa and match it up with some Comp Ultra-Pro magnum rockers and EDM lifters.

I also think the seat of the pants feel when going to WOT would be greatly improved by using a bigger mechanical secondary carb.

Even a pretty tight 11" converter is going to stall more than 2000 with a mildly built 4.375 stroke motor in front of it.
Porter Racing Heads......Building and racing Mopars since 1980

BDF

Thank you VERY much for the reply PRH,
I am reasonably sure the CR is 10.25 (+/- .05). When I pulled the valve covers and saw those rocker arms is when I knew 'things' needed changing and decided to change out the cam/springs/rocker arms &c. My preference in this case is 1.5 rocker arms, still debating pros & cons of the type of cams... :scratchchin:
Those are some solid recommendations  :icon_smile_big:

BSB67

Quote from: BDF on May 30, 2018, 11:42:07 PM
Thank you VERY much for the reply PRH,
  :icon_smile_big:

Maybe just pm him next so the rest of us won't spend an hour giving a thoughtful response.

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

BDF

Quote from: BSB67 on May 31, 2018, 05:20:53 PM
Quote from: BDF on May 30, 2018, 11:42:07 PM
Thank you VERY much for the reply PRH,
 :icon_smile_big:

Maybe just pm him next so the rest of us won't spend an hour giving a thoughtful response.
Thank you for YOUR time BSB67!
I appreciate and am considering ALL of the thoughtful comments & suggestions including anymore if forthcoming.
I am reviewing everything that has been suggested before deciding.
One of the reasons I posted the question was in case it may be helpful to someone else as it seems like most builds are for maximum power and not what I have in mind.
It's difficult to communicate effectively via thumbing an iphone...
:cheers:
Edit: I appreciated the thought that it may not be necessary to pull the heads to measure things for a cam selection :2thumbs:

c00nhunterjoe

Fwiw, i dont think i have ever seen a build on this forum that was built for maximum performance.

metallicareload99

I get the impression that we here @ DodgeCharger.com are regarded as being on the lower spectrum of "Performance" but I'm grateful that we have the kinda people around here that have posted in this thread.  I know I don't post a lot and I try to keep my questions to a minimum but I spend a lot of time on here reading what has been posted in the past


Quote from: BSB67 on May 31, 2018, 05:20:53 PM
Quote from: BDF on May 30, 2018, 11:42:07 PM
Thank you VERY much for the reply PRH,
 :icon_smile_big:

Maybe just pm him next so the rest of us won't spend an hour giving a thoughtful response.

FWIW, I'm not trying to stalk you or anything like that, but I've probably read every post you've made on these matters for as long as I can remember. Threads like these help me out.  You and other members post a lot of valuable information that benefits people who never or hardly post in the threads


Quote from: c00nhunterjoe on May 31, 2018, 09:04:39 PM
Fwiw, i dont think i have ever seen a build on this forum that was built for maximum performance.

Uhh, everyone probably has a different definition of "Maximum Performance" but this one exceeds my definition:


Quote from: 6pkrtse on February 26, 2018, 03:57:24 PM
Mine likes 2 big four barrels.

1968, When Dinosaurs Ruled The Earth

BDF

Quote from: c00nhunterjoe on May 31, 2018, 09:04:39 PM
Fwiw, i dont think i have ever seen a build on this forum that was built for maximum performance.
Thank you for the reply,
It 'seems' to me that a lot of what is typed can be misunderstood/taken the wrong way and perhaps this will be also.
I do try to choose words carefully but sometimes rush the thoughts.
I will try to stay away from general statements from here out and attempt to keep my questions simple and directly pertaining to the point. :cheers:
I.E:
I am NOT trying to eek 'maximum performance' from this particular engine.
I would LIKE the most TROUBLEFREE power out of a cam/associated parts swap w/out 'being on the edge' so to speak.


BDF

Quote from: BSB67 on May 27, 2018, 08:59:11 AM
Quote from: BSB67 on May 25, 2018, 08:27:39 PM

Do you have a cylinder pressure numbers?


Don't know if you answered this question yet?  If you don't have the numbers, they will be easy enough to get and will help in giving advice.  Piston part number and any other build details like CD, head gasket and chamber volume would help verify the compression ratio.  Understand that with the more uncertainty in your current set up, the more uncertainty in the cam recommendations.  None of this precludes us from giving recommendations, but there is a bit more risk particularly on the ping avoidance/gas goal.  Generally speaking, I think the direction you are going is correct, smaller duration lobes, wider LSA.

Here are some observations and opinions.

You're not looking for max power and giving up some power to make the the car more docile at low speed is worth it.  I'm also sensing that ideally you are more of a close the hood and forget it kind of guy.  Is that is correct?  If so, you might want to stay away from solids.  Myself, I prefer solids, but they are noisier, harder on valve train parts, and do require some additional maintenance.  The higher lifts that usually come with hydraulic roller cams will help make more power over a hydraulic FT.  With that, consider a hydraulic roller.  This is just one man's opinion based on what I think I'm hearing you say.  You should get clear on this yourself first.

Nobody talks about cam overlarlap anymore.  I think we believe we've become too sophisticated to over simplify a cam in this regard.  And probably true in most cases, but for a street car where idle quality matters, it is still a worthwhile number to look at and consider.  Smaller duration lobes and larger lobe separation angle will result in a smaller overlap.  The factory hp cam overlap is 46° (advertised/seat timing).  My guess is your cam has an overlap >80°.  The smaller the overlap, the smother and better the idle quality is.  My opinion, target 60°, +/- 4°.  As I'm sure you know, larger duration has a higher hp making potential (generally speaking and within reason for the combination).  You can read about the effects of LSA, but again, generally speaking, lower LSA seems to make greater peak power, larger LSA broadens out and flattens the hp curve. Typically, the LSA ranges from 106° to 114°.   Bracket guys with high stall converters like 106 - 108°.  Street cars balancing idle quality and performance will compromise with 112-114°.

So now you can take these three cam specs, overlap, duration, and LSA and plug and play with some understanding of what you gain or give up as you change any one of them.

So here are some examples of how you can mix and match.  The first is the least aggressive Comp Cam lobe profiles to the most.  Lift with 1.6 rocker ratio.

1) Thumr 3026 lobes
291°/291° (235/235° @ 0.050) on 114° with 63° overlap.  Lift is 0.555

2) Extreme Energy lobes 3316/3317
288°/294° (236/242° @ 0.050) on 114° w/ 63° overlap.  Lift is 0.555

3) Magnum high lift 3111/3122 lobes
286°/290° (230/236° @ 0.050) on 114° w/ 60° overlap, lift 0.600

4) Extreme Energy 3194/3196
282°/288° (230/236° @ 0.050) on 112° w/ 61° overlap, lift 0.620


Personally, not too sure of the merits of larger exhaust valve duration on a big cu.in, low rpm, low compression heavy street car with good exhaust.  My guess these would all run fine, and the power difference would not be that large.









I REALLY appreciate this detailed response!
I first read it after a 14 hour day (for the last 2 weks) & to tired to respond appropriately at the time. ALSO: my phone screws up at the worst times & I lost a lenghty, time conuming response when I tried the 1st time, so very discouraging.
I have reread many times & am reviewing the cams you listed.
Phone is acting up now so I'm not going to type much more
Now as it may disappear...again.
I thank you for the time as I know how much it takes of mine to do this  :cheers:
I will add that I too read all your posts with great interest, as I do many others here to glean knowledge.

BDF

Thanks for the guidelines, BSB67 & PRH!
That is the basic info I was hoping for to help make an informed decision.
I am still looking/comparing. I see why people have custom grinds made now as it is very difficult to find something off the shelf with all the parameters I am seeking.
Found & am using this to help compare:
http://members.uia.net/pkelley2/Overlap.html
Thanks again  :cheers:

BDF

Tearing down the engine to see what's what & upgrading to TF240s for better breathing... :cheers:

c00nhunterjoe

So did we pull the heads yet and see what pistons are in it?

BDF

Sorry for the lapse...been busy & away...
Yes, the engine is apart & builder likes the what he sees except for 2 cylinders that need honing and he said the ring gaps were too much. He went in to great detail about what they were & why they were wrong but I don't recall the particulars.
The pistons are Icon and static CR is 10.31:1. I didn't ask for a part # but will have a complete build sheet later.
The builder has been using Dema Elgin for all his cams for 50 years and he told me he was meeting with Dema today & will give me all the details soon. They both have all the car's specs & my desired performance/reliability desires and I am leaving the cams spec'ing & grinding to Mr. Elgin as I have confidence in his expertise.
Thank you all for the interest you've shown, this may be a slow build but I will update if anything noteworthy occurs.
:cheers:

c00nhunterjoe

Sounds like the homework is being done. Good choice. While ive never used elgin, he is like racer brown, does all of his work inhouse with attention to detail.

BDF

Yes, I'm happy with the builder's attention to detail & communication. He called today to tell me the cylinders will clean up with a hone & be round without taper and still have the thickness he wants.
I'm glad I didn't have to shop for a block... :2thumbs: