Thinking about a change. Opinions needed

[BigBlockMonte]

Hey all

I'm looking to do a change on the chevelle. Thinking of going with a different camshaft, maybe bump up compression a lil. Also doin a different trans.

 

Here is my current set-up on the car:

 

1971 Chevelle SS

468 Cubic Inch

Forged crank, Eagle Rods, Forged JE Pistons.

Pro-Comp Square Port Aluminum heads (2.25 intake/1.88 exhaust) 320cc runners.

Comp 924-16 springs, Comp stainless steal 1.7 ratio roller rockers.

titanium locks.

compression falls at 10.23

Camshaft is Comp cams XE284H Hyd flat tappet. 5.74/5.78 lift.

240/246 duration @ .50 .110 lobe seperation.

Edelbrock Air-Gap Intake Manifold

Holley 850 Carb. Vac Secondary-Electric Choke

3/8 fuel line from tank to carb

Holley 130lph mech fuel pump w/Holley adj fuel pressure regulator. Set at 6-7 lbs of pressure I do believe.

Hooker headers (2inch tubes into 3 1/2 collector.)

3" mandrel bent exhuast from collector to rear of car.

Mufflers are 3" Flowmaster 40 series.

Ignition is a Proform HEI (Springs have been changed to lightest springs)

MSD 8.5 MM wires

Autolite 5224 plugs

Initial Timing is 20 degrees, with the vac advance line off.

Timing at 3k rpms is 37-38 degrees with vac line off.

 

Trans currently is a Th350 mild shift kit.

Trans specialties Low Stall Converter 2800-3200

Duragrip Posi Rear w/Richmond 3.73 Gears

Rear Tires are 28" tall. 275/60/15

Front Tires are 27.1 tall. 255/60/15

 

 

I recently bought a Bowtie Stage 2 200-4r trans. It has a 2500 stall that came with it.

 

I was also looking at this camshaft.

 

http://www.lunatipower.com/Product.aspx?id=2135&gid=284

 

I'm just tossing this around. What do you think?

 

Car is a nice weather driver. I like to cruise to shows, and spirit drive through town, and nail it when I'm gettin on the highway, or a nice stretch of open road.

 

I build and tune 1st & 2nd generation DSM's (91-99) Eagle Talons, Mitsubishi Eclipses, & Plymouth Lasers

 

AWD Turbocharged 4 cylinder engines in cars that weigh roughly 2800 to 3500 lbs.

 

My last eclipse I owned ran 10.79 @ 127mph.

 

With the chevelle, I would like a consistent 11.50 to 11.80 car all day long without breaking a sweat. The Chevelle weighs without me in it 3660lbs w/1/4 tank of gas according the scale at the local salvage yard. I weigh in at 170lbs. Total of 3830lbs.

 

The car runs okay now, I'm just not real thrilled with it, I feel it should be a faster car, but then again, All I build and tune is these DSM's.

 

Please help me out on this. Thanks everyone in advance for reading through this and helping me.

[Sam (Bones)]

if it was me....

 

I'd leave the engine alone

[CrazyDavey]

as far as the cam swap I don't think there's enough difference in the new cam to make much difference. Like the one you have now it lacks lift, something big blocks with 320 heads like. I would be looking at something with at least .600+

 

If you were to go with a custom 3500 converter then a switch to a double pumper carb will work wonders.....also what are your currect 60' times? There's a lot to be had in suspension set up....JMO...Dave

[Mike 57]

I agree with Dave on the cam. I would go with a roller as funds allow, and more converter. If you think the new 200 can handle the engine I would put some gear to it.

[BigBlockMonte]

if it was me....

 

I'd leave the engine alone

 

Here's why I wanna tear it apart now. Recently I broke a valve spring, it was the single springs the pro-comp heads come with. I now learned they were good to .580 lift. I was right there, I was shifting the car at 6500. I replaced the single springs with the comp 924-16. I did it with the heads on the car using the existing shims that was already on the head.

Ok Fast forward, car felt okay, but then one day while the car was warming up, 1500-1700 rpms. I heard the car start missing real bad, I run out to shut it off, right before I did, I heard loud clacking. Shut it off, pushed into garage. Removed valve cover to find one of the valve locks were broken and the clacking was the valve smacking the piston. I'm worried. replaced the lock did a compression test, its still good. Then I noticed at that time I had 4 crack scorpion roller rockers. I ordered a new set of comp stainless steal rockers and all new comp valve locks. Replaced them in the car.

Okay Now for the real reason...... Im hearing that, How do I know the installed height is correct for the 924-16 springs, and the spring pressures are all the same. I'm also hearing if the spring pressure is to great, or the height is wrong, and they are not all the same, I'm probably wiping the lobes on the camshaft which is causing the car to feel slower. It made sense to me, because when I first put it together, it screamed, and now, I don't feel it. I'm told to remove the heads, take them to the machine shop, have them do the springs pressures, installed height etc to make sure they are perfect, and while I'm at it, to replace the cmashaft either with the same cam, or go alittle bit more.

So there you have it, Also the last thing is when the valve lock broke, I recoverd most of the pieces laying in the head, but there is still one or two small pieces that has to be in the pan now, which also has me worried. I do have a magnectic drain plug, But thats it.

Sorry to ramble on, wanted you to know my exact reasonings behind this sudden change.

[Mike 57]

You can do the valve springs on the car and measure with a valve height micrometer

[BigBlockMonte]

Think I just made up my mind, fortunately the springs I have are the same installed height as the single springs I took out. My machine shop guy said he wouldnt worry to much about the two little pieces from the lock, since I have a magnetic plug. Took a buddy of mine for a ride, he liked it. To me it should be more I would think.

 

So I have decided to switch out the camshaft for a roller camshaft. I don't know what would be the best for my situation. I hear the solid roller makes a ton more power and doesn't fall on its face in the upper rpm's like the hydraulic roller cams do. Don't know how true this is, so as always, I ask on here before I make a decision.

 

So what would be the best my application. Hydraulic Roller or Solid Roller.

 

I seen this one, that looked pretty stout: http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=499&sb=2

 

Here's another one: http://www.lunatipower.com/Product.aspx?id=2156&gid=289

 

And this one: http://www.lunatipower.com/Product.aspx?id=2144&gid=286

 

If you think of a another one, please let me know. I'm not making a move until I hear you guys. Thanks again

[71monteme]

if you are more street then strip, i would stay with the hydro. the solid roller needs more maintenance and it is harder on the valve train components.

i run an ultadyne cam that is close to the last lunati spec you posted (286) with the irons heads last year the car went 11.20's. this year with the procomp heads just like yours, i'm expecting to be in the high 10's. hope that helps your chosing.

 

thanh

[Mike 57]

I agree with Thanh on the street/strip deal mostly street go with a hydraulic. If you are set on a solid I have a mild solid roller I would sell, Comp solid roller ran 11.6s with it and a 3.42 gear.

I really think you should go hydraulic and don't skimp on the lifters.

[BigBlockMonte]

Mike that solid roller you have is one of the ones I was really interested in. I would like to do it, but if you feel like doing a hydraulic roller is all around best for me, then I'll concentrate on looking at some of those. The solid rollers look so much more stout when comparing, but if I have to readjust valves every other week, that would start to get old after awhile.

 

but just for kicks, do you have the whole kit or just camshaft.

[BigBlockMonte]

If you were to go with a custom 3500 converter then a switch to a double pumper carb will work wonders

 

Hey Dave, I was always told I should run a vacuum secondary carb being my car is an automatic and is heavy. You really feel running a double pumper on my car would make a difference. I asked because my neighbor told me to get a DP when I was building the engine at first. Told me to get a 750 or 780 double pumper, and I would be thrilled with it.

 

But most people told me to get a vac secondary and not to go under an 850 with my set-up.

 

I will say this, when I borrowed a 750 holley vac secondary, before I bought the 850vac sec. The throttle responce was great, (better than the 850 I have now), it was very snappy and had quicker response, you hit it and the tires would light up right now. The 850 I have takes a lil while to get goin.

 

 

[CrazyDavey]

well the thing is Mariano if you have a good converter, like a custom 3500 built for your car a DP will work great. Then you would know for sure it will get quickly to an rpm range that will handle a DP. With a smaller or stock converter then a vac is safer. I ran my 1000 DP with a custom 3500 for a while and it left like a rocket, took 4 tenths off my ET over the vac carb....Dave

[Mike 57]

I just have the cam.

[BigBlockMonte]

I contacted Lunati today through email for them to pick me out a camshaft for the car. I told them I was interested in a Hyd roller because of the minimal wear, low maintenance and good power.

 

Here's what they suggested.

 

Mario,

The cam I recommend is our Voodoo Solid 60241 241/249 on the

Duration @.050, .590/.610 lift with 1.7 rockers, 110/106 LSA/CL,

Rpm range is 2600-6800. The cam & lifter kit is 231.78 plus shipping

Direct from LUNATI.

 

Thanks,

 

Tim Langley

LUNATI CAMS

11126 Willow Ridge Dr.

Ph: 662-892-1510

Fax: 662-890-6309

tlangley@lunatipower.com

www.lunatipower.com

www.facebook.com/TheRacersCompany

 

-----Original Message-----

From: techsupport@lunatipower.com [mailto:techsupport@lunatipower.com]

Sent: Wednesday, May 11, 2011 11:54 PM

To: techsupport@lunatipower.com

Subject: Cam Recommendation from Website

 

 

CONTACT INFORMATION

Name: Mario

Email: bbc454@comcast.net

Phone Number: 724-986-7314

Cam Type: Retro-Fit Hydraulic Roller

 

VEHICLE INFORMATION

Vehicle Year: 1971

Vehicle Make: Chevy

Vehicle Model: Chevelle

Vehicle Weight: 3850

Vehicle Transmission: Automatic

Transmission Stall Speed: 2500

Vehicle Transmission Model: 2004R

Vehicle Gear Ratio: 3.73

Tire Height: 28"

Vehicle Intended Use: Street/Strip

Vehicle Requires Inspection: No

 

ENGINE INFORMATION

Engine Year: 1970-1979

Engine Manufacturer: Chevy

Engine Factory Cubic Inches: 454

Engine Current Cubic Inches: 468

Engine Compression Ratio: 10.25

Piston Bore Diameter:

Connecting Rod Length:

Crankshaft Stroke:

Desired RPM Range From: 2000

Desired RPM Range To: 6500

 

INDUCTION

Intake Manifold Type: Dual Plane (Edlebrock Air Gap) Ported Cylinder Heads:

No

 

CYLINDER HEADS

Cylinder Head Manufacturer: Pro Comp

Cylinder Head Material: Aluminum

Head Runner Volume: 320cc

Intake Valve Size: 2.25

Exhaust Valve Size: 1.88

Ported Heads: No

Rocker Arm Ratio: 1.7

Adjustable Valvetrain: Yes

Maximum Valve Lift Capacity: .630 (Have Comp Cams 924-16 Springs)

 

FUEL DELIVERY

Fuel Delivery System Type: Carbureted

Fuel Injector Or Carb Size: 850Cfm Vacuum Secondary Fuel Type: Pump Gas

Unleaded Fuel Octane Rating: 93 Octane

 

POWER ADDERS

Super Charger: No

Super Charger Type: Centrifugal

Supercharger Boost Amount:

Turbo Charger: No

Turbo Charger Count: One

Turbo Charger Size:

Turbo Boost Amount:

Nitrous: No

Nitrous Amount:

Nitrous Stages:

 

CURRENT SETUP

Current Cam Manufacturer: Comp Cams

Current Intake Duration: 240

Current Exhaust Duration: 246

Current Advertised Intake Duration: 284

Current Advertised Exhaust Duration: 296 Current Intake Valve Lift: 574

Current Exhaust Valve Lift: 578 Current Lobe Separation: 110 Current Intake

Centerline: 106 Area For Improvement: More Upper RPM Power

 

COMMENTS

Comments: Looking for a cam that has good street manners, has good vacuum

for the brakes,and will be able to propel the car to 112-115 mph 1/4 mile

trap speeds.

 

I figure a hydraulic roller is the best choice for low maintenance,minimal

wear, and good power.

 

If i'm mistaken, please advise/direct me to another camshaft you sell,

whether it be HYD roller, or HYD flat tappet.

 

I wouldn't mind a Solid roller or solid flat tappet, if they dont have to be

adjusted every other week like I hear.

 

My engine is in your hands. Thank you

[Ian]

I don't think that is a Roller cam, and can't find it on their or summits website....

[CrazyDavey]

it's a flat tappet, you can't get a good set of roller lifters for that price let alone a kit....I'm a Morel dealer and a set of hyd street rollers are around $350 and some good sportsman hyd lifters are going to be around $550, add another $300+ for the cam....anything more than about .550 lift should have the sportsman rollers...you will also most likely need new pushrods too....solid rollers are not a lot cheaper, anywhere from $330-600 depending on the quality level....JMO

[72MC]

 

Like Davey said above, even though my mill is a sbc, the hyd roller cam was $325 and my roller lifters were $550, full roller rockers were $450, and like Davey said, your pushrods will need to measured properly before ordering. On the bright side, they were awful pretty parts . Seriously though, since trying a full roller setup, its the only way go, IMO, but it is an investment/expensive. - Dave

[BigBlockMonte]

Yeah guys that was my point. I specifically said Hyd Roller in the body of the email, I did however say, if it not the best for my situation direct me to another cam. and he chose a solid camshaft.

 

I'm guessing the solid flat tappet will out perform the hyd roller??? Or maybe he really didn't pay attention to any I said in the email.

[CrazyDavey]

Mariano it's not so much whether it will out preform, it's what you want out of it. The hyd has better street manners as far as being quiet and pretty maintenance free (all rollers should be inspected once and a while). If you want to spin the motor to 6800, 7000 then you need a solid cam. The roller will also ease the worry of going flat because they do not require any special break-in procedures. If you're okay with a cam that will turn to the low 6000's then a hyd is a good cam (as long as you use good lifters and the correct springs).

 

The most important thing is matching the cam spec's to the rest of the motor. If you want to convert to a roller it might be worth your while to go with a custom grind cam (maybe $100-$150 more). That way you can be sure the cam will take advantage of the rest of your combo, I can direct you to someone who can do that if you like.

 

You don't have to rev them high to go pretty fast, I shift mine (a hyd roller) at 5900 and cross the stripe at 6100 and it runs pretty good...you can see my numbers in my sig (Chevelle)...Dave

[BigBlockMonte]

I want the car to do atleast 112mph trap speeds. While having good street manners, Using my existing 2500 stall with the 2004r. I dont have a problem at all shifting at 6k. Thats where I shift now anyway. I would really like the car to pull very hard to 6k keeping me pinned in my seat. The way the car feels now, I feel like I shave in between shifts. (maybe not that bad, but I feel there should be alot more with the combo I have) I could be reaching to high.

 

But Yeah Davey, I would really like the info on getting a custom camshaft for the car. Thats probalby the best way instead of buying of the shelf.

 

Thanks

[CrazyDavey]

PM sent...

[BigBlockMonte]

Called up Chris Straub, Left a message. While waiting for a return call. I called up Comp Cams to talk to them about a custom camshaft. Told them my combo. First words out of mouth were you need more camshaft then that. After talking for about 30mins.

 

He came up with a Hyd Roller Custom Camshaft. It would be

621/624 Lift

242/248 @50

110 Lobe Seperation

 

I can reuse my existing 924-16 comp springs. Which is a plus.

 

When I hear back from chris, I'll let you all know what his specs would be.

[BigBlockMonte]

Okay Talked to Chris Straub today, and now I am really confused and feel dumber. Told Chris my specs and from what I understand he wants to do a smaller cam.

 

I thought about this all day today, and since I'm coming from turbocharged engines, I have to put it in 4cylinder turbocharged terms to help me understand it. Please tell me if I am wrong in my thinking.

 

Before I get started, I am in no way, trying to disagree with what Chris Straub briefly told me today on the phone. I'm just trying to understand this better.

 

Okay like the last post, called comp cams and they suggested a custom grind of 621/624 lift 242/248 @50 on a 110 Lobe speration. Okay I thought that made sense since a few members on here in the past told me I need more lift. Okay

 

Chris is goin with a different approach and going smaller. Didn't give me exact specs, but told me the duration would be somewhere in the 220's range.

 

Okay, Is the camshaft similar to turbochargers, being said.

 

On a 4 cylinder turbo engine, The bigger the turbo we would put on the car, the longer it would take to make full power (or boost). It would be laggy down low until it reach its optimum range. For example. Small turbo may reach its full boost at 2500 to 3000 rpms, and make power till 5,500 to 6,000 rpms.

 

Okay, since the motors can wind out to 7500rpms from the factory, alot of us will put bigger turbos on the motor, okay the bigger turbos will make reach full boost by 4,000-4,500 rpms, but make power to say 7,000 to 7,500 rpms.

 

So with me choosing a camshaft, with me shifting at 6 to 6200 rpms, there is really no need to run a high lift, long duration cam since I won't be in the range where the cam will shine.

 

Am I thinking correctly on this, Please any and all inputs are very welcome to help me understand this alot better.

 

Thanks everyone

 

(I just plug in some cams from the cam quest software. And I'm seeing the higher lifts, longer duration cams, are making more Hp, but the torque is a low. And the smaller lift, lower duration cams have almost instant torque with the Hp a little lower not very much depending on cam, but one average the ones I'm looking at are 10 hp lower, but torque is upwards of 25-40 lbs more.

 

So basically smaller lift, lower duration more torque less hp, larger lift & duration more hp, but less torque to move the car quickly?

 

Am I thinking right?

 

[CrazyDavey]

So basically smaller lift, lower duration more torque less hp, larger lift & duration more hp, but less torque to move the car quickly?

 

Mariano, that's sorts it.....first understand that Chris is not going to give you the exact spec's. As a cam designer if he gives people the spec's whats to stop them from taking it to someone else for the grind, it's just business.

 

Bigger is not always better, it's about optimizing all of the components so eveything is working together. My motor has a very small cam compared to what many might think it has. Did he happen to say 220ish @ what? Not all grinds are measured at .050 so I don't know if that might be the case. What LSA did he mention? Also for your build the heads are pretty large so he might be trying to compensate for that with cam design. With those heads and an aggressive cam you would kill any low end torque which you need for a heavy car.

 

His strength is in the timing events of his cams. In my case for example he designed a lobe profile that opens and closes the intake valves very quickly allowing the cylinder to be "packed" for maximum pressure and combustion. As with you he made these choices based on what I told him I had and what I wanted. So the point is don't get caught up in lift and duration numbers. When you buy a Comp or Lunati catalog cam you are basically buying a compromise. Those cams have to work good in a variety of combo's but they are not ideal for most of the motors they go in. The cam he desinged for our Monte had less duration than the one that was in it but after the swap the car was 6 tenths faster in the quarter mile.

 

I have to call him tomorrow, I'll see if he'll shead any light on what he's thinking...

[Winston Wolf]

The more duration moves the power curve higher in the rpm band. It won't necessarily make more torque, it will just make it at a higher RPM. That in turn will produce more horsepower, since it's just a calculated number anyways. (tq x rpm / 5250 The trade off is less power below the torque peak. The key is finding a good comprimise for the parts you have in the rest of the car. More lift = more airflow = more torque/power, as long as the heads and intake will support it.