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Stroker OR roller cam engine?


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#1 Guest_Anonymous_*

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Posted 16 March 2001 - 06:01 PM

There have been many discusions on what type of motor to build given free reign but I wanted to narrow the choice of two options

1. A Stroker 383 with 6" rods and JE pistons
OR
2. A 350 with a roller Camshaft

The rest of the engine in either case:
4 bolt main bottom end
Edelbrock Al heads
Edelbrock RPM intake
Ericson Roller Rockers
Block Hugger Headers
Mallory Unilite Distributer
Holley Carb
T5 Borg Warner Tranny
Yoko's ADVAN 225 50 15" inch tires

The goal being the best street combination.
Thanks Chuck

ps
Forgive me if i have this wrong; but Roller Lifters/Cams don't really save that much power but rather enable a much more aggressive CAM profile-Correct? If that is the case then do these engines still suffer from big CAM syndrome (no vacuum, crappy idle etc etc) If anybody has a pointer to information on Roller Cams versus non Roller CAMs I would love to read up.

#2 Modern Motorsports Ltd

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Posted 16 March 2001 - 06:23 PM

quote:


Originally posted by chass23:

1. A Stroker 383 with 6" rods and JE pistons
OR
2. A 350 with a roller Camshaft

Forgive me if i have this wrong; but Roller Lifters/Cams don't really save that much power but rather enable a much more aggressive CAM profile-Correct? If that is the case then do these engines still suffer from big CAM syndrome (no vacuum, crappy idle etc etc) If anybody has a pointer to information on Roller Cams versus non Roller CAMs I would love to read up.



Howdy Chuck Posted Image an article I really enjoyed and can't even guess how many times I'd read it over the years http://www.idavette.net/hib/camcon.htm
the perfect article, what the current non roller build is, dyno run, what's needed to go roller, install, dyno, gains etc

Rollers do save power, it's a lot easier for a lifter to do it's job as a roller than as a hydraulic non roller lifter. It's job is so much easier it doesn't sweat Posted Image cause it doesn't heat up from the extra work. This savings in work (it does less work/less heat created/less hp lost) does add up to a few ponies and efficiency. I literally gained 2mpg with just roller rockers which surprised me but was my only change at that time with my 327.

HTH

Once you understand the differing lobe profiles it's easier to understand mannerism differences. If you want 300rwhp you will need a lumpy idled cam in a non roller motor that will be making less vaccuum. You can run quite a smooth roller cam/motor and get 300rwhp quite easily and have plenty of vaccuum. Manners are much better for a roller motor vs. non roller motor IF both are built for same overall peak power and similar (as best can be done, non roller is less broad and more peaky) power bands. For the same duration....ahh, I'll post in this post written by a good friend who might be around but I'm not sure he wants his name tagged to it or not...Let's just say it's well written Posted Image

The cam is the "ATTITUDE" of the engine and is the most responsible for when, how, where, the power comes on and also exhaust emissions. Choosing a cam is quite involved if you try and pick a cam for your application you have lobe separation, advertised duration, duration at .050" in. lift, lift under the curve, CAM intensity, and several other factors to mull over.
Here are a few things to help in choosing your cam.
Lobe Separation is the distance between the peak lift of the Intake and Exhaust lobes. This is also referred to as Overlap. The more overlap, less lobe separation, the rougher the idle, more exhaust pollutants and to a point, more PEAK torque. The Chev small block responds best (Max Power) to a cam with a lobe separation of between 105-108 degrees, with out much regard as to duration, lift, intake and exhaust flow. There is a down side to this much overlap. The engine wont idle very well, lots of exhaust pollutants, even worse with more duration as there will be more overlap for a given lobe separation. Also tighter lobe separation tends to deliver PEAKIER powerbands. Spreading the lobe separation to around 110 degrees makes the engine a little more civilized. 110 degrees works well for a strong street Chev small block. The factory uses between 112-114 degrees separation to meet emissions and give good driveability and mileage. This also gives a flatter power band at the expense of peak torque though. That is why when you install an after market cam with a lobe separation of 110 degrees even though the duration is the same it really comes alive, mileage and emissions suffers though.
Cam intensity is also another very important factor. With a more "INTENSE" cam, you can get the power of a bigger cam with the driveability and emissions/mileage of a milder cam at the expense of valvetrain wear and initial expense. Roller cams are VERY "intense" cams and are money well spent if you want every last bit of performance, though not necessary for building just a strong small block. The more intense a cam is the more lift you have under the curve. That is, when you graph out a cams profile you will note that a cam that gets the valves off the seat faster than a less "intense" cam it is said to be more "intense". This is a very good thing from a power standpoint. The down side is Valvetrain wear. The faster the cam opens the valve, the harder it is on the cam lobe itself and the springs as well. If you look at a Top Fuel cam profile you notice that the valve is literally shot off of the valve seat and slammed back down onto it. It runs in under 5 secs and has to replace the valve springs every pass as the springs are wore out. That is an extreme example but I think you get the point.
Duration is a widely used term in bench racing. When evaluating cams based on duration, try and compare the advertised duration and the duration .050" in. on the same cam. For example, a Comp Cams cam for a small block Chev with a advertised duration of 270 degrees and a duration @ .050" in. is 220 degrees. There is 50 degrees difference between these two numbers on this particular cam. Use this as a "reference" for the cams intensity. I use the term "reference" loosely. Some cam manufactures state their advertised duration @ .004" in. and others will state advertised duration @ .006" in. This will change things abit, you can get an idea of by how much by studying a few graphed out cam profiles. The cam I just mentioned is fairly intense. On the OEM side of the spectrum the small block Chev with a cam with 240 degrees advertised duration and 160 degrees @ .050" in. This cam is less intense than the other, therefore easier on the valve train, 100,000 mile + engine, weak on performance. The more intense cam will need at least the springs, if not the cam and lifters replaced by approx. 60,000 miles depending on the owners driving habits.
Lift is one of those things that you can't have enough of. The more the better, until Valvetrain reliability becomes compromised. Lets use the Chev small block as an example again. The 350 has a 4" in. bore with a 3.5" in stroke, (327 has 4" inch bore 3.25" stroke), Each 4" hole is trying to fill itself with 3.5" in deep column of air around a 1.94" in. valve head, approx. 1.75" seat diameter and that is not taking into account that the valve stem is also taking up room here as well. This is called the "open curtain area". As you can see the engine really has to work to fill each large cylinder through a small opening in a very short period of time. This is why multivalve engines make so much power per a given displacement, they have much more valve area than the traditional 2 valve per cylinder engines.


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#3 BLKMGK

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Posted 16 March 2001 - 07:07 PM

Hmm, I have flat tappet in both my SBC and in my Mustang motor. In both cases I wnet flat tappet because I was told that my HP desires could be met without the added expense of a roller cam. After reading that article, and some others in the past I'll admit, I'm wondering if my choices were wise. I guess I'll see how the Z does but it looks like a fairly simple upgrade to roller on my LT1 block could be an easy HP gain (sigh).

#4 pparaska

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Posted 16 March 2001 - 09:31 PM

Ross, great post and site.

I just wanted to point out someting about that bit about "Lift is one of those things that you can't have enough of." SUre, aas long as the heads actually continue to flow well at the higher lifts. Some heads have no gains over 0.40"

#5 Guest_Anonymous_*

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Posted 16 March 2001 - 10:02 PM

What a great article!
So the roller cam was good for ~40hp so
I guess the question remains what is a Stroker conversion good for?

Thanks Chuck

#6 DavyZ

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Posted 16 March 2001 - 10:11 PM

Great reading, Ross, but those of us on a tight budget are probably better off using a flat tappet cam, at least in the short run. Rollers become more cost effective in the long run since they are much less prone to wear. I went flat tappet due to extreme cost constraints, but would go roller in a heartbeat next time around if the money is there.

David

#7 DavyZ

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Posted 16 March 2001 - 10:13 PM

Chuck, sorry for forgetting about your post, but a mild 383 is relatively cheap and has tremendous torque, if that is what you want. The 350 has less low end torque which is not so bad considering the light weight of the car. The choice is yours.

David

#8 Modern Motorsports Ltd

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Posted 16 March 2001 - 10:49 PM

quote:


Originally posted by DavyZ:
Great reading, Ross, but those of us on a tight budget are probably better off using a flat tappet cam, at least in the short run. Rollers become more cost effective in the long run since they are much less prone to wear. I went flat tappet due to extreme cost constraints, but would go roller in a heartbeat next time around if the money is there.

David


David, I agree with you completely and I was running flat tappet and would still be if my roller motor hadn't worked out so cheap. $450US for a full vortec shortblock (<12k miles/mint bores etc)with new OEM roller lifters and a new ZZ4 roller cam from THE engine man at the main GMPP dealer in BC. I either got the cam and lifters for free or the full shortblock and then some.

I also have a little more 'insider' info on where Chuck's coming from and his prior plans and ongoing so painted my post appropriately Posted Image If one can possibly build on a newer block as their platform then going roller is a LOT cheaper as lifters routinely come available as do the cams (and the OE style/LT1/ZZ4/etc cams are cheap used in as new shape), and you can bolt up a T56 a lot cheaper as well. Big potential for overall savings. Local guy I came across has two nice 'new-gen' blocks as he called (vortec blocks). Bolt all old stuff on (anyone know if lifter bore is same/ie. can you run flat tappet lifters/non roller and then swap later on these blocks?) and enjoy.

And as Pete says and most anyone who seeks out this site is aware, all combos/cars/motors/cams etc only work as a matched package. Match your heads/cam/intake/exhaust etc etc or you're wasting dough.

How fast do you want to spend?




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#9 Racin_Jason

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Posted 17 March 2001 - 01:36 AM

Well to address the original question, I would go with the 383 hands down.

Rollers are great for efficiency, idle quality and longetivity...BUT...almost 40 cubes is going to do more for you in this case. The 383 will give quite a bit more torque..especially down low and thats where you really feel it. The 383 should realistically outpower the 350 throughout the band (ESPECIALLY under 3500rpm) if its cammed correctly. Given a roller 350 and non-roller 383...aslong as they BOTH have the CORRECT cam...the 383 is going to be stronger. The bigger engine will allow you to make more power, with less rpm at the same compression than a smaller engine would.

Nowwwww if you DO have a forged bottom, tight tolerances and good heads..you 'could' put a big roller in the 350 and spin it to 8000revs and make some serious power,alot more than the 383...but that wouldn't be a street car then Posted Image Go 383 and be happy.

Personally, if I had the money, I'd get a 400 and build a de-stroker 377. These rev-happy, high winding puppies would be absolutely WICKED in a 2600Lb car!

Good Luck with whatever you do!
Jason

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[This message has been edited by Racin_Jason (edited March 18, 2001).]

#10 RPMS

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Posted 17 March 2001 - 03:57 AM

Ummm... I have a question.

Why can't you have both? A 383 with a roller cam? If you're willing to shell out the time/effort/money to build a 383 stroker, what's an additional $50-100 to install rollers rather than flat? Best of both worlds.

Scott

#11 Guest_Jeff Rimmer_*

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Posted 17 March 2001 - 05:41 AM

Alright given this info posted, I'm giving second thought to my 383 buildup, scheduled for spring. I now have my block, crank and intake, but after reading posts I'm wondering if it is the best choice. Summit claims their 383 got 450hp and 440 ft-lbs by using their crank Keith Black pistons, custom ground cam and Summit stage II rods. Does this seem exagerated?

What kind'ov numbers should I expect using stock heads, with the same pistons and rods and RPM intake? What cam choices have people made to run the stroker motor?

#12 Guest_Anonymous_*

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Posted 17 March 2001 - 09:55 AM

To answer a couple of questions raised:

1: From Scott:

Why can't you have both? A 383 with a roller cam? If you're willing to shell out the time/effort/money to build a 383 stroker, what's an additional $50-100 to install rollers rather than flat?

Answer:

A roller CAM and Lifters is more like $600 NOT $50-$100 for a 1st gen 350.

2: Why not go 400?

Actaully i wanted to go with a 400 based engine; my first choice was a 377 or 426...Since I was going to go all custom bottom end anyway it wasn't going to be any more expensive but i couldn't find any 400 core blocks that I was comfortable spending the money on.

Thanks for the interesting conversation
When i had the choice i was going to add a roller cam and lifters unfortunately as Ross knows the choice was made for me by finding a cracked block and scored main bearings
The reason for the post to hear other peoples thoughts on the topic....In either case I now have a solid bottom end for future upgrades (Scat Crank, 6.0" Scat Rods and JE Pistons), The cam i went with is a healthy crane powermax http://www.cranecams...tm#4. PowerMax.

#13 Modern Motorsports Ltd

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Posted 17 March 2001 - 10:38 AM

quote:


Originally posted by Racin_Jason:
Well to address the original question, I would go with the 383 hands down.
...almost 40 cubes is going to do more for you in this case. The 383 will give quite a bit more torque..especially down low and thats where you really feel it. The 383 should realistically outpower the 350 throughout the band


I was surprised this didn't come up earlier. NO REPLACEMENT FOR DISPLACEMENT (talking V8 builds), you get extra hp/tq across complete power band with milder manners for same power as lesser cubed motor. But I have to disagree on need/wanting/the extra torque down low where you 'feel' it as you say Jason. We need extra torque their (in 1st gear anyhow, and after that who's below 3k) like a hole in the head. It really becomes a driver skill issue with many builds here as well as others as excess power/torque is present. That's where a Victor Jr. can only be win/win IMO, more power mid to top and less torque but it's still enough to be in excess so no loss is experienced Posted Image

I'd chose cubes over roller anyday up front. Easier to convert to roller later than cubes Posted Image

Ross (yes, in the end we will have it all!)



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#14 Guest_Fast Frog_*

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Posted 17 March 2001 - 02:58 PM

Hey guys!!

Good posts!! Most of you are hitting the nail on the head most of the time! I've got a 383 with a roller cam and it's a moving unit. Before I installed a roller, I had a hydraulic flat tappet cam with modest lift and duration. It was twitchy on the low end but dead above 4500. I went with a Crane HR cam with a little more duration and more lift and what a diff it made!! The car was almost as quick with the roller cam as it was without the roller cam with my Paxton SC before I sold the Paxton! 40-50 HP more is a good estimate. If you can, go roller! But the price is around $900-at least from JEGS. You've got to get the cam, lifters, roller rockers, cam button and good push rods-don't get the cheapy $29 ones.

If I had it do over again, I'd get the next step or two up camwise(Crane's "641" HR)and go 10 to 1 cr. I'd also loose the Edelbrock Performer RPM heads and go Airflow Research hds or Brodix -8 or ST10's with 2.08 intake and 185-200 cc runners. I'd also go 1 3/4" hdrs and keep the dual 2 1/2" exhaust. Also pick up 2 Dynamax "welded" 2 1/2" mufflers (Guys, the Dynamax welded is what's happening!! -check out their web site).

However, I'm still itching to do a big inch sbc 427 or 440. Posted Image

#15 BLKMGK

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Posted 17 March 2001 - 07:00 PM

I'm with Ross - we need torque in our 2500lb cars like we need a 6banger Posted Image Seriously, when I built my motor I told tyhem I wanted a single plane intake and told them upper end power was fine and not to try and go crazy down low. Besides, single plane intakes convert to EFI easier Posted Image

Performer RPM heads and RPM intake is what I wnet with. As for a 383 hitting 450HP - heck yes! The package installed on my car is good for 425horse on a 350 according to Edelbrock and according to a dyno run the engine shop did on their parts truck motor (lol). Some of th efolks running the numbers here think I won't get 450HP with my extra cubes but honestly that's okay. I can live with 400+ for now and will run a blower later if I really feel the need for speed.

One of the reasons I used an LT1 block was for the ease of going roller. My shop said a roller wasn't needed for my goals but I do wish that I'd done it anyway. A big plus with rollers is that even with the same lift and duration compared to a flat tappet you can have faster lift rates. This means your valve hit's it's lift faster and can "snap" open quickly. More area under the curve means more power everywhere. We'll see - I can always convert to roller later when I'm switching to EFI. Don't forget the steel distributor gear too!

#16 Mikelly

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Posted 18 March 2001 - 04:31 AM

Why not both? It isn't gonna cost you any more to stroke the motor than build a 350. Rods cost the same, pistones are the same, and the crank, maybe have a few extra dollars in the crank, but not much. Best money I spent with my engine builder was to spend my extra money on the hydraulic roller setup. My motor revs sooooo much quicker. The one downside to Strokers though is you can't rev them quite as high as you can a 350, but that isn't a bad thing if all your HP is still gained, you're just gaining it sooner!

Regardless of stroker or not, spend the extra on the roller valve train!

Mike

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#17 Racin_Jason

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Posted 18 March 2001 - 06:10 AM

Ron and BLK~

Being that I've never had such a light car with a V8 I suppose I underestimate how hard it is to modulate the power at low speeds. I was actually refering to the "feel it" experienced from roll-on acceleration at freeway speeds..there is where (on most street cars anyway..) you'll be happy you have the extra torque. But alas, I am but a mere grasshopper in this big land of Sensai's and I have many wax-on and wax-off's to achieve Posted Image

BTW: I'm with Mike on this one...why not BOTH? The 383 kits are about the same price as rebuilding a 350 and a roller 383 is a beautiful thing!

Jason

#18 Modern Motorsports Ltd

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Posted 18 March 2001 - 10:52 AM

quote:


Originally posted by Racin_Jason:
Ron and BLK~
BTW: I'm with Mike on this one...why not BOTH? The 383 kits are about the same price as rebuilding a 350 and a roller 383 is a beautiful thing!
Jason


Why not both as cost is about the same?? Cause cost can be v. different. Many (most on other lists I'm on) do not buy all new crank/rods/pistons) for a 450hp motor. Reliable shortblocks seem quite common IME and others. Mine was practically free as noted above and I just mic'd the '68 327 I ran for a few years for it's new owner and it was almost as new! Didn't need boring at all, just a hone/rering would've been fine. Same for quite a few others who've posted their patient/lucky finds here as well. If you've decided to spend all new for your design/build then their may be minimal cost difference but if used to barely used is an option it's different. Their are more and more newer style 350 blocks available used lately and given cams and lifters are a lot cheaper for them it just sways me that way.




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#19 Racin_Jason

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Posted 18 March 2001 - 06:55 PM

I didn't see a crank or rods in his list of parts. I'll just let Ron answer the questions because he seems to know 'exactly' what your situation is..

Ok Ross, I give up, its all you buddy..



[This message has been edited by Racin_Jason (edited March 18, 2001).]




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