383 rebuild - old dyno results & new cam ideas

Hello everyone,

While replacing my distributor and swapping the melonized drive gear over to the new unit I noticed some abnormal wear on the gear, unfortunately inspection of the cam gear showed similar damage. My plan is to pull the engine, evaluate the extent and possible cause(s) of the failure, disassemble, then thoroughly clean and rebuild. I won't be able to dive into the process for at least six weeks due to a recent surgery. In the meantime I'd like to go over my original build and get some of your expert opinions regarding the original setup, and advice on camshaft selection moving forward.

Current engine specs:
-3970010 factory 2 bolt block, 2 pc rear seal
-Melling HV oil pump
-SCAT cast crankshaft
-Eagle 5.7 forged H-beam rods
-Clevite H series bearings, rod/main
-SRP forged pistons, flat top w/2 vale relief (-5 cc)
-AFR 195 Eliminator heads: 70cc chamber (milled from 75cc), ported by local shop - INT. - 290 cfm@.550, 293 cfm @.600/EXH. 219 cfm@.550 and 222 cfm@.600, upgraded AFR HR valve springs: 1.29 O.D - 155 lbs@1.810, 412 lbs @1.21, 428 lb. rate
-Fel-pro 1003 head gasket, 4.166 bore / .041 compressed
-0.00 deck height
-Compression: 10.3
-COMP roller cam: 236 in/248 ex @ .050, lift .562 in/.576 ex, 110 LSA
-CLOYES double roller timing chain w/roller thrust button
-Lunati high RPM hydraulic roller lifters
-Custom length hardened pushrods
-1.5 Crane aluminum roller rockers
-Edelbrock performer RPM air gap intake - unported
-Holley 750 DP
-505.5 HP @ 6000 RPM/493 lb-ft @4800 RPM (see attached sheets)

Camshaft notes: The cam is a semi-custom COMP Xtreme Energy solid roller. No that's not a typo, the rep my machinist talked to when ordering the cam stated two things: (1) I would make more power (+30 hp according to his estimate) by running hydraulic roller lifters on the solid profile because the lobes were more aggressive; (2) I needed a larger spread between the intake and exhaust due to weak exhaust flow numbers. I say "semi-custom" because the lobes are off the shelf profiles but with a larger spread in between the intake and exhaust lobe than found in the catalog.

I would love to hear thoughts/opinions or past experiences regarding the solid cam with hydraulic lifters you may have. At the time it seemed to me like an edgy technique for making more power and I was all for it, I don't plan run this setup in the future though. I also should have questioned the large spread in duration between the int/exh, especially since the AFR exhaust flow is anything but weak. I liked COMP at the time and made the mistake of not seeking opinions from any other cam manufacturers, a mistake that will not be made again. I have already contacted four cam manufacturers regarding their recommendations and will contact a few more before making a decision.

Car specs:
-1967 Camaro
-75% street, 25% strip
-All steel except hood
-TH400 with 10" TCI 3000 stall converter
-3.73 rear gear, 12 bolt with Moser axles
-26 x 10.5 x 15 rear tire
-Cal-tracs with factory mono-leaf (would like split mono in future)
-Three way adjustable shocks (rear)
-QA1 single adjustable coil over conversion (front)
-Bolt in sub-frame connector, drive shaft loop
-Urethane bushings front and rear

I would also love to hear your cam recommendations, as well as any other comments regarding my setup.


The fun stuff:
Damaged distributor gear
20190428_220913.jpg
Dyno results: (are the BSFC numbers high? Others I have seen are around .3XX to .4XX)
20190428_202722.jpg
20190428_203105.jpg
And a few of the build (I love an engine all undressed during assembly lol):
383-1.jpg 383-2.jpg 383-3.jpg 383-4.jpg
23948_1142660547179_4476201_n (1).jpg
 

Maniacmechanic1

solid fixture here in the forum
If I was to use a Competition Cams Grind again it would only be a Hi Tech Drag Race series Cam.
I used them years back.

Iskenderien Cams is used in near all World Fastest Street Car shootout.
Those guys drive thier Race Cars hundreds to thousands of miles to each track to Race.
It's all on Facebook.
Winning the money With Iskenderien Cams and Title Winner of the Worlds Fastest Street Car Shootout.
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
solid roller lifter lobe profiles tend to be marginally more aggressive once you get past the initial part of the,
ramp thats where you could potentially gain some extra lift and duration, vs a hydraulic roller cam.
the question I would instantly have is ..
why not just run solid roller lifters that are significantly lighter in weight,
and have a several hundred rpm advantage in the upper usable rpm range?
yes the distributor gear and cam materials must both be compatible and well lubricated, during use.
btw, thats a well though out combo, the dyno seems to indicate you could use a bit more duration and,
richen the F/A ratio closer to 12.8:1 in the 4500 rpm-and above range

talk to crower but something closer to this and solid roller lifters would be an option
obviously clearances would need to be re-checked as would spring load rates
but Id certainly go full solid roller if upgrading
running hydraulic lifters on a solid lifter cam ,
effectively and significantly in my opinion,
limits the potential upper rpm power
something between these two linked cams sounds about right,

619.661.6477

https://www.crower.com/camshafts/chevy-262-400-torque-beast-roller-cam-268r.html


https://www.crower.com/camshafts/chevy-262-400-ultra-action-roller-cam-8620-billet.html
 
Last edited:

Maniacmechanic1

solid fixture here in the forum
We found out recent you beat on it a Front Engine motor plate is must have SBC.

Optional on BBC & Pontiac V8...still a good idea !
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
RICK, if you have the time could you run, both the crower cams,I suggested in the links
and his original listed cam so we could compare it to his posted dyno results?
I think that may be very interesting
 
Indycars if you have time and don't mind that would be great if you could run some simulations! I too am curious what the actual vs. simulated results would be for my original cam, and to see how changing cam specs would affect the results would be awesome. Below are some recommendations I have received for hydraulic rollers.

Crower: PN - 00471S
INT/EXH - Dur @ .050” Lift: 236°/240° RR: 1.5/1.5Gross Lift: .555”/.559” LSA: 110° RPM: 2400 to 6000 Redline: 6500

Custom grinds:
INT/EXH - Dur @ .050” Lift: 239°/246° RR: 1.5/1.5Gross Lift: .562”/.562” LSA: 109°

INT/EXH - Dur @ .050” Lift: 237°/237° RR: 1.6/1.6Gross Lift: .585”/.585” LSA: 108°


Thanks for the recommendations Grumpy. I am leaning towards replacing with a dedicated hydraulic roller grind as I have a good amount invested in the lifters and have been happy with their performance, but am open to anything at the moment and not against possibly converting to solid roller. My main concern is all of the horror stories I came across regarding solid roller lifter failures on the street when building the engine. I'm sure a lot has changed in the 8 years since, are there solid roller lifters that have a good reputation on the street nowadays? I'm very interested in what the simulations will look like.
 

Maniacmechanic1

solid fixture here in the forum
Solid rollers can fail and do fail.
Iskenderien makes the best Roller lifters today.
Needless design with a full Ampco Bronze bearing.
Only comes in solid lifter design.
 

Indycars

Administrator
Staff member
I need some more info, it will take a little longer to get the first sim completed. But it must be right,
everything else will be compared to it. If we go changing parameter (other than the camshaft) after
the fact then it's no longer a valid comparison.

- I need the cam card so I get all info and then I can change that to agree with your modifications. I
don't see a CC part number.

- You don't mention headers, so I need to know their dimensions .... Primary ID and type if different
from the standard 4 into 1 design. A link to the header would be useful also.

- I have flow numbers for the AFR 195 Street and AFR 195 Competition heads. Take a look at what I
have for the Street version and let me know how you want to modify them. I could put in just the two
flow lifts or just modify what I have. The Competition head flows are already bigger.

AFR 195 Street Flow.PNG
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
The main reason most solid roller lifters fail in street use, is NOT,
in most cases, the fault of the cams or lifters , its generally related too one of several install, screw-ups
(1) use of very high spring load rates
most people buy solid roller lifters and install them with valve spring load rates,
that are designed to allow 7000-9000 rpm
for some reason, people just seem to think... solid roller, I can reve these into the
stratosphere, stress is cumulative,
if you add 50% more valve spring loads and add a couple hundred, too 2 thousand extra rpm, your tripling or quadrupling the stress
P12CHARTS.jpg

use,and abuse parts they fail, the more abuse the greater the stress,
if the cams were used with the lower valve spring load rates and correct clearances similar to hydraulic roller lifters,
AND used with an ignition reve limiter that kept the engine under about 7000 rpm,
they would have an expected longevity similar to the hydraulic roller lifters
(2)
lack of valve train control, the higher valve spring load rates, generally suggested with solid roller cams,
generally REQUIRE
rocker stud girdles, and better quality valve train parts like rockers, pushrods, retainers etc.

that extra valve spring load rate matched to a more aggressive cam lobe acceleration rate
but with lighter weight roller lifters does put a significant increase in stress on the valve springs, rockers etc.
use hydraulic roller lifter valve spring load rates, limit the rpms to less than 7000 rpm,
and the lighter weight solid lifter actually induce less inertial impact stress

(3)

failure to understand that if you float the valves on a solid roller valve train, your putting extreme stress on the components
(4)
cast core cams will eventually wear, you must run a billet cam core, if long term durability is critical


SADI = Selectively Austempered Ductile Iron
The only benefit to SADI is cost. That's not to say a SADI cam can't make some power but as the RPM range increases so does the need for a billet cam and more spring pressure. You can lighten the valvetrain and help things out some though.
http://garage.grumpysperformance.co...d-high-spring-pressures-don-t-work-well.1489/
these are both cast core cams (look between the lobes) the dark surface is a flat tappet cam lobe coating, the polished is a roller cam
0705ch_08_z+camshaft_profiling+.jpg

castvssteel.jpg


billet cam cores look like this below
billetcam.jpg
 
Last edited:

Maniacmechanic1

solid fixture here in the forum
The main reason most solid roller lifters fail in street use, is NOT,
in most cases, the fault of the cams or lifters , its generally related too one of several install, screw-ups
(1) use of very high spring load rates
most people buy solid roller lifters and install them with valve spring load rates,
that are designed to allow 7000-9000 rpm
for some reason, people just seem to think... solid roller, I can reve these into the
stratosphere, stress is cumulative,
if you add 50% more valve spring loads and add a couple hundred, too 2 thousand extra rpm, your tripling or quadrupling the stress
P12CHARTS.jpg

use,and abuse parts they fail, the more abuse the greater the stress,
if the cams were used with the lower valve spring load rates and correct clearances similar to hydraulic roller lifters,
AND used with an ignition reve limiter that kept the engine under about 7000 rpm,
they would have an expected longevity similar to the hydraulic roller lifters
(2)
lack of valve train control, the higher valve spring load rates, generally suggested with solid roller cams,
generally REQUIRE
rocker stud girdles, and better quality valve train parts like rockers, pushrods, retainers etc.

that extra valve spring load rate matched to a more aggressive cam lobe acceleration rate
but with lighter weight roller lifters does put a significant increase in stress on the valve springs, rockers etc.
use hydraulic roller lifter valve spring load rates, limit the rpms to less than 7000 rpm,
and the lighter weight solid lifter actually induce less inertial impact stress

(3)

failure to understand that if you float the valves on a solid roller valve train, your putting extreme stress on the components
(4)
cast core cams will eventually wear, you must run a billet cam core, if long term durability is critical


SADI = Selectively Austempered Ductile Iron
The only benefit to SADI is cost. That's not to say a SADI cam can't make some power but as the RPM range increases so does the need for a billet cam and more spring pressure. You can lighten the valvetrain and help things out some though.
http://garage.grumpysperformance.co...d-high-spring-pressures-don-t-work-well.1489/
these are both cast core cams (look between the lobes) the dark surface is a flat tappet cam lobe coating, the polished is a roller cam
0705ch_08_z+camshaft_profiling+.jpg

castvssteel.jpg


billet cam cores look like this below
billetcam.jpg
Guys don't want to buy To Titanium parts Grumpy.
Cheep.
Crower has excerts warning in fine Print....Use Ti valves and retainers.
Skull and cross bones to identify easy Danger Zone.
 
Indycars,

Thank you in advance for your time and efforts with the simulations. The dyno tests were ran with 1 3/4 standard 4 into 1 headers supplied the the dyno operator, not sure of the manufacturer. In the car I am currently running Hooker 2131, but that may differ too greatly from the dyno headers.
https://www.summitracing.com/parts/hok-2131hkr

Intake: 274 ADV / 236 @.050 LIFT@lobe .374 / @valve .562 w/1.5 rocker
Exhaust: 286 ADV / 248 @.050 LIFT@lobe .385 / @valve .576 w/1.5 rocker

VALVE TIMING @.015
Open Close
Intake 31°BTDC 63°ATDC
Exhaust 77°BBDC 29°ATDC
LSA: 110
ICL: 106

Cylinder head flow:
0.2 0.3 0.4 0.5 0.55 0.6
Intake 151 207 273 284 290 292
Exhaust 121 158 196 212 219 222
 
Sorry the formatting of the text changed after I posted, shifting the number alignment. If it's too jumbled let me know and I can re-post.
 

Loves302Chevy

"One test is worth a thousand expert opinions."
Welcome. You said 75% street, 25% strip. But your can selection says mostly RACE. Someone isn't being honest with themselves.
Sure everyone wants the vehicle that you can drive to work every day, then drive 100 miles to the drag strip and run 10 seconds, then stop at a car show on the way back and win 1st prize. THIS IS NOT REALITY!!!!
As far as using hydraulic lifters on a solid cam, I am doing that in my 302 Chevy. Flat tappet or roller, I hope you realize that you DO NOT use any preload when doing that. If you really mean 75% street, then I'm glad you are now leaning towards hydraulic roller. Don't try any fancy tricks if you want your nice engine to live a long life in your beautiful Camaro.
 

Maniacmechanic1

solid fixture here in the forum
Welcome. You said 75% street, 25% strip. But your can selection says mostly RACE. Someone isn't being honest with themselves.
Sure everyone wants the vehicle that you can drive to work every day, then drive 100 miles to the drag strip and run 10 seconds, then stop at a car show on the way back and win 1st prize. THIS IS NOT REALITY!!!!
As far as using hydraulic lifters on a solid cam, I am doing that in my 302 Chevy. Flat tappet or roller, I hope you realize that you DO NOT use any preload when doing that. If you really mean 75% street, then I'm glad you are now leaning towards hydraulic roller. Don't try any fancy tricks if you want your nice engine to live a long life in your beautiful Camaro.
He has a,Turbo 400 Trans Mike with a 3000 Rpm stall.
He is playing hard on the streets.

I don't like the power band of his old cam.
Too Narrow.
Comp did a sheety job picking out.
Cast 9000 series Scat Crank.
2-bolt mains.
Redline 6200-6400 max.
Like to see 500 ft/lbs at 3000 rpm.
Peak out around 4000.
500-550 Hp by 5700 -6k.
 
Loves302Chevy - My car is 75% street, I set it up with the intention of not being a daily driver and more of a weekend warrior. It sees no more than 3000 miles a year. I drive it to work a few times a year, cruise around on the weekends, and put it on a trailer it if I want to go to the track. That way if anything were to break I don't have to come up with a plan "B" to get to car home from the track, which is about 50 miles away.

I agree that my cam selection was more "RACE" than "STREET", I didn't look at it that way at the time though. I planned to run a dedicated hydraulic roller but when COMP recommended I run this setup instead I changed my plan. They said given the tight lash specs of the profile I could run hydraulic lifters without issues. I assumed that I would be getting the best of both worlds: more aggressive cam profile (=more power right?) but not having to run solid roller lifters on the street (=more streetable right?). In the end I had more questions than answers regarding the efficiency and durability of my cam choice and felt I left usable power on the table.

Maniacmechanic1 - Once I got over the initial "awe" of spending a day at the dyno (my first time) I was disappointed by the lack of some information on the dyno printout. It's cut off the picture but the VE is listed to the right of the BSFC, the numbers all read 0.0 so I didn't bother to include it in the picture. Also - I recently looked at around 15 other random dyno printouts and noticed that the BSFC numbers seem to be between .3XX and .4XX on average. I see that mine are quite a bit higher between .6XX and .7XX, what do the higher fuel consumption numbers indicate?
 
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