Thread: 350 build bottleneck???

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I'm pretty new to the SBC game, most of my engine building experience has been just stock rebuilds and a couple 3800 supercharged performance builds. My question is what is my bottleneck gonna be with this build and what kinda numbers should I expect? Its a 350 bored 60 over cast number 14010207 going to use flat tops in it. My heads are 487's(76cc chambers) with 194 valves and a slight self done port job and gasket match. Edelbrock Performer intake, holley 650 double pumper, full longtube headers and 2 1/2 true dual exhaust. my cam with my 1.6 roller rockers is 512 intake, 520 exhaust 4/7 swap hydro flat tappet, and I got supporting springs for that lift. Going into a 78 elcamino...

Also this motor was previously rebuilt with that 60 over done but I can still see most of the crosshatch, would it be safe to just do a quick hone or is the block junk?

And whats with these sbc's grinding down the cam lobes? This one had about 7 lobes gone and the bottoms of the lifters looked like bowls. Reason I ask is the only other sbc I have messed with a 305 had done the same thing just not quite as bad...

Any help would be greatly appreciated with any of my questions...

The cam and lifter damage is do to the no zink oil that is now the norm.

I posted this earlier, but will do it again for those who may have missed it.

DISCLAIMER: THE FOLLOWING INFORMATION WAS GLEANED FROM MANY DIFFERENT SOURCES. SOME OF IT MAKES SENSE TO ME AND SOME OF IT DOESN'T. USE WHAT YOU THINK IS REAL AND THROW OUT THE REST OF IT. I HAVE NOT USED ALL OF THE SUGGESTIONS LISTED HERE. THROUGH THE YEARS, I HAVE ACCOMPLISHED MANY SUCCESSFUL FLAT TAPPET CAMSHAFT BREAK-INS, BUT I HAVE ALSO ROACHED A FEW. USE THIS LIST AS A GUIDELINE SO THAT YOU REMEMBER TO CHECK ALL THESE THINGS WHEN INSTALLING A NEW FLAT TAPPET CAMSHAFT. DO NOT TAKE EVERYTHING POSTED HERE AS GOSPEL. IF THE MANUFACTURER OF THE CAMSHAFT YOU'RE USING RECOMMENDS PROCEDURES THAT DIFFER FROM WHAT IS SHOWN HERE, USE THE MANUFACTURER'S RECOMMENDATIONS TO THE LETTER AND DISREGARD THIS INFORMATION.
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MISTAKES THAT MAY "FRAG" A CAMSHAFT AND LIFTERS.

1. Failure to remove all rust-preventative from cam and lifters with solvent once you get them home. (This advice does not include removing coatings applied at the factory such as phosphates. It is only suggesting to remove rust-preventative grease that may or may not have been applied to the cam/lifters to prevent rust in storage. This grease will not have the extreme pressure characteristics that Molybdenum Disulphide has and should be removed so that MD can be applied properly. MD is the black, tar-like extreme-pressure grease that is recommended by some camshaft manufacturers to be applied to the lifter crowns/cam lobes for initial camshaft break-in).

2. Failure to wash the cam and lifters with hot soapy water to remove the remainder of rust-preventative not removed with solvent. CAUTION; WASH ONLY THE CROWN OF THE LIFTERS. (THE VERY BOTTOM OF THE LIFTER WHERE IT CONTACTS THE CAMSHAFT LOBE). DO NOT ALLOW WATER TO GET INTO THE INTERIOR OF THE LIFTER BODY. BE VERY CAREFUL HERE IF THE LIFTER HAS AN OILING HOLE THAT HAS BEEN EDM'D INTO THE CROWN TO PROVIDE OIL FROM THE INTERIOR OF THE LIFTER BODY TO THE CAMSHAFT LOBE. Dry the cam and lifter crowns thoroughly with hot air from a hot air gun or hair dryer to remove all traces of moisture before applying Molybdenum Disulfide.
WARNING: DO NOT USE ANY ABRASIVE MATERIALS SUCH AS SCOTCHBRITE PADS OR SANDPAPER OF ANY KIND TO ACCOMPLISH THESE SOLVENT AND SOAP CLEANING OPERATIONS. USE ONLY SOFT, CLEAN RAGS. THE WHOLE INTENT OF CLEANING THE CAMSHAFT IS SO THAT WE CAN REMOVE RUST-PREVENTATIVE OILS AND GREASES THAT MIGHT HINDER GETTING DOWN TO THE BASE METAL IN ORDER TO PERFORM OPERATION #3 SHOWN HERE.

3. Failure to properly massage an extreme pressure lubricant such as Molybdenum Disulfide into the pores of the metal on all lobes and lifter faces. Moly will actually bond with the metal and give maximum protection to the lifter crown/lobe.

4. Failure to use an extreme pressure lubricant additive to the engine oil for camshaft break-in.

5. Failure to use the proper valve springs for cam break-in. You can't use the 300 lb over-the-nose springs that you'll eventually use in the motor and expect the cam to live at break-in. Assemble the heads with stock or weak single springs to break in the cam, then use one of the many tools available to change the springs with the heads on the motor. Alternately, assemble the heads with the springs you will run and use reduced-ratio break-in rockers, then change out the rockers after break-in. These rockers are available from Crower in different ratios for different motors. A popular ratio for a small block Chevy would be a 1.3:1 rocker. In other words, let's say the lift at the cam is 0.350" and the theoretical lift at the valve with 1.5:1 rockers is 0.525". Using the 1.3:1 rockers would result in lift at the valve of only 0.455", thus reducing stress at the camshaft/lifter interface during the crucial break-in period.

6. Failure to check for valve spring coil bind at max lift.

7. Failure to check for retainer to valve guide/seal clearance.

8. Failure to check for binding at the rocker/stud interface.

9. Failure to check for piston/valve clearance..... 0.080" on the intake and 0.100" on the exhaust is considered by many to be the minimum clearance acceptable. You will probably find the closest near-miss at the exhaust valve on overlap, when the piston is chasing the exhaust valve back onto its seat.

10. Failure to run the motor at high rpms (2500 or higher, alternating 1000 rpm's up and/or down to allow the crank to throw oil in different places at different revs) for the first 40-45 minutes of its life. NO IDLING. NO IDLING. NO IDLING. The motor should not be run at less than 2500 rpm's for a minimum of 40 minutes. If a problem develops, shut the motor down and fix it, then resume break-in. The main source of camshaft lubrication is oil thrown off the crankshaft at speed, drainback from the oil rings and oil vapors circulating in the crankcase. At idle, the crank isn't spinning fast enough to provide sufficient oil splash to the camshaft/lifters for proper break-in protection.

11. Failure to clearance lifters in their bores so that they spin freely. Lifter clearance should be 0.0012" to 0.002", with 0.0015" (one and one/half thousandths) considered close to ideal. Too loose is as bad as too tight.

12. Failure to initially adjust the valves properly. Using the "spin the pushrod until it feels tight" method will normally result in valves too tight. Jiggle the pushrod up and down with your thumb/forefinger until all play is removed, then turn the rocker nut 1/2 to 3/4 turn to set the preload.

13. Failure to inspect the distributor drive gear for wear. Too much wear can allow the cam to walk in its cam bore and contact an adjacent lifter.

14. Failure to have everything ready for the motor to fire on the first few turns. Fully charged battery, good starter, known-good carburetor with full fuel bowl, source of fuel to the carburetor to allow minimum 40 minutes of uninterrupted running. Ignition timing set. NO GRINDING ON THE STARTER. NO GRINDING ON THE STARTER. NO GRINDING ON THE STARTER.

15. Failure to prime the oiling system prior to firing the motor. Prime until you get oil out of the top of each and every pushrod. Observe the oil pressure gauge to be sure pressure is registering. Priming will aid lubing the valvetrain at initial startup. It's the last area of the motor to get lubed on dry start.

16. Failure to use new lifters on a used cam. Used lifters should only be used on the very same cam, in the very same block and in the very same positions they were removed from. Chances that the lifter bores will be machined on the very same angles on a different block as the block the lifters came out of are about equal to you hitting the lottery.

Now, this last bit of advice comes from Racer Brown, world-renowned camshaft manufacturer/engineer who ground the hot cams for Chrysler Corporation during the horsepower wars of the 60's.
"Overfill the crankcase by at least 4 or 5 quarts of oil so that the oil level comes to within an inch of the top of the oil pan. Install a set of fairly hot spark plugs with a gap of 0.050" to 0.060" to prevent oil-fouling of the plugs, which is otherwise inevitable under no-load conditions with all the extra oil aboard. During this operation, we want near-maximum oil flow, together with a maximum of oil vapors and liquid oil thrashing about in the crankcase so that the cam lobe and lifter interface lubrication is considerably better than marginal."

This advice from the Racer is too scary for me, but I included it so that you know someone, somewhere has done it.

Just a note to make you aware of the loading between the camshaft lobe and lifter crown. That pencil-point of contact, if carried out to a square inch, would be somewhere between 250,000 and 300,000 POUNDS PER SQUARE INCH.

Originally Posted by Bruce lee

The cam and lifter damage is do to the no zink oil that is now the norm.

Do they make an additive I should be using or will I be okay if I run full synthetic after break-in?

What's the static compression ratio? What are the specs on the cam?
You'll pick up around 30 hp with a high-rise, dual-plane intake such as a Performer RPM.

I'm sorry, but this reads like a magazine rebuild. First, what is the intended use of the engine? 4/7 cam swaps have NO value in street driven engines. Any benefit they show is usually above 7000 RPM.
What is the compression ratio, as a guess, I'd put it at about 8-1 UGH!!

\What is the duration of the cam?? It appears to be WAY TOO MUCH CAM for an 8-1 motor. Is this a street driver, street/strip or strip only car??

I wouldn't do ANYTHING until these basic questions and needs were addressed.

Originally Posted by techinspector1

What's the static compression ratio? What are the specs on the cam?
You'll pick up around 30 hp with a high-rise, dual-plane intake such as a Performer RPM.

I know it's a lower duration cam I gotta call the company to get the specs again. I wanna say in the mid 230s on each but I'm just pulling that outta the air... How bout just a spacer on my current dual plane performer intake? It's hard to find spreadbore performance intakes used and I'm on a budget... I'm not 100% but I think the compression even with flat tops is only in the high 8's. Should I get domes? I bought everything but the rebuild kit so pistons can still be changed.

This car is strictly a fun street car and very occasional tower... I drive it to work once or twice a month and maybe once a weekend, would like to take it to the track maybe a couple times a year... And I take it from the "ugh" that I need domes to get my compression up? That's one of the things I was worried about and the reason I have bought the pistons yet...

I have built many motors of all different sizes, and have never killed a cam !! and after reading all this crap. I'm confused! To much about nothing

I use farm tractor or Diesel grade oil, it has zink in it, there are others also, I use to break in my motors, (1st 3-500 miles on a street motor) then you can switch to synthetic. And use light valve springs & stock rockers till the cam & lifters are broke in.

Google flat tappet breakin and you'll find many more oils to use, and a lot better info!!!!!!!

Pat

i just machine up a 350 with flat tops and 76 cc head 9.3 cc you can break it in with joe gibbs or brad penstat oil they have zinc as other s as well

kejross, you're no different than thousands of other newbies who purchase a cam for their rebuild without knowing the static compression ratio, much less the dynamic compression ratio of their motor. You need to get some books and do some reading. You have no business trying to put a combination together without some knowledge of what you're doing.
Just a few of the things you need to understand....
Block deck height
Piston deck height
Piston compression height
Static compression ratio (you need to know how to figure this from scratch)
Dynamic compression ratio
Squish (how to arrive at it and what figure to use)
Camshaft (advertised duration, 0.050" tappet lift duration, cam lift, theoretical lift at the valve, intake centerline, exhaust centerline, lobe separation angle, overlap, timing events- intake opens, intake closes, exhaust opens, exhaust closes)
Head gasket bores and thicknesses, when to use what gasket.
Cylinder head intake and exhaust runner volumes. When to use what head.

Knowing this little bit of stuff will allow you to figure out what parts you need to do a certain job in a motor. It won't make you an engine builder, but you'll be a lot closer than you are now.

kejross, I have sent you a PM

Pat

This newbie with the typical rebuild needs to know what compression I should run with all the other components in the build... the .275 domes show 10.39:1, .125 domes show a 9.38:1 Where do I start having to use premium gas and race fuel? I'd like to run on premium or less, its too hard to find race gas around here. I also wanna thank everyone so far with the great cam break in tips. Also how important is degreeing the cam? my gear drive set has all the different inserts but I don't know anyone with the kit to degree it and Im not looking to spend 150 on a kit ill use maybe a couple times in my life...

ok with your open chamber heads i would say if you don't polish the combustion chambers them i would say 10:1 - 10.5:1 compression.

some people have luck alot higher 10.5:1 it all depends on combustion chamber efficiency, quench, timing, piston top shape, if the engine runs hot or cold, how much overlap your cam has, and so on.

it also helps if you buy aluminum heads.

p.s. go to a double roller timing chain insted of gear drive because the crankshaft sends harmonics to the valve train (not good), they've even been known to pop keepers out of the retainers(also not good). plus they take more horsepower, and they make a noise you like at first but you take a trip in the vehicle and you want to kill yourself when you are finished IMHO.

Randy

to add to the oil deal .i would tell you to use joe gibbs break in oil or brad penn oil for break in only ..WHY ? any other oil will have a hi leve of detergent in the oil that can work to wipe the zinc ZDDP you add to a stock oil even diesel . you can get on joe gibbs race oil they have alot of good info about oils. i have used diesel oil with a can of zddp but the joe gibbs or brad penn oil is made to do just the break in that is all