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Breaking in the 470

Steve009

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I’m finally getting around to finishing my 400 to 470 stroker. Bottom end has been done for over a year but covid put a bit of a hold on things. I’m a bit of a rookie with this high performance stuff. I’ve read a lot of back and forth about breaking in the engine. I know to use proper break in oil, high zinc, rev up to 2500 for 20min etc. The one thing my old man and I can’t seem to determine is the dual valve spring concept. Can a cam not be broken in with both inner and outer springs set up? Do the inners really have to come out for break in and then put back in for tuning on dyno day? Is this just an overkill myth or is it actually the case? My old man is old school and never remembers going through this on any engine he built back in the day but maybe thoughts have changed on this?
 
My old man is old school and never remembers going through this on any engine he built back in the day but maybe thoughts have changed on this?
I only helped build a few engines in the day. Technology has improved, but I'm not sure about the cam and lifter metals (recycled scrap). We built our engines, cranked them up and drove them easy until we couldn't resist any longer. We never worried about cam and lifter failure. All oils had zinc and there was lead in the gas. Lead was a valve train lubricant, and zinc hardened the necessary parts. We used the same theory that we were told by the dealers that sold the new cars. The dealership I bought my first new car from, told me to drive it like I was going to use it, but to just vary the speed for the first 3-5 hundred miles.
 
Good oil with the proper additives. 30 minute break in and fluid check and then drive it. You don't have to beat the snot out of it but give it a lot of short spirited romps.
 
I’m finally getting around to finishing my 400 to 470 stroker. Bottom end has been done for over a year but covid put a bit of a hold on things. I’m a bit of a rookie with this high performance stuff. I’ve read a lot of back and forth about breaking in the engine. I know to use proper break in oil, high zinc, rev up to 2500 for 20min etc. The one thing my old man and I can’t seem to determine is the dual valve spring concept. Can a cam not be broken in with both inner and outer springs set up? Do the inners really have to come out for break in and then put back in for tuning on dyno day? Is this just an overkill myth or is it actually the case? My old man is old school and never remembers going through this on any engine he built back in the day but maybe thoughts have changed on this?
With out knowing your cam and springs go with the cam manufacturers recommendations. Key is have game. Motor fires first crank and let it warm up. Most motors are ruined by stupid mistakes that cause excessive no fire cranking and fuel diluted oil. We built race motors as well as street motors fired them first crank and warmed them up. Made a tune and ran them race or street. Never had a failure. Needs to run on the first fire up.
 
I only helped build a few engines in the day. Technology has improved, but I'm not sure about the cam and lifter metals (recycled scrap). We built our engines, cranked them up and drove them easy until we couldn't resist any longer. We never worried about cam and lifter failure. All oils had zinc and there was lead in the gas. Lead was a valve train lubricant, and zinc hardened the necessary parts. We used the same theory that we were told by the dealers that sold the new cars. The dealership I bought my first new car from, told me to drive it like I was going to use it, but to just vary the speed for the first 3-5 hundred miles.

this is exactly what my old man says and he was a mechanic for 30 years. But maybe the current set ups require this. He also admits he never dealt with horsepower in the 600s so may be different. We are open to listening to others opinions on this.
 
With out knowing your cam and springs go with the cam manufacturers recommendations. Key is have game. Motor fires first crank and let it warm up. Most motors are ruined by stupid mistakes that cause excessive no fire cranking and fuel diluted oil. We built race motors as well as street motors fired them first crank and warmed them up. Made a tune and ran them race or street. Never had a failure. Needs to run on the first fire up.

mine is a solid flat tappet custom grind comp cams cam. 593 gross lift, about 130-160 spring pressure on the seat and about 340-370 open. Using trick flow 240 heads with Harland sharp heavy duty rockers. I wouldn’t say super high potent engine but aiming for around 625hp, 600ish torq. I’m not sure if these spring pressures qualify as needing to remove the inners because of high pressure. I agree though, the quick start up is key.
 
this is exactly what my old man says and he was a mechanic for 30 years. But maybe the current set ups require this. He also admits he never dealt with horsepower in the 600s so may be different. We are open to listening to others opinions on this.
From one old man to another. :) You know how it was done.
If your spring pressures are correct and not excessive, break it in like it is. If you have any doubts remove the inner springs and break in for 20 minutes at 2000 rpms or more, then reinstall the inner springs and make a second run for about the same amount of time and rpms. You should be good to go to the dyno.
 
The pros typically say less than 300 over the nose is okay... If it's more than that take the inner springs out.... It's allot easier to R&R the springs than trash the engine....
 
The pros typically say less than 300 over the nose is okay... If it's more than that take the inner springs out.... It's allot easier to R&R the springs than trash the engine....

guess I should be doing it with 340-370 then
 
guess I should be doing it with 340-370 then

Unless you really like building engines... When you lose a camshaft it's common to embed metal in the pistons, score the cylinder walls, rod & main bearings, score the crank journals... Trust me you don't want to lose a cam in a fresh engine...

Older worn engines sometimes have enough clearance that the damage isn't severe... With a fresh engine with tighter clearances chances of damage are much higher...
 
Does the camshaft manufacture recommend it per their instructions? Then yes, i would.
 
This is how I explain it to my customers who have decided to run a flat tappet cam that requires a dual spring to assure proper high rpm valvetrain control(or any spring with high open loads)......

If you don’t soft spring it, and eats the cam...... it’s just shame on you.
Simple as that.
 
This is how I explain it to my customers who have decided to run a flat tappet cam that requires a dual spring to assure proper high rpm valvetrain control(or any spring with high open loads)......

If you don’t soft spring it, and eats the cam...... it’s just shame on you.
Simple as that.

have you ever left them both in and wiped a cam out?
 
Does the camshaft manufacture recommend it per their instructions? Then yes, i would.

comp cams doesn’t mention anything about it



This is exactly what Comp recommends.....and pretty much every other supplier.

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I will say this. If you can swing it, pay the extra for nitriding. We had one HFT break-in go bad, lots of fuel wash due to a sudden stuck float problem, cranked forever without starting, got too hot once it did fire up, you name it...and that engine is still running great today (and it's a FORD ahhhh!) Of course I can't say for certain the nitride treatment is what saved it, maybe just luck..but who knows. By all accounts that cam (a fairly aggressive grind) should NOT have survived..
 
I will say this. If you can swing it, pay the extra for nitriding. We had one HFT break-in go bad, lots of fuel wash due to a sudden stuck float problem, cranked forever without starting, got too hot once it did fire up, you name it...and that engine is still running great today (and it's a FORD ahhhh!) Of course I can't say for certain the nitride treatment is what saved it, maybe just luck..but who knows. By all accounts that cam (a fairly aggressive grind) should NOT have survived..

yes I did get the nitriding. Heard good things about it as well.
 
I’m finally getting around to finishing my 400 to 470 stroker. Bottom end has been done for over a year but covid put a bit of a hold on things. I’m a bit of a rookie with this high performance stuff. I’ve read a lot of back and forth about breaking in the engine. I know to use proper break in oil, high zinc, rev up to 2500 for 20min etc. The one thing my old man and I can’t seem to determine is the dual valve spring concept. Can a cam not be broken in with both inner and outer springs set up? Do the inners really have to come out for break in and then put back in for tuning on dyno day? Is this just an overkill myth or is it actually the case? My old man is old school and never remembers going through this on any engine he built back in the day but maybe thoughts have changed on this?

YEP.... that's the way we do it on the Dyno all the time !
especially if the V/Spring pressures with the inner springs in place is anywhere even remotely close to 300# over the nose.

BIGGEST thing to remember.... is this is NOT the 'old days'... not just in Oils/Zinc but also the actual metallurgy of the cam Cores/Lifters/Parkerizing qualities just isn't there anymore !
Remove the inners.... run only the outers for break-in.... and even check/measure very closely to insure you have correct and NOT 'excessive' V/Spring pressures once the inner are re-installed after break-in.... lest break-in is successful, then to only to wipe a lobe from too much pressure after re-installing the inners !
 
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