Break in with or without vacuum pump

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lekid
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Break in with or without vacuum pump

Post by lekid »

I installed a vacuum pump on my car/engine last summer and we are now almost done the refresh on the motor and going to be going to the engine dyno soon.

I heard that you are suppose to run the engine without the vacuum pump first to seat the rings. Is that the recommended procedure? And at what point can I hook the pump back up? After 3-4 pulls when I feel the rings are seated?
Alaskaracer
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Re: Break in with or without vacuum pump

Post by Alaskaracer »

Connect it and run it. Won't hurt a thing....If your dyno guy does it right, the first two or three hits on the dyno will seat the rings, vacuum pump or not....
Mark Goulette
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lekid
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Re: Break in with or without vacuum pump

Post by lekid »

What is "doing it right"?

I have dynoed many times and have helped him dyno other engines and we never did anything specific. This is what we usually do:
Start the engine and let it warm up
Check timing and do one very small pull and stop at lower rpm to put some heat in it
Then we check the valve lash, let the engine heat soak
Then we do a few pulls without changing anything until the power stops increasing. We figured that is when the rings are seated.

Is that that right way?
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Re: Break in with or without vacuum pump

Post by gnicholson »

My thinking is that the same reason a vacuum pump increases ring seal is the same reason it will help seat the Rings faster. Especially if you are running low tension Rings designed for a vacuum pump
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Re: Break in with or without vacuum pump

Post by Alaskaracer »

lekid wrote: Sun Jan 21, 2018 1:13 pm What is "doing it right"?

I have dynoed many times and have helped him dyno other engines and we never did anything specific. This is what we usually do:
Start the engine and let it warm up
Check timing and do one very small pull and stop at lower rpm to put some heat in it
Then we check the valve lash, let the engine heat soak
Then we do a few pulls without changing anything until the power stops increasing. We figured that is when the rings are seated.

Is that that right way?
I have known a few in the past that would start the engine, let it idle until warm, shut it down, cool it, start it again, do a few easy pulls to a moderate rpm, shut it down, cool it, and repeat. They would do this several times before actual runs. Not sure why they would, but the only thing that seats the rings is cylinder pressure, and doing it that way isn't going to seat them. Full load sweeps will, and will seat them quickly. My dyno guy here starts the engine, verifies timing, then three full pulls. After that we start tuning. Only thing that keeps a pull from happening is if he sees something wrong while checking timing or on the first one....
Mark Goulette
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Speed kills but it's better than going slow!
http://www.livinthedreamracing.com
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vortecpro
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Re: Break in with or without vacuum pump

Post by vortecpro »

Who dyno's your engines?
Racing a NA NHRA stocker should be mandatory before any posting.
roc
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Re: Break in with or without vacuum pump

Post by roc »

Coloradoracer wrote: Sun Jan 21, 2018 7:04 pm
lekid wrote: Sun Jan 21, 2018 1:13 pm What is "doing it right"?

I have dynoed many times and have helped him dyno other engines and we never did anything specific. This is what we usually do:
Start the engine and let it warm up
Check timing and do one very small pull and stop at lower rpm to put some heat in it
Then we check the valve lash, let the engine heat soak
Then we do a few pulls without changing anything until the power stops increasing. We figured that is when the rings are seated.

Is that that right way?
I have known a few in the past that would start the engine, let it idle until warm, shut it down, cool it, start it again, do a few easy pulls to a moderate rpm, shut it down, cool it, and repeat. They would do this several times before actual runs. Not sure why they would, but the only thing that seats the rings is cylinder pressure, and doing it that way isn't going to seat them. Full load sweeps will, and will seat them quickly. My dyno guy here starts the engine, verifies timing, then three full pulls. After that we start tuning. Only thing that keeps a pull from happening is if he sees something wrong while checking timing or on the first one....
Mark, thanks for sharing this good info, I admire your informative posts. Just for my education, please confirm: you do these three full pulls on a fresh assembled engine without any babying or mercy?
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Re: Break in with or without vacuum pump

Post by Alaskaracer »

vortecpro wrote: Sun Jan 21, 2018 7:23 pm Who dyno's your engines?
Dave Slatten. Best builder in the area...
Mark Goulette
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n2xlr8n
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Re: Break in with or without vacuum pump

Post by n2xlr8n »

gnicholson wrote: Sun Jan 21, 2018 2:27 pm My thinking is that the same reason a vacuum pump increases ring seal is the same reason it will help seat the Rings faster. Especially if you are running low tension Rings designed for a vacuum pump
^^This. :D
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Re: Break in with or without vacuum pump

Post by steve cowan »

hi guys,
first i want to say i am not an professional engine builder or even in the industry,i am a high rise construction worker who enjoys building my own cars and engines,
my opinion is with low tension rings you would have to use a vacuum pump and with standard tension rings does not matter unless you are looking for more HP by pulling vacuum,there are current threads here on this subject,i want to tell a story of my own experiences with low tension rings a couple years ago on one of my own 383sbc builds,i am going to make a fool of myself but thats ok
i was putting a shortblock together and the oil ring pack was boxed incorrectly
they were low tension rings in a std tension ring box
i set all my ring gaps as per spec,including oil ring
i use a fish scale to check ring tension-it had 12 pounds
i thought thats a bit lite but due to my inexperience i thought it woud be fine
the box said 20lb std tension
well put it together,start it up,i am using roller cam so not breaking in like a flat tappet deal
runs well,idles sweet,sounds great approx 500hp engine give or take
went for my first drive as it is a registered streeter,smells a bit fumes i think fresh engine smell
drive approx 6 miles,back at my house and check catch can WTF
its 3/4 full of oil,this cant be right,empty catch can and retest with same results
block had been torqueplate honed,measured real nice as i have good measuring equipment
anyway long story short i had low tension rings with no vacuum pump and it was a puker
pulled engine,replaced rings and checked at 20lbs oil ring no other changes,motor good and came in with 2-4 % leak,no oil in catch can either
so this is why i have that opinion on vac pump,if somebody else has a different idea i would sure like to hear about it
thanks

steve c
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