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#1 |
Registered User
Join Date: Dec 2007
Location: manteca, ca
Posts: 77
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crank case pressure HIGH!!!
what would cause this my friends havin a problem with it... and its causing problems
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#2 |
Green club
Join Date: May 2002
Location: Central CA
Posts: 1,059
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Re: crank case pressure HIGH!!!
Blowby, meaning cyl pressures escaping past the rings.
How does he know this? Is the dipstick blowing out of the tube? Or is he throwing oil out of the breathers/pcv? Let us know.
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71 short/fleet ECE 4/6 drop, LQ4/700r4/3.42 gears 70 SS396 Chevelle 427/200-4R/3.73posi 61 Lincoln Continental, black on black Son you are going to drive me to drinkin if you don't stop drivin that hot rod lincoln |
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#3 |
its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,693
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Re: crank case pressure HIGH!!!
yeah, rings is abpout the only thing.
He does have a PCV valve on there, right? |
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#4 |
Senior Member
![]() Join Date: Sep 2005
Location: Lewisville, Nc
Posts: 10,234
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Re: crank case pressure HIGH!!!
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David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube |
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#5 |
Senior Member
Join Date: Jun 2001
Location: Shelbyville, KY
Posts: 3,269
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Re: crank case pressure HIGH!!!
Every engine good or bad will build internal pressure if not vented. Old blcoks had a breather tube that allowed oil vapors to vent. Then Positive Crankcase Ventalation (PCV) valves were used powered by intake manifold vacuum to suck out and cycle the oil fumes through the combustion prosess. If you have either a good vent tube or a good PCV connected to manifold vacuum, there should be no internal pressure. Huck
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#6 |
Car Knocker
Join Date: May 2001
Location: jefferson,arkansas
Posts: 664
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Re: crank case pressure HIGH!!!
Went to help a buddy the other day start up his brand new engine. He was waiting for me when I got there sitting in the drivers seat with a big grin on his face. Before I really got a good look at what he had, he started it. I was busy looking for leaks and setting the timing and bam. In his rush he forgot or didn't know that the engine needed to be vented. No provisions for valve cover breather or PVC valve. Blew is brand new Holley valve covers off of it. They were cast aluminum and broke around the bolt holes. Just a hundred dollar mistake.
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68 c-10,91 sportside bed,350 .030 over,4 bolt,10-1 comp,2.05 intake/1.94 exhaust,1.6 Harland Sharp roller rockers,edelbrock rpm cam and intake w/750 carb, 700r4, 3.73 gears,Jacabbs Electronic Igntion w/Accel HEI distributer and super coil. ZR-1 roll pan, filled tailights. Blazer tank. Hidden hitch. 2 1/2" Flowmaster 40's. Parts bought but not installed>> ford 9" posi with disc. CCP front and rear lowering kit 4/5. Cab corners,foor boards,rockers, cab braces, Phatom grill, Painless wiring kit. |
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#7 |
Registered User
Join Date: Dec 2007
Location: manteca, ca
Posts: 77
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Re: crank case pressure HIGH!!!
its a new engine so the rings should be good.... be has the holes for the pcv but has vents instead of a vacume hooked to it.. yes it leaks by the dipstick, and blows out the vents... as well as makes the pan leak
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#8 |
Senior Member
Join Date: Jan 2005
Location: SUNNY WARM BIKE RIDING COTTONWOOD ARIZONA
Posts: 2,097
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Re: crank case pressure HIGH!!!
JAY- thats NUTS !!!
COWBOY- sounds like rings are not seated yet. ive been here done this myself on my old blazer with vette covers. i kept blowing the rear main seal out. had the dealer fix it like 3x before he figured out my mistake/problem. had a hole cut in the covers and no more leaks. Last edited by QKENUF4U; 03-02-2008 at 03:49 AM. |
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#9 | |
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
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Re: crank case pressure HIGH!!!
Quote:
I would do a compression check to see where the pressure buildup is coming from. |
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#10 |
is Certifiable
Join Date: Feb 2008
Location: Hinesville, Georgia
Posts: 160
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Re: crank case pressure HIGH!!!
Yeah if it is a new motor you probably just need to seat the rings. For laughs throw a compression gauge on it like 68 said, that will let you know if its rings. I always ran my new engines at 2000 rpm for 20 minutes and then changed the oil. Ran it 200 miles in city only, never going over 40. Then changed oil. Then drove 1000 miles, normal city and highway driving. Changed oil again. Then I was all set. I would stick a PCV valve in it, so you can rule that out, leave the breather on the other side. All good advice here, this should help.
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#11 |
Registered User
Join Date: Mar 2004
Location: CA
Posts: 2,057
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Re: crank case pressure HIGH!!!
those aftermarket chrom breathers suck... i mean they dont suck, thats the probleom.
like said above get a pcv valve, and make sure the rings are seated. to seat the rings in a new motor i like to put it in 1st gear, weather automatic or manual and put around the neighborhood slowly, getting up to maybe 3-3500 rpm, and let the engine braking slow you down, if this makes scence. do it for maybe 15-20 min. |
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#12 | ||
Sierra Grande Club
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
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Re: crank case pressure HIGH!!!
Quote:
Quote:
![]() s/t
__________________
1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe. ![]() |
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#13 | |
Registered User
![]() Join Date: Aug 2005
Location: Hillsboro Oregon
Posts: 6,449
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Re: crank case pressure HIGH!!!
Quote:
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#14 |
Registered User
Join Date: Mar 2004
Location: CA
Posts: 2,057
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Re: crank case pressure HIGH!!!
it does make some scence, but i somewhat disagree that once the wear pattern begins and the peaks of the hone job wear the rings will never seats properly, they will always wear and so will the cylinder walls.
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#15 |
Registered User
Join Date: Mar 2004
Location: CA
Posts: 2,057
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Re: crank case pressure HIGH!!!
and im sure auto manufacturers would be aware of this if it were true, and scince ALOT of people belive (and can pretty mcuh prove) most new cars come with burnout chips to keep people from beating the crap out of thier new cars thier break in methods work pretty good.
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#16 |
Registered User
![]() Join Date: May 2006
Location: Wyman, Kentucky
Posts: 403
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Re: crank case pressure HIGH!!!
I hope whoever rebuilt the engine checked the ring end gap and staggered them on the pistons.
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1972 GMC Jimmy, 4WD, 454 CI, 350 Turbo, 4" lift, 35" tires The math teacher said my son "Bubba" could be a mathmatical genius. cause he's got 13 fingers! |
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#17 | |
Sierra Grande Club
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
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Re: crank case pressure HIGH!!!
Quote:
I haven't heard of such a chip, can you list a single car that has this? Every new rental car I've driven went straight to redline w/ the rev-limiter pegged...no problem! (worked at a car rental as a driver.) s/t
__________________
1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe. ![]() |
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#18 | ||
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
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Re: crank case pressure HIGH!!!
Quote:
Quote:
This is what I've read: New cars are programmed against over-reving to prevent damage to engine/transmission. I have also read that some rental car comapnies have a way to monitor your speed so that if you abuse the vehicle (speeding, racing) they will charge you extra... Back to ring setting... The way I've "broken" in my engine the last few times I've overhauled them is somewhat similar to the example by Motoman. For the first couple hundred miles I fluctuate my speed from slow to fast varying the rpm's so that at no time will the engine be at the same rpm for longer than, say, 5 minutes. Even to the point of putting it in neutral and reving it fast several times while driving... It's worked for me. |
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#19 | |
Sierra Grande Club
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
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Re: crank case pressure HIGH!!!
Quote:
They can track your speed by using On-star. Another debatable subject! Is there a way not to brake in a new engine? There are so many ideas out there it's going to be hard to prove. I don't think I'll baby mine, but not beat it either...Somewhere in between the two methods I guess. s/t
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1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe. ![]() Last edited by Sport/Truck; 03-02-2008 at 08:06 PM. |
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#20 |
Registered User
Join Date: Dec 2007
Location: manteca, ca
Posts: 77
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Re: crank case pressure HIGH!!!
yes there are a few cars that have the traction control/ anti burnout, pt cruiser, even the mustang has it.... to name 2 of them
Last edited by cowboyup1086; 03-02-2008 at 08:10 PM. Reason: typo |
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#21 | |
Sierra Grande Club
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
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Re: crank case pressure HIGH!!!
Quote:
s/t
__________________
1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe. ![]() |
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#22 |
Registered User
Join Date: Apr 2007
Location: King City, Ontario, Canada
Posts: 974
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Re: crank case pressure HIGH!!!
i know that some cars have rev limiters in park, not allowing the car to rev more then say 4000 rpm in park, but when you floor it driving it revs up right up to redline
the break in: when it came time to break in my 383, an engine builder in town said alot of the things mentioned in the article. and since i have a hyd. cam. there was no cam break in. he said 8-10 runs of hard accelerate to 5000 rpm or so, then engine braking back down. once complete, take it easy (but dont be afraid to step on it a bit) and the motor should be broken in. not to drag this on, but my dad knew a guy who had a little vega with a 426 hemi in it. he used to build the motor him self, put it in the car, fire it up, rev it up twice, but it on the trailer, and race it like theres no tomorow.
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- Jason If you can turn, Youre not going fast enough. Favorite caption: first car to 200 mph in the 1/4 mile, no parachute, drum brakes all the way around.. ..back when men were men. |
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#23 |
is Certifiable
Join Date: Feb 2008
Location: Hinesville, Georgia
Posts: 160
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Re: crank case pressure HIGH!!!
100 ways to skin a cat. Until now, my method has worked fine for me. That break in procedure on that page makes sense. I might try it on my next build. Redoing the original 350 from my 72 now.
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#24 | |
Senior Member
Join Date: Jan 2005
Location: SUNNY WARM BIKE RIDING COTTONWOOD ARIZONA
Posts: 2,097
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![]() Quote:
1. you most certainly do have a break in period (2000rpm for 20mins when you fire the new engine) roller cams are the only non-break in cams 2. thats a drag car, they like them loose so they rev and they get rebuilt at the end of the season usually Last edited by QKENUF4U; 03-03-2008 at 08:05 AM. |
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#25 | |
Registered User
Join Date: Mar 2004
Location: CA
Posts: 2,057
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Re: crank case pressure HIGH!!!
Quote:
none of the auto manufacturers admit to doing it but i work at a ford dealership, and do PDI's all the time, and you can definately tell the brand new cars dont have the nuts the used cars do with 5000 or so miles on 'em |
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