Motor sealing tricks for making vacuum in the crankcase?
#2747413
02/28/20 03:22 PM
02/28/20 03:22 PM
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Joined: Aug 2003
Posts: 43,204 Bend,OR USA
Cab_Burge
OP
I Win
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OP
I Win
Joined: Aug 2003
Posts: 43,204
Bend,OR USA
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I'm having issues on my bracket motors (Two) getting above 5.0 inches of vacuum with a big GZ vacuum pump The current motor is better than the one before it but not any where near 10+ inches, any things I should look for? I bought the pump used several years ago and sent it back to GZ for repair or rebuilding as needed, they called yesterday and said it tested good The current motor has a early Hamburger SS oil pan with the lower kick out in it with the drag link hole removed and covered up for more volume at a lower level. I put 11 quarts in it to get it on the tip of dip stick. I'm sure it has a tiny pin hole in it some where as it will weep, seep, some oil onto the pan when it sits all winter, no weeping or seeping during the race season though
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Motor sealing tricks for making vacuum in the crankcase?
[Re: HardcoreB]
#2747423
02/28/20 03:42 PM
02/28/20 03:42 PM
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Joined: Jan 2003
Posts: 4,272 Morrow, OH
markz528
master
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master
Joined: Jan 2003
Posts: 4,272
Morrow, OH
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So the way that I found my leak points was with a UE2000 ultrasonic leak detector. I borrowed it from work.
What I ultimately found was that I had a bad seal in the Indy valley tray. The vacuum pump had sucked in a portion of the RTV sealing the valley tray. Actually happened twice and I missed it with a visual inspection.
67 Coronet 500 9.610 @ 139.20 mph 67 Coronet 500 (street car) 14.82 @ 94 mph 69 GTX (clone) - build in progress......
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Re: Motor sealing tricks for making vacuum in the crankcase?
[Re: Cab_Burge]
#2747506
02/28/20 07:44 PM
02/28/20 07:44 PM
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Joined: Feb 2008
Posts: 714 Central TEXAS!!!!
sr4440
super stock
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super stock
Joined: Feb 2008
Posts: 714
Central TEXAS!!!!
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before i had a large electric vacuum pump, I had a old 1/4hp electric motor that used a long belt to drive the vacuum pump. I prefer to pull a vacuum to find a vacuum leak because i once had a relief valve that sealed great under pressure but would open up at 4in of vacuum. The owner said it was all sealed up because he had pressurized it and it didn't leak. Joe
Without Data, you’re just another guy with an opinion.
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Re: Motor sealing tricks for making vacuum in the crankcase?
[Re: dvw]
#2747537
02/28/20 08:56 PM
02/28/20 08:56 PM
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Joined: Jan 2012
Posts: 2,652 Stuttgart, Arkansas
rickseeman
master
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master
Joined: Jan 2012
Posts: 2,652
Stuttgart, Arkansas
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Ray Barton told me to silicone the harmonic balancer keyway.
2011 Drag Pak Challenger
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Re: Motor sealing tricks for making vacuum in the crankcase?
[Re: Cab_Burge]
#2747547
02/28/20 09:18 PM
02/28/20 09:18 PM
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Joined: Mar 2008
Posts: 89 Cedar Rapids, IA
69Mcode440
member
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member
Joined: Mar 2008
Posts: 89
Cedar Rapids, IA
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Make sure the valve covers and any oil fillers are sealed with an o ring.
Mike
Mike 69 440 Cuda 71 Dart drag car 70 Duster drag car Best et 9.32, 145.9 mph 2019 Ram 2500 4x4
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Re: Motor sealing tricks for making vacuum in the crankcase?
[Re: rickseeman]
#2747548
02/28/20 09:18 PM
02/28/20 09:18 PM
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Joined: Jan 2013
Posts: 174
hustlin hoosier
member
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member
Joined: Jan 2013
Posts: 174
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If you look at some of the old pictures of our engines built by best , you will see toe clamps from the head to the valley cover along each side. We had no luck until then . We even built 1/2 inch thick billet valley covers with no success. Pressurizing is a waste of time as the forces are reversed.
Last edited by hustlin hoosier; 02/28/20 09:21 PM.
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Re: Motor sealing tricks for making vacuum in the crankcase?
[Re: hustlin hoosier]
#2747568
02/28/20 10:08 PM
02/28/20 10:08 PM
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Joined: Mar 2003
Posts: 2,509 PA
moparacer
master
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master
Joined: Mar 2003
Posts: 2,509
PA
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I do nothing special to my engines at all and pull 12 inches with the Star Standard pump. Mine Idles at 5 on alky.
67 Barracuda street/bracket car 11.27-119 68 Dart 502 BB 8.70s-152 414 cid SB Dragster 7.65-174
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Re: Motor sealing tricks for making vacuum in the crankcase?
[Re: moparacer]
#2747573
02/28/20 10:30 PM
02/28/20 10:30 PM
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Joined: Dec 2005
Posts: 11,586 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,586
Fulton County, PA
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Leak test? Anyone use a smoke machine?
If the results don't match the theory, change the theory.
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Re: Motor sealing tricks for making vacuum in the crankcase?
[Re: CMcAllister]
#2747648
02/29/20 07:35 AM
02/29/20 07:35 AM
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Joined: Mar 2006
Posts: 9,843 MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,843
MI, usa
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Smoke machine will work. The air test with soapy water works excellent. The only thing it may miss is if a shaft seal is being pulled back away under vacuum. Doug
Last edited by dvw; 02/29/20 07:36 AM.
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Re: Motor sealing tricks for making vacuum in the crankcase?
[Re: fbs63]
#2748629
03/03/20 03:31 PM
03/03/20 03:31 PM
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Joined: Feb 2006
Posts: 474 Alberta, Canada
451Guy
mopar
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mopar
Joined: Feb 2006
Posts: 474
Alberta, Canada
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I smoked mine a couple of years ago and the smoke was pouring out of the rear main seal area. I took it apart and attempted to reseal it. It is better but I can still not make any vacuum. I have the star set up. I eventually removed it and put the pan evacs back on. I was sick of it blowing oil out of their fancy $400.00 catch can!
Thanx 451 Guy
512 cu in 71 Demon Super Street Car - NO LONGER - Broke Crank Best ET 9.57 @ 139.96
451 cu in Pump Gas - 71 Demon Super Street Car Best ET 9.99 @ 136.80
512 cu in 69 Charger R/T Best ET 11.39 @ 118.11
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