 ATTN: Engine guys - need a solution, Just a couple of questions |
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| ahdoman |
  Feb 27 2007, 08:15 PM
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#1
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It's phonetic...Ah-D-O-Man (Audioman)  Group: Members Posts: 667 Joined: 7-November 05 From: Santa Clarita, Ca. Member No.: 5,084 Region Association: Southern California  |
2.0 engine is out of the car with trans still attached.
Question #1 - I need to check compression (I know, it's easier before the engine is out but it's out). If I connect the battery (+ & -) to the solenoid will the engine turn over? Will this damage anything. Obviously I am not trying to start it just want to turn it over to measure compression. Question #2 - If I find that compression varies on some cylinders I would like to be able to determine if it is rings or valves leaking. My plan was to put my rubber tipped blower nozzle into the sparkplug hole, pressurize and listen into case, intake or header to see if I hear a leak. The problem is as soon as I pressurize the cylinder the piston moves to the bottom of the stroke. Any ideas as to how I can keep the cylinder on TDC? |
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| 911quest |
Feb 27 2007, 08:18 PM
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#2
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Member Group: Members Posts: 277 Joined: 26-March 06 From: Louisville Ky Member No.: 5,773 Region Association: South East States |
Buy a leak down gauge the piston has to be a complete TDC
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| Johny Blackstain |
Feb 27 2007, 08:24 PM
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#3
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Walnut Elite Stratocaster player Group: Members Posts: 3,434 Joined: 5-December 06 From: The Shenandoah River Member No.: 7,318 Region Association: MidAtlantic Region 
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Get the flywheel lock tool.
http://cgi.ebay.com/ebaymotors/VW-VOLKSWAG...1QQcmdZViewItem Attached image(s) 
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| Crazyhippy |
Feb 27 2007, 08:45 PM
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#4
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Insert witty comment here... Group: Members Posts: 1,659 Joined: 28-July 05 From: Home of the Coyotes, AZ Member No.: 4,493 Region Association: None |
Step on the brakes....
The flywheel lock is the ticket. BJH |
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| ahdoman |
Feb 27 2007, 08:50 PM
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#5
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It's phonetic...Ah-D-O-Man (Audioman) Group: Members Posts: 667 Joined: 7-November 05 From: Santa Clarita, Ca. Member No.: 5,084 Region Association: Southern California |
Any way to do this w/o removing the trany?
Also anybody got any comments on question #1? Believe it or not I've never had to hotwire a car so I don't know if that's the way to do it. |
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| SLITS |
Feb 27 2007, 09:34 PM
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#6
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None  |
While a leakdown test is best (you can buy a leakdown tester at Harbor Freight for about $65), you can do a compression test.
Hook the + lead of a battery charger or battery to the normal lead on the solenoid. Hook the negative lead to the starter case, tranny or engine. Using a screwdriver, jump from the + big lead to the spade terminal on the starter ... the engine will spin just like you were using the key. Make sure you hold the throttle wide open and pull all the plugs prior. |
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| McMark |
Feb 27 2007, 09:50 PM
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#7
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914 Freak! Group: Retired Admin Posts: 20,180 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
QUOTE The problem is as soon as I pressurize the cylinder the piston moves to the bottom of the stroke. Then you're not really at TDC. (IMG:style_emoticons/default/wink.gif) |
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| ahdoman |
Feb 27 2007, 09:55 PM
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#8
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It's phonetic...Ah-D-O-Man (Audioman) Group: Members Posts: 667 Joined: 7-November 05 From: Santa Clarita, Ca. Member No.: 5,084 Region Association: Southern California |
QUOTE(SLITS @ Feb 27 2007, 07:34 PM)  While a leakdown test is best (you can buy a leakdown tester at Harbor Freight for about $65), you can do a compression test. Hook the + lead of a battery charger or battery to the normal lead on the solenoid. Hook the negative lead to the starter case, tranny or engine. Using a screwdriver, jump from the + big lead to the spade terminal on the starter ... the engine will spin just like you were using the key. Make sure you hold the throttle wide open and pull all the plugs prior. Thanks Slits - If I do this wrong does it become an arc welder? Hey McMark... (IMG:style_emoticons/default/chair.gif) thanks for clarifiying that! |
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| Jake Raby |
Feb 28 2007, 08:34 AM
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#9
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Engine Surgeon Group: Members Posts: 9,398 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
The leak down test is a true disgnostic evaluation, compression tests are virtually worthless...
Buy the leak down and make sure it has DUAL pressure gaiges, the cheap ones have one and they suck! Get the engine WARM and then get the engine to TDC, lock the car in gear and lock the E brake....This will hold the engine at TDC... Listen for the leakage and go from there. |
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