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> Compression or leakdown test???, Which is preferred to sell an engine??
Mueller
post Mar 18 2003, 03:20 PM
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I know once I post this 2.0 motor for sale, I'm going to be asked a bunch of questions (no, I will not take trades (IMG:style_emoticons/default/smile.gif) )

Namely compression or leakdown values.......compression I can do myself so that is a no-brainer (famous last words)


Should I bother with trying to get a leakdown test for a Type IV motor???
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porschewiz
post Mar 18 2003, 03:33 PM
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Compresion test.... The leakdown test may vary depenting where the Piston is on its stoke. Some of the jugs walls will come egg shapped and lose compression mid-way up its stoke
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Brad Roberts
post Mar 18 2003, 04:45 PM
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Unless that engine can be warmed up... the tests are all worthless. Tell Brian Mifsud I said hello.


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Mueller
post Mar 18 2003, 04:48 PM
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I guess it would be hard to do the compression test while the engine is warmed up since it might be a bad idea to pull the plugs....

Oh well, the buyers will just have to "trust me" , LOL
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Brad Roberts
post Mar 18 2003, 04:51 PM
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What is wrong with pulling the plugs on a warm engine ?? Wives tail ?? Compression numbers themselves dont mean a damn thing. Consistentcy between cylinders is what I look for. 130/130/130/80 is not good.

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Mueller
post Mar 18 2003, 05:03 PM
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Wives tale???

I guess so, that is something I was always told not to do....by whom, I have no idea, I just always thought it was "wrong" to do so and that I could risk stripping the threads.
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Brad Roberts
post Mar 18 2003, 05:07 PM
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So... when I bring Wicker or Bontempi off the track into the hot pits and do a plug reading...straight off the track... I shouldnt ?? I'm in big trouble. There is no other way to get a decent compression check or plug reading. You'll be fine. The people that have problems are the people who cross threaded them to begin with or those that have TimeCerts. The time certs can come out if somebody didnt stake them in.


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GWN7
post Mar 18 2003, 05:19 PM
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I always understood it was best to do a wet & dry test on a warm engine. Watch for burnt fingers. (IMG:style_emoticons/default/smile.gif)
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Zeke
post Mar 18 2003, 05:47 PM
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I favor compression. If the comp is low in one or more cyls, the leak down can identify/isolate the problem. If the motor has good comp numbers, there's no need for a leak down. Another benenficial leak down is for the total engine. This finds vacuum leaks in the intake. You can do this with an intake valve open and the intake sealed. But you do this with a vacuum, not pressure. I belive NASCAR does this on restrictor plate motors. If they find a leak, they tear the motor down. A leak there is speed.
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Dave_Darling
post Mar 18 2003, 06:06 PM
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If you're just doing it to sell the motor, take the compression readings any way you want to. If they're cold, note that. (E.g., Compression (cold) 155/150/145/155 PSI.)

If you get warm compression and warm leak-down, you might be able to talk a prospective buyer into paying a little more $$.

Oh, and leak-down for these purposes is usually done at TDC. Just make sure you have a way to hold the engine there....

--DD
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Mueller
post Mar 18 2003, 06:12 PM
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Hey Dave...this would be a great way to have a running and driving 914 (IMG:style_emoticons/default/mueba.gif) (IMG:style_emoticons/default/mueba.gif)


hint, hint......hahahaha
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Dave_Darling
post Mar 18 2003, 06:37 PM
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Don't think I hadn't thought about it...
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Mueller
post Mar 18 2003, 06:46 PM
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A few nights ago while crawling back under the 914 I was seriously thinking of keeping the "loaner" motor and selling my fresh 2.0 since the thought of doing another engine swap in a few weeks/months is not very appealing right now..............one good thing is that I know I could bolt my Megasquirt on the "loaner" motor and be running again in just a few hours (IMG:style_emoticons/default/smile.gif)

I'm getting tired of working on the car....it always seems to be one step forward, two steps back (IMG:style_emoticons/default/smash.gif) (IMG:style_emoticons/default/smash.gif)
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chunger
post Mar 19 2003, 03:10 AM
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I could bolt my Megasquirt on the "loaner" motor and be running again in just a few hours



or hydralocked in a couple minutes (IMG:style_emoticons/default/blink.gif)

hee hee. . .
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Mueller
post Mar 19 2003, 11:28 AM
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Very funny 'Chung.....

That was a very strange occurance......all my fault since I had the injectors powered directly to the battery instead of using a relay.....

Can you bring my stim. to the dinner?

It looks like I have the "loaner" motor sold so I'll have to kick some ass and get my other motor fixed..........
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Dave_Darling
post Mar 19 2003, 11:40 AM
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Mike, I can bring my stim kit to the dinner if you like. It's not assembled, though... More DIY required! (IMG:style_emoticons/default/wink.gif)

--DD
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