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Quick compression question???

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Old 07-23-06, 10:18 PM
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Quick compression question???

Compression tested out to be around 70ish with the engine cold on both rotor.
Does this need a rebuild??
Old 07-23-06, 10:21 PM
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110 good
90 getting bad
80 bad
you probably need a rebuild soon if not now
Old 07-23-06, 10:30 PM
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if i warm up the engine and do another test, will it read fairly higher? or not neccesarily?
Old 07-23-06, 11:08 PM
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Lightbulb

Originally Posted by RevUp13b
if i warm up the engine and do another test, will it read fairly higher? or not neccesarily?
a warm engine will yield lower (worse) results. Your motor has very low compression.
Old 07-23-06, 11:12 PM
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if a motor is around 90 to 100. anyone know how long it will last.

saying you drive it carefully.
Old 07-23-06, 11:43 PM
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whats good in terms of 8.0, 9.0 etc?
Old 07-24-06, 12:28 AM
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Mine was tested at 90 psi on both front and rear housings 20k miles ago but it still runs and starts up with no probs at all. Vacuum is a bit low at 12-13 but I'm not worried.
Old 07-24-06, 12:28 AM
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hhhmm... so how long will it last with those kind of readings?
Old 07-24-06, 12:38 AM
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Also, the compression check method was done with a normal compression gauge and sumwhat modified and itll blow off preassure each time, so not sure how accurate can it be... it can only be higher if it is off right? or no?
Old 07-24-06, 01:09 AM
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Originally Posted by RevUp13b
Also, the compression check method was done with a normal compression gauge and sumwhat modified and itll blow off preassure each time, so not sure how accurate can it be... it can only be higher if it is off right? or no?
If the engine starts fine when warmed up and idles fine then your engine is fine don't worry about it.
Old 07-24-06, 01:24 AM
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readings after warm up were around 80ish and slightly lower....will it at least last me 20k?

How much would u pay for this car?

BTW: all this info is given by the seller of the car im looking into
Old 07-24-06, 06:01 AM
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Originally Posted by Mr rx-7 tt
If the engine starts fine when warmed up and idles fine then your engine is fine don't worry about it.
The owner did say the engine starts fine, idles fine, no hesitation, boost is fine (but at rare times it feels like the 2nd turbo doesnt kick in), never gave him any problems, never died on him, always starts.
Old 07-24-06, 10:04 AM
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Originally Posted by RevUp13b
The owner did say the engine starts fine, idles fine, no hesitation, boost is fine (but at rare times it feels like the 2nd turbo doesnt kick in), never gave him any problems, never died on him, always starts.
Get the engine properly compression tested at a mazda dealership with a rotary compression tester. You're crazy if you buy the car without having done that. both 70 and 80 psi mean 'needs a rebuild.' anything under 6 bar (about 90 psi) is an old, tired motor.
Old 07-24-06, 06:01 PM
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If you in the SF bay area take it to RE and have Chuck to test it for you.. he has a rotory compression tester.
Old 07-26-06, 12:44 AM
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Did you hold the throttle wide-open while cranking? Leaving it closed will give false low numbers.
Old 07-26-06, 01:22 AM
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not sure, the owner said he stepped on it, not sure about wide open though
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