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knocking, just rebuilt...

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Old Apr 11, 2006 | 09:52 AM
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knocking, just rebuilt...

i am brand new to the internals of the motor so please help see where i went wrong or what i need to do. I rebuilt the motor just droped it in. when i start it up the exhaust note sounds good but it sounds like the motor is knocking like crazy although there is very little vibration to the entire motor. Is this a timing problem or did i rebuild it wrong?
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Old Apr 11, 2006 | 10:01 AM
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Start off with the easy stuff:

1. What mods are on your car?
2. If you are using the stock ECU, did you check to see if you have any stored codes?
3. Have you done a compression test to check the new rebuild?
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Old Apr 11, 2006 | 10:06 AM
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i have a pfc tuned by chris sanders last year when i got my reman... mods are basicaly 3in exhaust and peter farrell ic. I do not have the comander with pfc and doing the compression today.. it sounds like its comming from rear housing
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Old Apr 11, 2006 | 11:17 AM
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compression is 110+ on front rotor and 86-89 on rear which is not good....
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Old Apr 11, 2006 | 11:22 AM
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nevermind its about 80 in the rear..*sigh*..
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Old Apr 11, 2006 | 11:56 AM
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knocking is the result of a bearing failure/spun, allowing freeplay between the rotor and shaft, letting the tips of the rotor contact the housings and irons. Go on ahead and tear it back down.
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Old Apr 11, 2006 | 02:05 PM
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not necessarily, it could also be loose flywheel bolts if you have a lightweight flywheel.
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Old Apr 11, 2006 | 02:14 PM
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why do you automatically think it's knocking? Could it just be misfiring? or do you actually hear a loud tap sound from the engine?
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Old Apr 11, 2006 | 02:53 PM
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yeah they're taps clack, clack, clack......consistant....O well at least i tried it..ill just send it in to get it rebuilt
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Old Apr 11, 2006 | 03:27 PM
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if it did spin a bearing you may be better off just getting a good used motor, lubrication issues in these engines result in a very costly rebuild.
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Old Apr 11, 2006 | 07:56 PM
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he probably means send it in to mazda for a core... well if hes smart i mean lol
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Old Apr 11, 2006 | 08:24 PM
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Originally Posted by mono4lamar
he probably means send it in to mazda for a core... well if hes smart i mean lol
what do you mean by this?
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Old Apr 11, 2006 | 10:08 PM
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He means your motor is probably FUBARd, and a rebuild will mean a lot of new (or used) parts that you'll have to get from somewhere. If it is a bad bearing, your e-shaft is definitely f*cked. Ask me how I know The point is to use your shitty core and get reman from Ray Crowe @ Malloy Mazda 1-888-534-3400. Going price is $2600 + core ($1000) right now I believe. Probably cheaper than putting yours back together. Only caveat is that you can't take the engine apart to use as a core. Good luck.

EDIT: BTW, damn, 110 psi compression on the front rotor? That's pretty good from what I understand... so sorry to hear of your loss on the rear...

Last edited by mdpalmer; Apr 11, 2006 at 10:25 PM.
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Old Apr 11, 2006 | 10:30 PM
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but it is a reman from a year ago with maybe 3k after the initial 2500 mile break in...thats y i tried to rebuild it myself
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Old Apr 12, 2006 | 09:58 AM
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So i was tearing it back down and i found that the slave cylinder head was in the bell housing!!! ive read in many places that it takes some time to gain full compression???
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Old Apr 12, 2006 | 10:14 AM
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Originally Posted by mdpalmer
He means your motor is probably FUBARd, and a rebuild will mean a lot of new (or used) parts that you'll have to get from somewhere. If it is a bad bearing, your e-shaft is definitely f*cked. Ask me how I know The point is to use your shitty core and get reman from Ray Crowe @ Malloy Mazda 1-888-534-3400. Going price is $2600 + core ($1000) right now I believe. Probably cheaper than putting yours back together. Only caveat is that you can't take the engine apart to use as a core. Good luck.

EDIT: BTW, damn, 110 psi compression on the front rotor? That's pretty good from what I understand... so sorry to hear of your loss on the rear...
Whoops, for the record, Ray's # is 1888-533-3400. If you go to Kevin Lander's website, he says that motors with used housings tend to have less compression during the break-in period than do motors with new ones. http://www.rotaryresurrection.com/
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Old Apr 12, 2006 | 10:27 AM
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Originally Posted by orangeglowFD
ive read in many places that it takes some time to gain full compression???
Yes - How long depends on how the surfaces mate initially after the rebuild. The better they fit, and the smoother the finish (the less imperfections from previous wear, etc.), the shorter the time.
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Old Apr 13, 2006 | 03:16 AM
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i have the front rotor pointing down and the rear rotor pointing to the side...i believe this is correct but thats the only part i see that i could have done wrong
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Old Apr 13, 2006 | 08:28 AM
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The compression on the rear will not raise to meet the front. Even on a fresh rebuild they should be close to the same from front to rear, then during the break in they will both raise evenly.
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