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what are signs of a bad motor?

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Old 10-08-02, 08:06 PM
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what are signs of a bad motor?

how do you know when your motor is going bad? what are some warning signs?

what exactly is required during an engine rebuild (assume i have shop, tools, etc)

what parts, and approx $$
Old 10-08-02, 08:17 PM
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here's the motor in question, it's a 93 with 71k on it:

Old 10-08-02, 08:24 PM
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that pic doesn't really help...i'm no expert, but from reading i would say compression, vacuum at idle, if it smokes of coolant are some signs of a bad motor. get the car checked out my a rotary mechanic if in doubt.
Old 10-08-02, 08:26 PM
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A common problem are the seals. When your seals start leaking oil, you should start getting worried. To avoid this a lot of people upgrade their seals to 3mm apexi seals. Also watch your "O" rings. When your "O" rings start leaking oil, Your Fucked !! I'm in this situation now My tech guy told me, with the labor time and cost to repair anything would cost me as much as to buy and install a new motor !! But that was just me, other people could be different, but I did get two different Rx7 techs opinions. I'm still saving for a rebuilt street port, and going single turbo. I plan to do it all at the same time.
Old 10-08-02, 08:37 PM
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about how much do you think that is going to run you?
Old 10-09-02, 12:24 AM
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Originally posted by RX7-2JOCK
A common problem are the seals. When your seals start leaking oil, you should start getting worried. To avoid this a lot of people upgrade their seals to 3mm apexi seals. Also watch your "O" rings. When your "O" rings start leaking oil, Your Fucked !! I'm in this situation now My tech guy told me, with the labor time and cost to repair anything would cost me as much as to buy and install a new motor !! But that was just me, other people could be different, but I did get two different Rx7 techs opinions. I'm still saving for a rebuilt street port, and going single turbo. I plan to do it all at the same time.
Ummm, NO.

3mm seals are apex seals, they don't leak oil. If the engine starts to smoke then it is either the turbos or the circular seals on the side of the rotors that are letting the oil by.

O-rings are similar to a head gasket on a piston car, when they go the car will start using coolant and eventually quit running. The difference is a rotary requires a rebuild when this happens.

Rebuild and single turbo at the same time, what is that gonna cost you, $7-8K?

Jeff
Old 10-09-02, 12:47 AM
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Re: what are signs of a bad motor?

Originally posted by 993kgt
how do you know when your motor is going bad? what are some warning signs?
Water seals...

The biggest and most confirming sign will be lots of pillowy white smoke, either at or shortly after startup, that goes away after a few minutes. Advanced seal failure shows up in the form of exhaust gas in the coolant system, which leads to coolant overflow as well as overheating.
Old 10-09-02, 07:40 AM
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is it likely that I will be needing to replace this engine sometime soon? what if the owner changed oil every 3000 miles and it's all documented? still a great chance?
Old 10-09-02, 01:57 PM
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oil should be changed very frequently in rx7's. I would change mine every 1500-2000 miles. I've heard of engines going at 50k and also some lasting all the way up to 120k. For the most part, i'd say you got about 20-30kmi before you have to replace the engine.
Check to see if the car is still using the precat. If it is, most likely your maincat is clogged, or will be clooged in the near future, and that can cause failures in the engine.
If your buying this car, be very cautious. Make sure you get the car check out. Especially check for any white sweet smelling smoke on start up. Theres some dirty people out that that will sell you a car knowing that it'll be time for a rebuild...******* bastards...
Nathan
Old 10-09-02, 01:57 PM
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oh and by the way. Damn, your engine bay looks clean as heck!!
Old 10-09-02, 03:09 PM
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i know! for 71k miles and stock, the engine bay is clean!
Old 10-09-02, 04:14 PM
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If you turn up the boost any your days are numbered. If you keep it bone stock and just drive it and dont be ragging it you might make it to 100k if your lucky. You start modding it and turning up the boost and you can expect to spend $5K on a new engine and turbos installed very soon.

You're seals and getting very brittle and weak

STEPHEN
Old 10-09-02, 04:29 PM
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clean freak !!! nice engine bay
Old 10-09-02, 04:39 PM
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some signs are "sobbing" "complaining" "smiles on the faces of the local rotary techs" "your bank calling because you over drew your account"

well thats my signs anyhow...

rotary reliability and racing builds great motors and has great prices too...they built mine for a very fair price 7148398018 ask for nick...if you plan on shopping around.

Ive lost two motors in the time i have had this car...one with bad o rings (hard starting..coolant smoke out exhaust and coolant on the plugs) and the second at the track which was a side seal (shaking motor...low compression...loss of power)


thats bout it

when in doubt check the compression.

j
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