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Overheating engines, rebuild

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Old 09-13-08, 10:17 PM
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Overheating engines, rebuild

So, I'm looking to purchase an RX-7. It's extremely cheap, runs, and has an extremely good body and interior. However, it does overheat. After talking to him about it, it was apparently never ran much while overheating, except one time - he mentioned that a few wires insulation melted?

I plan on rebuilding the engine myself regardless of the RX-7 I purchase. However, according to numerous sources I have read, an overheating engine is possible to rebuild, but have seen only two things mentioned.

Warped plates - what do I need to be aware of here?
Warped rotor housings - what do I need to be aware of here?

A wild assumption is that the engine is junk as it got hot enough to melt insulation off of a wire or two?
Old 09-15-08, 04:56 AM
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if its in good nick and its not going to cost you more to buy a good core engine for a rebuild as well as the cost of the car wont buy you a good runner then maybe go for it but remember if its warped its fucked and new housings arnt cheap allso when buying core engines for a rebuild i think that mazda tolerences on housing condition are a bit slack i think they realy just wanted them fixed well enough to get you out of their hair till the warrenty expires so it is a difficult choice with using a core engine thats done 50000k the housings are only realy good to 100000k so do you want the good 50k out off them or the bad 50k this could be an expencive buy but saying about housing life i have an rx3 with a 10a that has never been touched and its on 160000k
Old 09-15-08, 05:09 AM
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I would stay far away from an RX-7 that has been overheated. You are asking for a large repair bill in the future. Try to find one with a recently rebuilt engine or one with low miles.
Old 09-15-08, 10:56 AM
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Originally Posted by Rowtareh?
I would stay far away from an RX-7 that has been overheated. You are asking for a large repair bill in the future. Try to find one with a recently rebuilt engine or one with low miles.
Why?

Does an overheating engine cause damage to parts other than the engine itself?
Old 09-15-08, 11:29 AM
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Generally, no. It's just engine damage.

However the rebuild price adds up quickly when you need to replace housings at $550/ea.

Dave
Old 09-15-08, 11:42 AM
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Not to mention the headache that can be avoided by pulling the engine by not buying the a car with an overheated engine.


However, if the price is reasonable for the car, it could be beneficial, but very very rarely is.
Old 09-15-08, 11:43 AM
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Originally Posted by dgeesaman
Generally, no. It's just engine damage.

However the rebuild price adds up quickly when you need to replace housings at $550/ea.

Dave
I was figuring on picking up a JDM engine initially if the engine was that bad. I figure between the old engine, the JDM engine, and a rebuilding kit I'd be able to get one engine working when it was time to rebuild.

Not to mention the headache that can be avoided by pulling the engine by not buying the a car with an overheated engine.


However, if the price is reasonable for the car, it could be beneficial, but very very rarely is.
https://www.rx7club.com/showthread.php?t=781666

What I understand to be the "shell" and the "interior" are near perfect.
Old 09-15-08, 11:45 AM
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I am assuming you are getting either a Turbo II or an FD? Post up the information you have and the price for the car.
Old 09-15-08, 11:47 AM
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Originally Posted by Rowtareh?
I am assuming you are getting either a Turbo II or an FD? Post up the information you have and the price for the car.
$600 - it's in the above post . I actually am not particularly interested in a turbo, as I lack any experience in that area - my automotive experience is solely in the NA area. Throwing a turbo on top of that is a bit much ~.^.
Old 09-15-08, 12:15 PM
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Hmmmm. Not a bad price and body seems to be in really good condition. Have you seen the car in person yet? I would not commit to buying the car before seeing it in person.


Also, I would not bother with picking up a JDM engine. That's a waste of time. How many miles are on the engine as it sits?
Old 09-15-08, 12:21 PM
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Originally Posted by Rowtareh?
Hmmmm. Not a bad price and body seems to be in really good condition. Have you seen the car in person yet? I would not commit to buying the car before seeing it in person.


Also, I would not bother with picking up a JDM engine. That's a waste of time. How many miles are on the engine as it sits?
40k-60k since last rebuild. Why is a JDM engine a waste of time, out of curiousity?

I'll definitely take your advice on waiting to see it in person, however.

Last edited by Blaen99; 09-15-08 at 12:24 PM.
Old 09-15-08, 01:20 PM
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Originally Posted by Blaen99
Why is a JDM engine a waste of time, out of curiousity?
1. you said you didn't wanna go turbo, ALL of the JDM second gen RX-7's were turbo
2. no telling what condition motor you will get, it's generally assumed you're going to do a rebuild when you get it
3. all the usual headaches that go along with a TII swap
Old 09-15-08, 01:41 PM
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Not to mention it's much cheaper to rebuild a S4 N/A motor as long as nothing is warped, cracked, flaking, etc.
Old 09-15-08, 08:00 PM
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Thank you guys for the info

A Koyo racing radiator, new OEM thermostat, new OEM water pump, plus an Atkin's engine (Not rebuild of this one) + porting and polishing is well within my planned budget in this car, as well as a cash reserve for other problems that pop up.

Would $500 be a sufficient cash reserve for other assorted problems beyond what I am replacing? I expect some, but am not sure as to the exact amount I should be budgeting for.
Old 09-16-08, 10:54 AM
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Yes, 500 is more than enough for an FC. Clutch is not near that amount nor is a flywheel if you needed to replace that.
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