So I've finally saved some money up to get my car going again, and I need some opinions on what I should do. I rebuilt an engine myself a while back and spun a bearing, so I swapped the original engine back into the car and blew a seal on the front rotor a few months ago. The way I see it, I have two options. 1) frankenstein parts from both engines together, getting them lapped & trying housing resurfacing, replacing bearings, and replacing seals again. 2) There seem to be some nice used engines from J-spec with compression tests done on them. My dilemma is that I was budgeting between $3000-$4000 for my rebuild, and that's right about the J-spec engines cost as well. It seems to me like I would be much better off buying an engine that's at least guaranteed to have compression than trying to resurface parts from two engines that have over 100k miles and attempt to squeeze as much life out of them as I can. I don't doubt my ability to build another engine, but it just seems silly to put an equal amount of money into building an engine whose components simply don't have as much material left on them.

If anyone has any experience with J-spec engines I would love to hear about how they do. I'm a little skeptical because I know compression tests can be manipulated to show higher readings. Thanks for reading and any advice you can offer, and happy new year!

 

Japanese engines are identical to US ones so it's no different than buying any used rotary. If compression can be demonstrated - great. The problem is you can't accurately test compression on a cold engine out of the car, so it's a bit of a gamble. But I agree that Frankensteining together tired parts of previously expired engines is a worse gamble.

Ideally you get yourself a known good rebuilt engine from a rebuilder, but that might be out of the budget range you stated.
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If you have to stick to that budget, it might be worth the gamble.
If you can afford to spend more or use credit to 'expand' your budget, I recommend splurging on a new engine.

I got mine installed just over a year ago and love it.
I drove it with failing compression for 2 years before it died.

​I thought once it started, it ran like normal, but I didn't notice the gradual lack of performance & throttle response.
The difference is very noticeable now.

It runs like it did when I first test drove it with 18k miles.
I'm very happy I chose to spend money like a drunken sailor.

Not only did I drop a new engine in it, I had many other things fixed on a 20 year old car that need fixing.
After it sat for 3 years, including new tires, I spent around $9k on it.
I don't regret it.

I had a mantra at work as related to time, but it applies to spending money on rebuilds as well;

"There's never enough time (or money) to do it right the first time, but always enough to do it over "

Is it worth it to gamble on a $4000 engine when new ones go for a couple of thousand more?

I haven't priced them lately.
A year and a half ago you could get a new engine for $6100, Idk what they are now.

​​Say you spend $4k and are unhappy with the results.

Would you then wish you had spent more to buy a new engine?

Also, the time invested in it as well.
I value time much more now.
The extra expense was worth it to me to get it done 'right' the first time.

If you haven't read it yet, read the Rebuider's thread.
Plenty of useful info in there.
Of special interest to you might be the thread I linked with Kevin from Rotary Resurrection explaining the pros and cons about budget rebuilds.

Good luck!

https://www.rx8club.com/general-auto...-265177/page9/

 

From what I've seen new/reman/rebuilt engines are a ways out of the price range for me. I'm likely picking up this engine tomorrow and I plan on giving it my own quality analysis inspection. I can update this thread later on once I get it in the car to show everyone how it's doing & how good of a purchase it was (or wasn't) if anyone is interested in seeing that.

Thank you for the responses, I feel moderately better about pulling the trigger on it now

 

I was able to buy a JDM engine and transmission for $1700.
6 port Automatic. Wiring harness was cut so i had to rip and replace with original. First engine swap for me. It ran like a champ after working on O2 sensor and MOP issue.





Can't speak to the reliability as I was offered cash for it and it's gone! Probably sold it too cheap. But it was a fun quick project.

 

Congrats on the sale.

If I was 20 years younger, knowing what I know now, I would try fixing & flipping them.