Anyone have experience buying a motor on ebay or some website?

I plan on rebuilding it once I receive it, but what makes things unuseable? like rust in the housings, deep scars in the housings? What else?

 

i've now bought two engines via Ebay. one was shipped, the other i went to pick up. both of them were piston engines though. one thing i will say though, is vendor is probably one of the most crucial factors.

unfortunately, many things can be wrong with the engine. depending on the vendor, there may or may not be a form of recourse if you happen to end up with one. i guess that only matters if you plan to use it immediately after getting it. since you stated you're going to rebuild it anyway, none of that matters.

in addition to the possible scenario that you receive a pristine or just a low compression engine, you're looking at major negative scenarios: (1) it was DOA (blown in some way or fashion) or it was stored in a careless fashion (e.g: maybe water got inside it) and damage occurred from that.

more to your question, housings can be killed by physical trauma, but to a lesser extent, they can die from too much heat. broken apex seals will oftentimes take out everything in that chamber, so rotor and at least two housings can be reduced to junk. less likely, but certainly possible, shafts can bend or break. obviously, any oil flow issue is also going to cause severe mayhem.

the bottomline is you simply won't know.

 

i didn't realize that you had another thread going: https://www.rx7club.com/new-member-r...-gtus-1082790/

no worries, but you could have just asked this question there.

 

Oops sorry. Ah. No way to salvage the housings if theres rust or scratches? Would it be better to just buy new housings? Is that even possible? Like buy everything, shaft, rotors, housings, all the hardware, etc brand new?

 

Possible to some sense, but you could buy almost 3 other rx7s and probably take all the engines and make 2 runners if your gonna buy all NEW internals

 

The rotor housings new are around $1,500 a piece. So just in new housings you are looking at $3000. For that you could get 2 good usable cores to build from.

 

possible to buy the parts brand new? yes. yes, it is, but why buy a core at all at that point? you could buy a factory reman (i think they are still available) and either take the chance of using it or have it disassembled and endowed.

with rust, there is some refurbishing that is possible. i can only report on my own experiences, and so far i have been able to handle most parts that have rusted (mostly past stuff that i did not store properly because i didn't know better back then ) what you have to watch for with rust is the pitting that sometimes accompanies it. surface rust can usually be sanded away in varying degrees.

scratches are a bit more tricky than rust. it totally comes down to location and how deep they are. for example, i have, again taking a page from past experiences - before i became good at porting engines, the grinder would sometimes "skip" and gouge the sealing surface of the housings, and i could use them anyway, with seemingly no consequence. on the other hand, if the scratch comes about because of ingested debris or a broken seal, you're less likely to be able to use that housing.

hold on ... what? have prices gone up THAT much in 3 years? i priced some REW housings a few years ago and they were only about $700-800 depending on the dealer/source. also, i never contacted Ray/Malloy, which may or may not have been slightly better.

 

Where do you buy a factory reman? Is that better than a used motor online with low compression? Does low compression mean a blown seal?

Yah buying parts new might be out of my price range then.

 

Factory reman's are currently not for sale maybe/hopefully they will be again in the future?
Low compression could mean several things like others have stated expect to have to rebuild any motor if not you got lucky
GL

 

So im confused. I thought if its low compression then its a blown seal. And blown seals ruin the internals which can't be reused for a rebuild.

 

Incorrect. Low compression could just be a worn engine and could be completely rebuildable. BUT, its always a crapshoot, you never know what you'll find when you crack it open. Even when an engine runs great and you take it apart, there could be more damage than what you'd expect.

Rule of thumb, if your going to biy a JDM engine off ebay, set another 3K+ aside to cover the rebuild and other unexpected things

 

Ah darn. Ok. This helps a lot thanks! Gonna have to contact a few sites for motors now. Is there a document that gives tolerance numbers for irons, housings, rotors to see if they're reusable?

 

Try JDM Engine World. The engine i got from them was good. Stop making new threads.

 

as Lduley said, low compression is not synonymous with a blown engine or even a physically damaged engine. an engine can have low compression because it is worn out or damaged in such a way that it remains rebuildable.

warning ... unsolicited advice ahead ... i would try to exhaust all other options before buying a complete engine online. it may take some time, but you should be able to find one for less than they usually go for online. if the engine is basically just a usable core, it would make better sense to get it for the lowest price you can. there's a huge rotary community all up and down the west coast. plug yourself in, go to meets and BBQs and such and see what you can turn up. i understand that you can also meet some really shady people that way, but with all due respect, you're not yet a level of knowledge to suss through an engine anyway, so you will be better advised to get some help. does that make sense?

as for where to find tolerances, download a copy of the FSM.

 

Thanks for the help guys. I'll figure something out.