So i have a buddy of mine who had to get is engine replaced because his went bad. he said his mechanic told him the dynamo in the engine had split. now im curious cause i havent heard of such a part and after extensive research, havent been able to find the part he is talking about. can someone aid me in what this part is and shed some light on where exactly it is located if it does exist. Any input would be greatly appreciated. Thank you

 

Get a new mechanic!!!

 

Yeah, it doesn't sound like the guy knew what he was talking about.


If the mechanic told him that he needed an engine replaced because the alternator failed, then your friend got hosed. I wouldn't expect that the mechanic would be outright fraudulent like that, but it's possible.

 

Well he told me that he had loss all compression and for him to say his mechanic told him it was the dynamo that had split seriously made no sense to me.lol well as far buying this motor off of him for a project motor it could work out in my favor.

 

Find out if it overheated at any point first though. A motor that lost compression due to overheating or the eventual compression loss from a prior overheating probably has some warping in it that will make some internal parts completely junk.

It may not matter for whatever you are doing.

 

So this is what happened. My buddy needed his radiator replaced initially and so he had one guy do it. He was in Arizona while this were to be done. He came back and the mechanic told him his engine lost compression and needed to be replaced. He then took it to a different guy after that incident. The new mechanic was the one who replaced it because it had a "split dynamo". So i do not think it was over heated at any point but i will ask him.

 

But he told me it had never overheated.

 

Whether or not it's worth it all depends on what you are going to do with it. If you are going to disassemble just to poke around and never expect to make it power a car, then yeah, even a trashed engine has some value.

If you want to rebuild it and stick it in an 8 and expect it to last, that's where the prior history gets a bit more important and the engine's value drops.



You haven't said how much you would be buying it for OR what you are doing with it, so we can't really tell you if it's a good idea.


The stories you are giving us are incredibly shady though. I'm not saying that you are lying, but I'd bet that someone is lying to some else in that engine's history. Even if only through unintended ignorance.

 

ok well i am hoping to still be able to use the rotors and housing if possible. i wanted to replace the apex seals and port it. i can do all the work myself. not sure on exactly how much the price would be considering the condition. he said he wasnt sure how much he would be thinking of selling it for. but yeah thats why i wanted to come on here and get some of your guy's opinion. not sure how much i was going to offer him for it.

 

Ah, so re-use in an RX-8. Off-hand, I'd expect a price of no more than ~$300. Again, depending on history. Re-using rotors is likely, re-using housings is not. Each housing can run you $1,000+ (dealer retail is $2,000, though you can find them cheaper elsewhere that doesn't have as severe of markups). Then you need all the gaskets and seals, which can be another $1,500 or so. You would probably need the irons lapped (resurfaced), though it's possible that they might not be worn enough. Precision measurements will be needed on everything.

You could just buy it, pull it apart, and put new seals in it, but it's probably not going to pass a compression check from the start, and it's unlikely it would run more than 10,000 miles or so past the point of re-assembly.

It is often cheaper in upfront money to buy a quality rebuilt engine from a vendor than it is to rebuild yourself. Almost certainly cheaper in the long run (unless you become an overnight engine building genius, can find the parts for far cheaper and/or you could re-use everything legitimately).



So as mentioned previously, it can still be something fun to play with, but that is what you are looking at if you want it to be a respectable engine powering an RX-8...

 

well my father is a mechanic so i mean i would be able to find parts and machine work cheaper than normal, although i am aware that parts for this car cost an arm and a leg. also this wouldnt be a weekend job...i am planning on taking a while in this thing.

Thanks for all your help btw, its been very informative.

 

As long as you know what to expect...have at it!

Just make sure your expectations are realistic, even if it's just an expectation to lose money for the education and fun of it (there are worse reasons for people to throw away money )

 

The other reason is i got a lot of miles on my car and not sure how much longer the engine will last. not that im driving my car super hard, i do do regular maintenance to it, but i do eventually want to build it up and thought buying a used motor and working it up would have been a good idea.