82streetracer

iTrader: (1)

I have heard various things and I would like to get a clear answer. Any reason not to use one???

I got mine from corksport, but I recently heard that j-spec engines are unreliable.

eViLRotor

iTrader: (2)

Well, with J-spec's you always take your chances. Yes, they are low mileage, but you don't really know how well they have been maintained or how long they have been sitting.

That said, most of them turn out great. You know you are getting a factory mazda block.

To me, the ideal way to go is to get a J-spec, then rebuild it...that should give you a great engine for a long time to come.

banzaitoyota

JSPECs are a good start for a rebuild if you don't have an engine to begin with. What do you think, there is a magical covered junkyard full of PRISTINE low-milage, never-raced, properly maintained engines waiting to be shipped to the US?

DomFD3S

Well, if you think about it. IF you are referring to j-specs for FCs, you have to understand the FCs are 10+ year old cars. Therefore, you may end up w/ a j-spec engine that was sitting in a junkyard for 10+ years.

Some companies do offer a limited time warranty on their motors. Some (if not all) claim to check the compression on the motors.

IMO, I would use a j-spec as a spare motor. Have it rebuilt prior to installation. That way, you can keep one motor as a smog motor and another as a street/track motor. (That is what I'm planning to do right now).

Bridgeported

I think it's generally safe to buy and run a j-spec engine without rebuilding it first. Just make sure you get it from a company that gives you a printed out compression test with the engine and some type of warranty.

KiyoKix

A J-spec engine is just as much...if not a BIGGER risk than a US engine of the same year. You have no way of inspecting the engine before you get it to the door. But either way if you're doing it just because of the latest JDM (I hate that phrase ) they it's pretty pointless anyway. If on the other hand you have a real reason for specifying a J-spec engine then it's most likely worth spending the dough on it. I agree...if you don't have an engine to begin with then it's not a bad idea, otherwise just stick with what you have and get to work. The only time I see going out of you way for one is if it has completely different specs or some significance as compared to the US/EU/AU engine that would cost less and could be inspected before you buy it. 13B imported...nah. RB26...that you can't get here yes (even the SR20 is questionable since you can get an SR20 here anyway...just turbo the engine).

CrackHeadMel

iTrader: (2)

from my almost year on the board, but no handson experience, ive read that more people have good luck with there jspec's than bad

but there have been the theads labled "i put my jspec in, and it blew up in 5 miles"

sometimes followed by "i tookapart my jspec and its all corroded and worn out, nothings usable"

its like a gift bag that costs alot, you really dont know what your getting, untill you get it

poor college student

from what i've read here on the boards... i think the best way is to rebuild the j-spec before you put it in... i mean, you never know what happened to the engine before you got it, right?

jeremy

iTrader: (1)

i don't think the j-spec engines had any higher compression or anything. someone corect me if i'm wrong. that being said, i would rather have a pineapple rebuilt so i know its going to be a good motor.

another thing that bothers me is the craze over there of using a wire screen instead of a filter. better hope no one was doing that with the engine you are about to buy.

KiyoKix

Hey done right the wire screen thing is great...it's just when people put on any old wire screen that kills you. I still doubt I'd do it for a long term thing, but it's better than no filter at all.

BlackRx7

then there are some of those post like holy crap, my j-spec is bridge ported, has a T-60 turbo, 1000cc injectors, ect, but yah, a great man once said, "Life is like a box of chocolates, ya never know what ya gonna get"

jeremy

iTrader: (1)

um, can't remember but there is a micron tolerance and i'm pretty sure that a screen, short of a brillo pad, isn't going to cut it. "hey, it keeps birds and mice out of the intake". just saying that i wouldn't want to be purchasing that motor.

CrackHeadMel

iTrader: (2)

there wa a thread here a while ago, i think in rotary preformance where somene mesured the amount of air that goes though a k&n cone and one of thoes steel coffee filter screens, and the cone outflowed it quite a bit

82streetracer

iTrader: (1)

okay, I am 18 and spending way to much money on this project as it is. When I got the engine the first thing I did was pour some atf down the spark plugs (tons) and cranked the engine by hand. The turbo has zero play. the engine is really clean and nice.
I am going to run it as is. Break it in slowly with very low boost and double premix.

I will keep you updated

BlackRx7

NOOO NOT ATF!!!!!!, Expect the side seals to go very soon!!!!!!! smoking out the ***

Bigretardhead

some companies also claim to start their engines before they pull/sell them(to make sure they run).

ATF makes the side seals go?

dr0x

Jspecs dont need to be broken in.

CrackHeadMel

iTrader: (2)

a jspec is another mans trash, its some motor that some lucky japanese guy threw out while getting a new motor

damn lucky japanese people

Sandmeister

Seems everyone rips on Jspecs.....though everyone I know that got one, they ran great for many, many, miles. Just buy one that does compression test, and gives the unlimited mile 6/12 month warrenty or whatever, and I think you are fine.

KiyoKix

I'm not saying that I'm gonna try the screen thing, just saying it's better than nothing...besides those mice and birds do make terrible things happen in the engine . Also I'm not ripping on J-specs, I'm just saying don't get caught up in the JDM (damn...that phrase again!) craze when you could just as well get something that's right down the street for the same price or lower that'll work just as good. Sometimes J-spec is the only way to go, but in this case I don't think that's how it is at all, no big differences to worry about.

82streetracer

iTrader: (1)

I am not getting caught up in the jspec theme.
this is in a FB not a FC
a jspec engine is the best deal I have found on used engine with low miles.
How does atf **** the side seals. When I got my 82 the first thing the guy who sold it too me said was to atf it (he has a sa22 with 220,000 miles (burns a little coolant at startup but thats it)

Corksport has a warrenty for 12 months on the engines.

as for being old. My old 82 engine (TWENTY years old runs like new. It makes strong power all the way to 8k with 90k miles) it was stored for 13 years before I bought it.

I am not worried.

no "i knew a guy that had a jspec engine and it failed" ****

somebody with REAL experience tell me what problems theyve had. Not something they heard.

banzaitoyota

"I am not worried.

no "i knew a guy that had a jspec engine and it failed" ****

somebody with REAL experience tell me what problems theyve had. Not something they heard."

Talk to VOSKO, 3 failed J-Specs in 4 months

https://www.rx7club.com/forum/showth...ighlight=JSPEC

eViLRotor

iTrader: (2)

ATF is very corrosive, and was never designed to be put into engines...

jeremy

iTrader: (1)

atf is corrosive to brass i believe, aka eats synchros. as far as i know all it is toucking in the motor is iron steel or lead, correct? please people, give some info other then, "drugs are bad 'mkay?"

82streetracer

iTrader: (1)

this has been brought up numerous times in the first gen section.

Atf is about 90 percent detergents,Its to keep the complicated valve bodys of autos moving properly.

Running ATF in a engine is a very old trick. They did it all time in the 60s and 70s to clean the carbon out of leaded vehicles.

I atfed my old 12a and it better compression and I was able to lower the Idle. Smooth Idle at 650 rpm