im about to buy this renesis but i want to start it first before buying, anything else i need aside from radiator, fuel pump, battery?
do i need oil coolers if only to start for a while? any sensors i need to bypass? BTW, the engine is just on the top of the crate with loom and ECU
thanks!

 

That's not going to happen. You might be able to get a rough compression test on it if you have a starter and a battery. It's not like the old days.... the ECU has an immobilizer to contend with.

 

Beyond what you listed, and whatever modules would be talking to the ECU and giving it the go-ahead to start (body control module? ignition switch?), you're also missing the MAF

 

it has a starter, so I can do compression test.. I believed there is a way I can bypass the immobilizer? anything that needs to hook on the panel gauge that requires to fire it up?

 

Why would you want to fire it up anyway? You’ll need the exhaust attached so you don’t mess up your ears. I honestly think you’ll end up doing more damage and won’t get anything from the “experiment” other then startup noise.

A compression test will give you more then enough info to make a good decision about buying it. Beyond that, any reasonable shop worth a damn will give a startup warranty, so if the engine is dead when you install it, you can bring it back.

 

firing it up will give me a clue that all sensors, wiring, rotor, ecu is in good condition before i buy, just to ensure worth i will pay for
im planning to start it just a around 1 minute to see if if everythings fine

 

Just do the compression test as the others have said . Make sure you normalise the rotation speed against the chart and make an allowance for it being cold . Anyone know how much that should be ?

 

It’s a couple Psi difference. No big deal. It’s either healthy numbers or they ain’t. Warm / cold won’t change a thing.

I prefer to run mine cold so I don’t burn my ***.

 

thanks guys, im planning to take a look with the engine this weekend and see what should be missing, i will try to crank also and see compression numbers,
By the way, it will not be installed on rx8, it will be a transplant on a sprinter thats why im reengineering to start it up on the crate

 

Sprinter? O_o

 

there it goes,

 

not that one, its a toyota spinter ke25

 

Cold compression numbers will not give you a good indication of health. Any junk yard or recycler engine is a roll of the dice. Depending upon the price, it will still be a good deal given all of the various parts you'd need for a Renesis swap. Mazda will sell you a 0 mile reman engine for $2800-3800 -- if you get a good deal on this one, the short block could be used as a core to Mazda for a reman, assuring you have a healthy engine for your build.

Another note: That looks like an 04-05 engine based upon the vacuum line routing. I'd look for a 2006+ motor as they had better OMP programming and theoretically would show less housing wear as a result. If going the reman route I suggested, it won't matter what year your donor engine is it will just be a core for a new reman, likely with fresh housings.

 

Says you. I’ve personally tested about 7-8 RX-8s both hot and cold and noted very minimal changes in compression between hot and dead cold engine. You’re telling me that a 5-10psi difference in reading vs a 120psi OEM spec on a new engine is that much of a difference that you NEED to pull HOT numbers or else...? Lol. Come on now. Either the engine is healthy or it’s not.

i understand metal expansion, and getting actual Hot Running data but at the end of the day, you can still judge a block with just cold numbers.

No way it will read 60psi cold (bad engine) but show 110psi hot (good engine after it warms up).

Sorry bud. My real world data says it doesn’t matter what numbers you pull.

 

Hot numbers will generally be lower, actually.

Hence all the failing engines that can crank just fine on cold starts and yet refuse to start after the car warms up.