puma

iTrader: (2)

can it be done?

like if i bring the engine to mazda with everything (tranny, manifold, turbos, etc.)

can they just spin the starter with a battery and check the compression to see if the engine is blown?

thanks a lot

puma

rxrotary2_7

i thought about doing it when buying a motor that was out of a car...never did it though. you can turn my hand and listen for distinct sounds. not very accurate though. but asking mazda to do somthing that *complicated* could get you tossed in jail.

puma

iTrader: (2)

haha yeah well what if we borrow their tool?

anyone knows if we can do this?

Snook

iTrader: (12)

yeah but that tool is very expensive

why don't you call the mazda dealership and see if they have the machine to do it and if they will?

rxrotary2_7

yes you can. a friend of mine is a mechanic and when dealing wiht the insurance company, they required an actual read out of each rotor face. mazda lent the tool to do the actual test so there was an actual test documented....

puma

iTrader: (2)

ok but in theory is the idea of making the starter turn to take the compression with the engine out is a good idea?

paw140

It should be fine. Except according to the factory service manual, you are supposed to check the compression with the engine hot. Make sure you have the throttle wide open.

And about borrowing tools from dealearships... maybe in the case of an insurance company, they will let you borrow their tools. But in my experience, they will NEVER let you borrow anything. I've tried to borrow various tools from Honda, Toyota, and Chevy dealerships, and they flat-out told me 'no.' Even if I left a deposit, or a credit card, or anything like that, they would absolutely not let me borrow anything. Maybe you'll have better luck.

GoneSilent

motor out, impact gun, flywheel nut = the readings you seek.


Have to add this, might want to put a little oil in the spark plug holes if its been sitting.

rxrotary2_7

oil would cause a false seal between the apex seal and housing...causing false reading.
wouldnt it?
reason being...the old ATF trick to get old carbed 12a's to start after sitting for so long. this helps aid in causing a tight seal to help build compression (and lube it up) to get an old motor to start.
i would suguest against putting oil in the plug holes. but thats just me.

turborotarypower

just get a TII bellhousing and starter and wire it up to a jumper pack or battery, then connect your compression tester

rxrotary2_7

MEL IS ONLINE!!!

i think thats what we are all suguesting. but why do you say to use TII stuff?

turborotarypower

well you can use the FD stuff! i have always used TII parts because i have some spares laying around and don't wanna remove the bellhousing off my FD tranny!

rxrotary2_7

i bet you do...

puma

iTrader: (2)

hmm ok, well then i guess it can be done.

thanks guys

Mazderati

iTrader: (3)

If you just want to verify that the apex seals are not completely destroyed you can perform a pseudo compression test via a breaker bar and some muscle.

Use the breaker bar and a socket to turn the bolt on the end of the eccentric shaft and listen for a series of "chugs." For every half revolution of the breaker bar, you should here one chug. Making three complete turns of the breaker bar you should end up hearing six chugs. One thing to note, however, if one seal is gone, that means that two rotor faces are not being sealed, hence you would only hear four chugs if that were the case.

Bruce Turrentine must be accredited for this, and many other, great bits of information.

Good luck.

Kyle

rxrotary2_7

thanks Kyle. i think we covered that already, but nice detailed description for those who are not familiar with this process.

paw140

This is a TERRIBLE idea! Your impact gun would not turn the crankshaft once the compression hit, and you would tighten the **** out of the crank pully bolt. And you'd be screwed if you broke the bolt.

I've also read that using an impact gun on driveshafts and crankshafts is not a good idea because of the enourmous shock that it will throw throughout the entire drivetrain. I've heard this is especially bad for the transmission.

puma

iTrader: (2)

how is the compression going to be if it is a water seal that failed?

supracosworth

I found a used 13B today at a wrecker and attempted to do a compression check by attaching a normal compression guage to one hole and put plugs the other three. I then used a breaker bar to turn the crank and the guage reads.......nothing. The needle didn't even flicker. Is the "six chug" test described by mazdarati the only test I can do to the engine? Anything I can do to test the o-ring seals?

rxrotary2_7

rotating motor by hand w/ a tester is going to do nothing. leave it open and *listen* for the chugs. i guess for O rings you could leave out a spark plug on each rotor, seal off the coolant openings on the motor and presurise it. see if it holds.... that would be a kinda crude way, but it *may* work...

turborotarypower

as long as it has a chug for each side it should be rebuildable! this technique i have used before to check out engines.