gaijinrx7

iTrader: (5)

Picked up a barn find that supposively had the motor rebuilt 8 years ago by Mazda racing. Peeked in the intake ports and the rotor housing surfaces are all fresh and there is still petroleum jelly in seal areas from rebuild. Appeared to be a blue substance on the apex seals. I go. The whole car for stupid cheap and the motor was basically free with all the other goodies I got. Starts was bad so I got a new starter and wired it get a good crank for the test and the tester jumps to 35+ on all faces with the needle pushed in but then maximum compression is only around 70-75. There is no intake mani or turbo mani on the car. Am I looking at a rebuild here? Ps car is s4 t2
I will upload a video and pics tonight. Thanks

-xlr8planet-

iTrader: (3)

I heard that you measure compression after a first run, never before.

Im not sure what numbers you should have on a "never run" rebuild

Keep us posted if you get it started.

FelixIsGod29X

iTrader: (50)

If the rotors are in a certain position some of the apex seal springs may have been compressed the entire time. Maybe not but maybe so? Did you push on each apex seal to check if its stuck or free? Iv'e heard of lots of engines that ran after sitting for years but no guarantee.

Considering its a fresh rebuild then ideally compression is suppose to go up after you put miles on the engine, but it should have good compression to start with i would think.

I personally would crack it open, inspect/check clearance of everything then put it back together, even if mazda racing supposedly rebuilt it. Gasket kits aren't that expensive anyways.

brian_skotch

iTrader: (6)

The motor needs to build compression if it's fresh. The "blue stuff" you're seeing is probably hylomar which is a sealant that is applied to the coolant seals and o-rings.

bluemp301

iTrader: (5)

I say put some oil down the leading spark plug holes and turn the engine by hand a few times to help lubricate/build compression. After that I'd get a new set of plugs and put in some fresh oil to try to get it started. It's usually bad for a motor to sit that long but maybe having petroleum jelly preserved the seals. Worst case scenario you have to tear it all down but I'd try to at least fire it first.

7speed

Drive it! Break it in, then comp. test it.

gxl90rx7

iTrader: (1)

i would just put some 2-stroke oil in the spark plug holes, get it started and put some miles on it, see if the seals will break free. they probably just got corrosion on them and are sticking

gaijinrx7

iTrader: (5)

Well I need to build the squirt and make my dpipe and exhaust then I'm just gonna fire it up. Thanks for all the replies

FlyinFalco

Don't worry about the compression being so low if it was freshly rebuilt. U won't show decent compression till about 1500 miles. Proper break in is first 1500 miles, no more then half throttle or 4k and no boost. Within that period depending on how in depth the rebuild was at 500 miles change the oil, also at 1500. After u hit 1500 miles u can pass 4k and build some boost, but not full boost or full throttle until after 2000 miles. Also side note, try and find out if it was ported at all because if it is u will get a fuel cut at 11psi which will give u boost spikes and chance blowing an apex, or causing bad internal damage to your housing.

gaijinrx7

iTrader: (5)

pretty sure it was ported

FlyinFalco

ok well with it being ported, depending on how your going to run your car u r going to have to look into an ecu, to eliminate the fuel cut at 11PSI or make sure u can control your boost and dont go over 10 to be safe. like i said though at 11 psi u will get a fuel cut on the stock ecu and u dont want that to happen, u will overboost or boost spike... and ruin your engine

gaijinrx7

iTrader: (5)

no worries man, im gonna run squirt. thanks for the help