I'm looking into buying 13b turbo engine from a local engine importer. They agreed to let me test their 13b engines for compression as they don't test it there. They have like 20 in stock. My question is how do I test those engines for compression, is just like the regular cylinder engine or is there a specific process to it. What are good values for compression on those engines? Is there a difference in compression between S4 and S5 engines?

Thanks

 

You can use a piston engine compression tester if you remove the Schrader valve. You will wan t look for 3 even pulses above 75 PSI. 100+ PSI is considered excellent.

Of course, you need to spin the engine over at cranking speed to get a reading, which could be problematic if the engines are packed on pallets.

 

Look in through the exhaust ports, and you can inspect the condition of the apex seals. Oil and water seals will be a gamble, not much you can do about that unless you can actually see the motor running....



.

 

In addition to what Kentetsu said, get a long flexible LED light (with a 6" or so flexible section). You can get them cheap at the checkout counter at an autoparts store, or at Wal-Mart. Take that and a flat screwdriver with you. You can turn the engine over by hand and push on each of the apex seals to see that they're not stuck in the rotors. You can then snake the long light into the exhaust ports and light up the bottom of the combustion chamber. You're looking to see a clean chrome surface with minimal chrome flaking at the front and rear edge. Hopefully you'll find none. You'll need a tranny bellhousing or tranny, and starter in order to compression test the engine, by the way.

A half-assed inspection is still better than none

 

Before wasting any time with removing the turbo and bolting up a transmission bell housing and starter, pull 1 set of spark plugs and turn it over by hand. You should hear 3 distinct "chugs" per rotor.

Also, before you spin a starter motor in any of the engines, squirt a tiny bit of motor oil into the plug holes. Too much will give you artificially high compression numbers, so keep the amount small.

 

Thanks a lot for all your input!