aw614
aw614 Reader
2/22/22 12:48 a.m.

I feel crazy asking this, but I was getting ready to just pull my head off my integra since I have a short block coming soon and decided to drain the coolant and oil. Could I still do a compression and leakdown test without those fluids, my valve cover not bolted down, and my header disconnected? Will those affect my results? Like will the leakdown test results be off b/c I have the valve cover off and have no coolant or pressure in the cooling system? With the header off, I could at least see if the exhaust valves are sealing at least? 

And with the compression test, it sounds like dangerous cranking a dry motor with no oil in it? 

Short story, my rebuilt b18c1 had always seemed to burn oil, but ran and made power, but started acting up last year and the last autocross I was at, cylinder 4 was fouling the plug with oil and it ran really rough. I originally just wanted to pull my head off get it checked out, then replace the short block and then inspect everything on the block but after seeing my exhaust valve ports, I kind of want to run the leakdown and compression tests to see my numbers after I pulled my header see my cylinder exhaust valve ports.

My cylinder 4 exhaust valve port looks like this:

Cylinders 1-3 exhaust port all look similar with carbon build up, but nothing like cylinder 4

 

codrus (Forum Supporter)
codrus (Forum Supporter) PowerDork
2/22/22 1:59 a.m.

All that the leakdown test cares about is rings, valves, and head gasket sealing properly.  You've got an intact shortblock with a head bolted to it, right?  Should work fine.

I don't think I'd want to crank the starter to to turn the engine over without any oil for a normal compression test.

 

 

A 401 CJ
A 401 CJ SuperDork
2/22/22 7:49 a.m.

If it were an engine I didn't really care about (like my employer's), I'd probably crank it with no oil.  I mean it's just a compression test and the surfaces should still be fairly slippery from when had oil.  But OTOH, just how hard is it to put oil in it?  Seems like cheap insurance to me.

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) SuperDork
2/22/22 8:08 a.m.

Leakdown with no fluids is fine. I wouldn't do a comp test without oil.

aw614
aw614 Reader
2/22/22 8:40 a.m.

Thanks guys, that's what I thought about the leakdown test and also the compression test, just wanted to run down my gut feeling before doing anything. 

But yeah my head and block are still connected together and I can still rotate the motor. Getting cheap oil isn't an issue either. 

 

Opti
Opti Dork
2/22/22 12:26 p.m.

A leakdown wont necessarily find the source of oil consumption. If its stem seals the valves are closed so they arent checked, and if its "rings" oil scrapers wont affect leakdown or compression. 

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