Leak down test

[frisnosity]

Is a 30 dollar leak down tester a bad tester?

[wrightz28]

Leak down tester?

You mean a compression gauge, leak down is just one of the tests you can perform with it.

[frisnosity]

kinda the one that im looking at had two gauges and a connection for an air compressor. I rebuilt my prelude motor and i cant get the car to start. So i want to figure by using compressed air, see where the air goes. I think that my timimg is off, of my valves are messed up. It been a long story, My other thread is in the prelude forum. I would like to bounce some ideas off this crowd cause most of u prob dont surf the honda threads. anyway so i shopped on ebay and found a what i think is a descent kit. But i think i may be able to make somthing for better for a little cheaper. look up "leak down" on ebay motors, youll see em. any insight

[KCMike]

No doubt a $30.00 leakage tester would probably not be the best but it could work for your purposes. Check the instructions and any other instructions you can find for doing cylinder leakages tests. All of the ones I have used have called for: 1. Engine at operating Temp. 2. Cylinder under test at top dead center of compression stroke, (this is a biggy) . I would compare the readings from the engine you suspect faulty to an engine you know has good compression. It is important to note that smaller engines generally show less leakage than larger ones. Be sure you research and understand the test before you make any decissions. This tool is like any. You can have a $300.00 leakage tester and get inaccurate results if the procedure isn't done consistantly and correctly. Good Luck.

[frisnosity]

the car doesn run at all so having the motor warm isn't going to happen. I trying to figure out why the car wont start. I think my timing is off by one tooth or maybe my valve seals are shot. After i had a valve job done i had to adjust the valves. But when i rebuilt it again with new rings and higher compression pistons i didn't adjust them again. That might be the problem. I could get away with just connecting a hose into the head and see or hear where the air goes. I did a compression check while trying to start the car and the needle just bounced. It didnt build or hold pressure, leading me to think that a valve is open still. When i turn the motor by hand i hear the pistons moving air. And for a fact the motor is non interference so i know there is no bent valves. I just need a starting point.

[maxwedge]

Sounds like the engine is out of time or your compression gage is bad, try another one for starters.

[KCMike]

maxwedge has a good point about the compression gage. It should not bounce. It should hold after you crank the engine. Does it leak back down to 0? Your schrader valve may be leaking. I have to relplace them often.

[frisnosity]

Thanks for the info, they did leak back down to 0. none of the piston built or held compression. Has anyone ever heard of teflon coating on the block. I took a ball hone to the block which afterwards may how not been a good thing to do. I guess i have some investitgating to do when some warm weather finally gets to me!

[HotZ28]

I am sorry, but a discussion about a Honda Prelude engine, does not belong in the Buick Electra forums. Your engine is obviously leaking compression by the valves. If you did not adjust the valves after reassembling the engine, you made a mistake. Go back and adjust the valves according to specifications!