no compression

[woomer]

ok heres what i know and alot i dont know - just bought a 1991 talon NON TURBO was told there was some head work done and bigger cams installed ---- said after he tore the motor apart and put it back together he couldnt get it to run ----this is about all I know ---- so any how - i ran a compression check -------- and believe this 0-0-0-0 checked the timing - its dead on ----any ideas out there ?......i mean perhaps the head work was done wrong?.....valves etc ---- yes the pistons are moving up and down in the bore but im not getting a single pound of pressure - couldnt lift a feather off the plug holes?......please - some one shoot me some possibilities here ------ yes im thinking bent valves - but all of them?........could there be any other reason for this?......please toss some ideas here at me .......

 

[haswesley]

Sounds like classic bent valves or engine is out of time. Take the valve cover off and see if any of your valve springs are compressed when the lobe is straight up. This will tell you if you have bent valves because the spring will remain compressed when they should be closed. Also, check timing marks on front of engine.

 

[woomer]

Sounds like classic bent valves or engine is out of time. Take the valve cover off and see if any of your valve springs are compressed when the lobe is straight up. This will tell you if you have bent valves because the spring will remain compressed when they should be closed. Also, check timing marks on front of engine.

ok im very sure the timing is on --- checked it several times and it appeares all the springs are doing what they are suppose to be doing any other suggestions again im asking - all the valves bent to give me the zero compression?.....is that possible?

 

[haswesley]

All valves being bent is VERY possible. Happened to me going 80mph down the freeway. Bent all valves and some even broke off. This is common. But, the valve springs, or at least some of them, would not be compressing up and down normally if the valves are bent. The only other possibility is burnt valves. But, unlikely that valves in all 4 cylinders would be burnt. And, even if they are, you would most likely still push 10lbs or so. Or, something wrong with pistons like broken ring lands. Also, unlikely, but this has also happened to me. If everything looks okay, the only other option is to remove the head and inspect. Let us know what you find.

 

[woomer]

ok im going to pull the head off tomorrow ------ if and if theres only mild nicks in my pistons am i ok?.......i was going to remove the cams and retry the compression test?.....or do you think thats a waste of time? also like i said this motor never ran since the so called head work was done ...... so its not like i was going 80 simply cranking the motor over ..........

ok checked all the springs ------all good ------- guess ill have to pull the head ---

 

[snowborder714]

woomer, please use proper posting from now on. This includes spelling, capitalization, punctuation, grammar, etc. Your posts are very hard to read.

 

[icet34]

So, what ever happen here? I have the same issue on my 1996 tsi awd, i set the timing myself, it ran fine, stopped and shut it off. When i went back to start it, it would just turn over. :-(. i checked the timing. looks good! i recently put a new head gasket on the vehicle, like the day before, didnt think that it would just run one second and the next time i went to start it nothing... I have spark in all 4, and im getting fuel, timing looks good. but i have no compression in any valve... :-( booo i have a brand new crank sensor and plate on it. :-( HELP :,-(

 

[haswesley]

Something dawned on me when I read that both of you have no compression, but your timing is correct and no bent valves. This is very strange that all 4 cylinders have zero compression and no bent valves. Are you sure your doing the compression test properly and your compression gauge kit is working properly? To do a compression test, you need to remove ALL 4 spark plugs to allow the starter to turn the engine over with minimal resistance. Next, ensure the compression gauge hose is inserted in one spark plug hole and tight. Have a helper press the gas pedal ALL the way to the floor and hold it while he cranks the engine for about 5 seconds. Watch the gauge as the helper is turning the engine over. The gauge needle should jump to the maximum compression after 5 seconds.

 

[woomer]

So, what ever happen here? I have the same issue on my 1996 tsi awd, i set the timing myself, it ran fine, stopped and shut it off. When i went back to start it, it would just turn over. :-(. i checked the timing. looks good! i recently put a new head gasket on the vehicle, like the day before, didnt think that it would just run one second and the next time i went to start it nothing... I have spark in all 4, and im getting fuel, timing looks good. but i have no compression in any valve... :-( booo i have a brand new crank sensor and plate on it. :-( HELP :,-(

I found out that I did bend the valves - even if it were ever so slightly - it was enough for the zero compression ---found out later the guy that shaved my head down went to far ---hence forth the reason for timing being right and yet a zero compression reading --and the other problem I was having was a set of after market cams were installed and apparently they were way too big for my basicly stock motor

woomer, please use proper posting from now on. This includes spelling, capitalization, punctuation, grammar, etc. Your posts are very hard to read.

Im apologizing for my spelling and grammer to every one out there that had a hard time understanding my posts ....but compared to a few others - I thought they were not that bad This is a great forum but a little hard to use search to get a direct answer to some problems ..

 

[BogusSVO]

woomer... what is your head thickness? what cams did you use?

I have seen when big aftermarket cams are installed, then the cams rotated over to TDC, and the act of rolling the cams over cause valve to valve interferance bending the valves.

 

[92AWDHX40]

Had the same problem, timing perfect but nicked valves just enough for low compression.

 

[woomer]

woomer... what is your head thickness? what cams did you use?

I have seen when big aftermarket cams are installed, then the cams rotated over to TDC, and the act of rolling the cams over cause valve to valve interferance bending the valves.

025 was milled off -- i then tried using these cams in a stock head - timing was dead perfect upon start up but these cams would not allow the motor to rev up and it became very hard to start .....i just dont understand it but I did install the cams staight up meaning linimng marks even - any advice on why?.......remember this is a non turbo car .