[RESOLVED] no compression cyl3. valves?

[WILOWNU]

just put a new headgasket on my car over the last few week. while the head was off I sent it off to get decked. The machinist took the cams, and valves out to deck it, and then reinstalled them. now before all of this the car ran fine, it just white smoked from water getting in the combustion chamber. Now since everything was installed, and I did the timing, there is no compression in cyl3. what gives? did he bend a valve? or is there a way of not putting them back in all of the way? are the lash adjusters set wrong? can any of these happen? please help!

well i guess everyone is as dumbfounded as I am...

However I did a little work on it, I removed the lash adjusters and bled them/cleaned them/primed them. I reinstalled them and still no compression in cyl 3, also not seeing any compression in cyl 2 now. my comp test shows results of 140-0-0-140ish. i believe the other day it was 140-0-130-140. I will keep working on it, but some input from anyone who has had this or knows about this would be helpful.

 

[keltalon]

seems as if #2 and #3 valves maybe bent!

 

[WILOWNU]

but how would a machine shop not see that if they dissassembled/inspected/reassembled the head?

 

[rush2252]

It sounds like a HG not sealing to me. Especially since you dropped 2 then 3. They share mating Gasket. If the valves are bent USUALLY you can tell with the VC off. I would bet on a HG. Zero compression is odd for a bent valve. Unless they didnt get seated well but you would still see some compression.

Kolby

 

[diambo4life]

0 compression = either hole in piston or a broken valve. You will get some compression even with a bent valve. It is NOT the head gasket.


Do a leakdown test and you will know for sure.

 

[rush2252]

0 compression = either hole in piston or a broken valve. You will get some compression even with a bent valve. It is NOT the head gasket.


Do a leakdown test and you will know for sure.

so he burned two holes in two pistons? Not likely.. He had compression in number 2 then it dropped to zero as well. Coincidence the two are mating cylinders side by side sounds like a blown HG. BUT do a leakdown for good measure.

Kolby

 

[WILOWNU]

pistons were perfect when I had it tore apart...but then again the valves looked good too. the surfaces were decked before I put an OEM hg with copper gasket spray on it, and arp's torqued to 80 ft/lb's ....i just need to buy a leakdown tester.

 

[diambo4life]

so he burned two holes in two pistons? Not likely.. He had compression in number 2 then it dropped to zero as well. Coincidence the two are mating cylinders side by side sounds like a blown HG. BUT do a leakdown for good measure.

Kolby

The reason I don't think it's the HG is that one of the cylinder already had 0 compression while the other had >100psi of compression. If they both had 0 compression from the beginning, then the HG diagnosis would have been consistent. JMO. Leakdown should tell the story though. Keep us updated.

 

[rush2252]

Ahh I see what your saying Didnt mean to sound defensive. I hope its not bent valves. Ive seen crazier things. My buddy performed BSE on a 6bolt and had the head built and when we set the time and started it ran for a few minutes and died. It jumped a few teeth and bent all 8 intake valves in a matter of seconds.


I think he just has bad luck though
Kolby

 

[tkelly27]

Sounds like you are bending valves. The rings would pretty much have to be nonexistant, or the HG completely gone to give 0 compression. Check your timing again. One way or another, that head is coming off.

Leak down testers are $30 at harbor frieght. The % gauge doesn't work for shit. Just use the regulator to get it up to 100psi, then hook it up and see what you are getting.

 

[WILOWNU]

im just gonna take the head off of it tomorrow and send it back to the machine shop to have the valves checked.

ended up being 4 bent intake valves in the 2 and 3 cyl....

 

[bling5tatus]

You can hook air up to your compression tester and see where air blows out, it's not going to give you % but you'll see where it's coming out at. Just an idea for those that don't want to buy a leak down tester but still need to find out where the air is leaking.