hg or warped head?

[scrappys93talon]

Ok so i have a 99 spyder with a 2.3 stroker, arp studs, mls hg,
Now here is my issue
Got my stroker running again and i keep loosing compression on #2 from 160psi to 0psi going from cold to warm, just built the head with ss undercut valves and new mls hg, what i dont get it i get compression when the engine is cold but loose it as soon as it gets warm, all other cylinders are within 5 psi of eachother at 160psi when warm except #2, no oil in water or water in oil
Mind you the whole engine has been rebuilt within the past 3 weeks, car ran fine for the first week then i lost #2. Wtf is going on?

 

[DSMattitude]

Mitsu MLS or cometic? And have you re-torqued the studs at all?

 

[2gmitsueclipse]

Try a composite head gasket. Re-torque after a couple of heat cycles.

 

[pauleyman]

Why not do a leakdown and find the source.

 

[donniekak]

Agreed. Do a leak down when it's warm with no compression and see where it's going. Sounds more like a valve related issue to me.

 

[scrappys93talon]

New ss undercut valves, hand lapped in by dsmpat on here.

Tried a composite hg and it lasted about an hour before i lost #2 (which is why i pulled the head and did a leak down test of the combustion chamber and found my valves were having a major leak so i installed the ss undercut valves)

Did a cold leak down test by pumping up #2 and can hear air across all 4 through the sparkplug shafts,

Im wondering if my head is warped or if ive got a bigger problem.

Mind you this is the second hg on the motor to loose #2

 

[scrappys93talon]

Mitsu MLS or cometic? And have you re-torqued the studs at all?

Studs were re torqued after 3 heat cycles, my problem is i get 150psi on #2 when its cold and 30psi warm

 

[scrappys93talon]

Ok so i have a 99 spyder with a 2.3 stroker, arp studs, mls hg,
Now here is my issue
Got my stroker running again and i keep loosing compression on #2 from 160psi to 0psi going from cold to warm, just built the head with ss undercut valves and new mls hg, what i dont get it i get compression when the engine is cold but loose it as soon as it gets warm, all other cylinders are within 5 psi of eachother at 160psi when warm except #2, no oil in water or water in oil
Mind you the whole engine has been rebuilt within the past 3 weeks, car ran fine for the first week then i lost #2. Wtf is going on?

This is not valves leaking, i had that issue before and installed new ss undercut valves and did anothe leakdown and it was at like 1% leak down, no way is it the valves, can my hla's pump up completely and keep the valve open?

 

[BogusSVO]

Yes the HLA can pump up some and crack the valve off the seat when warm.

It would mean valve tip height is off, too tall

Then the spring tension compresses the HLA as the engine sits and cools then the valve seals again.

 

[scrappys93talon]

Thanks bogus i was leaning toward the hla's, another question
What are the chances that i could have a cracked or broken piston ring? When dsmpat and i put the head togeather with the new valves i didnt put the hla's back into the same places to see if the issue changed cylinders and it didnt...

 

[BogusSVO]

If you have busted compression rings on a piston, the fastest, easiest way to find out will be a leak down test.

but it would not come and go, the low compression would be there cold or warm, and chances would be good you be blowing blue oil smoke too.

 

[scrappys93talon]

Blowing a little smoke, hit the gas hard enough and the dipstick will pop out (not sure if this is a common issue with a 2.3) and did a compression test lastnight after i got off work and now i have 0psi in #2 and 150psi in 1,3 and 4

 

[BogusSVO]

Its common for the 4g to pop the dipstick

the 3 main causes are..

1) wore out or missing o ring on the dipstick and/or stretch out tube

2) improper PCV system, Read Calan's write up on it.

3) bad rings allowing excessive blow by, a leak down test would show this, you would hear air escaping out the oil filler cap and/or out the dipstick tube