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1.9 rockers help quick!!

Sabrewings

Sabrewings

New member
I'm putting my top swap together. With the 1.9 rockers it sometimes doesn't seem to want to do the compression check. I can see some air bubbling up around the intake valve.

Here's what's weird. I put a stock rocker on the #1 intake valve. Turned the crank into it and let it sit. Held pressure about a minute before it started dropping. Without moving the crank, I pulled the rocker (since the valve is closed). I put the 1.9 on that same spot and look in and immediately I see the valve open quite a bit. I pull the crank back a bit, then go forward and the valve seems to be closed. Now it seems to pass the compression check.

I don't get much reading on the gauge, but what it does go up it seems to now hold. Is this inconsistency something to do with hydraulic lifters?

Thanks!

Also, can someone tell me what I should see on a good pressure check?
 


This may sound weird, but I've seen it happen twice and done this personally with the advice of Trannyman Dave.

If you've had the entire top apart, it is possible for small amounts of debris to get trapped between the valve and head allowing it to bleed off compression. Brian and I had one do this very thing and thought we were screwed when it was leaking past the valve (a lot). He called Dave and we did what I am about to described and it corrected the issue immediately.

Pressurize the cylinder in question with an air compressor and then lightly tap the top of the valve stems on that cylinder with a rubber mallet. Any debris caught in there will get blown out as the tapping opens the valve. Watch your eyes if you have the UIM off as the intake valve might blow it right in your face.

Not saying I know 100% that this is what's wrong, but if it is debris caught in the valve, this will remedy it immediately.

Good luck.
 


FWIW all the cylinders are suppose to be within 3% of each other.
 
They were all the same. All like 30 PSI when I gave it a good stroke. FWIW, I don't know if I made the piston go all the way up since I couldn't turn the crank very far at once. But they were all the same with the method I was using so I guess it was okay.

I hit another snag in that the coil pack bolts that I took out of the car don't work with the new coil pack plate. Gonna have to go to the dealer for bolts tomorrow. I wasn't able to start it because of that. It's mostly together but when I hit that bolts thing I gave up for the night.

Stock lifters, stock pushrods, just 1.9 rockers and L76 springs with LS1 style retainers.
 
Is the reason the bolts won't work because you're putting an intercooler on it?
 
No. These are just the six bolts that hold the coil pack down. The ones that used to be in my car are too big for the aluminum adapter plate I got off a 97-98 Buick Regal. Gotta get them from a dealer then, I guess.

And thinking more about the compression I'm sure it's fine. I was turning it from the top with a breaker bar, so the 1/4 turn max I could get at a time wasn't helping. The fact they're all about the same I'm hoping it's okay.
 
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Sabrewings said:
No. These are just the six bolts that hold the coil pack down. The ones that used to be in my car are too big for the aluminum adapter plate I got off a 97-98 Buick Regal. Gotta get them from a dealer then, I guess.

And thinking more about the compression I'm sure it's fine. I was turning it from the top with a breaker bar, so the 1/4 turn max I could get at a time wasn't helping. The fact they're all about the same I'm hoping it's okay.
Click to expand...


Not sure if the bolts from an 02 gt would work. But you're welcome to them if they do. :th_winking:


Just let me know and i'll ship them out. If you need them quicker then that's cool too.
 


I'll know tomorrow. I doubt they will though. My g/f is taking me up to the dealer and we'll see what happens. I'd really like to have this at least running tomorrow.
 
Oh, and here's a teaser pic:

DSC02769.jpg
 
Yeah, it's got a 3.8" for now. I wanted it modular before I put it on. I've got to find six coil pack bolts for a L67 now.
 
how much exhaust do you have? just the plog and a downpipe? the rockers dont give THAT much breathing room. that stock pulley might be all you can run for now.
 


Bio248 said:
how much exhaust do you have? just the plog and a downpipe? the rockers dont give THAT much breathing room. that stock pulley might be all you can run for now.
Click to expand...

Yeah. Plog and DP. That's why I'm playing it safe. If I can iron out the tune to no knock, I might try a 3.4. Otherwise I'll wait until I get headers or an IC.
 
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