Measuring them isn't that hard. Further LS7s and Morel Drop Ins have a rather large preload range.

https://www.corvetteforum.com/forums...ow-to-use.html


https://ls1tech.com/forums/generatio...ngth-help.html

https://ls1tech.com/forums/generatio...rior-ls7s.html

 

This is great. That video from Katech is helpful in understanding the measurement process. My heads are currently off, though. What's the best method to measure while the heads are off, or do I need to wait until I have everything bolted back together?

That LS7 vs Morel lifter thread is informative. I think I'm going to stick with the LS7 lifters, the camshaft I'm running is fairly mild (http://www.compcams.com/Company/CC/c...csid=1400&sb=2).

 

You need to measure the push rods after the heads are on and torqued down.

 

Calling all bolt/thread experts.....

So when I was removing the heads awhile back, one single bolt (smallest, on top of the block) on the passenger side gave me some grief coming out at the very end (top) of the thread. The bolt felt like it was free, but somehow wasn't letting go of the threads at the top. I ended up applying minimal force by pulling upwards slightly on the bolt, and it eventually caught and came out successfully. The bolt had no thread residue or shavings on it, and the entire way out other than the very end it felt normal.

I'm now cleaning out all of my threads in preparation to re-install the heads, and I'm realizing this bolt hole/thread is being stubborn and not allowing me to hand torque any of the old bolts (created a chaser bolt with dremel, doesn't like that either) or my new ARP head studs.

Any suggestions? I've read on some other forum posts that installing ARP head studs, which I already have, will usually catch even on bad threads. In my case, it seems to only be the very top of the thread that's having issues.

It's bolt #24 if that matters.

 

The bolt holes need to be spotless before installing any fasteners. They make a real thread chaser tap for the purpose of CLEANING the threads. DO NOT use a normal tap! SOAK the holes with carb cleaner and then blow them out. Use a pick to clean the threads to start. If you hand clean the top few threads, you can start a cleaner tap good enough that you wont cross thread the hole. THAT WOULD BE BAD! Hand pick clean the top threads and go from there. Make sure that you order the correct metric cleaning taps for the holes.

If you can not easily thread in the new studs, clean some more and try again.
REMEMBER,, there can NOT be any liquid or debris in the bottom of the hole or you will damage the block when you bottom out the fasteners. The studs have an allen hole on top of the stud to help get the stud in the block. You shouldn't have to use too much force to get the stud into the hole and bottomed out. Measure the hole depth and mark that depth on the studs so you know when you are at the correct depth. If you have to, clean up an old bolt and run it in and out of the hole to be sure that its able to fully seat at the bottom of the holes.

 

Buy larger OD pushrods, pushrod flex and weak springs will cause that damage.

 

I'm going to clean the holes out and then use this ARP chaser to get the threads healthy again;

ARP 912-0001 Thread Cleaning Chaser, M8 x 1.25"

The pushrods are already 7.425, but I just recently purchased a COMP Cams pushrod length tool that I'm going to use to measure. I'm planning on going with a preload of .100 with LS7 lifters (what BTR recommends).

 

Update: everything is put back together. I attempted to start the car last week, and had zero oil pressure — none. I thought the new oil pressure sensor I installed was possibly bad, so I installed a relocation kit for the OPS and reinstalled my old known working one for now. I also purchased a dual connection oil filter plate that allows me to keep the oil temp sensor connected while I use my mechanical oil pressure gauge on the other port.

I just tried to turn the engine over again with the coil packs disconnected and had zero oil pressure again. Not even a budge on the mechanical gauge. When I disconnected the mechanical oil pressure gauge, there was no oil residue anywhere.

How could this be possible? I figured if I installed my Melling high pressure oil pump incorrectly or pinched the O ring — both which I was very careful with — I would at least have some pressure. I’m getting absolutely none. It seemed to only fit inside the gears on the crank one way, so I don’t think I could have missed that, or even installed everything else if this was wrong.

Thoughts?

 

I'm betting that oring. I've heard many say they were very careful and it ended up being that oring. Did you change the cam??
Did you fill the oil filter before installing it back on??

 

I’m going to be so pissed if it was, I was so damn careful with it. Sat it on the snout of pickup tube and gently centered and seated the tube inside the pump.

I installed a new cam, but it was a replacement for the exact same cam so same specs.

 

What about filling the oil filter. If not that might take a little longer to build up pressure.

 

I haven’t done anything with the oil filter, and I’ve only powered the car on twice. I should also mention that when I first turned the car on with the coil packs connected, the engine fired up (no oil pressure) and instantly started revving as if I had my foot on the throttle, I got nervous and cut the engine off. While getting some verbal courage from Bill Curlee, I powered the car on a second time and this time it seemed to idle more normally, although wanting to die with the RPMs fluctuating between ~1k and 0 — still no oil pressure — and I powered the car off after about 5 seconds once again.

Ive turned the engine over for a total of probably 10-15 seconds with the coil packs disconnected monitoring oil pressure which never seems to come.

Changing the filter is probably a good idea, although prior to this work it was fine.

 

Sorry bro i was hoping that was the case. From my experience that's all the help i can give you. Hopefully somebody else has an idea before you start tearing into it.

 

The O ring is on the PICK UP "SUCTION" side of the pump. The pump moves fluid very well, It will NOT pump air very well. If that O ring at the pump flange is compromised, the pump will not be able to draw oil from the oil pan sump. It just draws air around the bad O ring.
If you put a pin hole in a soda straw above the liquid level and try to suck the liquid out of a can, all you will get is air. Same principal.

The ONLY other thing it can be is a stuck open pressure regulator slide valve inside the pump. I've see a brand new pump fail because the slide valve piston bore was not machined properly and when the piston went open to regulate pressure it stuck open. We could duplicate the failure by manually pressing the slide valve to the open position and it would stay open and not slide shut on its own. They can also get stuck open if there is debris in the slide valve opening. If you get ZERO pressure in the mechanical gage, STICK A FORK IN IT..ITS DONE, Tear it back down and asses the failure mode.

ON A SIDE NOTE and I was so paranoid about my ZERO OIL PRESSURE symptoms, (caused by an electrical issue) after the second tear down, and needing to insure that the O RING was good.. I Ran my engine with the front cover off for long enough to see pressure on the gage. YES, it works and it wasn't as messy as one would think.

Call me if you need to.

Bill

 

I just wanted to update everyone on what ended up happening. I should have been more specific looking back about what upgrades I had. I upgraded my entire timing set with a COMP Cams timing set that includes a double roller timing chain and gears, which also requires oil pump spacers so that the wider double roller chain doesn't rub against the pump. One of the spacers has a hole that needs to line up on the oil passage port. Mine was off and the oil passage port was blocked. Once the spacer was positioned properly, 40PSI on my melling high pressure right away.

Thank you everyone for their time and help on this project. The last piece I need to fix is a bad knock sensor which I believe is because I broke the lip of the sensor off while trying to remove and inspect the cam via valley cover. I'll be replacing both sensors and wiring harness this weekend to remedy my P0327 CEL.