Oil pressure gauge always pegged.

[GoToGuy]

It's a tough battle sometimes, we have all been there, like toss a match and walk away. It's when knowing to take a break. Come back with fresh mindset. Yep I can do this. Good luck!

 

[Schurkey]

I'll answer questions and dig back into this mess - in due time. Today was a gawd damned disaster with other things that needed my attention.

Believe me, I want this ON THE ROAD. Even if it means swapping back to the original heads (which, if anyone were to ask me, I think would solve a LOT of problems)

I'm not seeing any problems you're currently having that have anything to do with the actual engine, let-alone the cylinder heads. Well, not upgrading to a roller-cam, and therefore having to deal with "cam break-in" is causing some nervousness and worry.

Yes, buying those heads was a mistake. But you're past that now...I think.

You've got pop/hiss, stalling, and glowing headers...but I suspect it doesn't matter what long-block you have in there, you'd still be dealing with those problems because the source of the problem(s) are the rest of the truck bolted to that long-block, not the long-block itself.

 

[Road Trip]

The pop/hiss + glowing headers thing. I might have missed this earlier, but do you
have a hydraulic (hydroboost) or vacuum-assisted power brake setup? In my own past, I've
had a couple of real head scratchers that turned out to be leaky brake vacuum booster
diaphragms. IF you have a vacuum brake booster setup, temporarily either pinch the
vacuum line closed -or- disconnect the line & cap off the connector at the intake.

No guarantees that there aren't other issues, but again IF you have a vacuum booster
it would be good to eliminate it from the list of possibilities.

And I agree with @Schurkey's suggestion to try to advance the timing a little to see if you
can make the engine run better. Even if it doesn't it will give us a little more info to
noodle on.

Best of luck -- hang in there!

 

[DeCaff2007]

The pop/hiss + glowing headers thing. I might have missed this earlier, but do you
have a hydraulic (hydroboost) or vacuum-assisted power brake setup?

Vacuum assisted. Who's GMT400 doesn't have power brakes? And, to be honest, I had been wondering about that. I don't really have a way to test a vacuum line that big, so plugging it for the time being might be a good idea.

Also:

Balancer @ TDC and dist cap off.

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I don't think that's too awfully far off, but I corrected it anyway.

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Still NO idea on the pop/hiss. I checked for ANY evidence of leaks, all vacuum lines, radiator hoses, and whatever, you know?

The Wife was there and she heard it, too. She said it sounded like it came from the throttle body. I let the fuel pump prime several times and I don't see any leaks at all.

I'm going to give it another go here shortly. This time, I'm finding a way to set up a camera so I can see the headers for myself.

OH - btw - the oil pressure gauge is probably working fine. Turning the key to run puts it at zero again.

Cripes, if I'm having this many problems at break in/startup, how is this engine ever going to be reliable? That was supposed to be the primary goal here.

 

[DeCaff2007]

OK... I have what may potentially be good news.

Still no idea what that pop/hiss was. HOWEVER, I did exactly what @Schurkey said to do with the ignition timing (advance it 5 degrees for purposes of cam break in). It fires RIGHT UP.

.... for about 2 minutes. Then, the RPM's start dropping again. Gave it just a LITTLE bit of gas to see what that does and all of a sudden the throttle body starts backfiring again. EFFFFF.

Ok, no panicking this time. I checked the ignition wires and they are solid. Good to go. That was ALWAYS a problem before. Pulled the driver side valve cover because last time the throttle body did this, I had two rockers loose and a wiped cam.

Hmmmmm..... what caused this again?

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Notice how far the rocker nut is backed off? It did that by itself. FWIW, I was able to take that nut off by hand.

Note: I had noticed that, even with brand new locking nuts, some of them went on normal (like, required some effort to thread and adjust them), and some of them went on like super, super easy. WHY? All of the locking nuts are BRAND NEW.

Do I need to put all new studs in now? They are thread in as opposed to press in so it wouldn't be hard. I would just have to adjust the valves again.

I checked the rest of the rockers and the two on cylinder 7 are a smidgen loose. Like I can just wiggle them by hand.

Also, I checked the lifter where that rocker is off. It's ok this time!

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Well, you know I had to check the passenger side. Wife said the passenger side head wasn't glowing this time. Finally, progress. Also, no rockers had fallen off the push rods, either. Cylinder 4 exhaust rocker was a smidgen loose, though.

So what have we learned? The RPM drop during break in is caused by rockers nuts backing off and causing the rockers themselves to lose preload and fall off the push rods. Then, backfiring occurs through the throttle body because one of the valves for that cylinder isn't opening.

How do I solve this?

 

[Schurkey]

1. Verify the valve tip where the rocker "fell off", to assure it's not damaged.

2. Inspect valve cover, assure that the cover doesn't interfere with the rockers where the four cover hold-down studs go through the cover.

3. I'd buy new nuts. Kinda "your choice", either go to the local GM dealership/mail-order and get sixteen Genuine GM rocker nuts, something like this although these are not GM:
www.amazon.com/Comp-Cams-1400N-16-Competition-1400N16/dp/B000CIS6LU/ref=pd_rhf_dp_s_rtpb_dse_gccp_d_sccl_2_2/146-3669001-6347469?pd_rd_w=XRxSf&content-id=amzn1.sym.bd729ef1-498a-4698-af50-62a8451fe601&pf_rd_p=bd729ef1-498a-4698-af50-62a8451fe601&pf_rd_r=0TV66MZ1350E2JT5V1S5&pd_rd_wg=8mSrS&pd_rd_r=a1e82295-6846-49bc-a588-4841a6aea75a&pd_rd_i=B000CIS6LU&psc=1

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...or head over to Summit/Amazon/Jegs/whereever, and get SHORT poly-locks that will fit under the valve covers.
ARP has multiple part numbers, but no listing for length on Amazon. May want to research this. Here's an example:
www.amazon.com/ARP-300-8244-Thread-Size-Rocker/dp/B005ASZKMA/ref=sr_1_9?crid=2EN41GAFXHGSM

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The advantage of the poly-locks is that it makes valve adjustment very easy...finding zero-lash is a breeze, and that's the trouble-spot for most folks. OTOH, you've got to be very careful to get the set-screw tight enough to actually lock the nut in place. Generally this means backing-off the poly lock some number of degrees of rotation, snug the set-screw, and then cram the poly-lock AND the set screw back tight that same number of degrees. This maintains the proper adjustment while getting the set-screw REALLY tight.

 

[Hipster]

Many times I've disconnected the booster and blocked off the passage on the intake or manifold for cam break-in. Hooked up a mechanical oil gauge etc. Primary concern is getting the cam broke in and again you're getting caught up in fixing other issues. After the first fire that slathered on cam lube is long gone....the thing not to do is fire it 10 more times because run-stop-run- stop run-stop is NFG during cam break-in. Everybody tried to talk you into a roller... not once... but twice for these very reasons. if this engine is to survive you need to sort out and end these other bs issues before turning the key again.

 

[DeCaff2007]

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EXACTLY what I bought from Rock Auto last time. You telling me some were randomly bad? I mean, they are nothing more than 3/8-24 locking nuts.

 

[Hipster]

EXACTLY what I bought from Rock Auto last time. You telling me some were randomly bad? I mean, they are nothing more than 3/8-24 locking nuts.

I've had aftermarket heads where they weren't as tight as they should have been. I ended up changing out the studs for ARP studs and all was fine/nuts were fine after that. The problem was the chinesium studs. Diameter or the thread pitch was off so that lock nuts weren't so locking. Welcome to the world of aftermarket parts that aren't what they should be. This is why many people will say aftermarket heads need disassembled and checked out and thoroughly inspected before install.

 

[DeCaff2007]

Many times I've disconnected the booster and blocked off the passage on the intake or manifold for cam break-in. Hooked up a mechanical oil gauge etc. Primary concern is getting the cam broke in and again you're getting caught up in fixing other issues. After the first fire that slathered on cam lube is long gone....the thing not to do is fire it 10 more times because run-stop-run- stop run-stop is NFG during cam break-in. Everybody tried to talk you into a roller... not once... but twice for these very reasons. if this engine is to survive you need to sort out and end these other bs issues before turning the key again.

I did research putting in a roller cam. Initially too expensive, for one thing, but the other thing is it seems to require special parts like a different timing chain, some kind of cam plate, different distributor gear, and IIRC, I had a hard time finding a factory spec cam. IMO, that's a lot of nonsense to go through for zero power gain.

I digress. I think it's time to get those ARP studs you mentioned. It will put my mind at ease.