My 454 Rebuild

[BuiltToWork]

And me? I don't mind a problem...but I *hate* a mystery.

@Spareparts and @Road Trip
I don't know how I can help but a mystery would drive me insane.

 

[Keeper]

Fascinating issue. I've got 2 '99 454's in use. I've had one since new and the other for 13 years. Both have had issues, but neither have had anything like this (which is regretful, because I'd love to pass along some insight).

Nothing to add except... Stay In 'Er Minner!

 

[Spareparts]

I can record a log in hp tuners if anyone wants to view it tomorrow after work Of a cold to hot cycle.

 

[BeXtreme]

I can record a log in hp tuners if anyone wants to view it tomorrow after work Of a cold to hot cycle.

I have HP tuners and would take a look at the log. Make sure you have all four o2 sensors and the knock values on there.

 

[Spareparts]

I have rebuilt many many engines and this is the first one that has gave me problems.
Im done trying to figure this one out. I have spent to much time and money on something that should be running perfect for all the energy i have put into it.
It's VERY disappointing, So. Rebuild another engine or trade it off for a newer one.
I i get a newer one i will probably end up doing all the same work i have already done except rebuild the engine. Again though it will cost my truck and 6K
If i rebuild another engine it gonna cost around 6K.
I don't look at a vehicle like i'll never sell it for what i have into it. Never made a dime from selling a vehicle but i have made lot's fixing up boats.
I don't wanna do all that work again to another newer Suburban and realistically ill be driving another 15 years or so unless i drop dead sooner or get hit by a train.
My Suburban is totally capable of going that long with a good rebuilt engine. Sooner or later it will need a trans but for now its working fine so i guess the smart choice is to rebuild a engine on a vehicle that is in excellent shape but for the engine, no dents, no rust otherwise and a maintenance history i 100% know for the last 2 years which is everything.
So i guess thats the way im going.

 

[Road Trip]

...Or, Keep mine and rebuild another engine over the winter starting with a GM Performance 454 bare block. When done i would be into it around 6K for what i want but all new with aluminum heads.

Whatever happened to the original old, smooth-running but low hot oil pressure engine?

Do you still have it? If you do, you should really consider using it as a 'seasoned' block
instead of a new 'green' GM Performance 454 bare block? (Grumpy Jenkins & others
have long held that putting quality machine work into a 100,000+ mile engine gave
them better results than putting the same level of machining into a 'green' block and
having it inevitably shift after so many heat cycles. (Better ring seal, etc.)

I know that the engine had low hot oil pressure, but it looks like a good chunk of that
could be traced to that goofy lifter that partially came undone? (Take a close look at
the attached photo -- you can see where the block surfaces + lifter collar were cleaned
by extra oil flow escaping from the problem lifter?)

Of course, you would want to tear it down & perform a careful inspection, but depending
upon what you find this may well give you a better (seasoned) block that will *keep*
all the precise machine work done to it.

Just a thought.

 

[Spareparts]

As a fellow GMT400 big block owner, over here in upstate NY I am really feeling your pain
& frustration concerning this (to date) Bad Actor 454.

Since you mentioned that your original engine was smooth, but the new engine was
never as smooth...so obviously you aren't chasing a phantom issue. In other words,
this specific engine bay** was (and still is?) capable of supporting a smoothly running L29.

And so far no joy, but *not* due to lack of trying. You have alternated between black box
and 0411. You have had gone to the trouble to verifying the fuel injectors all flowed the
same. Several passes at the ignition system. Used a temp gun on the cats, then went on
to measure the actual exhaust back pressure. Fuel pressure checks. Been capturing/sharing
data with a scan tool. Etc., etc.

****



I'm not the disagreeable type, but in this I beg to differ.

Anyone swapping between the black box <> 0411 box more than once for t-shooting
purposes, or checking for equal spark on all 8 individual wires, I'm thinking that you are
working at a pretty high level. And I think we need to upgrade you from tenacious to this:

You must be registered for see images attach

(Compliment, BTW)

And me? I don't mind a problem...but I *hate* a mystery. So, IF you go ahead & persist
with fixing this, I would like to offer the following remote support:

* I have a known-good, smooth-running '99 L29. It is currently still running off of the
original black box that the truck was built with. IF you would like one or more items
cross-checked in my engine bay for proper operation I will cheerfully do this. (ie: Giving
you what we used to call "known-good, flown good" parts to troubleshoot with --
considered 'better than new'. (!)

* Our current problem definition is a rough-running misfire that defies diagnosis. This
to me has the feel of test procedures / test equipment that has insufficient resolution
for narrowing this misfire down. But I don't know for sure. Therefore, although I still
don't know where I am finally going to end up with for troubleshooting tools, I'm thinking
that for now I'll get the same/similar tools as you and see what kind of misfire counts that I
get over here under my hood, and then we can compare. (ie: Just how clean/misfire-free
can a '99-spec 454 run on today's 90/10 gas/corn diet?)

Are we looking more carefully at how these big blocks run than 99% of the folks still
using them? (I don't *think* so?) At any rate, I really want to understand all this *before*
it happens to me, so it only makes sense to get involved from a purely selfish standpoint. :0)
And not if, but when we figure all this out it will be good data for others down the road.

Got a few other ideas, but the main point of this is that IF you decide to start fresh &
really put this to bed once & for all, I will be happy to assist in any way I can, up to and
including using my own truck to try to replicate what you are seeing.

What can I say? We troubleshooters have to stick together, through thick & thin...

:0)

**aka: "Power Barn" (courtesy @ralmo94 - I like that!)

Im not working at a higher level. Just fallowing suggestions and experience.
Im at the point of thinking it's a very rare hard to find mechanical issue as in a week valve spring on the #7 cylinder exhaust valve.
Compression tests ok but thats at a low cranking rpm and the spring has no trouble keeping up. When accelerating i can feel the miss but it is not registering at all except at idle.
I might try changing that spring's on #7 this weekend but im not going to go after it doggedly anymore.

 

[Spareparts]

Whatever happened to the original old, smooth-running but low hot oil pressure engine?

Do you still have it? If you do, you should really consider using it as a 'seasoned' block
instead of a new 'green' GM Performance 454 bare block? (Grumpy Jenkins & others
have long held that putting quality machine work into a 100,000+ mile engine gave
them better results than putting the same level of machining into a 'green' block and
having it inevitably shift after so many heat cycles. (Better ring seal, etc.)

I know that the engine had low hot oil pressure, but it looks like a good chunk of that
could be traced to that goofy lifter that partially came undone? (Take a close look at
the attached photo -- you can see where the block surfaces + lifter collar were cleaned
by extra oil flow escaping from the problem lifter?)

Of course, you would want to tear it down & perform a careful inspection, but depending
upon what you find this may well give you a better (seasoned) block that will *keep*
all the precise machine work done to it.

Just a thought.

That is my thought also but the bearings were not that great either with plenty of copper showing and unfortunately i sold the block as i do not have room to store an engine.

 

[Spareparts]

BTW here is a pic of the plugs i changed out last weekend after maybe 3 weeks running.

You must be registered for see images attach

You must be registered for see images attach

 

[Piratehunter]

I would take this one apart and inspect and measure everything, and deal with a better shop to correct whatever you find. The current issue you're having with the knocking may be a simple fix. upgrade your valve springs. did you try taking off the fan belt to eliminate noise from everything on it? we're all stumped with the misfire issue.