My 454 Rebuild

[BeXtreme]

Ohya definitely more power than before with the old engine and no blow by. It idles slightly rough and almost feels like a weak cylinder driving but compression is the same on all holes and all plugs look good.

Did you switch to adjustable valvetrain? This could be poorly adjusted valves too. Did you degree the cam when you put it in? My stock 454 with 280,000 miles on it had higher compression numbers than that even with both intake and exhaust valves leaking on most cylinders. I haven't checked the rebuilt one yet

 

[Spareparts]

If anything the adjustable valve train was a little loose but i did switch it back to the stock setup just to make sure that was not the problem.
I did not degree the cam. Never have so that might have finally bit me in the a**.
It seems like the cam might be bad either ground wrong, Installed wrong, Alignment pin drilled wrong? I just can't think of anything else it might be.
I would think i have enough heat cycles and WOT pulls the rings have seated but maybe i should give it a couple weeks then check compression again.

 

[Spareparts]

I changed back to the original black box ecu to help trouble shoot things last monday.
Had a shop do a crank relearn and a little trouble shooting.
Looking at fuel trims it seems to be running a little rich. The injectors are 5 O motorsports. Maybe they flow slightly more than stock?
The map sensor reads 9.5 at idle so that is reading low. Bad sensor a possibility or bad cam or cam timing?
Cylinders 3,4,7 have miss fires on short term but nothing in history. Cap and rotor are new from Summet the blue color cap/rotor. Maybe that is bad?
I'm still kinda leaning to something up with the cam. If the data is correct then it has to be off a tooth or ground wrong. Low vacuum Low compression. I don't believe it is off a tooth as i repeatedly checked that several times.
What are your thoughts?

 

[BeXtreme]

I changed back to the original black box ecu to help trouble shoot things last monday.
Had a shop do a crank relearn and a little trouble shooting.
Looking at fuel trims it seems to be running a little rich. The injectors are 5 O motorsports. Maybe they flow slightly more than stock?
The map sensor reads 9.5 at idle so that is reading low. Bad sensor a possibility or bad cam or cam timing?
Cylinders 3,4,7 have miss fires on short term but nothing in history. Cap and rotor are new from Summet the blue color cap/rotor. Maybe that is bad?
I'm still kinda leaning to something up with the cam. If the data is correct then it has to be off a tooth or ground wrong. Low vacuum Low compression. I don't believe it is off a tooth as i repeatedly checked that several times.
What are your thoughts?

Injector data is definitely different for the Bosch injectors if that is what you are running. Are they 19lb ones? Did 5 0 provide a datasheet?

If it was my engine, I'd beg or borrow a leak down tester and see if something is broken mechanically. Then, if I didn't find anything, I would look at pulling the intake to degree the cam and see what it shows.

 

[Spareparts]

I don't believe anything is mechanically broken. Compression although on the low side is even on all cylinders. I would think that excludes bent valves. There is no blow by visible i can see with the engine hot, pvc unhooked and the breather plugged.
In about the first 200ish miles it used about 1/4 qt of oil. In the last 300ish it has used none i can tell so im sure rings are seated now.
There is no blue puff of smoke at cold or hot start up.
Thinking about it for a while now and it does seem a little doggy in the lower rpm range but from about 2,500ish rpm and up it starts pulling HARD!
From all i have read a retarded cam can act this way.
I'm convinced the cam is ground wrong or somehow i installed it a tooth retarded even though i checked it about 20 times.

 

[Spareparts]

About ready to order a few parts but have a couple questions if anyone knows the answer. I'll be installing a good used original gm cam from my old engine.
From reading it seems the original stock timing chain/gears are a little loose when new allowing about 1/2 slop on the chain and this is normal.
My new installed set has about the same but could be marked or machined wrong.
I'm wondering if ordering a Cloys .005 shorter set would be a good idea. This set or just go with the chevy performance set that will have about 1/2 slop?
I'm also ordering a degree wheel so ill need to learn that when i have it apart also cuz i want to know what the current one is set to.

 

[Spareparts]

Would a video of fuel trims possibly offer another clue to the problem?

xc_hide_links_from_guests_guests_error_hide_media

 

[Spareparts]

So was at work today and was thinking about this some more and wondered if ignition was the problem causing the slight rough idle and misfire counts im seeing.
Left a little early from work got home and tried a timing light on each wire looking for the steady flash, flash, flash you would expect. When i got to #3, #4 the flash was very erratic.
So i changed the new cap and rotor with a known good used set which resulted in no change. Next i changed the two wires on 3, 4 and no more erratic flashing from the timing light.
All cylinders are firing as they should according to the timing light flash, flash, flash. Slight miss is still there.
Well see if driving another day or two will clear up giving the ecu time to adjust. Doubt it will make a difference but im for sure gonna find out.
The plug wires are new AcDelco wires. Never in my life have i had a bad plug wire and i for sure never thought new AcDelco wires would be bad but sure enough two are bad without a doubt.

 

[L31MaxExpress]

So was at work today and was thinking about this some more and wondered if ignition was the problem causing the slight rough idle and misfire counts im seeing.
Left a little early from work got home and tried a timing light on each wire looking for the steady flash, flash, flash you would expect. When i got to #3, #4 the flash was very erratic.
So i changed the new cap and rotor with a known good used set which resulted in no change. Next i changed the two wires on 3, 4 and no more erratic flashing from the timing light.
All cylinders are firing as they should according to the timing light flash, flash, flash. Slight miss is still there.
Well see if driving another day or two will clear up giving the ecu time to adjust. Doubt it will make a difference but im for sure gonna find out.
The plug wires are new AcDelco wires. Never in my life have i had a bad plug wire and i for sure never thought new AcDelco wires would be bad but sure enough two are bad without a doubt.

I will not even use AC Delco wires now. There were once pretty decent though. After having multiple sets come apart at the boots that were not very old, I refuse to use them.

 

[Spareparts]

Managed to get some work done looking for whatever the problem might be.
Degree wheel did not show up so that did not get done.
Timing chain was pretty close to dot to dot but the timing chain has a little slop so not perfect. I installed a new Cloys brand chain and gears that had a tighter chain. I forgot to take a pic once installed but again, dot to dot.
Not to bad a job really. Hardest part is taking all the oil pan bolts out except the last two so the pan will drop down to clear the lip of the timing cover.
Before i tore into it i bought a vacuum gauge and it showed i was wasting my time with putting a new chain/gears in as vacuum was a rock solid 19 inhg.
After i get it finished up and running again tomorrow i guess the next place to look would something with the ignition or intake.

You must be registered for see images attach

You must be registered for see images attach