The Official Vortec 454 Info thread

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Schurkey

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The vibration is kind of a low frequency pulsing that (at it's worst) will rattle the dashboard. I think I've narrowed down the cab vibration to be directly related to engine speed/rpm (as evidenced by replicating the vibration while at a dead stop, in neutral, at about 1500-2000 RPM).
Assuming the engine runs good and doesn't misfire, I'd be looking at a failed torsional damper, or out-of-balance flywheel/clutch.

Possible issues with exhaust system mispositioned, exhaust hits chassis somewhere.
 

scottr55

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Thanks Brody!

First off, our factory MPFI injectors are not considered reliable or even worth keeping in the truck if they're removed for maintenance. A common mod is to replace them with a bosch style injector which will have a 4-hole atomizer tip. This will give you a slight bump in MPG, but you won't notice a performance benefit.

Ford 4.6 (and many other v8's like the '90's 5.0/5.4's) used "yellow top injectors", which are 19lbm/hr @ 3 bar, which match pretty close to our factory injector's flow rate of 24lbm/hr at 4 bar.

5-0 Motorsports injector number for 5.0L mustangs:
0280150556, FOTE-D5B (Yellow-tops)

GM MPFI injector flow rates
1986-’93: 22 lb/hr (43.5 psi)
1994-’96: 24 lb/hr (43.5 psi)
1990-’92 ZR-1: 20 lb/hr primary, 20 lb/hr secondary (2 per cylinder) (43.5 psi)
1993-’95 ZR-1: 20 lb/hr primary, 20 lb/hr secondary (2 per cylinder) (43.5 psi) (redesigned for ethanol resistance)
1997-’98 LS1: 28 lb/hr (58 psi) (maro/fbird 98 only) (Use L29 clips?)
1999-’00 LS1: 26 lb/hr
2001-’04 LS1/LS6: 28 lb/hr PN 0280155931 (What I use and have injector data for use with HPtuners) found in CADILLAC CTS 2004-2005, CHEVROLET CAMARO 2001-2002, CHEVROLET CORVETTE 2001-2004, PONTIAC FIREBIRD 2001-2002, PONTIAC GTO 2004

2005-up LS2: 33 lb/hr
2006-up LS7: 39 lb/hr
2008-up LS3: 41 lb/hr

LS1/LS6 engines all came equipped with Delphi EV1 injectors.
Different p/n's have different lb/hr rated injectors

12533952, 12482704, 12561462 are rated 28.6lb/hr @ 58psi.
12456154, 12555894 are rated 26.2lb/hr @ 58psi.

BSFC: .42 FACTORY
1bar=1atm=14.7psia
4bar = 58.8psi (Factory pressure) 19lbm/hr at 3bar is 22.01 @ 4bar

Common practices:
Most guys go by the factory plug specs and just roll with it. For our trucks and anyone looking to tow or get some more performance, this is a bad idea. It has been dyno proven and was previously posted on FSC that a plug gap of .045" vs .060" eliminated misfires under heavy load on Gen VI 454's.

Intake gaskets are a common problem. Plus the factory-fill dex cool turns to mush as it breaks down and also oxidizes all of the picked up iron molecules from the block. If you pick up a 454 and it eats/leaks coolant it's likely coming from the lower intake.

My tips on the intake manifold job are
-Use blue loctite, or pipe dope, to seal the intake manifold bolts when you tighten them down. Chevy techs recommend loctite, my Gen 6 engine building book says pipe dope. Its whatever you prefer. The oil pressure sending unit for your dash gauge is just behind the intake manifold. I broke mine when aligning it to install. Its not hard to replace if you break it, at least when the upper plenum is off.
-Be careful pulling out injectors. I pried under the sides of the bodies of the injectors and intake casting a little at a time on each until it popped out. Use a liberal amount of ATV or WD-40 (compressed air beforehand) to help save the bore and your O-rings. If you're upgrading your injectors:

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-The A/C compressor can just unbolt and you can lay it back on the passenger fender on an old towel. I removed ALL of the harness around the manifold, which requires going all the way back to the oil sending unit on the bottom of the driver's side of the motor.

Upper plenum: Felpro ms95787
Lower: Felpro ms95826

Cam stuff:
Stock Camshaft is ******** 6* via the factory timing set. If you change the timing chain out to an aftermarket unit YOU WILL CHANGE CAM TIMING... expect the engine to perform a little different. A ProGear PG4149ST Timing set will put cam back at 0*
(GM #12552296) camshaft lift .480 intake / .483 exhaust, duration @ .050" 204° intake / 209° exhaust, LSA 118. 119 intake centerline
Material Steel, Camshaft Type Roller lifter

A few guys have gone the distance and installed a "ZZ502" (GM part #12366543) cam to get the engine to breath and make power. This is a great leap, as you have to pull the heads and have the valve stem guides machined down. At anything over .500 lift (with stock retainers, up to about .520 with different retainers) the spring retainer hits the guide upon valve opening.

Stock intake lobe: 1.607" - base circle 1.326" = .281" x rocker arm ratio 1.7 = .477" valve lift
Stock exhaust lobe: 1. 610" - base circle 1.326" = .284" x rocker arm ratio 1.7 = .483" valve lift

ZZ502 intake lobe: 1.608" - base circle 1.298" = .310" x rocker arm ratio 1.7 = .527" valve lift
ZZ502 exhaust lobe: 1.618" - base circle 1.298" = .320" x rocker arm ratio 1.7 = .544" valve lift

Comp 1411-16, ARP 135-7102 studs, with ARP Posi Locks will fit under stock valve covers.

98-2000 454’s use 3/8” pushrods and have the appropriate guideplates. 96/97 have 5/16 rods and plates. https://www.gmt400.com/threads/my-9...i-need-or-should-do.46579/page-4#post-1068683

GM performance parts #12495518 is for adj rocker arms. New lock nuts are part #3896648


Oil cooler hose parts, because the factory ones leak like crazy and are usually blowing on everyone. If you change hoses, use ones with STEEL hose crimps, not aluminum... those leak.

Here are the NAPA (Balkamp) PNs for the oil cooler hoses and block fittings:
Hoses: 823-4070 & 823-4071 ($20 ea)
Fittings: 730-4951 w/o check valve ($6)
730-5636 w/ check valve ($4.74)


Edlebrok performance heads with factory Combustion chamber size 100-110cc, valves set for .700 lift, I-2.190 E-1.880, 3/8” guideplates : http://www.summitracing.com/parts/EDL-60499/

GM Vortec EGR blockoff plate p/n is 12554606. It gets you an EGR blockoff plate for the Vortec 4.3/305/350 engines. Its part of RPO NM8 as are the following 2 parts. 12556596 gets you the part that screws into the drivers side exhaust manifold for EGR feed. 7/8-14 UNF-2A THREAD) 12556597 gets you the cap that screws onto 12556596 and caps off the exhaust manifold.

IDK who this was, but I quoted them: "According to Federal Mogul, our stock springs are super weak - seat pressure is around 85 pounds. I'm going to run the stock rotators still; I'm not sure why everybody with cams is deleting them. They can handle over 400 pounds of open spring pressure and it's not like our engines hit high RPMs." and this guy tested his to be 95lbs. So, there's room to improve to get a few more RPMs out of the engine.


I thought I had more, but that's basically all the nibbles and bits I saved from the FSC 454 thread.

I also have a book (some call "THE book") on building/rebuilding the Gen5/6 big blocks. Usually $500 on ebay but I found some used book place online selling it for $25. Does anyone think I'd get my rear caved in if I scanned it and made a PDF?
I have a 99 gmc k3500 7.4 I replaced my injectors With the bosch 4 holes great product i also deleted the cats and got the cam correlationt to .1° but my truck is running super rich.. how do i fix this
 

Schurkey

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I have a 99 gmc k3500 7.4 I replaced my injectors With the bosch 4 holes great product i also deleted the cats and got the cam correlationt to .1° but my truck is running super rich.. how do i fix this
1. HOW do you know the truck is "super rich"? O2 sensor readouts? Smell of the exhaust? Gasoline smell in the garage overnight?

2. As usual, connect a scan tool, look for "codes" but mostly look at the data stream.

3. How old are the typical "tune-up" items? Plugs, plug wires, cap 'n' rotor, PCV, verify cranking compression, verify ignition timing and timing advance, fuel filter, fuel pressure, charcoal canister, etc.
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This is what my truck comes up with on my bafx in dash command
Six codes for O2 sensors, multiple codes for the same two sensors. How old are those two sensors? Unless they're quite new, I would look at the wire harnesses, if the harnesses aren't damaged, replace the sensors. After that, clear the codes and see what comes back.

If the sensors ARE nearly new, I'd be wondering if there's hidden damage in the harness; failed computer, or just plain factory-defective sensors (cheap Chinese junk?)
 

Mangonesailor

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This is what my truck comes up with on my bafx in dash command
Did you pop a fuse? Check for voltage at the o2 plugs. How does your maf read? If you're using dash command, what are your fuel trims? What are your knock counts? Do you have any misfires on any cylinders? You have codes for the knock sensors and the o2 sensors, so, what's common between them... is there a familiar ground or power source for them? Did you get 19lb bosch injectors or larger?

There are LOTS of possibilities why your truck is allegedly running rich... or just smells rich.
 

RichardSwinger

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Update on vibration: I feel like a dingus. I'm still learning how to truck, and apparently tire rotations make a world of difference. It was a two week wait but my trusty local truck shop finally got me in for a "shakedown" on the vibrations and found no smoking guns. They recommend a balance and rotation which I gladly went for and it made a HUGE difference, the dash vibrations at 35-50 are almost completely gone and what I would guess are "normal" for a 23 year old HD truck. I asked, and they said the worst of them was off by 2 ounces. Not sure how much that is in the big picture of things, but that and the rotation make it feel like a different truck. Looks like I'll need to add that maintenance item to the routine when I do oil changes.

I also had them install new upstream O2 sensors and a belt tensioner/pulley sourced from the local GM dealership. I had been getting sporadic codes for both bank one sensor #1 and bank two sensor #1. I wanted the tensioner replaced after watching it oscillating by about an 8th of an inch at idle. In comparison, the new tensioner doesn't move at all at idle. I still need to log some more driving time, but I swear the idle vibration has gotten better too.

The shop said they were fairly sure that those parts were original from the factory. 23 years and 165k miles ain't a bad service life for that stuff!
 

Mangonesailor

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Wonder if he's on here lurking?
If he was he'd probably swap the whole dizzy out for a better one instead of just changing the cap/rotor... he didn't even do the dizzy gear.

I'm interested in his header install and whenever he decides, I hope, to put a cam in it. I'm guessing he put injectors in just to make content since he didn't put intake gaskets in.
 

WillB

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Wondering if I can get some help on this issue I've contiunally had since I bought this truck. When it gets warm, I will have a weird idle issue and occasionally die. So far we've replaced the IAC, EGR valve, upper plenum gaskets, plugs and wires. My mechanic thinks it may be ECM related. It's hard to explain how it acts but I'll try to the best I can. When in gear and at a stop sign for example it will idle down to 200 or 300RPM and try to die. Truck will idle back up and idle fine if I take the truck and put it in neutral. It is more promenant in reverse, almost has the feeling of taking off in a manual. Makes pushing snow a pain in the ass.

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