93 K2500 Suburban 454 Holley Sniper Upgrade

[LC2NLS6]

All I need to do now is retorque the intake manifold per the weian instructions.

The 2 inch Mr Gasket air filter did the trick. Death wheeled the cleaner stud shorter and ran a die over it.

One thing I forget about wrenching on cars, you spend hours and hours cleaning parts, then deciding to paint them black. Have a steady supply of brass wire wheels to put on drills. You'll want a vice or vicegrips to make it easier. And brakecleaner, get 4x the amount you think you need.

 

[LC2NLS6]

I also need to make a new set of spark plug wires, this $5 set is waaaay to long, and one was broke so I had to use that for the coil and an old crusty wire on #4 from the old set.

 

[LC2NLS6]

The self learn got all confused as the first 20 minutes was cam breakin time. Drove it around today and it went super lean at tip in say 33% throttle. Couple lean backfires taking off at a stop sign normally, backfire through the intake at 20 AFR, but after 10 miles she started clearing right up at the 13.4-14.7 as desired. The learning is 10x better than the learning on my racecar on the Holley HP EFI. I have learning mostly off on that for street duty.

 

[LC2NLS6]

I also fried the TPS sensor when I had the factory computer on a different switched than the holley. It always read 100% tps. Slapped my 310,950 mile stock sensor on, worked perfectly...

 

[Erik the Awful]

Dots on the 454 on the cam sprockets need to be both at 12 o clock. That is 1 TDC (compression - needed to use the Holley clear plastic hyperspark dizzy setup tool), if you do dot to dot like every other engine, it is 180 out.

The crank doesn't care. You can install the cam 180* out from the crank, and if you turn it a full crank rotation, guess what? The dots are lined up. So long as you stab the distributor at TDC on #1 with both valves closed, it'll run.

 

[LC2NLS6]

180 out on the cam was the issue. I installed dot to dot, did not move the crank during install. Dizzy installed to spec per instructions. It did not fire, except flames out the intake. I moved the wires on the cap 180, fired right up and purred like a kitten. So, dot to dot is tdc on 1 on the wrong stroke. I can confirm looking back, every engine I had a hand on was this way, except my Turbo Buick (waste spark system from the factory so it did fire on 180 out lol), assuming dot to dot was compression stroke, and was not.

 

[Schurkey]

The crank doesn't care. You can install the cam 180* out from the crank, and if you turn it a full crank rotation, guess what? The dots are lined up.

True.

So long as you stab the distributor at TDC on #1 with both valves closed, it'll run.

How many folks mistake "both valves closed" for "overlap" when both valves are almost closed? Especially with hydraulic lifters that may bleed-down enough for the valves to close.

 

[LC2NLS6]

On my Buick and this, both low compression engines. I throw a socket on the alternator (belt on and ign off lol) and with one hand can roll engine over and stick my finger in #1 to feel the compression.

 

[Erik the Awful]

180 out on the cam was the issue. I installed dot to dot, did not move the crank during install. Dizzy installed to spec per instructions. It did not fire, except flames out the intake. I moved the wires on the cap 180, fired right up and purred like a kitten. So, dot to dot is tdc on 1 on the wrong stroke.

Your cam was fine. You installed the distributor 180* out. If you have the dots lined up, put the covers on, and immediately install the distributor on #1, your distributor is 180* out. Having the dots lined up puts the cam at TDC on #6, not #1. Always check your rocker arms on #1 when stabbing the distributor.

 

[LC2NLS6]

Technically yes, but the cam was 180 out first for compression stroke on 1. The Holley hyperspark has a tool. Says go #1 compression tdc. That means the dots both 12 o clock on the 454. It is a clear cap, it marks roughly where #1 cyl is on the cap to be phased per instructions. Mark it, slap the sniper on and it should fire up perfectly without a timing light at first. If the dots are 6 and 12, then its 180 out and not on 1 compression stroke.

Over and over on the internet I keep seeing the same message on why I did it wrong all these years, need to be 12 and 12 after lining up at 6 and 12 dots so its on 1 compression.

https://www.chevytalk.org/fusionbb/showtopic.php?tid/198828/

http://www.crankshaftcoalition.com/wiki/How_to_install_a_distributor