455 Tuning - 08/09/2014

While the rest of the car is toast and history, the engine is still in very good shape. No reason to cut the car up completely and render it immobile, especially when there's work to do on the engine. I need to find out the condition of it and what status it is in.



Original carburetor with all brackets and linkages. Solenoid comes on when ignition key is in "Run" position, an anti-dieseling feature.



Linkages on other side. Note the gasket material on the vent for the air cleaner, never seen one still installed. Carb secondary lockout doesn't work, so secondaries will hang open every time.



Pulling out spark plugs for a compression test. The spark plug wires are all plastic wrapped (almost look original). Piston head in #6 shows some carbon buildup, but after 89k miles or so I'd expect it.



Plugs all came out nicely, some are a little gooey but I suspect it's because the plug wires weren't fully seated as several came off way too easily. Previous owner put Bosch Platinum plugs in it, all gapped to 0.035". He might be my new hero, he used anti-seize on every single one!



Plugs all out!

I couldn't get the engine TOO hot, but I did get it roughly to 160-180 or so after 10 minutes of idling. I don't want it to run long, the timing cover is weeping coolant at a pretty hefty rate due to gasket failure. Here are the results though:

1: 135
3: 140
5: 140
7: 135
2: 145
4: 140
6: 130 (probably should be 135, it was halfway between the 2)
8: 145

Meh! Those numbers are better than my brand new 400 in the '69! And very similar to every low compression Pontiac v8 I've ever had. For comparison, my previous 1973 455 was 115-125 all around and my '78 Bonneville was 130-140 all around with 1 dead cylinder and another weak. This appears to be a very strong engine for 40+ years old.

Not one to let sleeping dogs lie and be in the dark...
Ignition timing results:

Initial: 10° at crank at 600RPM
Vacuum advance: 30° at crank (15° can)
Mechanical: 24° at crank, all in at 2600RPM

Pretty standard fare. The vacuum advance is working, which is great! I unplugged the TCS solenoid from the intake to restore vacuum advance full time and the idle smoothed out considerably. I also fixed a cross-wire on the 5 & 7 wires as they were running perpendicular to each other. I changed the routing on the loom so now they are parallel the entire way. No more misfire at idle!

Here's a video of it running. Listen to how smooth and crisp it is. No shaking or hesitating.



All back together!



You can see the water pump spew "coolant" out the timing cover seal. It's closer to mud than coolant, but it's good to get all this gunk out of the engine. New timing chain, timing cover set, thermostat, and water pump are on order and will be installed.

Not bad, engine runs great. Shame about the roof... At least the remains of this car will make other B-body fans and owners very very happy.

Return to 1972 Grandville

Last updated August 9th, 2014