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401 ci Buick NailHead Compression Check

Compression looks good so next week maybe it will start and even run with a little work

The Gasser should be ready to start soon. The fuel pump, carburetor and distributor, ignition coil are on the motor and the spark plugs, spark plug wires, radiator and hoses and ready to install. I will find top dead center on #1 compression stroke and install the plug leads and set 20-30 degrees of initial advance and give it a few bumps with new premium fuel and a shot of starter fluid to see if it will turn over.

New Ignition System

I updated the engine with a complete new ignition system with a 50K volt coil built in. I turned the engine over by hand with my breaker bar with a compression gauge on the #1 cylinder until the top dead center marking on the dampener was a zero while the compression gauge showed #1 on the compression stroke. I then marked the position of the distributor rotor in the engine and labeled the distributor cap from 1 to 8 clockwise and using the firing order and the engine plug layout I installed plugs and ran plug wires 1 to 8 to the correct plug # 1 to 8.

With the new ignition system installed I used my timing light on each plug wire while turning over the motor to confirm that each plug and plug wire was operating.

Time to see if it will run

With the ignition sorted I turned on the fuel at the moon tank and cranked the engine over and checked that fuel pressure was at 6-8 lbs and flowing via the see through fuel filter.

With compression, fuel and ignition the engine should run or at least try.

She is alive!!!!!

Using the ignition power switch and starter button on the dash that had installed and tested and wired to the new distributor.

I checked the accelerator squirters in the carburetor, closed the choke and hit the starter and I was rewarded with a few bangs, a backfire or two and a loud exhaust note as the Gasser tried to come to life. I think she is ready to run pending a timing adjustment which is a two person job that me and few rowdy gear head guys can handle next.

Adding the final details

With good compression and oil pressure I replaced the oil pump primer rod with the distributor and turned the engine over with the breaker bar to zero degrees on the harmonic balancer and checked cylinder #1 for top dead center, I checked that #1 was on the compression stroke by checking the valves on #1 to make sure both valves were closed. With the distributor in and the cap off I check the rotor and marked the cap 1 to 8 based on #1 at TDC on compression and ran the plug wires to the plugs following the firing order.

I wired + 12VDC from run terminal on the ignition to the coil and distributor for power and hooked up my timing light to another battery .

With compression, timing, ignition and fuel in the Carburetor (checked the accelerator pump squirters too. It should start if I wired the plugs correctly

Ignition System installed, Plug Wringing, Coil, Distributor

Prep for starting

I set the engine # 1 cylinder to top dead center by removing the valve cover and rotating the engine over by hand until the timing was at zero degrees on the harmonic balancer and checking that both the intake and exhaust valves were closed and then I checked the piston with the spark plug out to make sure it was at the top of its stroke. I rotated the engine over another 720 degrees with a pressure gauge just to double check that the #1 was a top dead center on the compression stroke with the valves intake and exhaust both closed.

I then installed the distributor and noted where the rotor was, and installed and marked the cap from 1 to 8, installed the plug wires on the cap in order and to the plugs following the firing order for the nail-head engine.

I will need to wire the ignition switch for 12vc to the distributor in the run position and install the coil wiring and ground, the starter wiring is all ready installed and tested

But will is start

The Gasser should be ready to start soon. The fuel pump, carburetor and distributor, ignition coil are on the motor and the spark plugs, spark plug wires, radiator and hoses and ready to install. I will find top dead center on #1 compression stroke and install the plug leads and set 20-30 degrees of initial advance and give it a few bumps with new premium fuel and a shot of starter fluid to see if it will turn over.

Start Up Prep and Detils

With the starter and compression checks completed its time to get ready to start the 401ci Nailhead Motor

  1. Check timing mark on balancer by finding top dead center of cylinder #1
  2. With the motor at TDC on the compression stroke install the distributor and spark plugs.
  3. Point rotor to where #1 will be on cap
  4. Label distributor cap 1 to 8
  5. Set initial advance to 25-30 degrees
  6. Install spark plugs, and plug wires to the correct cylinders
  7. Install wiring for ignition power to distributor and coil
  8. Install new fuel pump, carburetor , fuel lines etc. and test pump with starter
  9. Install radiator, thermostat and hoses to motor and fill with coolant
  10. Install exhaust headers
  11. Hook up timing light, vacuum gauge
  12. A little starter fluid and see if it will start or a least try

A 425 for the gasser

I was able to pick up a 425 with dual 4’s in California from a wrecked 65 Buick Riviera that the owner said was running when the car was hit in the rear. I have it in the back of my pickup and will drop it into the Gasser frame with a transmission and then prep it for a test run by pulling the plugs, lubing the cylinders with Marvel Mystery Oil, turn it over by hand and letting it sit a few days.

I can then set the rough timing by finding top dead center of cylinder #1 and checking the timing mark on the harmonic balancer.

425 Motor on the hook

Engine Motor Mounts

The 425 needs different mounts to match the already existing frame mounts that were used for the engine that is in the machine shop. I ordered a new set of mounts from Speedway Motors that include the block mount bracket and hard rubber briskets and hardware.

Image 1 - Buick Nailhead Engine motor adapter mounts 364-401-425 1957-1966 hot rod vintage