Author Topic: 67 429 Engine  (Read 2355 times)

Marty Krizay

  • Guest
67 429 Engine
« on: January 04, 2005, 02:42:30 PM »
About a year ago, a neighbor and I rebuilt a 1967 429 engine with the assistance of a local machine shop.  The rebuild included new cam, main and rod bearings, pistons and rings.  The machine shop cleaned-up and machined the block and the heads.  For a year the car (67 fleetwood) ran great.  Last week, there was a humming sound and substantial leakage of antifreeze from under the dash and along the firewall of the engine compartment.  I suspected a blown heater core.  This weekend, I started the car to show my neighbor all the coolant leaks.  The car started billowing huge amounts of white smoke out of the rear exhaust.  My neighbor and I believe that somehow, I now have a blown head gasket.  My question is how do I know for sure I have a blown head gasket,.....and did a blown heater core contribute to blowing the head gasket?  Which do I fix first?  If the head gasket is blown, what could we have done wrong in the original installation of the gaskets a year ago? HELP!!!


Mike #19861

  • Guest
Re: 67 429 Engine
« Reply #1 on: January 04, 2005, 02:58:54 PM »

 It does sound like the haed gasket has blown, but I cant think of a connection between this and a blown heater core except that perhaps the cooling system pressure perhaps was allowed to go too high. The result of a defective rad cap.

 There are a few ways to diagnose a blown head gasket.

 The first would be to remove and inspect all of the spark plugs. Check for any wetness on the tips, or a bright white colour. This will indicate a blown gasket, and on which cylinder it is blown.

 The second is to pressurise the cooling system with a cooling system pressure tester. Remove all of the sprk plugs. Top up the system and pressurise it to the maximum allowable, as noted on the cap. Usually 15 psi. Let it sit for about 1/2 hour and note any pressure drop. You can then crank over the engine carefully by bumping the starter. Stand clear of the sides of the car while doing this. If there is a gross leakage of coolant into any cylinder it will push it out the spark plug hole with dramatic results.

 The third is to start the engine and place the overflow hose into a bottle of water and note to see if a regular stream of bubbles is pushed through the overflow. This is compression escaping into the cooling system and being forced out the cap.

 Of the three methods, the first is the easiest and most reliable, if it shows results.


JIM CLC # 15000

  • Guest
Re: 67 429 Engine
« Reply #2 on: January 04, 2005, 03:07:45 PM »
MARTY, pull the plugs look for water on plug as yuo remove them.
Which ever side has water,replace the head gasket, you may want to have machine shop check it for "a true flat surface" torque to specs. Isolate heater by connecting the hoses together.
run engine until temp is normal and re-torque head. (wont hurt to re-torque the other head at the same time, as you will most likely get two (2) valve cover gaskets).
then, remove heater core, take to a radiator repair shop and have fixed.
Good luck, Jim


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