: Change engine...

07-08-04, 08:03 PM
My 472 -68 had a broken piston so I'm gonna change the engine with a 500 -74.
Could I just take away the airpump, all hoses and the smog things and just plug all holes? Then I'm gonna change the distributor to the old one. And put my old Holley to the -74 500 engine. Any problems to do this? What should I think about? What can go wrong?
I'm a beginner in these cars, but I like my old Caddy.:) Thank's for all help with my other questions.

barge master
07-14-04, 07:13 PM
Their pretty much the same animal, you should have no problems. I'd consider an HEI distributor though.

07-15-04, 05:48 PM
I don't know why you'd change to the old distributor. 74 was the first year for HEI.

07-16-04, 01:23 AM
I don't know why you'd change to the old distributor. 74 was the first year for HEI.
I don't know if it should be any more parts who is working with the Delco Remy (HEI)? distributor, I just got a complete engine. It's only one red kable in to the distributor, to the ignition + I presume?
Would be thankful for help so I can use this one.

07-17-04, 01:44 AM
Correct. It should be labeled B+ or sonething like that, along side TACH. You only need to connect B+ to the ignition switch (same wire that went to positive side of the coil on the old system) Everything else is contained in the distributor.

lux hauler
07-17-04, 08:01 AM
Correct. It should be labeled B+ or sonething like that, along side TACH. You only need to connect B+ to the ignition switch (same wire that went to positive side of the coil on the old system) Everything else is contained in the distributor.A HEI needs full system voltage.....There's more that has to be done. I don't have time to get into it right now. If no one else gets to this, I'll get it later today.

lux hauler
07-17-04, 11:03 AM
Ok......You can't use the same wire that went to the positive side of the coil. That wire is a resistance wire (9.6 volts?). The HEI needs full system voltage (13.4 volts?) to run properly. It's still a fairly easy swap......I'm not real good at explaining stuff but I'll do my best at explaining how I did the one in my truck..

The things you'll need for the swap: a good HEI distributor, HEI spark plug wires, spark plugs (plugs and wires for any 1976 Cadillac 500 should be fine) and a length of 12 guage insulated wire.

First....disconnect the battery and coil wire (don't need any accidents).

Bring the engine to TDC on the compression stroke. Note the location of the spark plug wires on the cap. Pull the distributor cap off and note the location of the rotor (the HEI rotor will need to point in the same direction). Remove the distributor. Install the HEI the same way the old distributor was installed (rotor pointing in the exact same direction). Mark the old plug wires so you know where they came from. Remove the spark plug wires from the spark plugs (leave them on the cap for reference). Gap and install new plugs (.045" seems to work best on small bock Chevys......not sure about these engines but that should be about right). If you haven't done so already, install HEI cap. If the distributor is installed correctly and the engine is at TDC (compression stroke), the rotor should be pointing in the direction that would have been the firing position for the number one cylinder. You can now install your new plug wires according to the firing order (remember that the number one cylinder on the 472/500 is at the very front on the passenger side....it's not like a Chevy). Install them just like the old ones were installed. If you took the time to note and mark everything, it should be simple. If you left the old wires on the old cap, you can use them as a reference.

At this point the old coil can be removed. You can either remove or tape aside the old wire coming from the ignition. There is also a wire going from the + (positive) side of the coil to the solinoid on the starter. That wire can be removed or taped aside. If you choose to leave the old wires, make sure they're taped well.....don't need them arching/shorting out. It would be best to remove them.

At this point, you can hook the battery up......just be careful!!

Now to power the new HEI. As was said before.....the points system couldn't use full system voltage while running....the HEI needs full system voltage. To get full voltage, you need to run a new wire from an ignition swiched source. I'm not sure what there is for ports in the fuse box on these cars but if there is a switched open port, I'd use that. Check to make sure that whatever source you use for power, is switched with the ignition. If it has full power all the time, the engine will not shut off with the ignition. Run the wire from the BATT+ side of the HEI to your switched power source. Once you're connections are made, you're ready to fire it up and adjust your timing. If at all possible, run the wire through the firewall along with other wires through a grommet. If the wire rubs the metal, it can short out. If you can't run it with other wires, get a grommet that will fit the wire, drill a new hole in a safe location, install the grommet and run the wire through there.

It might also be a good idea to put a fuse in your new power wire.......I'm not sure how many amps the fuse should be though. My guess would be that 10 or 15 amps should be plenty.

07-18-04, 10:27 PM
Ignition source can be taken from the yellow wire at the windshield wiper motor. For some reason, that is hot with ignition and on crank, and it has full 12v at both times. I used that wire for when I converted to electronic.

lux hauler
07-18-04, 11:01 PM
My only concern with tapping into another accessory's power source is the possibility of over-loading that accessory's fuse. It's always best, if at all possible, to put things on their own circuit. You can up the size of the fuse but that could cause a problem if there was a short in the original accessory.....the fuse would then be bigger than it was originally designed for and that accessory could burn up before the fuse would blow. There may never be a problem but there's always that chance.

07-20-04, 02:46 AM
Thank's for your answers. I'm not sure of this with HEI... is it the name of the electronic distributor type? And the manufactore is Delco Remy?
Now I must change it because I heard a sound in my engine and it came from the distributor's vacuum diaphragm, took the hose off and it was quiet, so it must be a vacuum leak. I can also move the vacuum clock forward and back about 10mm, could not be good...

/Peter in Sweden