500, 472, 425, 368 Discussion, Improvements to a stock '73 472 in Cadillac Engine Technical Discussion; First time poster! Looking forward to contributing in the future as i learn more and more about my new baby.
First time poster! Looking forward to contributing in the future as i learn more and more about my new baby.
Friend of mine purchased for very little scratch a very low mileage '73 Fleetwood with around 27k on the clock, mint interior, decent exterior and minimal rust/no rot. Motor doesn't look 27k but the previous owner is a friend I trust and it was his mothers car. Hardly "well documented" but for the price $700 it couldn't be ignored.
Long story short she runs/drives but a few tell-tale issues that are fairly easy fixes are present. High idle/long deiseling/timing issue and most likely needs a tuneup. Overflow coolant poured out because I am positive once the motor reached operating temp on a test drive the t-stat was closed up/stuck. Cheap part luckily.
I have read some post concerning upgrading to HEI as I believe this motor is set up for points at the moment and obviously new plugs with a larger .060 gap and wires.
93 Octane I am sure is the fuel i should tune with.
Is there any other 472 efficiency/modernization mods I should consider on a bone stock Cad? Converting the A/C as well? Car is not a daily driver but reliability and squeezing as much mpg as I can would be great.
Were motor mounts still an issue for rot/etc? Any basic help would be appreciated. Car will be flatbedded to my friends garage and all the typical fluids/hoses/etc will be replaced and gone over.
Automobile(s): '80 Fleetwood Coupe, 1994 and 1995 Mercedes 140 Coupe
Re: Improvements to a stock '73 472
The 1973 camshaft is different from most years according to a few internet sources who sell Cadillac performance pieces. I agree mostly except with regard to the year. Back in 1980 I drove a '72 CDV. In 1982 I traded to a '71 CDV. The '71 was a dog compared to the '72. I tried everything to make it run like the newer engine except for internal engine changes. Nothing worked. Many years later the info comes out about cam and/or cam timing changes probably due to owner low power complaints. Either my '72 had a replacement engine from a '73 or some '72s got the 73 cam. Dunno.
My point is your '73 may have the hotter cam situation and might benefit from higher octane gas even with the low compression.
Make sure the radiator is not gooped up internally. Is the air coming by the fan HOT with the engine hot or is it just warm? Also make sure the fan clutch is doing its thing. The external temp sensor coils on these fans get loaded with debris. Use some fast drying solvent spray to clean it.
Dieseling can be from a hot engine plus too high an idle. Someone may have cranked the carbonator mounting bolts too tight causing a baseplate warp and throttle hangup.
Gas pedal linkage adjustment was always a good way to wake these cars up. Make sure your secondaries open all the way with the pedal to the metal. Takes an assistant.
H.E.I. is nice but you will go nuts mixing and matching stuff. If it were me I'd keep the vac and mechanical advance from the standard distributor and all vac lines factory. Otherwise I'd grab the entire fuel and ignition setup from a '76. This requires changing the oil pressure sender to make the later choke work.
There was a vacuum switch on the front of the block which disabled vacuum advance to the distributor. I'd eliminate that unless you can verify the thing still works OK.
Mechanical distributor advances on these are notorious for binding. that can kill your starter motor, cause poor economy and make the engine run hot. Make sure the advance is OK.
The vacuum advance diaphram should be checked to see if it holds vacuum too.
Make sure the starter has the little bracket which holds it to the engine block. Mech hack nics leave these out because they think everything works like a Chevy. Cadillac starters in these years do not use mounting shims either.
If you search my really old posts on this site there might be more stuff.
We got the car tuned as i did not have the engine analyzer or a timing light. Needed some expected items like a battery/valve cover gasket but the idle calmed down with the tune. Still have slight dieseling effect on some shutdowns but I won't have the car back for a few days. Rear shocks and some other minor details will be worked out but I would like to try a few of the improvements/suggestions you have both made.
Again, sorry I goofed on the year but the seller was mistaken.
you can remove the fan to help a bit and put in an electric one. For HEI swap you have to remove one of the dual belts. I bet more than likely it is 127k or more miles. replace all the vacume lines will be a big help as well. I have a few of mine taped off while I try to figure out where they should go <.<