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1964 Cadillac low compression motor advice

Started by kokerscad, October 06, 2016, 08:10:12 PM

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kokerscad

Ok, I've posted some topics about my 1964 Fleetwood 60 special, the car was sent to California new and therefore has a low compression motor, as far as I can tell, it has to do with the Pistons installed, anything else? I would like to delete the "California emissions controls" which is a pcv valve from valley pan to carb base, as well as the vent from left valve cover to air cleaner, and of course get new Pistons. The car has been moved to Colorado where there is less oxygen, and she runs terrible, can this help? I'm wondering what dealers did in the old days when the cars were new to get them to run properly, I've already replaced all vacuum hoses so I have zero leaks, and next is another carb rebuild. There has to be a way to make my car run like it is supposed to, like it did in 1964. Need any advice. Thanks
C.Dias CLC#27578
1965 DeVille convertible
1964 Fleetwood 60

"Cadillac Kid" Greg Surfas 15364

No such thing as low compression for CA. Only low comp was for export
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

kokerscad

Greg, It is clearly marked on the build record from gm, for cars being built, under the low compression engine column there is a "2",  there are 2 other cars built on that sheet where the outlet codes start with 7s and 8s, those are codes for California, from research and the the shop manual, state that cars going to California have a lower compression ratio and use different Pistons as well as a pcv valve and closed positive crank vent, if we can both get to the bottom of this to clarify that would be great
C.Dias CLC#27578
1965 DeVille convertible
1964 Fleetwood 60

savemy67

Hello Cole,

As it would happen, today I just returned a '64 shop manual to the owner on whose Eldorado I have worked a little.  So, I can't help you and Greg clear-up the issue of California car compression ratios.  Can you post the shop manual pages that describe the low-comp specification, and maybe a photo of the build sheet?

As for the PCV set-up, if it is operating normally, I don't think it will have much impact on engine performance, even at altitude, all else being equal. I do think rebuilding and modifying your carburetor will affect performance if you plan to operate your car above 4000 feet most of the time.  Does your car have a Rochester 4GC carburetor?  This carb should work fine at altitude as Lou Unser won the Pike's Peak Hill Climb in 1961 with a 4GC.  I encourage you to seek out a reputable carb rebuilder familiar with Rochester carburetors.

Replacing pistons will require complete disassembly of the engine.  If you get that far, are you prepared to correct whatever problems may be encountered?  You should be able to get your car running the way it did in 1964 without installing higher compression pistons (unless you have a tired, high-mileage engine in need of a rebuild anyway).  Good luck.

Respectfully submitted,
Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop