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472/500 Cadillac engine difference question

Started by Scot Minesinger, March 07, 2014, 11:20:07 AM

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Scot Minesinger

Question I have is that was fairly sure the 500 is an interference engine (please confirm) such that if the timing chain failed valves and pistons would collide resulting in disaster.  Is the 472 an interference engine too?

Understand that the primary difference between the 472 and 500 that utilize same pistons (at least bore is the same) is that the stroke is longer on 500, and 500 has different firing order.  Otherwise 500 is similar to 472.

Thanks in advance.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

The Tassie Devil(le)

G'day Scott,

Never heard of any GM timing chain failing in any of the V8's.   The weakest part is the Camshaft Gear, and if it got to the point that the chain started slipping, the engine would be running that rough, it wouldn't start.

I do not believe they are an interference engine, and would also like to know.

Yes, the bore is the same for the 472 and 500, but the pistons would are different in that the Gudgeon Pin in the 500 is closer to the piston crown.   If it wasn't, the crankshaft would drive the piston up into the head.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

35-709

The firing order is the same for 472s and 500s.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

TJ Hopland

I think the 68-70 engines could possibly have an interference issue if the timing chain skipped far enough. 

I think the 71+ are fine because of the lower compression. 

I'm not 100% sure on that but I do know its not something you hear about being a problem.  With the plastic covered sprockets failing so often if it was common to get damage you would think we would hear about it more.

Yep firing order was the same. 

500's (only eldo's 70-74) often had different carb numbers and distributor part numbers.  Not sure what the difference was, guessing lightly different 'tune'.   Since they were originally only in the FWD Eldos the oil pans would be different than the RWD cars of the same era.    Otherwise the engines were the same.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Coupe Deville

Out of curiosity what year did timing gears have a plastic coating on them that breaks apart that I keep hearing about?

-Gavin Myers CLC Member #27431
"The 59' Cadillac says more about America than a whole trunk full of history books, It was the American Dream"

Scot Minesinger

Timing gears on the 472/500 all utilized the nylon coating on the gear from 1968 thru 1976.  The nylon coating idea originated before 1968 and continued after 1976.  Not sure what year the nylon coating thing started (early-mid 1960's) and what year it ended (early 1980's during the shift to higher quality and durability).

I have read where Greg S writes that the 500 is an interference engine, just wondering if the 472 is as well.  Sorry about firing order wrong fact.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

"Cadillac Kid" Greg Surfas 15364

Small chamber heads (ALL through 73) Yes.  Large chamber 74 and later) NO.
Greg Surfas
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-