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70 Deville timeing gear

Started by r thomas, July 18, 2010, 03:56:08 PM

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r thomas

I have a 70 Deville convt. with 90m miles.  Should I change the gear and chain on the camshaft. Does it have a gear with plastic covered teeth, like the Pontiacs ? I know they failed, usually well under 100m miles.  Just wondering if I should be worried,,

"Cadillac Kid" Greg Surfas 15364

car,
100K seems the limit for the original, nylon/plastic toothed cam gear.  They typically give plenty of warning (uneven idle, sluggish performance) but often go out without any, resulting in bent valves and/or pushrods.
If you plan on driving the car any distance from home replacement of the timing chain, oil pump kit) and water pump would be in order.  Water pump primarily because you have to remove it to do the timing set and they do have a finite life.
I would also recommend (to the objection and contradiction of others to follow) dropping the oil pan just the way the factory manual suggests.  You will be able to clean off the oil pick up screen, check the condition of the innards (for gunk and metal pieces) and if done correctly this is the only way that I have seen where the end result is a leak free pan/timing cover seal.
Greg
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-

r thomas

Thanks very much for the info, Greg.  This is what I kinda feared. Guess I might as well do it now.  Thanks again. Cargray

bcroe

After 40 years that timing set could fail without warning.  I read about another failure every month.  Bruce Roe

TJ Hopland

Make sure you get a Cloyes branded chain.   I have heard many bad stories about regular replacement sets, especially the lower sprocket shattering.  Cloyes makes 3 different grades.  They have a stock type chain that I am told is as good as the original (except all metal) and will be fine for what most of us do with our caddies.  I believe its in the $50 range.  They then make 2 roller chain models.  The roller chain is like a bicycle / motorcycle style of chain.  Both sets use the same sprockets.  The less expensive one has an 'imported' chain that is supposedly very good quality and the more expensive one is still a made in USA chain.  Those are in the $100 range and what the performance guys use.  Not sure if those are always in production or if they made a switch and there are still both still floating around on the shelves.

If you pull the distributor out (and your engine is not horribly dirty inside) you can get a slight look at the chain and cam gear.  Even better if you have or know someone with a bore scope but I have found that you can get enough of a look to tell if its the plastic one and how bad its cracked.     
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

Ted in Olympia WA

Here's one of the engines I tore down, it was a 1972.  The nylon was almost 100% gone but it still ran fine.

http://www.cadillacpower.com/forum/viewtopic.php?f=1&t=9344&p=98834

The 68-73 engines are interference engines so if loose a timing chain you will bend a few valves.  The 74 and later engines do not have this problem.

I agree with TJ to replace it with a good quality Cloyes unit; in fact I would only use the roller type.  This is not a place to save $60.

TED
Selling used Eldorado Parts from 1971-1978.  Member Number 25659.

Guidematic


On the other side of it, if the nylon is coming off the gear you can run the risk of it plugging up the oil pickup and causing oil starvation.

That's a bit more catastrophic than bending some valves.

Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69

r thomas

Thank you so much to each of you,who took time to answer my question....Bless You