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1970 Cadillac timing chain 35k mileage -replace yes or no?

Started by Scot Minesinger, October 25, 2012, 09:41:16 PM

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Scot Minesinger

Thinking about a friend's a 35k original mileage 1970 Cadillac sedan DeVille with original brake pads, spare, paint, vinyl top and all.  The car runs fine.  The body is not perfect, so they plan to bring it to 100% mechanical perfection so that it can be driven and enjoyed.

Should the nylon coated timing chain be replaced, I'm thinking yes, but hate to fix what is not broken.  Thoughts?
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

waterzap

Yes, replace it. You don't know what condition it is in. Also, once it starts breaking, pieces land in your oil pump pickup and then that needs to be cleaned out too. No way to predict when the pieces start breaking off.

Pieces might already be missing. My Eldorado timing gear was still in good condition, but I am glad I replaced it. Just less risk of something going wrong down the road.
Leesburg, AL

The Tassie Devil(le)

The one problem with the nylon-covered teeth is that nobody knows when it is going to disintegrate.

I have seen high-mileage engines with the gear still intact, and yet others with it completely missing.

As it sounds like the vehicle is being rebuilt (must have had a hard life in its' 35,000 miles to require rebuilding) I would be replacing the set.

But one question is, has the 35,000 miles been put on it over the past 42 years at a constant rate, (833 miles per year) or all at once, then stored, or simply not used.?

Non-use of a vehicle can do more damage than is commonly realised.

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

"Cadillac Kid" Greg Surfas 15364

Scott,
Timing chain replacement can be a lot of work, so before you go ahead (and in all probability if it has not been replaced it will need to be) do a visual on the chain/gear by either pulling the distributor or the fuel pump to do your inspection.
The small chamber motors are "interference3" motors, meaning that if the chain slips and the cam timing is upset the valves will hit the pistons.  Not good.
Time also ages the valve seals which sould be inspected of courese by pulling the Rocker Arm covers.
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-

TJ Hopland

I would at least look at it.  You can get a slight look at the chain and sprocket by removing the distributor.  If the engine is fairly clean you can get a pretty good look at it.  If its dirty its harder to tell what you are looking at.  If you know someone with a bore scope you can get a nice look at it. 

Same as everyone else I have seen low mileage cars where they were shot and high mileage that were not that bad.   The last 10 or so years the age seems to have been extra hard on them.   One slightly nice thing is in theory you can change one in the RWD cars without removing the engine.  I dont think I would do it that way just because its not that hard to remove engines and at this age it could benefit from some other seals and a good cleaning when its out anyway. 

For buying a replacement I have heard bad things about many of the brands out there.  Only brand that still has a good consistent rep is Cloyes.   They are a big name that has been around forever.  All parts stores and shops can get them from their usual sources.  They have 3 grades.  There is a stock type which is fine for stock type engines.  They also have a couple roller chain options.  A roller chain is like a bicycle chain and supposed to be better.  Any will be fine.  The other tip I give people is when the timing cover is off (which is just fairly thin sheet metal) have your mechanic weld a couple nuts to the inside for the 2 (or is it 3?) water pump bolts that only thread into the cover.   Its very common to strip those since they are not threaded into much and they are like 1/4 the torque of the rest which thread into the block.   Its a huge hassle to find that problem (or cause it) after you have everything assembled.  With those nuts you would have to be really careless to damage those threads, I suspect the bolt would break first.   The nuts will be on the inside of the timing cover so you would not be able to tell that they are there without removing the timing cover and looking on the inside. 



The distributor drops in just to the right of that threaded hole you see at the top of the photo and ends up on the right side of the gear you see there so you can see that if you were looking down the hole the top edge of the chain and sprocket would be at the bottom of the hole in the block. 
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

Scot Minesinger

Thanks guys, I was thinking the same thing.  I have changed them before, have the 9/16" fine thread tool to thread into crank shaft and everything.  The car is fine if you were going to drive it 833 miles a year for a while longer.  It will be driven probably 5,000 miles a year.  The chain will be replaced.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

bcroe

Choose when to change the chain, or the car will choose it for you (at the side
of the road).  I assume tires are current.  Every time I get a car, it gets new
front calipers, brake hoses, and front lines (304 stainless is good).  Cause, I
don't want any big surprises if I jam on the brakes.  I do the rear too, maybe
a little later.  And gas tanks often start leaking, mine come off about every
15 years.  god luck, Bruce Roe

R Schroeder

Does anyone know how many years they did these nylon coated gears ? Was the 78 included in that type of gear ?
Roy

Scot Minesinger

Yes, this is a 35k miles car where even the untouched climate control works (can't believe the charge was never all leaked out after 43 years - some has it chills, but not ice cold).  Even the brake pads are original.  The spare has never been out, the hoses and clamps are all original, and all rubber parts are original.

What will be done for starters:

1.  Complete new brake system, master cylinder, brake booster, all steel brake lines, all flex brake lines, all calipers, ally pistons,  and all pads replaced.
2.  Complete fuel system renew, gas tank dropped sent to Loopers-sealed and repaired, new steel one piece fuel lines front to back, new rubber fuel line, new fuel pump, new fuel line pump to carb, and of course rebuilt carb.
3.  Complete new exhaust system, it leaks a little now
4.  Complete new front end such as 4 ball joints, all rubber bushings, center link, steering gear (the rebuilt ones really tighten up that steering-best thing), idle arm, pitman arm, tie rods, rebuild rag joint, and etc.
5.  Complete new tires, shocks, springs, tires, belts, hoses, filters, fluid flush and change etc.
6.  Replace all refrigeration hoses.
7.  Replace radiator
8.  Timing chain with new front engine seal, probably will replace original water pump too.

Since the exhaust will be removed and the center link will be removed, it would be crazy not to drop the pan and install a new rear main seal.

Amazingly the car is not dropping any fluid!  Still probably will at least re-seal the transmission.

Do you think I should re-seal head gaskets, intake manifold and exhaust manifold gaskets?  The engine seals of today will outlast myself and probably my son.

The car will be driven and enjoyed, not trailered ever.  The value of a Sedan is low compared to a coupe or convertible, but the driving fun is equal.

Thanks for the advice, any tips on handling a low mileage original will be appreciated.

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

bcroe

Sounds like a good plan.  When I did my 79 22K mile front end, I only
replaced the (mushy) rubber bushings.  The steel ball joints, etc
should be good (assuming they were greased), if the boots still hold
grease.  In my decades, have had 2 brand new replacement upper ball
joints break.  Don't replace good with unknown. 

Hope you get a good replacement radiator.  The imported stuff doesn't
have the capacity of original; I finally had a custom made for my 77.  I
also replaced the heater core; they like to leak after a couple decades. 
Bruce Roe

Gene Beaird

Quote from: Scot Minesinger on October 29, 2012, 09:55:12 AM
<SNIP>

Do you think I should re-seal head gaskets, intake manifold and exhaust manifold gaskets?  The engine seals of today will outlast myself and probably my son.


That list looks pretty ambitious, but I'd really not fix it if it's not broken.  I'd R&R the rubber bits, like you indicate, but the metal fuel lines and brake lines?  I don't see a real need, unless road salt has eaten them up.  I wouldn't bother replacing the springs, unless the car has seriously sagged.  Replacing the bushings, steering links and ball joints will certainly be a good thing. 

I'd probably do a good close inspection of the entire braking system, replacing only the brake shoes, if they're seriously worn, and the brake hoses, because they're probably cracked and dried out by now, but unless the MC and wheel cylinders are leaking, I'd let them be, opting for a good fluid flush and see what happens. 

I'd NEVER replace the head gaskets on a 472, unless you had one already leaking.  These engines are really quality units, and I've never heard of head gasket problems on any of them.  The rear main seal is also iffy, to me, especially if it isn't leaking.  If you do replace it, though, get a neoprene seal installed.  Just make sure it's properly fitted.

Resealing the transmission is a great idea.  While it's out, I'd have them replace _all_ the seals, including those in the clutch drums inside the transmission.  The installer tools for the internal seals requires some specialized tools that only a transmission shop will usually have, so getting this done while the transmission is out is probably prudent. 

Sounds like a nice ride.  I hope you get to enjoy many years of cruising in comfort. 

Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

blue68deville

#11
Welcome to the low mile car world!

I've got a 53k mile 68 sedan. It's nice to have a low mile car. I've done a lot of work on it, and it's a great driver.

That said, I would do the safety items, belts, hoses, and suspension rubber first. Then drive it, and see what else pops up. There may be more pertinent repairs that become obvious with some use.

Your steering box can have the play adjusted out. I would do that and reseal as needed before buying a reman. Those reman units probably have more wear than the box in your car. The reman guys usually replace seals and bushings only. The worm and sector gears on some of those reman units are pretty sloppy, I bet yours are just fine.

I inspected my timing gear thru the distributor hole, it looked great. So that went on the future repair list. I can reinspect periodically and go from there.

My steering links are ok for now, all have fresh grease and are tight. I did replace the idler and lower ball joints since they were loose.

My rear main leaks, but not badly. I would say a trans (internal and external) reseal is more important.

And just for the record, mine didn't leak a bit right at first. After that first 1k miles it was a different story.

Are you doing all the work yourself? If so, enjoy. Low mile cars come apart very easily, particularly the front end stuff.

Don't forget the driveshaft, if it's a double CV there are no grease zerks so that 40 year old grease is not flushable.

I would also advocate for a dual exhaust, you will notice a power difference. The factory system is pretty small for 472ci.
Clay Tynan
68 Sedan DeVille
Centennial, CO
CLC #27486

Gene Beaird

Quote from: blue68deville on October 31, 2012, 11:11:52 PM
<SNIP>

Don't forget the driveshaft, if it's a double CV there are no grease zerks so that 40 year old grease is not flushable.

I would also advocate for a dual exhaust, you will notice a power difference. The factory system is pretty small for 472ci.

Luckily, those joints _usually_ start squeaking when they need to be replaced.  Not always.  It can't hurt to at least physically-inspecting them when you're under the car for some other reason.

Clay - not meaning to hijack, but our 68 Calais needs an exhaust, end-to-end.  Did you just go to a muffler shop and have something custom built, or is there something off the shelf that'll work?  Not that our Calais needs any more power for what we do with it, but it can't hurt much.   ;D
Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

blue68deville

Gene,
I just went to a local place and had them run 2.5" all the way to the rear bumper. It's tucked in pretty well so you don't see the tips from the rear. I used a pair of Thrush turbos that have the same dimensions as the stock muffler. It sounds nice outside the car, and is quiet inside with the windows closed. Windows open you hear a nice note, but it's definitely not loud.
I mainly noticed the power difference on the highway, it feels stronger and takes less throttle to pull long grades.
Clay Tynan
68 Sedan DeVille
Centennial, CO
CLC #27486

Gene Beaird

Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

Scot Minesinger

Guys,

Thanks for all the advice.  This car will be driven 5k miles per year, sometimes cruising on the Washington, DC Beltway maintaining pace with modern traffic.  I can't really afford a wait and see thing, so probably will replace anything rubber and anything that is likely to fail.  A breakdown costs a grand in lost time and aggravation not to mention the repair.  Want it very reliable.

The advice on the heads, steering gear and other things has been very helpful.  It is great to receive the perspective on what some people would replace and others would not.  The only reason I considered replacing the steering gear is tighten up the feel and if this is adjustable that is great.

The steel fuel lines and brake lines often rust from the inside as those liquids draw in moisture.  Those lines will be replaced and are first on the list.  They are inexpensive, but laborious.  Will be doing most of the work myself over the winter.

Since, I will replace the timing chain, exhaust and the center link, the oil pan has to be dropped.  It would be nuts not to replace the rear seal, a fifteen minute job once the pan is off.  The car does not drop any fluid, but you know it will once it is started to be driven regularly unless I take care of these seals now.

I have dual exhausts on one 1970 Cadillac and single on my other.  To me power is identical.  Plus, the single is quieter, and seems more powerful on the single, more go with less noise (like the engine is not working as hard).  Maybe the dual system is faster and better mileage, but the difference is indistinguishable to me.  The duals are nice, because it lets people know that you have a real engine under the hood.  Probably will go with stock single exhaust system on this car.

If I were going to drive this car 500 miles a year to various car shows, then would not bother with half of this stuff.

I want it so if we decide to drive from VA to CA, we fill it full of gas and drive away.

Thanks again. 

Scot
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)

The only thing that will be accomplished by adjusting up the steering box is taking out any play at the steering wheel when going straight ahead.

Tighten it up any more, and you WILL be replacing the steering box, as you will be damaging it.   And making it very hard to drive.

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

bcroe

Quote from: Scot Minesinger on November 02, 2012, 02:28:53 PM

I have dual exhausts on one 1970 Cadillac and single on my other.  To me power is identical.  Plus, the single is quieter, and seems more powerful on the single, more go with less noise (like the engine is not working as hard).  Maybe the dual system is faster and better mileage, but the difference is indistinguishable to me.  The duals are nice, because it lets people know that you have a real engine under the hood.  Probably will go with stock single exhaust system on this car.     Scot       

When I converted a large engine to duals, I could not feel any difference.  But my stop watch
showed a clear 10% reduction in 0-60 time.  When you start off at low rpm, it really doesn't
make much difference.  But as the engine winds up, there is a lot more exhaust & back pressure. 
Acceleration decreases at higher rpm, but it doesn't decrease as much with duals.  Bruce Roe

The Tassie Devil(le)

One of the biggest improvements is to open up the stock Air Cleaner snorkel to let more air in.

When you look at the diameter of the inlet, and compare that against the Carburettor Throttle Plates, there is a vast difference.

Getting the Exhaust out of an engine doesn't do much unless you can allow the air to get in.

The Original air movement in these engines was designed for normal speeds, quietness, and not performance.

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

62droptop

i installed dual exhaust on my 62 and felt a difference and improved mpg
you can get nice quiet mufflers that flow well and will be pretty much quiet as stock
the late 50's cars had factory duals

agree on opening up the snorkel too, i know the idea on the stock was a venturi, but will is too small

enjy the car

you may find some of the leaks may stop once you start driving it
i have used lucas products in the trans and the leak stop in the engine to soften the oil seals with success many times