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1964-1967 429 Service Issues

Started by Bryan J Moran, December 02, 2022, 09:16:19 AM

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Bryan J Moran

Antecdotally only - I have heard the 429 from 1964 to 1967 had reliability and quality issues. I am considering the purchase of a 1966 CdV. 

My questions are - is this true that this era's 429 has reliability and quality issues from your experience and if true - are the issues something that can be repaired or removed through process or improved parts? 
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Dave Shepherd

When I worked for Cadillac back then, we had 2 common problems,  oil pump loosing prime when doing an oil change and waiting too long to install a new filter, which should also be filled with oil during the process. Also in the 67 model year the front engine "y" pipe was double walled and after a few years, the inner wall of the pipe collapsed causing a severe loss of power, this stumped some of the dealer's  techs until it became common knowledge.

Bryan J Moran

Thank you Dave - nothing like 1st hand experience!  As an auto mechanic for 8 years I always filled the new oil filter with oil, maybe 75-80% full.  As most of us know, also rubbed a thin line of oil on the gasket and never over tightened, but that is getting off topic. 
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Dave Shepherd

To add the early Comfort Control hvac in 64 was troublesome.  I wrote some tech info on these systems back then as a field troubleshooter as they called it.

badpoints

I think that the 429 was a good engine at the time. The problem is that it was a short run and was replaced by a more modern design 472. Many parts for the 429 are hard to get. Even the mounting position on the 429 is so different that replacing the engine with a modern engine is difficult.

Bryan J Moran

Quote from: badpoints on December 02, 2022, 12:35:27 PMEven the mounting position on the 429 is so different that replacing the engine with a modern engine is difficult.

Replacing the engine with a 472 was actually a consideration. (I have not purchased any car yet). 
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Chuck Swanson

#6
Been following posts on 429s closely since 2010 and besides what Dave said, have not heard that at all.  Timing chain covers can corrode, and exhaust manifold can crack over time.  Have many 429 cars and no major issues.   Manage the 65-66 FB page along with others an no major complaints vs the NorthStar pages/ forums for example as a comparison.   
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James Landi

Adding my two cents having owned several 429's, I found the engines to be rock solid; however, the nickel and dime repair humps that occurred were almost laughably  predictable--- alternator, water pump, pipes and mufflers, jambed heat riser--all occurring after 60k and 80k  I never had issues with the climate control and its cooling/ dehumidifying system, but vacuum hoses leaking would create annoying issues including arcane problems with the repreposed tin can vacuum reservior that would develop leaks from constant flexing, so that the engine would run rough at idle, and vacuum door locks could lock you in the car and the climate control would fail to operate because of insufficient vacuum on that firewall mounted vacuum actuated switch (one could squeeze the bottom, and bingo, the blower would commence to blow, thus indicating a vaccum fault). I think those engines were well engineered, and with proper care would last and last.

64\/54Cadillacking

The 429 is basically a bored and stroked out 390 block. The engines are extremely similar and use a lot of the same parts.

My 64 Cad doesn't have any issues with the engine, although the 429 block in my 64 is actually from a 67, but the top end stuff is still from a 64 (intake, heads, carb,).

Sure theres the oil pump issues, nylon timing gears with these engines, but honestly they really don't have a lot faults or major problems. Cadillac built very stout motors back then and I am sure if full synthetic oil was a common place at that time, most pre-mature engine wear and problems wouldn't really exist since high quality of materials and machining were built into Cadillac engines.

They can have low oil pressure problems, which can be temporarily mitigated using higher viscosity oil such as a 5W-40 or 20W-50 motor oil.

Although the 472 was a great engine and the most bulletproof of all Cadillac engines, the one thing that struck me as sort of "cheapening out" of the engine, was in the valve train. All the previous Cadillac engines including the 429 pre 67's, all used a shaft mounted valve train which is much more durable, performance oriented and is less prone to having valve lash problems and valve train wear vs the stud mounted valve train in the 472.

Stud mounted valve trains were always usually used in lower end vehicles or cheaper small block engines for the most part.

Also Cadillac switch from a rear sump oil pan starting in 65, to a front sump which could possibly lead to oil starvation while going up steep hills or on hard acceleration. Just look at Mopar engines, they never truly made it hot rod racing due to the relatively small front sump oil pan and small oil pickup on all there V8's which basically starved the engine of oil on hard runs at the track that scorched the bearings and basically destroyed the motors after one hard pass.

Not saying you're going to race your Caddy, but it's interesting to know how these small changes over time were due to some cost cutting measures IMO that could affect long term reliability of these engines if driven hard. But I am pretty sure the majority of us here don't drive our Cads hard, so you can most likely ignore those 2 changes Cadillac made (front sumo oil pan/stud mounted valve train).

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Jason Edge

#9
I have owned 5 driver 1964's with the 429, including my current 1964 Coupe de Ville which I have now had 26 years and think these were very dependable engines. I have also parted 58 1963/64 Cadillacs, mostly 1964's with the 429, and one additional flaw I see is the cracked intake manifolds especially with the higher mileage engines or those where the heat riser was stuck closed to some degree forcing the fire hot exhaust gases across the intake manifold from left side to right side. In addition to making the engine run like crap, they eventually crack the internal choke tube and the exhaust manifold cavity itself. Unless you crank and drive your car in super cold conditions I would recommend removing the butter fly in the heat riser (I did) or adding a spacer. As others have posted the RH exhaust manifolds were more prone to crack (again, might be affected by closed heat risers forcing that exhaust to carry almost double the load), but I also see this more with aftermarket, fabricated exhaust setups behind it where there was constant pressure pulling on the manifold.

I think overall the 429 is a great engine, just as the one year only 1963 390 (which was the basically the same engine without the increased bore and stroke in 1964), and the only things that really degrade the engine are external influences such as closed exhaust systems, busted vacuum lines, busted distributor vacuum advance, and worn ignition and fuel supply components.
The one inherent flaw that comes to mind with the core engine block assembly itself would be the nylon coated teeth on the cam gear. After 100K miles This nylon coating started to come apart and gum up inside the engine. For that reason I always recommend changing the timing gears and chain out with an all steel setup.

Back to my 1964 CDV with 429, I finally broke down and rebuilt it in 2012 with 158K miles on the engine... not because of any real mechanical issue, but because it was simply starting to leak more oil around the gaskets and seals than I wanted to clean up off the floor, and of course I wanted to freshen up with new internals. From memory I was still getting around 130 to 140 psi per cylinder. Oil pressure was also good... so there's one testament to the 429.
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