checking out a 429

[Dave Greenburg (#3830)]

This weekend Im going to be looking at a 66 Fleetwood.  I havent had much experience with the 429 engine.  Anyone have suggestions on any peculiarities or things to watch out for that might not be apparent to someone who is much more familiar with the 390?

Thanks,

Dave Greenburg
59 60S (getting lonely?)

[Hank Modica CLC 17604]

Hi Dave,

Aside from the normal checks one might do...

Look for signs of excess oil burning. Ideally follow the car
while someone else drives her and see if she smokes more
than normal. 429s are extremely tight and a low mileage
gently driven car may have a sticking ring problem.

Id also very closely examine the exhaust manifolds for leaks.
Be sure the engine is quite cold, start her and listen
and look closely.

All told, though, these are great engines.

                   Regards, Hank

[Dave Greenburg (#3830)]

Hank:

Thanks for the tips.  I know these engines dont take too well to rebuilds, so I want to be sure and find a healthy one.

Dave

[Chris McBride]

sir,

I dont profess to be an expert on these motors but only offer these anectodal observations based on my owning a 64 CDV with a 429 and my constant reading on the 63-63 cadillac community website and the 65-66 cadillac community website.  The Self-Starter magazine had a lengthy article several years ago which offers greeater technical insight and you may wish to obtain a copy of same.
 
Our 64 has 130k and still performs remarkably.  When I checked the compression at 125k, it still had between 150-170 pounds in each cylinder.  If asked, the old beast would still light the tires with no difficulty and "merge and pass with authority" on any interstate.

I agree with Mr. Modicas comments particularly about the exhaust leaks.  Based upon my observations of the messages on those pages, a common plight appears to leakage from the passenger side exhaust manifold (at least in 64) and/or the heat riser assembly.  Also, the choke tube assembly (which runs inside of the intake manifold) is apparently problematic (again, at least in 64).  

These are not necessarily difficult or expensive repairs but perhaps items of which you may wish to be aware.  

The following quotes are typical of many messages Ive seen posted:

"Does anyone know why the air heat tube for the thermastat choke inside the intake manifold always cracks?   Every manifold Ive seen is cracked in exactly the same location. I swear that because they crack hear it sounds like an exhaust leak because that tube runs the width if the intake and the noise emit thru the opened hole on the other side".  

I dont know how extensively you intend to inspect this engine (visually v. compression/lead down testing).  If the prospective car is an expensive investment, you may wish to consider using either of those tests since others have agreed with your observation on rebuilding.  

“Rebuilding one of these beasts can be quite a bit more expensive than more standard motors like say a Chevy.  One issue the 429s have is the fact that the cylinder walls are already so thin . . .  (Also there are many parts on this engine that are 4, 3, 2 or even 1 year only.  Interchangeability with other GM engines of the same year is almost non-existent. NOS parts are hard to find and often the used stuff is in worse shape than what you already have. On the bright side, there are sources to find these parts.  Many of these vendors are listed on our group site.  Ebay is a most valuable resource for NOS, used and reproduction stuff.”

I did, for example, have some minor difficulty finding the "kick down" switch for the carburetor when it stopped working.  The neighborhood auto parts store were not helpful but I found one after a short internet surf.

Finally, the 64s are sometimes prone to "heat sink" and/or "hot start" issues (problems which are also not that difficult to resolve), the water pumps are a bit of a pain to change (that metal tube construction is easiest if you use your third arm), and the location of PCV valve (under the intake manifold) presents some difficulties.

Most have reported great satisfaction with these engines, most particularly after updating them with electronic ignitions and chokes.

Ive always admired the Fleetwood, loved the luxurious trim found in em, and would love to add one to the fleet some day.

Good Luck.  Sorry for the long post.  Happy hunting.  

Chris McBride

[Ralph Messina CLC 4937]

Dave,
   I’m in the process of a complete restoration of my ’66 Brougham. They are fabulous cars, and IMHO the last of the old Cadillac luxury. The 429 engine occasionally gets a bad wrap only because the 472 that superseded it was a better engine. My engine is completely rebuilt and I had no problems locating new engine parts. The parts were something like $1800. Many engine accessories, alternator, voltage regulator, heater valve, carb kits, fuel pump, water pump etc are also available from Delco or NORS. The engine is no more difficult to rebuild than any other. My engine has about 100 miles on it so the rings aren’t completely set. I have 160 psi compression and I expect it to go up as the engine breaks in..  
  Exhaust manifolds are a problem on many high horse power engines from the 50’s and 60’s, and a good manifold can be expensive. The heat riser is available through NAPA, and I’ve even seen them on the Internet. The intake manifold choke tube is another issue. They corrode over time and rot away loading the choke up with exhaust carbon. The tube it self was used on many 60’s GM big blocks and can be found using the part number and looking for it under other GM brands. I’m not familiar with the cracked intake manifold experience you mentioned. The biggest problem is the aluminum timing chain cover that has an integral oil pump housing. The maximum oil pressure the pump is to produce is 35 psi. If the clearance between housing and pump gears is too large (low oil pressure) there is no way correct it other than replacing the housing. The housing is also prone to cracking around the bolts that mount to the block. You’ll have an easier time finding an honest politician.
If this is a high priced car, you may want to bring a knowledgeable mechanic with or find a CLC “expert “local to the car.
The most expensive thing about these cars is the trim, fit and finish. Paint, chrome and upholstery are far more expensive than the mechanical items.
Hope this is some help,
Ralph

[Dave Greenburg (#3830)]

Im going to file aways all this 429 info. for the next one that comes along.  Went and looked at the car today, and although I didnt get to the point of running and checks on the engine, because the rest of the car was junk.  Engine felt and sounded good, but the rest of the car was a project, and way overpriced.

Dave
59 60S