Rebuild 429 or 472/500...?

[Antoni Deighton]

I have a '67 Eldorado that I'm slowly bringing back to life (the P.O. put ~100 miles on it in 10 years).

I've gone through and done the standard stuff: new hoses, belts, fluids, plugs, points, etc.
I've also had the carb rebuilt, and when test driving it, the water pump failed. After towing the car to my mechanic to have the water pump replaced, he now tells me the bolts have corroded, and the timing chain cover and oil pump need replacement. Surely there's not much more that can go wrong, right?

Anyway, I'm wondering if I should replace all of the above while the engine is in the car, or pull the engine and rebuild it? (How much is that likely to cost me?)

OR

Should I replace it with a 472/500 from a '68 or later car? (How much is that likely to cost?!)

I have a 425 in my '78 Fleetwood and it is truly an amazing engine, that has needed very little work other than the basics, so I'm getting a bit frustrated by the 429.

I look forward to getting input, hearing comments and any suggestions,

Thanks!

Antoni

[Dave Shepherd]

Can't complain about a 45 year old engine, I just did w/pump and fan clutch on a 10 year old engine, the big blocks are not a bolt in, so addt'l money is going there plus unless you have a known big engine that doesn't need a rebuild then not much is gained here. A rebuild will vary depending on cylinder condition, crank condition, hardened valve seats? Could run 4-6k, plus removal and installation.

[Antoni Deighton]

After I did a bit more research I came to the same conclusion. For some reason I thought a 472/500 swap was pretty straightforward, but it seems like it would be quite a commitment!

By the time I'm done I will have replaced the timing chain, water pump, oil pump, radiator, voltage regulator and rebuilt the carb, plus all of the rubber, and main gaskets, I don't think there's any need to pull the engine or the heads (famous last words). She was idling nice and quiet before the water pump bearing blew, so I'm crossing my fingers and gritting my teeth hoping this will be all she needs to keep her a nice smooth driver while I attend to the body and electrical, etc...

Thanks again,

Antoni

[The Tassie Devil(le)]

G'day Antoni,

To assist you in your final decision, replacing the 429 with the 472/500 will also necessitate in possible replacement of the Exhaust, the front parts anyway, and the Radiator, and not sure if the Bellhousing pattern is the same, but if not, the necessary transmission components to mate everything up.

But, replacing the Timing Chain ant the Oil Pump in a lot of cases require dropping the Sump to get a good seal at the front, which means pulling the engine, as the Front Wheel Drive makes it a lot more difficult than an engine in a RWD chassis.

Bruce.

[Antoni Deighton]

Interesting! Thank you.

Well, the bellhousing of the 472/500 is different to the 429, so the transmission would have to be changed.

I'm already replacing the radiator, since when the water pump bearing blew, it pushed the fan forward which then gouged the radiator!

I didn't know about the need to pull the engine to replace the timing chain. I'll keep my fingers crossed that the timing chain is in good condition, but given all the other problems this car has thrown at me I won't bet against it!

I'll keep you posted,

Cheers,

A.

[TJ Hopland]

The 429 is not like a Buick where the bottom of the timing cover is flat where it butts into the oil pan?   Its like the rest where the pan really needs to drop to remove the cover?

["Cadillac Kid" Greg Surfas 15364]

Antoni,
If you are not going to do the work yourself, a conversion to a later motor (472/500) has the potential to be a real money pit. The easiest conversion would use a later (71-76) engine/transmission/final drive, but again the "details" as Bruce says will unfold as the project progresses.
You did not indicate the condition of the engine in the car now, other than the water pump and the need to remove the front timing cover to get out the broken bolts.
I think most of us with 429s have had to do the same thing, and it is a labor intensive job.  With an Eldo it would be a "toss up" as to whether trying to remove and replace the timing cover with the engine in the car would be easier than actually pulling the engine and doing it with the engine out so you could remove the pan and be sure of being leak free. 
Again, you did not mention the engine's condition, but if the engine has over 100K miles, and never had major service (read that o'haul) pulling the engine and freshening it up as indicated would ensure you of many many carefree miles.
Greg

[Antoni Deighton]

Greg,
Thanks for the post. Here's what I know. I bought the car a couple of months ago. It has about 73.5K miles on it (mostly likely original given the condition of the interior, pedals, etc.) The previous owner bought the car 8-10 years ago, but claims only to have driven it about ~100 miles in that time. Even if it was 500 or 1000, it hasn't done much recent mileage.
As far as the engine goes, after buying the car I replaced the fuel lines, most of the vacuum hoses, and belts. I also replaced the transmission and sump gaskets and all of the fluids (coolant, oil, transmission fluid, differential fluid) and the inline fuel filter and air filter. With the car running and driving (a little rough and with hesitation), I then overhauled the carb, and replaced the plugs and wires. I didn't replace the points since I have a Pertronix setup I am going to install. However, I then took the car onto the freeway at which point the water pump blew taking out the radiator with it!
My original question was prompted by the idea that the engine was causing an unusual amount of headaches. But on the other hand, with a new radiator and water pump, nearly everything will have been overhauled or replaced! The only things I will not have done are to pull the heads or check the valve train, but there has been no ticking or unusual noises when the engine is running.
If I had known what to expect I would have pulled the engine the day I rolled it into the garage, but I wasn't expecting so may surprises!
Would anyone with previous 429 experience let me know what the weak points of this engine are, and what precautionary maintenance I should perform to avoid problems in the future?

BTW: It goes without say that I've also gone through the brakes and wheel bearings, etc, but I just wanted to focus on the engine in this post.

Thanks again,

Antoni

["Cadillac Kid" Greg Surfas 15364]

Antoni,
Timing chain, Valve seals, valve springs and the front timing cover itself are major "wear points"  When you pull the timing cover, replace the timing chain and gears, and install new gears in the oil pump segemnt of the cover. If all else is in good shape, you should be carefree (hah) for miles.
Greg

[Antoni Deighton]

Greg,
I have to replace the timing chain cover (it's corroded and the bolts are rusted in). Do you have a good source for new timing gears and new oil pump gears? I was planning on using a good used quality unit, but will happily replace with new if I can find some.
Also, I was planning on replacing the valve cover gaskets. I guess I should be looking at replacing the valve seals and valve springs at the same time? (My concern has been that the engine was sitting for a long time with some springs compressed and some extended, so if you say the springs are weak, I should definitely consider replacing them!)
Thanks again!
A.