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Building a new 500 caddy for a 14 ft Viking Need help with top end valve train

C

Charles

Member
Building a caddy 500
For a Viking 14 ft Hull, need help on valve train, stock or upgrade,not trying to race , just a turn and go motor
 
The correct answer is completely contingent on the intended use and the subsequent RPMs.

The factory rocker system/design is adequate for Direct Drive RPMs provided everything is in good shape.
Having an engine though, that's nearly half a century old with that little valve train wear is not likely, but can happen.
If you are refreshing one, you should minimally replace the Rocker Arms (and quite possibly the Rocker T s).

If your going to use a gearbox, then a shaft rocker system would most likely be considered mandatory.
This is a big can of worms that need not be opened here and now if you're going to run DD.
If this IS your plan, knowing the gear ratio and intended prop will imply an RPM range which will mandate your available options.
 
Thanks Deno, bought the boat put it in the water went 1/2 mile up river and something came lose ? think rocker or something.i have a fresh block and heads and going to biuld it stock maybe 30 over. I am running direct drive . Do not intend turning it over 3k to 3.5 k
 
Deano said:
The correct answer is completely contingent on the intended use and the subsequent RPMs.

The factory rocker system/design is adequate for Direct Drive RPMs provided everything is in good shape.
Having an engine though, that's nearly half a century old with that little valve train wear is not likely, but can happen.
If you are refreshing one, you should minimally replace the Rocker Arms (and quite possibly the Rocker T s).
Click to expand...

More often than not what I see with broken rocker arms and bent push rods on a Direct Drive engine was that some "machine shop genius" decided to install "high performance" valve springs. They slap in a Chevy spring "because they know what works" with 50 or more pounds of seat pressure and it is a guaranteed failure point. The factory set up would be just fine if left alone and kept under 3,000 rpm.
Anything beyond that and it is time to take out your wallet and get a shaft system from Mr. Branch.
 
Planning on std springs with roller rockers , 30 over on pistons, line bore new crank, I had a combi hull with a caddy turned around 3300 at top end never had a problem
 
When you say roller rockers I just want to clarify that what you need is a "shaft system" where there is one long shaft and they all ride on that assembly. I have seen good ones as cheap as $550 but they were non-adjustable and conventional. Currently a fair guess would be a adjustable roller set up from Branch would be $900 give or take. There have been some big increases in prices as of late due to shortages of materials. Recently a fellow I know purchased a T&D adjustable roller shaft and it was $1,400 but T&D is the best you can get. Their (T&D) geometry is perfect most of the other companies adapt a 428 Ford Cobra rocker to the shaft but T&D makes their own stuff.

I would call and check what Mr. Branch recommends for you and what is actually available to be purchased. That non-adjustable entry level shaft may be ideal for you and a savings.

What prop were you spinning on your old boat?
 
Charles I chewed on this for a few days but feel it is worth saying.

With Cadillac your gonna find two types of users. Those who have one that rarely needs anything but an oil change and those who have gone from problem to problem and then there is OneEye who went LS.....lol.

In an airboat specific build there is no one in the U.S. with more experience than Mr. Branch, so when your getting advice be sure your source is proven. The parts companies often call him for Tech assistance.

There are a few places in the country with big shops and web pages selling products. One outfit is more focused on extreme all out power so they push the platform to the extreme limits and beyond. That doesn't exactly translate to reliability or "usable power" in an airboat. The other is more a retail site with very limited tech knowledge but a lot of talk. They do have a host of nice parts to sell.

My point here is the Cadillac is not a Chevy. It has little tiny nuances that if ignored or done improperly lead to a fatal condition. When done right and used within the build parameters the platform will give a decade of service.

There are folks on here who may not care to comment who have learned the hard way by having engines build by shops that basically were ignorant to the Cadillac 472/500 platform. Engines that didn't last but a few hours or even failed at start up because the "genius" at the machine shop put bolts that were to long into the timing set and they catch the blocks casting. I have already told you about shops setting up heads with big heavy race springs that lead to cam and rocker fails. I am lucky to get to see some of this first hand and let others know about the issue.

There are some good Cadillac folks out there but you have to know who and where to find them.
 
I have a fresh block, 30 over pistons , using shaft mounted rocker system on std heads new valves and spring on a dd. Will put on dyno to bread in cam which is a torque cam
 
Sure enough loved my DD caddy. Got run very hard but was always reliable. Still like to hear one coming down the river, they have there own sound.

And yep today I am an gearbox and LS guy. I like my 3 miles to the gallon. Don't think I would see that with a BBC or a Caddy built for a gearbox but then those motor are usually on bigger boats. When it comes to airboat motors I like them all and each has it's place.
Good luck Charles
Please post the dyno numbers very interested.
 
Deano said:
The correct answer is completely contingent on the intended use and the subsequent RPMs.

The factory rocker system/design is adequate for Direct Drive RPMs provided everything is in good shape.
Having an engine though, that's nearly half a century old with that little valve train wear is not likely, but can happen.
If you are refreshing one, you should minimally replace the Rocker Arms (and quite possibly the Rocker T s).

If your going to use a gearbox, then a shaft rocker system would most likely be considered mandatory.
This is a big can of worms that need not be opened here and now if you're going to run DD.
If this IS your plan, knowing the gear ratio and intended prop will imply an RPM range which will mandate your available options.
Click to expand...

Good info Deano, I don't get on here much anymore but the post of a new caddy 500 peaked my interest? The op really didn't say old iron/nickel or something really "new"! I guess the viking hull is a dead give away to vintage of the build?
No issues there either with a good restored viking from ground up!
Of course it's similar to the past thousand post of please help with no response?
 
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