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500 caddy timing

S

snookstalker

Well-known member
hey yall, I just picked up an apache 13x7'3" with a 500 caddy. Just put a 72 x38 wide blade wood prop on it. Looking for any tips and advice. Anybody know the propper timing? I have not put it in the water yet, but the motor seems to run very well-fires right up, no smoke. It currently has foot steering and a single rudder. I imagine I will probably be changing to dual rudders-the foot steering? well I'l just have to see how I like that. Never driven one with it.
thanks, Dan
 
Snookstalker, Caddies are notorious for breaking timing gears and chains - but, if it ain't broke.....

Plenty here will offer sound help. Waterthunder is the MAN on car motors.

Better dump that single rudder quick. I've seen two airboat wrecks - both were with single rudder airboats and they happened on the same trailride.

I'd think hard and long about adding a stick steering system to the foot steering. Foots is for walking and scratching - not for driving except at slow speed while froggin'

Good Luck with the new toy. Bet that was the boat on Airboattrader.com
 
I am glad for this question and can't wait for Waterthunder to provide his words of wisdom on this one. I am changing my timing chain to a heavy duty type with news gears. I hope that timing is part of my problem now. I am only turning 2100 rpms on the trailer at 2/3 throttle. When I go full throttle I have no futher responce. Will the rpms be different on the trailer than running on the water? My prop is now set at the 1 mark. I have read that timing on a small block Chevy is 30 to 32 deg. total timing. I was going to start there.

Thanks
KJC
 
I would defiantly install a cam button to control your cam walk. They cost under $12 and will help prevent cam walk. When your cam walks in and out from acceleration and declaration it prematurely stretches your timing chain especially in a standard transmission car or airboat. If you are happy with your performance now I would check your total timing and use that as a reference. I haven’t messed with that many Caddies and I don’t want to parrot what I have heard with out testing it first myself. I would set your total timing the same as you have it now but since your direct drive I would consider locking your timing down and remove all advance. This really improves snap and throttle response along with increasing torque and horsepower at lower RPM’s. You will see a small differance in max RPM from the trailer to the water.
 
I HAVE A CADY ALSO PROP 72X42 ALL I GET OUT IS 2300 OUT OF ON TRAILER OR IN WATER AND MY BOAT 8'3" WIDE AND 13' LONG NOT COUNTING RACK I HAVE FOOT STEERING ALSO LOVE IT !!!! BOAT IN CLASSIFIED ADD UNDER 5000 TO 9000 YELLOW AND BLACK HIGH SEATS ON IT:lol: :lol:
 
I’m thinking of building a cheap airboat for my wife. A direct drive car motor. I guess I’m getting bored again and I’m only down to 72 projects. I believe I want to go with a 455 Olds motor and a Warp Drive. I have been kicking around the idea of a Caddy but the 455 OLDS has some very good perks to it.
 
We run a 16 foot x 8 foot wide fiberglass flat bottom airboat with a direct drive 455 Olds. The boat is heavy with poly on the bottom and a ways up the sides. We run a 74 inch Sensenich Q blade prop set to the #2 mark. It turns 2750 on the trailer and just over 2800 in the water. We don't run many hills in Nebraska but if I am alone in the boat (200#) I can drive onto a sandbar, drown a few worms then drive back off with no trouble. The 455 works great for us.
 
sorry, I forgot to put this into my last reply. I also have an aluminum boat with a 350 Chevy direct drive that I am converting to a 500 Cadillac. How closw will the engine stand be? Should I start over or can the stand I have be modified?
 
i found a very old chilton manual
1972-73 472 caddy 8 degrees btdc
1975-76 500 6 degrees btdc
1977-78 425 18 degrees btdc @1400 rpm

this manual was printed in 1979 and only covers 72-79

if this is incorrect, i apologize, im just reading and relaying
thanks
 
Please note those timing figures are for initial timing at idle with the vacuum advance disconnected. I would suggest setting your timing this way. Then read your total timing at max RPM what ever total timing you have. I would lock down your distributor or atleast install a curve kit and use that as a starting point. The manuals specs are close to a small block Chevy. So you will probably end up finding out somewhere between 30 to 34 degrees of total timing will be the ticket.
 
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