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cad 500 failures

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fatboy0054

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I was wondering what lead to yall failures ! Was it the bottom where yall running stock stuff or hard stuff ! Just tring to get some info to gather ! I know yall both just went with boxes ! Going to have more rpms than yall! I think just trying to keep thing s togather or break more stuff!Which ever comes first ! Thank you for your input ! I read was yall posted but wanting a little more ! rods pistons cam
 
hey fatboy0054, i had a stock bottom end my failure was just plain stupidity on my part. i put a a transdapt duel oil filter relocator on my caddy it had a picture diagram and readable instuctions. i choose the picture it showed the lines backwards but the instructions read correctly.didn't read i just looked.then i did not check my lines by using common sense by double checking so 20 minutes after my riding, went through some black crap with a boat load of people hit a real nasty spot had to work it too get loose.then a noticable drop in oil pressure then a knock back to the ramp.then i pull up on the dike to load my boat and just a split second before releaseing the throttle k-boom.
 
What I'm about to post might be useless to you guys who run Caddys.
If it helps, Cool. I have no idea if this is valuable, but here it is.

I was talkin' to a guy a few days ago who had been a mechanic for the biggest Cadillac dealership in NE Florida for 32 yrs. I told him that I was an airboater and that a lot of folks were still running the Cad motors on airboats, but that it seemed to me that they were having reliability problems with them ...... did he have any ideas? Here's what he told me .....

He said that the heads of a Caddy were their weakness, and that just a few degrees above normal for any period of time would cause problems. He said that in a car the water temperature reading was taken directly from the heads (so they should already have a port for a temp probe) and not from anywhere else like a probe in the intake manifold coolant. He suggested that y'all take your temp reading from one of the heads directly .... that the heads might be running hotter than you realize.

As I said, this might be useless to you. I know nothing about Cad motors, but if it helps ....... 8) .

feather
 
hey big feather,thanks for asking questions to other knowledgeable people to help out even if you dont run a caddy,its nice to know this southern airboat family watches out for each other.the big caddy's do not have coolant passages in there intakes.and the stock temp sender spot is between the thermostat housing and the distibutor it is a direct water passage link between the two heads.
 
Was just thinkin bout this. Ya know, I just don't remember many failures of any kind in the DD days. Now that redrives are popular there seem to be quite a few. Just wondering if there is cause & effect? May be nothing to it, just seems that way.

Scotty
 
OK, Bondsman ... thanks. I really didn't know. Just thought I'd pass it along.

You're right, Bear. Spinnin' a motor that was never meant to be spun sets up a whole new set of problems. My gut feeling, just from listening to what's been posted, is that a lot of the problems are timing related.

BF
 
THANKS YALL ! JUST WANT TO FIX THE THINGS BEFORE MY WALLET GETS FIX ! POTTER AND CHRIS SAYS I AM GOOD TO 6000 TOURQUE SAYS THERE PRETTY WELL BUT THE HP CLIMBS ABOVE 4000 MY TARGET RANGE ABOUT 5200 SO I DID WALLET MY SELF TO THIS POINT ! DONT WANT TO WALLET MY SELF FOR A WHILE ! THANKS GUYS ! I NEED TO PUSH MY :D LEAD SLED ! THE BOX SORT OF MAKES IT EASY WHITE BUT RPMS ARE NOT CADS STRONG POINT ! JUST WELCOME TO THE PERFORMANCE WORLD OR WALLET :D
 
Much like Ken's post....I admit to not bein a Caddy expert, and my advice should be taken as such.

Bein a motor guy, and the things I've seen of the Caddy....The bottom-end looks to be solid, and capable of some decent HP/TQ (Well beyond it's original design). The heads look fairly decent for their era, and with the right masaging capable of some good numbers as well. But just like any other luxury car engine, it's designed for smoothness and bottom-end TQ, and the oiling, as well as cooling systems are maximized for low RPM. The minute you put them in higher RPM duty, the system has to be re-thought.

If you run DD, the engine should be pretty spot on for the avg guy, but will see more load than it was intended being in an airboat, and will create more heat/stress.

If you put a gearbox on it, and spin the RPM up....Put some race engine thought into the oiling, using some simple fixes, and do the same with the cooling, and I think the engine would make a serious player. I.E. All the engine "should" need is consideration to the increased velocity/volume of the oiling and cooling system, and I see a killer engine on the cheap. JMO

I'll be happy to share some 411 on what I mean about cooling system pressure drop/flow manipulation, and oiling system design parameters with consideration to flow/cooling/shear, if you find you're in need. But be warned...I don't know Cadillacs...Just metal parts that perform a function. ;)
 
FELBER THANK YOU SIR I HAVE DONE MY HOMEWORK I THINK ! OILING HAS GOOD FALL BACK TO THE PAN ! WATER, MORE THAN ENOUGHT VOLUME !HEADS FLOW ABOUT 330 GOT SOME CHEVY 2.19 INTAKE S AND KEPT STOCK SIZE EXSAUST BLENDED THE PORTS FAIRLY WELL ! CAD BLOCK ARE NOT THE EASY TO CUT !ZERO DECK IT , SCAT RODS ,COMP CAM , BALANCE, KB STEP DOMES ,1,7 ROLLER ROCKERS THE CAD GUYS SAY GOOD TO GO ! SO WHO KNOWS ! I JUST WANTED THE POUNDS THREW MID RANGE JUST TRYING TO GET THE BEST BANG FOR THE WALLET! I BUILT IT SO I CAN FORCE IT IF I HAVE TOO ! BLOW THREW TURBO , IT S IN MY MIND ! JUST CANT GET MY WALLET TO AGREE ! THANKS :shock:THANK TO YOU AND DAVE THANKS I DO LISTEN :shock:
 
i was honest big feather that it is great that you asked for other input and was supplying info to us. I did not mean to soud sarcastic the way i posted my last message.that was not my intention.
 
Felber, the Buick 455 had some of the same issues. Especially with the high RPM Oiling. There was a book published about Hot Rodding the Buck that had a decent rework of the oil system. If such thing is still in publication it would likely apply to the Caddy as well, or at least the principles. Im not a Caddy man, just if the book is still out there it might help Caddy owners. All of the Buick oil reworks were simple and easy and well within the reach of any back yard mechanic.

Scotty
 
I never took it that way, Bondsman. No problem here, buddy.
I love 'em all ..... DD, belt drive, A/C, gearbox motors, all of them. I've never seen an airboat that I didn't like. That's why I'm so passionate about doing everything in my power to help us keep them.

I want my granddaughter to be able to run one too.

feather
 
All of my failures have been with head gaskets and in the end were timing related issues. My timing was off by about 15 degrees which resulted in four head gasket failures and one wrecked piston. I finally got my timing right this last go around and I have found all the power I should have had from the beginning. The engine sounds crisp and has a lot more cackle at idle than I have had in the past. With that said...I built my engine to run 5500 rpm regularly but after putting it all together I found out the best performance is with the blades pitched so the engine turns around 4200 rpms WOT. I'm running a 15 X 7.5 Alumitech and it typically moves on the ground around 2700 - 2800 rpms. I have not had any problems with the bottom end or top end but I went to Stage II rocker setup from Cad Co while still direct drive and the ported & polished 2.19/1.92 heads as well (Pro Street heads I believe as advertised by Cad Co.) I'm running about 10.5:1 compression with Ross forged pistons and a Comp Cam 270H. I went with a 2:1 reduction and now wish I had went 2.38:1 so I could put in more pitch with the same rpms I'm running now. Waterthunder has posted numerous messages regarding reduction ratios with more pitch and less rpms and it has certainly worked for me. The cads have massive torque at lower rpms and fit that setup well even after the mods. Ruagatr (aka Maddog @ cowboyseven) has a radical caddy on his boat and AFAIK has been pretty reliable.
 
Resisted posting the first time through. My thoughts are as follows. No oiling problems at all with the Big Cadillac. Never heard of an oil failure. The only time its an issue is when someone drops a rocker and the lifter pops out. Oil pressure goes to zero. Thats why the serious guys bush their lifter bores. The real problem areas are the heads---they dont flow well stock, but particularly the weak valvetrain. It wont live over about 3800 for a long period of time, and if you dont change the valvesprings from the original spec, it wont live for 5 hours without floating the valves. The timing is always a problem area becasue guys unknowingly mix and match the dampners and the pulleys. And so the "mark" really isnt the mark. So it looks good, but it isnt. And many folks mistake where the number one piston is...and time the engine to number 2....which has poor results. This is my 32nd year running Cadillacs, direct drive for years of course, then gear reduced for the last 12. Mine is pretty much an all out effort, except i keep the compression at 10.88-1 with my aluminum heads so I can run pump gas. My new propeller is reported on in another thread. Best, Charles Morehead
 
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