Cadillac 500 Build for my 1984 Regal (LOTS OF PIX)

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online170

G-Body Guru
Oct 28, 2010
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Problem #2 i learned much later was a vacuum issue. But at the time seemed like a carburetor issue. My new demon 850 from Barry Grant, brand new out of the box, would not idle! I got to break the engine in OK on the stand with it, but it would not idle. It just dumped fuel out of the boosters to the point where it would flood itself. Its not my first rodeo when it comes to carbs, so this was very confusing to me.


I tried to stick the old edelbrock 750 on there, and it wasnt doing exactly the same thing, but it was not cooperative with me just the same. Sometimes it would run, sometimes it wouldnt. I was getting very annoyed with not even being able to drive at this point.



So after putting it away in storage for a while, i purchased a Holley 750 dbl pumper, and another Demon 850. I rebuilt all 3 carbs, not the edelbrock. In my brand new demon 850, i found this;



So it was likely a very worthwhile exercise. After rebuilding all three carbs, i tested them on my malibu, which is driven regularly and has a known working SBC 350. All three carbs drove fine with the car. Idle, under load, WOT, you name it, they were good. Put the 850 (new one) back on the caddy, and sh*t, it still didnt work. Tried the Holley 750, same thing. So i stopped at this point, since the issue was not with the carbs. At this stage, the car went into storage (2015) and it would stay there till mid summer 2016.
 

online170

G-Body Guru
Oct 28, 2010
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This summer, i was disheartened with it enough that i was considering buying another car. But got some help from freinds and we went at it methodically. I had some time to consider the issues logically and that was very necessary.

The carb issues were caused by a vacuum leak. I wasnt sure if it was at the carb pad, or the intake to head surface, so i removed the intake, cleaned everything and checked for straightness. Got rid of the gaskets, and used RightStuff on the head surface. I used another permatex product on the carb pad, and sealed the Spreadbore-to-Squarebore adapter to it. The carb pad was not straight when checked with a ruler. New gaskets all around.

After this, some tuneup stuff had to be done since the carb had been flooded so badly, and the oil was fuel washed. I needed new plug wires as well. Sorted all that out but i still couldnt get it to start. At this point i was ready to drive it off a cliff.

 

online170

G-Body Guru
Oct 28, 2010
726
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Talked to some people, and i narrowed the issue down to 2 problems.

1) Timing
2) Compression. <<<<----- Wait What??!? Isnt it a new engine???? Yep. @#$%@^ !!!!!!!!


So firstly, the stock HEI distributor wasnt cutting it. The cam wanted some wierd timing so i locked it out and installed my programmable 6AL2 MSD box so i could have better control of the timing.

Secondly, i ran a compression test, and 4 of the cylinders were below 100psi. No wonder it wouldnt light off for me. So with flooring it, and flooding it, and trying all kinds of tricks, i somehow got it to fire. It sounded like it was running on 5 cylinders, and i ran a vacuum hose into an ATF bottle at 3000rpm and let it suck it up.

From sitting in a humid environment in storage for so long, i guess the valves that werent fully closed were now not sealing, and i had no compression. After letting it sit for 72hours after the ATF treatment, i did a leakdown test, and all cylinders showed a healthy 15%, and they were all the same.

I reset the timing by taking out the distributor and stabbing it in correctly, cranked it over and it lit right off! Finally!

Let it warm up, set the idle mixtures a bit, and took it for a quick cruise, only to find out i have many other issues, like old brake fluid, and slipping 2nd gear in my TH400.


 

online170

G-Body Guru
Oct 28, 2010
726
319
63
No matter. Whats the first logical thing to do after getting the car going after so long??

Thats right, a burnout. And now its bedtime. More updates soon.
 
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Gozer442

Master Mechanic
Aug 9, 2016
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Ontario, Canada
What a fantastic build! That 500 Cadillac has enough torque to pull Jupiter out of orbit! Holy hell! Great to see someone taking a chance on the oddball motors, and showing the world what Canadian ingenuity can produce.
 

axisg

Comic Book Super Hero
Jul 17, 2007
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Glad to see you back at it !! You ever hear of Khan anymore ? IIRC you were both from Ottawa way.
 

online170

G-Body Guru
Oct 28, 2010
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He's my brother lol. Still around, car's still around too. Just busy as hell.

 
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MrSony

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Nov 15, 2014
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Des Moines, Iowa
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