Richard Holdener is gonna boost a Cadillac 500

cadillac512

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My best guess is the engine rattled (detonation) due to too much timing for the temp of the non-cooled boost air, the pump gas , and early peak torque rpm. The pressure spike from detonation is extremely destructive. I remember when Dave Brode built his twin small turbo blow through Cad and gave it just a bit too much throttle on the test drive...no more than 10 psi but rattled for a half sec before he let off and both gaskets were gone. I don't consider 28 degrees of timing a safe starting point for a Cad with 10 psi on pump gas.

Terry
 

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I agree that he should have started lower on the timing. On one of the early videos in the series it showed them using 39 degrees of timing on one of their dyno runs. At least that's what the showed on the screen.
 

48Austin

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But is the blower version going to be Roots or fake turbo? BIG engine needs BIG blower, BIG heads, BIG cam, and BIG pipes! Kinda like these. my slut.jpg Oh! These are my private custom built pipes. Nobody gets to polish them but me.
 

Darius

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"WHY did it break"

Actually, early in his verbal diagnosis Holdener provides evidence of what may have been a major contributor to the failure.

He speaks about erratic ignition timing, about it not being stable. He conjectures that it might be a case of the elastomer in the dampener being degraded and allowing movement of the pulley's timing mark. Indeed that is a possibility as I've had that happen on a different engine build. But let's focus on timing itself. His reference to the engine liking 39* of timing before taking it down to 28*, and yet timing still being erratic even at that low point, opens the door to timing chain stretch and/or mis-matched timing tabs and pulleys. Remember this is the David Freiburger engine, the one with parts robbed from it and who knows what part added to it.

In any case, screwed ignition timing, combined with excessive back pressure from a too small turbo, on top of 9.9 pounds of boost without the benefit of good gas or intercooling, is a recipe for blown head gaskets.

Just one man's opinion. Your mileage may vary.

bro. "not unhappy with the power output, but with the methodology of the test," d
 

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I could definitely see the timing thing being a big contributing factor. I play hell trying to get my motor timed right for some reason (even with a pretty low mileage timing chain and an HEI distributor) which causes a lot of either hot start problems or starter kickback if I run too much (she likes LOTS of timing but only after running) which I should be able to fix with the new ignition system.
 

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I installed a 5 pin HEI Module this summer which does 10 degrees of retard. Some do 5. I can run initial timing 14-16 degrees now no issue. Highly recommended.
I could definitely see the timing thing being a big contributing factor. I play hell trying to get my motor timed right for some reason (even with a pretty low mileage timing chain and an HEI distributor) which causes a lot of either hot start problems or starter kickback if I run too much (she likes LOTS of timing but only after running) which I should be able to fix with the new ignition system.
 

cadillac512

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Quote:. "He conjectures that it might be a case of the elastomer in the dampener being degraded and allowing movement of the pulley's timing mark.:

What Cadillac 500 has an elastomer damper? They are all solid hub/sheet metal pulley or solid cast iron hub/pulley two piece. The only "damped" one I know of was a '70 (maybe '68-9 as well) and it was just a small damper sandwiched between the hub and pulley...timing marks were not affected even if it came completely apart.
The lesson here the way I see it is BE CAREFUL with the tune. Sneak up on it so you don't break stuff. Way safer to run too little advance and too much fuel to start with,then advance the timing and lean it down a step at a time.
Hopefully it just a set of gaskets (and good head bolts damnit!) and it will be ok. I'd like to see it done properly and make big power.

Terry
 

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Hello Bro. Terry,

I have a "yes and no" proposition for your consideration concerning a Cadillac harmonic balancer.

As you suggest they did make them, but they might have been stock on engines beyond the 1969-70 model years.
While rare they do/did exist. In fact, I believe that I have two of them in my garage ... not that both could be found, mind you. However, one may be attached to the crankshaft of the Studebaker engine.

https://harmonicdampers.com/index.php?main_page=product_info&products_id=27


You are correct that there would be no effect on timing in that the pulley, which has the actual timing mark, is bolted directly to the crank hub at to the center of the damper. So any deterioration of the rubber in the damper would have no effect as only the outer ring would slip.

As your earlier post suggest, the key is in the tune which includes working your way up when adding timing, or introducing power adders. Better safe than sorry.

bro. "hoping for the bright side," d
 

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5one9

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I have 4 of them. Two are ‘70 model. The other two were later. Maybe they were transplanted. I run one with a stamped pulley on my Malibu engine.
 

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So what would a "safe timing" setting be? 20-22? Lower, higher? I thought as boost goes up the timing goes down? Maybe the ignition he used had it built in. My msd digital 6 2 has it all.
 

5one9

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I don’t believe any stock-ish head gasket will hold 15psi with this head bolt pattern. And since they don’t make MLS gaskets that only leaves one reasonable choice to go along with head studs. Copper.
 

cadillac512

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Thanks for the info on the dampers, Bro D. Didn't realize they had 'em past '70 but they do look same as earlier and don't affect the marks so THAT excuse for blowing it up is BS,LOL!
I would have set timing at 20 to start, then do some pulls and look at plugs to see what's going on. Location of color change on the side electrode will tell timing and "pepper" on the porcelain will tell early signs of detonation.
I like the grade 9 bolts like 5one9 has pictured in one of his posts. Studs would be great IF they were waisted down to provide proper stretch at the proper torque settings. As supplied, I don't like the way they torque up "solid" with almost no stretch at all. Feels great BUT if the gasket relaxes at all there's no "stretch cushion" to allow clamping force to remain high. IMO if one wants to run studs they had better be ready to retorque the bolts a few times 'til they are sure nothing is relaxing any more. MLS gaskets would be ideal.

Terry
 

Darius

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I'm with Bro. Terry about starting low on the timing and working your way up. Again, I'd rather be safe than have Big Balls - which equates to sore, Sorry, balls!

Lots depends on the octane of the fuel you use. From the beginning of my build I knew the fuel would NOT be pump gas. At first the plan was for propane, kept liquid until leaving some specialty injectors. Propane has an research octane rating 110, and a pump rating of 104. https://www.google.com/search?q=oct...j0i22i30l6.7943j0j15&sourceid=chrome&ie=UTF-8
I had run liquid propane through a converted mechanical fuel injection throttle body that was laying around. It was neat to make a hard pull with heavy boost, then find frost on the intake - with no signs of detonation.

Anyway, plans changed to E85 with it octane rating dependant on where you live. Here it is only 70% ethanol. That lower blend gives approximately 102 octane while E85 would be about 109.

Bro. P.J., you are correct that when boost goes up, timing comes down. But even that depends on the octane of the fuel you are running, as well as the camshaft timing and static compression. There are no simple answers. That is why you have to factor in all of the above variables -- and THEN decide if and at what point the timing should be backed down.

Again, my engine was built with heavy boost in mind and that is why studs, both head and main, were in the plans. Mine were some specialities grade nines that Marty got from -- I think it was Milodon.

Even with all of my preplanning, including a high octane fuel, timing with start low and work its way up to meet what the engine likes - and will live with.

bro. "fingers crossed," d
 

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Agreed. I have head and main studs. I will install cap straps per suggestion from one of our former members. I am installing a larger cam to kill off some cylinder pressure and add airflow. H-beam rods, forged pistons, and ring gap I already have. I have o-ringed block and copper head gaskets and I’m still paranoid. With a Procharger and intercooler I’ll be starting at 18 degrees which is half of my NA total.
 

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@Darius @5one9 @cadillac512 - question about the dampner/balancer. I couldn't really tell from y'alls discussion but is it essential to run one? We took the pulleys and dampner off mine yesterday (which does appear to have the rubber ring, it's a 72) to do some measuring and the face of mine is pretty beat up. We were thinking about chucking it up in the lathe to make a shoulder than cut a timing wheel on the plasma that would fit on the balancer instead. We then had a discussion that the flex in the rubber might effect the timing trigger so we're most likely going to cut off the rear power steering pulley (and just run one belt instead of 2) and sandwich in a trigger wheel. The big concern there is that with that much offset I won't have a good positive location on the crank pulley so if the balancer isn't essential I could make the trigger wheel the same thickness as the dampner flange without having to offset everything and still have a good center to work with.

Thoughts?
 

cadillac512

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The damper is not necessary in my opinion. I ran all four of the Cadillac engines I built without the dampers...(ran the race car engines with just the hub and a single groove pulley) with no problems. The factory ran the heavy iron pulleys sans damper in the later 500's as well.

Terry
 

Darius

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I agree that it is optional. Some will want it and others not.

I've use a balancer in each of the two Cadillac engines I've built and neither one of them has run nearly as fast, or as well, as Terry's. :notworthy: There might be a lesson in that - or not. ;)

bro. d
 

48Austin

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What about timing marks? Blower pully? Didn't CadCo offer a SFI one piece unit at one time?
 
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