Idle decent in Park, engine dies in Drive on '66 Toronado

[NTX5467]

As the cam is "used", the break-in process is not as critical as it would be if it was a new one. The reason for the 1.5-2Krpm range, initially, is for oil slung off of the crankshaft to oil the cam lobes as there's no pressure oiling for the lobes as such.

I'm not sure what the Mellings oil is. I know that the smaller bottle of GM Cam and Lifter Pre-lube is a somewhat sticky liquid, so it should stay put. Adding some of the black moly lube for new camshafts, the paste, might be good to add into the mix. I suspect many speed shops might have some in various camshaft brands. Being a paste, it'll stay put, too.

Whenever I bought my '77 Camaro new, after the first few thousand miles, I ran it with Castrol GTX 20W-50. It did well. When I pulled the intake for a timing chain and camshaft/lifters and 4bbl upgrade (at 92K), there was no accumulation, with such little "stalagtites" on the bottom of the intake that many other guys took notice. When it was swapped for a 350 at 576K, the installer used Valvoline 30 for the initial run-in oil. At the first change, several thousand miles later, I started with Castrol 20W-50 again, but I changed it rather soon. Reason??? I could tell that the engine lost a little of its "edge" with the heavier viscosity oil compared to the 30 oil viscosity. It felt a little doggy, in comparison. I downsized to 10W-40 and the way it ran with the 30 viscosity oil returned. So that's where I stayed until I upgraded to Rotella T 5W-40 synthetic.

Nothing wrong with the 20W-50 oil, by any means, just that it takes a little more power to run the oil pump with the heavier viscosity oil. I never noticed anything with the original 305, but then it still had the 2bbl Rochester set-up then. Now it's got a spreadbore Holley 4175 (1979-spec Chevy L-82 emissions spec replacement carb) on a Holley 28-Z Z-Line intake manifold . . . which is what was on the previous 305. I never ran the 305 on 10W-40 either, so the issue of lost power due to the heavier oil never had a reference point as it did on the 350.

Thanks for the update! I hope things keep on progressing nicely!

NTX5467

[Guest Twilight Fenrir]

Whew, after a full day of crunching, I got my car back together, and it seems to run great again

The fuel inlet issue was the aluminum plug that was poured into the front after the carb was manufactured... I drilled it out, and stuck a piece of tube with a much too large bolt in it for testing purposes and it stopped leaking. I'll tap it and put in a threaded plug in the next couple days.

The vacuum is still all over the place though... I'm sure I need a valve job after 130K miles, but still...

Anywho, car is running, I'm happy. Thanks again for all the help

[NTX5467]

Which port are you using to check the manifold vacuum with? Does you vacuum gauge have a restriction in the inlet tube, to dampen vacuum pulses? Just curious.

Glad it's running again!

NTX5467

[Guest Twilight Fenrir]

Which port are you using to check the manifold vacuum with? Does you vacuum gauge have a restriction in the inlet tube, to dampen vacuum pulses? Just curious.

Glad it's running again!

NTX5467

I'm using the accessory port, on the manifold..

Dunno about the damper, prolly not... It's a vacuum brake bleeder.

[Guest rsd9699]

Glad it is back on the road!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! And you still have summertime to enjoy the thrill of American muscle car front wheel drive - lets hear it for your amazing repair!!!!!!!!!

I agree with NTX5467 that the vac gage needs a throttling mechanism. I use my Dad's gage and it is over 60 years old and has a screw to help eliminate the huge swings.

I would not expect a valve job in just 130k - I have over twice that and no problems with valves. My experience with the Olds is the timing chain and gears wear in as the mileage gets on them. The fellows I spoke to in the wrecking yards said Olds was good to go for 300k and Chevy's for 200k.

[Guest Twilight Fenrir]

Well, she's off the road again for at least a day or two... lost my brakes completely XD Damned single reservoir. Well, I'll find the leak and get it fixed... I really want to wait until winter to do my front disc conversion...

[Guest rsd9699]

Just out of curisoty, have you rebuilt the brake system since you owned it? Rubber only lasts 15 or 20 years at most if the car is driven fairly often. After that time peior and the car has rested for any length of time, mother nature starts to work on it. Your in a salt area - I would knock off 5 years just to be safe. I like disk brakes but would never retrofit a car unless it truely is a daily driver. Drums work really well unless your being pushed down Pikes Peak by a semi.

Sorry that you had another minor setback but still lots of summer left.

Ron

[Guest Twilight Fenrir]

Just out of curisoty, have you rebuilt the brake system since you owned it? Rubber only lasts 15 or 20 years at most if the car is driven fairly often. After that time peior and the car has rested for any length of time, mother nature starts to work on it. Your in a salt area - I would knock off 5 years just to be safe. I like disk brakes but would never retrofit a car unless it truely is a daily driver. Drums work really well unless your being pushed down Pikes Peak by a semi.

Sorry that you had another minor setback but still lots of summer left.

Ron

Drums don't work so well on a 4800 lb car... Even at the time, the Toronado was lampooned for its brakes.

I do plan on driving it daily in the summers. So it's something pretty important. I already have all the parts to do the conversion too.

The car hasn't moved significantly since 1981, it's been in a garage. I'm pretty sure I jnow where the leak is, I think it's the tee on the rear axle.

Is there any particular reason I cant use my new 2-reservoir booster/mc from a 69 toro? I bought it for my disc comversion, but if I can use it with my drums, I won't have to worry about loosing all my brakes due to one pinhole..

[NTX5467]

Sorry to hear about the brake issue!

I suspect the '69 booster mounts up where your current one does? Other than that, the current chassis has one line that goes to the front pair of brakes and one line that goes to the rear pair of brakes. All you've got to do is the "plumbing" to get the appropriate line from the dual reservoir master cylinder to the appropriate pair of brakes. If you have the lines and proportioning valve from the '69, I'd think that would be a good start.

The reason for the coiled brake lines, coming out of the master cylinder, is that as the chassis (or front subframe on a unibody vehicle) moves down the production line, the cylinder "floats" on those coils. The booster is on the body at that time. After the "body drop", then the cylinder and booster are bolted together.

To evacuate the system, on the assembly line, they pull a vacuum on the system and then allow the designated amount of brake fluid to enter via the master cylinder reservoir. No "wheel cylinder bleeding", as might be done "in the field", or "pressure bleeding".

The ONE thing on the conversion master cylinder might be IF it's a designated "disc brake" master cylinder, it'll not have the residual pressure valves in it as the drum brake cylinder would . . . on the front side where the disc brakes would be.

I remember power drum brakes and still have a few cars like that. I KNOW that it takes a little remembering which one is which, lest front teeth contact steering wheel when just moving them in the driveway! I also remember when stopping performance was directly proportional to friction interface between tires and road surface . . . where miscalculations resulted in skid marks and tire smoke (not related to exhibitions of acceleration).

One problem with drum brakes is that we've lost so many sources for high quality brake linings over the past few decades. One brand has harder linings, with poorer braking performance and another brand works much better. Before the federal specs in the later 1960s, there was a wide variation in quality, fade performance, and longevity in brake linings.

Personally, I like the solid pedal feel of power drum brakes. When we got our first car with power front disc brakes, the pedal felt a little mushy at "full stomp". The car did stop well and was not quite so touchy for powe brakes (as the earlier cars were). As the power disc brakes take more pressure for the disc brakes to work (compared to similar drum brakes), it can make the car easier for anybody to drive and not have teeth/steering wheel contact (even with lap belts on). But that's just me.

Keep us posted on how your projects progress!

NTX5467

[Guest Twilight Fenrir]

Sorry to hear about the brake issue!

I suspect the '69 booster mounts up where your current one does?

The ONE thing on the conversion master cylinder might be IF it's a designated "disc brake" master cylinder, it'll not have the residual pressure valves in it as the drum brake cylinder would . . . on the front side where the disc brakes would be.

I haven't tested it... but the '69 should bolt directly to it. The plumbing is, of course, different. All the lines come together in tee mounted to the subframe, then one line comes up to the existing MC. I figured it would be easy to disconnect them from the Tee, and plumb the rear to the front reservoir, and the front to the rear... (I would prefer to do it the other way, front to front, rear to rear for simplicity... but that defies the standard)

Oh, hey, look at that I never thought of that... There are no seperate Drum or Disc parts for the '69, despite it having both as options... They appear to have used the same MC/booster... Awesome That eliminates any uncertainty I had, thanks!

[Guest rsd9699]

My 69 98 still has the drums and I have the parts from a 70 to convert it to disk. At 5200 pounds - I never had a problem or questioned that I was going to stop - be that in Houston, Dallas or Ft. Worth traffic conditions.

I know that the proportioning valve is located in a different place on the 98. I recall that it was close to the rear axle and I would guess that the Toro and 88 equiped with disks are the same. My interchange shows the booster to be different as the pedal efforts is greater on disk than drums due to the self-energizing action of the drums not found in disks.

NOS brake shoes are always the way to go if you can find them. Pads are a little different and the new ones from Ray squeak less with a properly turned rotor.

I thought the coiled lines were to eliminate metal fatigue in the lines from the rubber mounted body and frame during the course of everyday driving flexing between the body and frame.

Please post if your leak was in the rubber line at the rear or in a metal line. Less than $100 to replace all the rubber parts in your system. If the line is bad - i would think that they are all borderline bad and would replace them all for safety.

Ron

[Guest Twilight Fenrir]

But, your 98 has several things my Toronado does not. The Toronado did not have a proportioning valve at all. It just had the booster, master cyl, and the brakes with nothing else. All 4 wheels get equal pressure. The car stops alright once or twice, but if you make two hard-stops in a row, the brake fade is rediculous.

I think I still have the original shoes on there. I don't plan to replace them just yet, because there's nowhere around here that can arc my drums to new pads.

The leak appears to have been at my master cyl itself... I went ahead and replaced it with my '69 dual-res setup, and it works wonderfully.

It turned out really well. The pedal is way firmer than it used to be... kind of annoys me, actually, but the car seems to stop a bit better too. There's not nearly as much fish-tailing when I stomp on the brakes either.

I have a set of hoses for the rear, and a set for the disc brakes when I put them on. But I plan to wait until I do get the disc brakes on, as I am hoping to put DOT-5 in the system when I do so. They only have to hold up another couple months.

[NTX5467]

The wheel cylinders might all get the same pressure, BUT the mechanical leverage comes from the diameters of the wheel cylinders. Why the rear cylinders are usually a little smaller in diamter than the front ones, not to forget that how that interfaces with the master cylinder piston diameter figures into the total mix, too.

The earlier drum brake set-ups didn't have a proportioning valve in them, just a "mechanism"

to indicate when one end of the brake fluid circuit lost is capacity to hold fluid and pressure. This was related to the "Brake" warning light on the instrument cluster.

By comparison, front disc brake vehicles had something which looked similar, but also proportioned the pressure to put more to the front before the rear brakes got any pressure at all . . . plus modulating the "Brake" light on the instrument cluster. Without this pressure proportioning, the rear brakes would lock up before the front discs really started to work. In later years, the disc brake "metering block" came to be called "Combination valve" as it both proportioned pressure and also served to turn on the "Brake" light.

It's usually harder to lock up the brakes on a front disc brake vehicle, compared to a full drum brake vehicle, which might help explain why they seem to stop better in all situations. Of course, fade resistance is an issue in repeated hard use with disc brakes . . . UNLESS you've got some of the earlier full-metallic segmented brake pads from the earlier 1960s. These brakes came on the 1961 Impala SS cars, from the factory, but were generally removed by drag racers as it took heat to make them work, which meant that with cool brakes at the starting line, it was difficult to stage the car against the brakes. Putting normal brake shoes on remedied that situation.

In earlier times, such factory brake options might have been spec'd for California Highway Patrol vehicles in the factory parts books. In the Allpar has Dodge, Chrysler, Plymouth, and Jeep car, minivan, and truck information website, there are some stories by Curtis Redgap on the mid-50s CHP vehicle tests, where the Dodges had factory metallic brake shoes, which still stopped with the drums glowing very "red" from heat.

In order to increase the fade resistance of normal brakes, some companies added brass slivers to their lining composition. An upgrade in fade performance, but not like the full-metallic linings. Almost all larger trucks use drum brakes, even now, especially with air brakes and also on their trailers. I suspect it would be quite difficult to design a compact actuation system, air powered, where air pressure keeps the linings "off", for these vehicles and trailers.

It always seemed interesting that so many GM cars, if they got even close to a mud puddle, would lose their brakes until they got dried-out. Yet similar Chrysler and Ford products didn't seem to have this issue, nearly as bad.

If drum brakes are so "unsafe", how'd we live this long . . . or ever survive without cupholders that weren't on the inside of the glove compartment lid?

There is ONE unwritten rule about drum brakes, though, which might have issues with some environmentalists . . . you have to keep the drums clean inside. The accumulated "dust" in there, from lining weak, can significantly decrease ultimate stopping power. In prior times, when I first became aware of this, it was from a dealership mechanic who used air pressure to "blow them out", but it also put a cloud of dust in the air in the shop. Later, I'd use water pressure to do the same thing. Now, the correct way to do that would be to remove the drum, put a drain pan under the wheel, and then spray it all with brake clean, then correctly dispose of the "run-off". Same thing, more work, more environmentally friendly . . . better drum brake stopping power.

I'm glad your temporary change has worked well. What about the engine vacuum issue?

Take care,

NTX5467

[Guest Twilight Fenrir]

Wow... that's alot of information, very enlightening, thank you

The best support I can muster for my Toro's brakes being aweful is this link, which happens to quote ALOT of magazines at the time of the Toro's release.. (The bright yellow highlighted sections)

Drum Lessons

As for the Vacuum... it was suggested that my vacuum gauge is not really suitable for measuring it, as it may not have a damper to take out the subtle irregularities. The car is running great now, heck, yesterday i took it for a 100 mile cruise on 4.4 gallons of gas... I got over 22 MPG on a carbureted 425! I know fuel injected engines that don't get that kind of economy!

"If the Toronado has very adequate go, it also has inadequate stop. The engineering which resulted in the Toronado’s drive system should have been extended to the car’s braking system. Drums of 11-in. diameter and shoes of 2.75 in. width in front and 2 in. width in the rear provide a total swept area of 328.2 sq. in. This is insufficient for a car whose gross weight is in excess of 5400 lb. when fully passengered, fueled, and conservatively cargoed. In two intentional panic stops from 80 mph, the Toronado brakes demonstrated unacceptable fade characteristics, that is, lockup which induced noisy slides and anything but straight-line deceleration. A totally unintentional panic stop in a freeway situation left one Car Life driver with trembling hands, icy perspiration and a total lack of desire to drive the Toronado ever again . . . unless the car is given discs or a front discs / rear drums, with a limiting device (a la Thunderbird, Continental and Ford 7-Litre) to prevent rear-wheel lockup. The present drum system, without such limiting, allows the wheels under the light rear end to halt completely for sustained, squealing, squirming slides. All of this is in light of the statement by Oldsmobile engineers: The Toronado does not need disc brakes. Car Life disagrees."

Edited August 29, 2011 by Twilight Fenrir (see edit history)

[Guest rsd9699]

Glad it is on the road - just be safe! The life you save just may be your own.

The power story is true of Olds since the first V8 - a lot of get up and go but no way to stop until the early seventies. Took some time to figure out the disk brake system and how drivers actually used them.

Your comment about water and dust on the shoes raised my eyebrows. My 56 Caddies have a slit on the outer surface of the drums. I guess that was to allow the dust out but boy - water does get in them and then you have no brakes unless you applied the brakes before you went through the water.

Morpar brakes were different than govmo's as they used dual wheel cylinders. Only owned a 54 Chrysler with hemi and powerflite. Took forever to get up to speed but the brakes seemed okay for the late sixties traffic I was exposed to in the far reaches of west Texas.

Ron

[Guest rsd9699]

One thought about the firmer brakes with the MC change. I wonder if the the booster sucked brake fluid into itself? You will not know until you remove it and shake it. I have had several that had 3 or 4 ounces of fluid in them. I saw the MC levels go down but thought it was just the wear but found out that the vacuum can suck it in past the failing MC seals.

Ron

[NTX5467]

Glad it is on the road - just be safe! The life you save just may be your own.

Morpar brakes were different than govmo's as they used dual wheel cylinders. Only owned a 54 Chrysler with hemi and powerflite. Took forever to get up to speed but the brakes seemed okay for the late sixties traffic I was exposed to in the far reaches of west Texas.

Ron

The Chrysler "Dual Servo Contact" drum brakes did use two wheel cylinders, one for each brake shoe. But these were only used for a few years, starting in '59(?) - '62. Before and after that, they were normal single wheel cylinder drum brakes. The DSC brakes were reputedly hard to adjust well. I doubt they could be self-adjusting, either, but I'm not sure about that.

The earlier Chrysler disc brakes were internally-expanding friction discs, allegedly similar to aircraft disc brakes of that era. In one respect, the friction discs might be likened to two manual transmission clutch discs, with friction material on one side, but paired for each wheel. I remember seeing some pictures and reading a little about them being the first use of disc brakes on an American automobile. They sure were different from the later disc brakes!

------------------

I fully respect "Car Life's" assessment of the situation. I really liked that magazine for their more engineering-oriented approach to testing vehicles AND finding out why they were not as good as they should be. Seemed to be much more scientific that "Motor Trend", back then. Their articles were well-written and understandable by almost anybody that could read. Plus some great pictures of the cars and what made them tick. LOTS of great tech articles, too, many of which I referred to 30 years later.

One time, they had a conversion chart to adjust vehicular performance for variations in weight, axle ratio, or power. I made note cards on road tests from all of my car magazine collection. Then, I took each vehicle's data and corrected it to a 4000lb car, 3.23 rear axle ratio, and H78-14 tires. From there, I took the 1/4 mile corrected trap speed and used their chart to get a rear wheel horsepower number. This used a common platform vehicle to yield highly viable engine power numbers. Then, using that data combined with a "Hot Rod Magazine" dyno test of a Chrysler 383 in 1968, I determined there was about a 16% power absorption in the drivetrain between the flywheel and the rear tires' contact patch on the pavement. With all of that use, the pages of the magazine had to be handled VERY CAREFULLY! Not to mention the additional use my K&E Slide Rule got! That personal project sure did keep me out of trouble!!!

Hated to see "Car Life" get gobbled up by the Petersen Publishing Company, with all due respect.

One thing tended to bother me about the power differences between the Chrysler 413s and the 440s that replaced them. By comparison, the 413s had decent performance in the bigger cars, but the 440s were much better. My project's power numbers were much more graphic. Then, years later, at an area Dodge dealer's obsolete parts warehouse sale, there was a 413 exhaust manifold. I was shocked at how small the runners were in the exhaust manifold, much less the "log" configuration of those times. By comparison, the 440 manifolds were "high performance", even for the normal ones. Mystery solved . . . the poor 413 and 426/365 Street Wedge just couldn't BREATHE very sell on the "exhale" side of things!

Thanks for that great link on the Toro brake issues!

Take care,

NTX5467