60s-70s big Chevrolets vs. big Fords

speedshift

Yeah, I think that's the basic idea. The high intake manifold vacuum you have with mild valve timing comes from not having the intake and exhaust valves hanging open at the same time for as long--"overlap" as they call it. There's less leakage from the cylinder through open valves into either the intake or exhaust manifolds. That "tighter seal" increases low rpm combustion pressure, increasing the need for higher octane, at least as I remember it.

With a really long duration cam you have exhaust gases leaking back into the intake manifold and diluting the air/fuel mixture at low engine speeds--that's what gives the engine the rough idle and poor low-speed throttle response. That must be why '70s smog cams had long duration--poor man's EGR.

I had a chance to dust off a few more brain cells and what I was getting at is this...

IIRC you use a manifold vacuum gauge to set timing by rotating the distributor until you maximize manifold vacuum--the engine is in an optimum state of happiness.

But I'm wondering whether this state of bliss engine-wise is still the goal. You've got variables like valve timing and compression ratio, even axle ratio and vehicle weight, predicated on gas of a higher octane than what's available now.

You've also got a combustion chamber design that dates back to 1957 or so and is relatively inefficient at handling high combustion pressures compared to a more modern design.

Throw in a crude, relatively inflexible 2-bbl. carb that's jetted lean and can't dump a load of raw fuel to cool down the combustion chamber. Plus carbon deposits that have increased the effective compression ratio and created hot spots.

So I'm just wondering if you're not forced to set the timing on sylvester's car by ear these days.

Mr_Shiftright

I guess as long as it doesn't ping you're okay.

Not all engines respond to bumped timing though, interestingly enough.

speedshift

I have a theory that it's a good test of a combustion chamber's efficiency. A good design can handle the higher combustion pressure you get from advancing the timing (or increasing the compression ratio) so it makes more power.

jsylvester

So, I can ditch the timing light, and adjust by ear? That is what the mechanic did when he set the timing, but I think he retarded it a bit too much. I recall some thought that was a bad way to do so, it could damage the engine.

For better or worse, a big inefficient American v-8 sounds like a good first car to learn on - relatively simple and forgiving of mistakes.

Per the manual, the dwell angle on both the 289 & 390 is 26-31*. All 390 2 barrels came with one of 3 "dual advance" distributors (the manual did show me how to find the part number and manufacture date - I'm trying to figure out if the distributor could be original, I'm hoping the points are not)

I'm starting to see why the old mechanical timing is still preferred for low rpm weekend cars - it is not exactly rocket science once you understand it.

I'm trying to plan my restorations now, as the girl I'm dating is dropping hints on marriage, which means instead of spending money on resealing the frame, fixing the minor flaws in the 8 year old paint job, etc., I'll have to buy dumb things like furniture, carpeting, etc.

carnut4

get one of those "inductive" ones-they have a clamp that you just clamp on the #1 plugwire-don't have to remove the wire or fiddle with one of those adapters. Makes it a lot easier. I have both kinds-after using the first one for years, I finally bought the better one. They aren't that expensive. But then, I love tools, I've hawked bargains at swapmeets, etc, and built up my stash of stuff over the years. Actually, a timing light is a nice thing to have if you're going to be doing tuneups yourself-even if you do time by ear, you can use the timing light to just see exactly where you are. But DO check and adjust the points before you set the timing. You can buy a combination dwell/RPM gauge fairly reasonable at most good autoparts stores.

Mr_Shiftright

Timing by ear is okay on some engines, like sturdy and not so fussy big V8s. What you need to watch out for is advancing timing too much. If your engine is pinging audibly, you need to back it off or you will drill a hole right through the top of the pistons.

"Pinging" is actually all your engine's internal parts rattling around--in some severe cases, even the walls of the cylinder bores are flexing under the strain of premature combustion presssures.

And never, ever tune modern engines that way.

It's really not "tuning by ear". That is a misnomer. It is tuning by ear AND road test, over and over again.

speedshift

Yes, it's definitely trial-and-error. Lots of fiddling and driving. Even then the engine might be detonating and you couldn't hear it, which is why I suggest you back well off the point you can hear it ping.

But there's just no way around doing it this way, at least in my experience. Setting it to factory specs will just hole a piston.

I'd at least check into a water/alcohol injection system. The latest ones (well, circa mid 1980s) offer some flexibility the first ones didn't have.

pally

Buy a pertronix ignition, install it, (takes 10 minutes)

Then set your timing by ear making sure you set it with the gas you intend to use everyday.

I did this in my 67' Galaxie with a 390 and set the timing to run on regular gas.

jsylvester

Have you tried higher octane, and did you see any difference in performance? I'm assuming the higher the octane, the better the performance as I will not have to retard the timing as much.

Is Pertronix an electronic ignition system?

Mr_Shiftright

It depends on whether your engine is designed to use high octane. If not, it would be a waste of money. You'd need to know your compression ratios for one thing. Or you could try the "butt-o-meter" and see if it runs better.

carnut4

My 62 Impala has the original 327/250 horse engine, with a 10.5 compression ratio. You'd think that'd be too much for 92 octane gas, which is the best I can get around here. And, I have the timing set to 4 degrees BTDC, as per spec, and I've never heard any pre-igniton. And, I listen for it too, all the time. But I know you can't always hear it-sometimes just a slight noise on heavy open throttle at low-medium speed. I'm surprised. I have used the octane booster, but not every tank.
Of course, I did pull off the heads just to see what was there, cleaned all the carbon off the pistons, and had new valve seals installed. Now I know it's all clean inside and out.
Anyway, surprised it's never pinged with compression like that.

jsylvester

The factory compression ratio on my 2 barrel 390 is 9.5 to 1 (The 4 bbl version on the full size Fords had a 10.5 compression ratio). Of course, I've never taken the heads off, and I don't have all the details on the restoration that was done back around 10 years ago, so who knows what lurks in the combustion chamber.

As soon as I finish building my shed, the car's ignition is next. I'm anxious to start tooling on this issue.

Thanks to everyone for their help. I think I'll try the dwell timing, and do the seat of your pants/tune by ear method and see if the results are satisfactory.

isellhondas

Back when I had my beloved '62 Impala SS 327/300 HP, I never used a timing light. Heck, the gas station I worked at didn't even have one!

We just used a dwell meter to set the points at, I think 30 degrees.

Loosened the distributor and set the timing by ear. The old timers laughed at timing lights!

I was taught that we wanted just a slight ping under load, barely noticible. That meant you had it right. I remember a bit of trial and error.

One time, I did borrow a timing light and set if to factory specs. All I got was a sluggish car!

My '65 Riviera was the same way. It really ran so much better with the timing set by ear.

How I miss those two cars!

andre1969

...to factory specs when it came time for the emissions test. The car would run like crap and get worse gas mileage. Then after the test, he'd set it back to where it ran better and got better economy.

I've always set my cars by ear. We still have Granddad's old timing light somewhere, but it's broken.

carnut4

My Dad's old 62 Impala with the same 327/250 never got timed with a light, to my knowledge. But I was always under the hood fiddling with it, points and plugs, etc. We didn't have a timing light then, but I wanted one. I've timed a lot of cars by ear, too, with good results. For performance, the deal was always to advance it slightly over what stock was anyway, and ideal was like you say, slight ping under load. That's about where my 62 is now, after setting it stock with a light. But, I had to have a timing light, cause I love tools, and it is interesting to set the timing by ear and then hook up the light, just to see where you are. You did have to disconnect the vacuum advance, though, or you'd get a false reading.
With my 55, and the 327 I had in there, I changed the weights and springs in the distributor, and then set it by ear, and it flew! That was the fuelly cam with the valves set at .030. What a sound.

Mr_Shiftright

Don't ever try to time an air-cooled engine like VW or Porsche by ear, however, or you will blow it up for sure.

carnut4

and what a pain it was to hook up a light to it, with that little spring on the end of the plug, trying to get at it, etc. That's what made me want one of those inductive ones, where you just clamp on to the plugwire. I mostly just timed it by ear, and you could tell right away whether it was safe or not. I knew enough to back off real quick with that aircooled motor.
That reminds me of the trouble I had with that little Solex carburetor, and the little nozzle in the top always clogging up, causing a crapout on low speed acceleration. After having the dam thing apart over and over, and trying to clean that little tube with 90 degree turns with Berryman's, I finallytook it down to the VW parts, and the guy opened a drawer right there at the counter filled with new ones-for 50 cents. I wonder how many people fiddled with that problem, not knowing they could press in a new nozzle on top for 50 cents and solve the problem.

jsylvester

The plug wires, distributor, and points look pretty new. The coil looks pretty old. Would a higher output coil be worth the cash?

Looking back, when I trashed my 69 Catalina, the reason it ran so badly was probably due to the timing being way off. Oh yeah, the brakes had to be pumped to get the car to stop, and the heater core went out as well - no heat or defrost in winter.

Was there really any major differences in the ignition systems of GM and Ford?

Mr_Shiftright

Well the ability to set dwell while the engine was running was a very nice feature of GM ignitions, but as for the principles or technology, no they were the same very old and tried and true stuff, right out of the early 1900s. I guess Chrysler pioneered E.I. in the US, right? I'm not sure.

speedshift

Yes, you didn't even need a feeler gauge to set GM points, just the hex wrench that came with the points and condensor. Very handy.

As far as I know, a stock OEM type coil will easily cope with the engine's secondary ignition demands past 5000 rpm.

With a low-revving street engine, more isn't necessarily better, just more expensive. The stock set-up isn't merely adequate, it's as much or more than you'll ever need. Just make sure it's in good shape and of good quality.

andre1969

...but I think 1971 was the first year that Chrysler had electronic ignition. The system was supposed to be ultra-reliable...at least until Lean Burn made its appearance in 1974!

amazon

In place of a minivan, I'm thinking about getting a 68-72 Caprice or Impala wagon. I know that they just guzzle gas, but other than that, what do you think about that idea for a family hauler? I would install an OD transmission, and 3-point seat belts in the rear seat as well.

ghulet

...as long as you can stand the gas usage. They are at least easy and relatively cheap to fix (the engines, anyway). I do think an earlier (say '65-68) might be a tad bit more fuel-efficient than the later ones (especially if it has a 283 or 307, in the case of the '68), but I guess they won't be a whole lot different. I think you'll have an easier time finding an earlier one than one made after '68, for some reason. The '69-70s are hard to find, and a nice '71-72 is not much easier. Check autotrader.com (the 'antique' search engine on the bottom). FYI, the '69-72s are called Brookwood, Townsman, Kingswood and Kingswood Estate; earlier and later than that, they retain their sedan names (Biscayne, Bel Air, Impala and Caprice, respectively). I think the front seats at least had shoulder belts from '71 on (maybe even earlier), as I remember my '71 Buick having them (mounted separately, from the headliner basically).

You certainly wouldn't have trouble finding your car in the supermarket or mall parking lot if you bought an old wagon instead of a minivan!!

ghulet

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ghulet

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ghulet

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ghulet

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ghulet

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ab348

The '71 and up models with the clamshell tailgate are relatively tough to find and I hear that the tailgates are problematic. But it certainly is neat. The problem with those is that they are whopper-sized although in some respects they are a better car than the earlier models.

If I were considering such a thing I think I'd go for a '68-'72 Olds Vista Cruiser. At least they have a bit of "cool" factor.

ghulet

I do like the Vista Cruiser. There were several years, in fact, that neither Buick nor Olds even produced a full-size wagon (1965-68 for Buick, '65-70 for Olds) because the Sport Wagon and Vista Cruiser were on longer wheelbases than the Skylark/Cutlass sedans, could be configured as 9-passengers, and had big engines (up to 455 cubes). Of course the cool glass roof panels are fun. Add the bonus of slightly more managable size, and you have one of the best wagons of the era.

If I were looking for a big, old station wagon, I'd definitely consider brands other than Chevy (Pontiac/Buick/Olds, Ford/Mercury, Mopars), since, as with other cars, they're cheaper and likely even more rare. Of course, with any old wagon, finding unique body, interior and trim peices is likely not going to be easy.

ghulet

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ghulet

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ghulet

...when you pick up the kids from soccer practice in THIS ('it is being represented as a running car [i.e., more expensive], though we haven't taken the time to get it running since it was removed from storage'):

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ghulet

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ghulet

...no rust ever, from AZ, 390 engine easy to find parts, $2500. Sounds like a winner to me, though I'd like it better if it were a Colony Park (the fancy one with 'wood' sides):

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ghulet

...this guy cracks me up. Take some so-so, non-digital photos of an unwashed car (with a bit of rust and faded wood decal, in this case), write all over them, then ask about three times what the car's worth. What a plan! I've seen other cars being sold by this dealer, most of which are also overpriced by a factor of two or three:

http://adcache.collectorcartraderonline.com/10/1/8/3996918.htm

Check out http://stationwagon.com/ for more wagon stuff.

Mr_Shiftright

THREE times what it's worth?!! How about FIVE times? CPI lists a clean wagon for $3K.

ab348

Some neat finds there. I don't think I've ever seen real-life examples of those '67s. The Buick is nice but I suspect the Merc would be a bit stark inside. I really like that '65 Buick wagon but I wouldn't want one for a daily driver. I had a '64 Skylark and that 300 V-8 and 2-speed auto trans was barely adequate in it, let alone a much heavier wagon. And a '65 has no safety features like a dual master cylinder or a collapisble steering column. The '64/'65 Skylarks also had the world's skinniest steering wheels which are guaranteed to be cracked 35 years later. But I still like it.

I figure if you were to get a big wagon you may as well go all-out and I am a sucker for those fuselage Chryslers from '69 to about 73. A friend has a '71 New Yorker hardtop and I love it. That wagon you found is ridiculously overpriced though. He has had that car for sale all year.

speedshift

One good thing about that Buick camper conversion--no one would ever cut you off. Or even make eye contact.

Mr_Shiftright

Who came up with the idea that Buick owners had "estates" around which to drive their wagons? Well, I guess if Chevy owners can be in Monte Carlo and you can drive your Cadillac to Eldorado, then hey, why not?

Here's a question I don't know the answer to: when was the last year Chevrolet made a "Sedan Delivery" and what chassis was it based on?

mrwhipple311

Technically the last I recall is the 74(?) Vega wagon that could be ordered without the rear side windows, I drove one once but havent seen one in many years.

Prior to that I think possibly mid sixties Chevelle 64/65. I know there was the 2 door wagon I think there were sedan deliveries also.

speedshift

I'm pretty sure it was 1960 and based on the car chassis.

Mr_Shiftright

You know, I can't decide if I just dreamed it or if I actually saw a '59 Sedan Delivery one time, maybe on an El Camino chassis. Myabe Gunnell's book (the "Encyclopedia of American Cars") has info on this. I'm away from the office so I don't have a copy handy.

speedshift

I checked and it doesn't say.

I'm 99% sure I've seen at least one '60 sedan delivery. In fact it was just recently--the only question is whether it was a '59 or a '60 and I'm pretty sure it was the latter.

As far as I know the El Camino chassis was just the passenger car chassis.

ghulet

...(Standard Catalog of American Cars 1946-75) lists '58 as the last year a sedan delivery was available. There was a 'utility sedan' available until '61, but that was a two-door coupe without a back seat (aka 'business coupe'), IIRC, and not a two-door wagon with blocked out rear side windows, which is what we're talking about, right? In any case, this book has been wrong before and may be wrong now, cuz I think I've seen '59-60 sedan deliveries as well. Hmmmm....?

carnut4

sedan delivey back in the early sixties. It was a local Fuller Brush man car, making calls in our neighborhood in So. California. Somehow, I remember also seeing a picture of a 60 in a brochure or something somewhere. But I remeber no other Chev sedan deliveries after that, except for the Vega.

speedshift

Business coupe = proto hatchback? With ignition on floor could be proto Saab.

ab348

I bet this would be a great one for you!

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jsylvester

The price guides for early 70's Ford Country Squires seem to show them very cheap. Of course, they all rusted like crazy, hard to say how many are left.

Mr_Shiftright

Lessee....early 70s Country Squire....the CPI suggests about $2,600 for a clean daily driver #3 car. That sounds just about right. For a car with some needs but running and complete, not stripped, rusted or banged up, about $1,500 should do it.