MichiDan

The trip to the homecoming meet was a reminder to me that despite the big car look and comfort, a 64 Starfire is not a real highway cruiser.
The math doesn't lie...
1:1 trans gear
3.42:1 starfire rear gear
27.5 inch tire
3000 R.P.M. equals 71.8 miles per hour.

Of course, any of these factors can be changed but I have no pressing reason to do so. I'm already running about the tallest tire out there for 14" rims, coker classic p225/75R14. An overdrive trans is not really in the plans with a good functioning slim jim in place. Rear gear I could see swapping, but not this summer.

I did NOT run the car 3000 rpm all the way up to Lansing as it seems a little high to me. But I'd like to hear what those who know these engines more than me would say about it. What's a comfortable constant RPM for a 394? Were they designed for high RPM use or no?

oldcutlass

Think about it, these cars ran all over the country with those gears and at those RPM's day in and day out. If the engine is in good shape, you have good oil pressure, and operating temps are normal, there is no reason it can't do it now. What makes you think it can't?

MichiDan

...one of your points. Operating temp.
Engine is in great tune but it did run hot, uncomfortably hot, while plugging along on the highway to the show. Yes, it was a hot muggy day. It did not ever boil over - but I was expecting it to.

Hot can mean all kinds of things, which I am looking into one by one, even perhaps a bad gauge (brand new). But I thought my first question to the group as I go through this would just be about where these old rockets like to run RPM-wise.

If 3000 RPM all day long is no big deal that's fine, maybe I'm being too gentle on the thing.
But for example my other car is a solid lifter 454 Chevy. I shift it at 5700 at the track, no worries. But I don't run it around town at 3000 RPM.

oldcutlass

What temp does it get too on the highway at speed and at extended idle?

redoldsman

My 54 has about the same rear ratio and the original hydra-matic with the 1:1 final ratio. At 3,000 RPM's it is running about 70 MPH. Out on the highway I run 65-70. I usually have a GPS in the car so I get an accurate MPH. I just installed an aluminum radiator because it has run pretty warm ever since I put the AC in it but that is another story I won't go into. I don't think 3,000 RPM will hurt your car.

MichiDan

This gauge looks GREAT with rest of the instrumentation of a 64 Starfire.
Precise it is not.
Could have been 230 or over if I can trust this gauge. It did eventually stabilize at that, and as i said it did not boil over, nor did the dash 'hot' light ever come on. The idiot light is still hooked up and lights as the car starts. Pickup point for the new gauge was left rear of intake manifold.

I don't want to wander this thread too far into the cooling problem though. This engine is new to me so I was pretty curious if the big thing like to wind or not.

oldcutlass

I'd verify the accuracy of the gauge.

MichiDan

Was just looking through the service manual ... the set temp for the 'hot' idiot light is 243 degrees. Plus or minus 2 degrees. Pretty darn hot.

Greg Rogers

I think that because we are all used to our daily drivers running about 1700 at 70mph it feels like 3000 rpm is way too high. But as mentioned earlier the big Olds was designed to run at that RPM.

jaunty75

By what definition? The boiling temperature of a 50/50 antifreeze/water mixture at 16 psi is well over 250F, so 243 is still a long ways away from boiling.


The hotter an engine runs, the more efficient it is as combustion is more complete, less buildup of deposits, and so forth. People have an obsession with low operating temperatures and think that anything over 200 is going to cause their engine to burn up. I put a gauge in a '75 Nova I owned many years ago. It consistently read 210 to 220F whenever I ran the car, and it did that for the 10 years I owned it. Never a problem.


People like to call them "idiot" lights, but keep in mind one thing. If there were only an idiot light in your car, it would never go on, and you would never worry about the engine overheating. But now that you have a gauge, you obsess over the engine's temperature and can't enjoy your car. I'm not so sure that an idiot-light-only situation isn't the better thing. People drove these cars by the thousands back in the day with nothing but an idiot light, and they never had a problem. By putting in a gauge, a problem has been created where there wasn't one before.

Oldskeeper

I drive my car between 60 and 72 MPH all day long. Living in Ontario with the metric system the fastest we are supposed to travel at is 100 KPH or approx 62 MPH and when in the States I drive what the sign says.Driving to Home coming in my 63 98 hasn't been a problem, my wife keeping up to me has. When these cars were built 75 MPH was the standard speed limit so I wouldn't worry about cruising.
Steve

Jamesbo

I thought the speed limit was 55 MPH

MichiDan

Jaunty75, you point is well taken. A gauge reading way over on the far edge does make me worry, I couldn't help it. it didn't stop me from going to the show, but it worried me.

As far as 243 degrees being hot, the factory picked that as temp to trigger the idiot light, so I guess that defines hot to Oldsmobile that year.

redoldsman

Jamesbo, I think it was Richard Nixon who signed the 55 mph speed limit into effect in 1974 because of the first energy crisis.

One aspect of the "idiot" lights are how much more noticeable they are than a gauge. If a driver is not very astute they may not pay attention to the gauge as it creeps over. If a red light comes on it is like it is in your face.


Another aspect of the higher RPM's at 70 mph is wear on the engine. There is no question engines last a lot longer today than they did in the 60's and 70's. There are a lot of contributing factors but I think the lower RPM's today add to engine life.

61Bat

Funny, after I added the console with tach I do drive more conservative now. Not sure of the gear ratio but my tires are 26" tall (15 inch rim) and 75 mph is 3000 rpm. I usually cruise around 2800.

As a note my dads old cabin cruiser with BB Chryslers used to cruise nicely at 3000 rpm all day long.

RetroRanger

I'm about 3000 at 70 mph w a BBO I don't usually run to much hi way tho 15-20 minutes at a time usually. I would prefer a lower rpm but I have no plans to change anything

Charlie Jones

Starfires were equipped with a 3.42 rear for one reason , acceleration . After all , they were Oldsmobile's "Sports Car "
Most of the rest of the 88 and 98 line had either a 2.69 (no A/C ) or 2.87 (w/ A/C) .
Even the stick shift cars had a 3.23 ratio .

The rear end center section can be swapped out easily . And any 59 thru 64 Olds or Pontiac rear center section will fit .

MichiDan

Exactly, and that pretty much takes it back to the top. Todays mindset looks at this big car and thinks, man that thing must float down the highway easy. But that's not really what it was made for. I guess I need a nice 98 alongside the starfire that I can choose for the long highway trips.

I'm not changing the gear. Just good to learn a bit more about the 394.

coldwar

Changing the diff to a higher (lower numerically) gear set makes perfect sense at some point, and has been done since these cars were new with adult drivers. Your around town driving will be just about the same from the drivers seat with something like a 3.08, yet will still have plenty of pickup for merging when you depress accelerator for downshift. With some patience and persistence you might scare up a center section for very little money. Change pinion seal and paint, ready to install. I'm a bit rusty but make sure any you acquire has a fill plug, not all do across the Oldsmobile-Pontiac lines 1958-64. Do not use 1957, different axle spline count. Save your 3.42, or drive it down here to north central Ohio and I'll do the swap for free including parts if you want to let the 3.42 go. Good luck

64Rocket

I believe 57/58 were the 28 spline. so '60 to 64 were 31 spline.
3.08 and 3.23 would be a great up grade. A little easier on the RPM's

oldcutlass

Did we ever verify temp?

Oldsfan

I swapped the 3.42s out of my '62 a number of years ago. I found a carrier laying loose in a wagon at a junkyard and scarfed it up. Turns out it was a posi 2.69. It certainly dropped the cruising rpm (this car travels cross country) and increased the gas mileage. But, it created other problems. 2.69s turned out to be too high. The transmission shift points changed because the valve body thinks the car has 3.42 gears. And I had to replace the right side motor mount every year.

Two years ago I swapped back to the stock gears. Shift points returned to normal and I haven't had to replace a motor mount yet. Our theory is that the Starfire engine had too much torque for the 2.69 gears, which were normally used with the low compression, 2bbl engine.

I, too, have gotten used to an 8-speed overdrive transmission. When that Starfire shifts into 3rd and stays there, I wonder why it stopped shifting...

MichiDan

Nope. Added 2 bottles of water wetter because it's cheap, and have only taken a few trips since the homecoming. No sustained highway drives, so no temp worries.
I need to get a gun or something to really give that gauge a check.

Weezer

Meh... my Starfire runs the same RPM's (for obvious reasons), and even before I recored the radiator, everything was peachy. I will say, though.... based on what we know about lower RPM's making big engines last longer, I try to stay off the e-ways or at least keep it to 65mph as a constant cruising speed. I'm not even going to type what I was just thinking, for fear of jinxing myself.

Nailheadcanuck

The 3.42 is great for acceleration; is that the only ratio available in a Starfire?
But yes, I could see it hitting about 2700-3000 at highway speeds. For that reason my highway cruiser, a 66 Buick Electra, has a 3.08 ratio. It lopes along at about 2300 at 60, and about 2700 at about 80. I have the biggest rad available; it's a modernized re-core of the original. The car hardly gets hot anymore. So the option you would have would be to sacrifice some "off the line" for some highway speeds, your fuel economy will increase and your engine will be happier.
I subject that car to a grueling cruise every year, I take it through the mountains to the coast. The speeds can vary between 60 and 80, depending upon the stretch of road. The temperature gets near 100 in some places, particularly up in the Okanagan valley. So slower running but higher speeds and a big rad is a must.

Don R.

These cars were designed to run at higher rpm like most performance cars of the era and were driven that way to high mileage by most owners with the A/C on full and the radio turned up. We are just not used to it due to modern overdriven drivetrains. If the drivetrain is in good shape the rpm's are not a problem other than gas mileage and with these cars you just can't worry about that. Drive as is and enjoy.

OLDSter Ralph

This thread has been quite insightful. I have a 64 Starfire and had thought about setting up a couple different 3rd members ("pumpkin", center section, or whatever people call it). My goal was to have one with 4.11 or 4.56 gears and another "for the road" (2.56, 2.87, 3.08, 3.23). From this thread, I have decided the 3.08 is my choice.
I thought I could swap them between my '57 and the '64. Yes, I know I would need new 31 spline axles for the '57.

Charlie Jones

You would also need a set of custom made 29 spline axles for the 64 .
Probably easier to swap ring & pinions . Or diff side gears .

OLDSter Ralph

I would use the 59-64 Anti Spin for both cars, therefore, need new axles for the 57. Anti Spin wasn't even available in 57 and the later axle splines are supposed to be stronger.