Whats the right cruising speed for the 37-38 year models?

[DBT]

Hi Folks

Looking to see what others say on this. Whats your comfortable crusing speed for your 37-38 Buick?

I ask as the manual [bless its little heart] states a top speed of 80 mph but does not state a cruising speed.

Now I suspect you probably can reach 80mph but only for a few seconds before pistons start smashing into valves etc etc, especially if like me you run a Limited with its extremely low final drive.

So whats your Interstate speed ladies and gents?

It will be interesting to see if there is any difference between what the Special, Century , Roadmaster and Limited owners say. I am expecting some variation out of preference but also because of the two different engine sizes and the fact that the models ran different final drives.

I wonder who will be the fastest too?

Kind Regards

David

[Matt Harwood]

I expect my Century to cruise pretty happily at 60-70 with the 3.90 gears in it, and have heard from several sources that the big Buicks don't mind this at all. The Limited with its taller gears might want to knock about 10 MPH off of it, but I think 60 MPH would not be abusive. Doug S. has been driving these cars for decades and drives them hard, and reports no failures at those speeds. He even suggested 75-80 would be reasonable in my Century, but with ancient brakes, I don't think I'll press my luck.

Hope this helps.

PS: The Centurys are <span style="font-style: italic">always</span> the fastest!

[West Peterson]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Matt Harwood</div><div class="ubbcode-body">He even suggested 75-80 would be reasonable in my Century, but with ancient brakes, I don't think I'll press my luck.

</div></div>

On the freeway that's not a problem. In town, it's not so much the brakes as it is the tires. I've easily locked up my brakes, they're doing their job, but the bias-ply tires just seem to slide across the pavement.

[egor]

DBT:

It might depend on the car. I've had two '38 Specials, one that would sound like it was working too hard at 55, and my current car that cruises without complaint at 65. The Limited has an even higher gear ratio than the Special, but the 7.50x16 tires compensate, so if I recall correctly, the wheels are actually turning a little slower than the Special on 6.50x16's.

I agree that a 70 year old long stroke engine wouldn't take kindly to 80 mph, and then there's the question of stopping.....

[jeff]

Oh boy, my favorite topic!

For years I have been asking the same kind of question, with respect to my Special. Like you, I have consulted the shop manual (80 mph), plus the owner's manual, plus various write-ups in magazines. Everything seems to suggest I should do a bit better.

Of course the Century, with it's small body, big engine, and favorable 3.90 : 1 ratio, is a good high speed cruiser. In fact, they named it the Century due to it's ability to hit 100 mph. (don't try this at home!)

My Special, with its 4.40 : 1 ratio and smaller engine, seems to be all done at about 50 mph, although I have taken it to 60 mph for a short time. I had a baseball glove on the seat next to me to catch the pistons if they came through the hood. Didn't have to. Its happy speed is 35 to 40 mph.

I have the same shortfall with fuel mileage, only getting about 12 mpg instead of the 15+ that the owners manual states. This fact, plus the fact that my car started out as total junk, leads to my continued interest in other owner's experiences. Could something still not be quite right with mine? (new spark plug wires this weekend - hooray!)

If anyone has a set of 3.9 gears, send 'em over. I have been keeping my eyes open for about 10 years now and have concluded that they are pretty scarce. Always open to cost-effective solutions, like post-war differential swaps. (I think this works for slightly newer models, not as easy for '37 and '38 owners) I will have to pass on the suggestion to go with newly machined gears or custom overdrive setups. I believe in the old version of the hobby, and won't put more into the car than it's worth, or more than I put into my home or kids' college tuition! It's supposed to be for fun!

So, let me know what your experiences are - until then, see you on the back roads.

Jeff

[jeff]

Suchan,

Your two Specials had the same final drive ratio? Same wheels and tires? Sounds like mine performs like your first one.

There's variation in every man-made item, wonder what the spread of engine dyno data would have been for 10 new Buick 248 engines?

Jeff

[egor]

Hi, Jeff.

Both cars have the 4.44:1 rear end. My current car has radial tires a bit larger diameter than stock (closer to 7.00x16 than 6.50x16), but even allowing for that, it still runs better at higher rpm's. I just got lucky with the second car. I think every motor has a personality based on how it's been driven and cared for in the past, and my current car is a happy camper.

[DBT]

Interesting.. and useful thanks.

The Limited's stock final drive is 4.56:1 which is low. Not good for touring.

I've been told that my car might run one even lower than that, but its happy to cruise at 45-50mph and even 55mph is ok and this seems to tie back with what Jeff and Suchan mentioned [well at least for one of Suchan's Specials].

That said it does sound very busy at 55. I think the tyres are right [i run 750R16 radials - which annoyingly wont fit in the sidemounts so I had thought before today that this is a bigger tyre than stock and was cutting me some extra mphs but clearly not as it sounds standard now (then why dont they fit the side mounts? #$#^@!)], so I have myself a very relaxed tourer at best.

Braking has been ok. Pretty impressive actually at Freeway speeds given its age and weight - it hauls down from 55 evenly and smartly.

But 50-55mph will not do. As I am planning a run upto Thailand at the end of the year [@1200 miles each way] the ambition is to swap out the 4.56:1 with a Century 3.90:1, the idea being to lift the crusing speed to 65-70 or better without stuffing the engine.

In the few times I have braved higher speeds [75mph] I noticed the front wings starting to flex which was scary to see first time - have others noticed this?

Regards

David

[jeff]

Wow, you win the touring award for 2008! What a great trip that will be. And to think I was worried about someday making a run to Pennsylvania. Love to hear stories about driving these old cars. Take some photos, will you?

Regarding your sidemounts, my friend has the same issue with his Packard - still running bias ply tires, but I guess a more modern design?

Can't really comment on your front fender flap... you'll need a Century owner to address that! But I will say that my fenders needed a bit of repair where the fender support bracket attaches to the outboard edge - you may want to check that.

Jeff

[Guest ewing]

My 38 Special feels best at about 55 mph on my speedo, and I think my actual speed is closer to 60 mph.

How many guys check the accuracy of their speedos? My guess is most are reading a little low now.

[The Old Guy]

My 37 likes 80+ ,but it has a 2.56 rear axle, and a 455 V8

[Guest ewing]

do your front fenders flap??/ flex.... just before take off?

[Guest ZondaC12]

I actually have a Flowmaster on mine mounted under the backseat footwell, and then dumped off there. It sounds really cool! However, at about 50 mph there is a decent drone from the exhaust, so if I take it up to 60 it really quiets down!!! However, then I listen and put my head down closer to the floor and hear the noise from up front....and it does sound kinda busy. If I force myself to deal with it after like 15 minutes I get used to it and of course I have my portable radio playing on the seat next to me and that takes care of most it of really!

But I feel less worried at 50, and of course as previously mentioned 35-40 is its happy place. HOWEVER, I want to note that up there around 60......the RIDE is amazing. It smooths out like nothing else, and truly does "float over the road" like people always say about stuff with this soft of a suspension.

[Scott S]

What a difference a few years makes. For all who may not be satisfied with 50 mph, the owner's manual for my '23 suggests that 15-20 mph is fast enough for most drivers. As long as I do not have to stop too quickly, I can cruise comfortably at 35-40 mph.

[jeff]

Scott,

You bring up an interesting point. I have often considered the following...

The next time you think your car drives like a truck or isn't fast enough, imagine the guy who just took delivery in 1938 of his brand-new Buick. His last car may have been a Model A Ford, or something else from the late 20's or early 30's. He was probably amazed at the increase in power, reliability and refinement that the Buick offered.

Of course, this pertains to any car, of any vintage. (except maybe the Yugo)

[Mark Shaw]

My 13 thru 31 Buicks run nicely between 40-45 MPH. I consider that to be good cruising speed for tours etc.

I just bought a 38 model 48 last weekend at the All Buick Show in Puyallup WA. It is an all original un-restored 39,000 mile car except for a repaint and a few electrical items that can easily be changed (sealed beams & new voltage regulator).

It also has a Century rear end that the previous owner advised would run about 5 mph faster than the speedo reads. He said the original rear end ran 5 mph slower than the speedo reads.

I can't wait to pick it up this Thursday....

(Note photo of the two guys in straw hats dickering....)

So, now I guess I have officially run out of parking space......

[eric_b_1937]

After restoring my Buick special engine I kept it under 50 mph to break it in. After 500 miles I bumped up the cruse speed to 60 mph. I have about 1500 miles on the engine now with no obvious problems. Some times driving 30 miles or more at 60 mph. I have accelerated the car up to 75 mph on short bursts and I think it will be an even better runner as it wears in more.

Before I tore down my engine my odometer read 98,000 miles it could have actually been 196,000 miles from the looks of other wear on the car like cracked wheel bearings and major differential wear. It was running on 4 pistons three pistons had holes next to the rings and blowby, loose rockers, slight scoreing on cylinder walls. In this condition the engine was pretty loose with no low end power. It took over a mile to get up to speed on the free way but it ran at 70 mph continuous for 40 miles. It had some oil blow by, but it did not self destruct.

I'd like to hear about some actual real wear problems with running a restored 37/38 buick engine at 70 mph for the life of the engine and the milage, teardown results. Any Great Racers out there? Most of what I read on this board is speculation about bursting engine catastrophy's like you see at the drag strip. I'm going to run mine at the speed limit like a normal car and see if it breaks.

4.44:1 rear end

[egor]

Congrats, Mark!

Can you post some more pics after you bring her home? It seems like a nice '38 changing hands is a rare occurrence nowadays.

[Matt Harwood]

What a pretty car! Enjoy it.

[DBT]

Eric B

Feeling a little sheepish here but after running the Limited at 80mph for 30 minutes I ended up with stuffed big ends and an engine overhaul.

So that was costly.

When we pulled it apart damage was restricted to big ends with a little scoring from the cylinders. The damage was consistent with overeving. We did notice that the camshaft was out considerably around the centre set of pistons which would not have helped the situation at all either.

Now I run a Limited ratio so running 80 for that long frankly just shook out the weakspots quickly. If I had kept my speed to 75 would it have kept together? who can say.

So I'm at 600 miles since the engine overhaul now, have kept the top speed to 55mph and run mainly between 45 and 50mph. It runs very well but sounds quite busy at 55. Until I sort out that final drive I think this is where it stays for now.

Regards

[Matt Harwood]

This has been covered about a billion times, but every time this comes up, there are discussions about lower gear ratios in these cars. Apparently they are interchangeable from a wide variety of years (1936 (or earlier?) through 1953 (or later?)), but low ratios are very hard to come by and often in questionable condition. I know The Old Guy has a set of later Dynaflow 3.42s in his '40 Super. I think tooling up a set of new 3.42s might be a good idea. It's not too late for me to put a set in my Century, and I'd probably do it. These cars are comfortable cruisers with adequate brakes for 65 MPH travel. Given the road conditions today and the low 1st gears and decent torque in these cars, they probably won't be dogs around town, especially not the way they're driven by enthusiasts (i.e. gently). It stinks to worry about tossing a rod just keeping up with traffic.

I know we've tried to do this, but perhaps some kind of more organized--and widely publicized--group buy for them would help drive the price down. Whomever spearheads this could also try marketing them to a wider audience than we have here, say in the Bugle or even Hemmings, etc.

Does anyone know if these Buick rear ends (the rings and pinions) are the same as other GM cars of the same vintage? That could be an even wider market. I might even be willing to be that person if someone could help me with the applications research. Perhaps I could round up some investors to put them into production and sell them individually if there's a big enough market.

Someone has already done much of the legwork in finding someone to do the work (or even already had it done). Is that someone here?

Or has this been discussed to death and not gone anywhere? I don't know who would pony up $1500 for a gearset, but what about $750, or $500?

Thoughts?

[jeff]

Matt,

I found the discussion from a year or so back.

http://forums.aaca.org/ubbthreads.php/topics/396899/1938_3_615_Rear_End_Ratio_Gear.html#Post396899

Seems like you may have a shot at a complete swap with a post war car, but earlier cars from the thirties cannot. Gear sets end up around $2400 (maybe $1500 with volume) and OD setups are also pricey.

At least that's what I get from a 2 minute scan of this thread. Let me know if you see a new angle.

[Mark Shaw]

Suchan,

Thanks, I will post some photos on the "Me & My Buick" forum after I get the car home.

[eric_b_1937]

Stuffed big ends? Can you translate to a technical term.

So what was your engine milage when you Stuffed the big end?

I did the same as you, took my car out, drove it hard and found out what needed fixing pretty quickly. I think 65 mph is the best speed for my car. I would like to find out what kind of milage/engine life to expect at that speed.

[Guest ZondaC12]

He said "no scuffing on the cylinder walls" so I would take it to mean he burned up one or more rod bearings/snapped a rod/etc. Bottom end, as we would say. I also gotta say the way these engines are, the bottom end really IS a lot bigger! I guess our cylinder bores are not quite that wide and the pistons are surprisingly small as a result!

Always neat to be exposed to different jargon like that.

Another thing--I believe it's 1940-1955 that the rear ends can be interchanged. So 1940 and up could update the ring and pinion, but anything before, we gotta try and find Century gear sets or of course pay up and have one made. I wonder if they have a CNC machine at my school

[DBT]

Apologies - I must have slipped into Australian backyard mechanical for a moment there.

(I keep forgetting we are divided by a common language).

Paul got it - what you describe as the bottom end. Where the conrod connects with the camshaft. The high speed was too much for it and the white metal melted on two of the ends, the ends became loose with one getting quite out of shape. Very noisy. Amazingly she still could pull quite well.

Quick action of pulling over meant the damage was limited.

At what mileage? Well if you are to believe the speedometer then it happened 80000miles and I'm currently at 80600. Dont think thats the first time round somehow. QED: When we pulled the camshaft out and measured the tolerances it was as about as straight as a banana! Must have been whipping around something awful at that speed.

I read the old email link thanks - Did Glenn Tyler get his gears made up after all I wonder?

Regards

David

[RShepherd]

Regarding the man who might have traded a Model A in for a 1938 Buick and marveled at its power and refinement: If, instead, he traded his Model A for a 1938 Ford V8-60, he probably wondered how eight cylinders could produce so little power!

[danhar1960]

G'Day Dave

I think you mean CRANKSHAFT Dave. The conrods connect to the crankshaft. I remember seeing your '38 in a thousand pieces many years ago. It truly is a beautiful beast.

Danny

[Only Buicks]

Hi All,

I did go forward and had a set of gears made for my 38 with a 3.60 ratio. I cannot however tell you how it all worked out because by the time the gears showed up I had received the right offer and sold the car. So if anyone wants to try I have a gear set for sale. They ran $2,400.00 make an offer. These where custom made by Phil Bray at ORF Corp. These take more than just a CNC machine to produce as they are Hypoid gears and require some pretty specialized gear making equipment to produce. Best way to contact me is by email.

Glenn

gt1059@aol.com

[DBT]

Danny,

Cant imagine why I wrote camshaft... nup.. just a blonde moment.

Interested in your comment about knowing the car before though. Couldnt get a whole lot from Basil when I bought so have relied on the club for a lot of the info frankly.

Any info you have would be great! Latest pics from run into Malaysia are hopefully attached:

[Matt Harwood]

Wow, does that car look great on the roll or what?