Old Engine Sound

[55 Fargo]

Hi all, do any of you get a little concerned with our flatties when the rpm starts to get up there.

Mine has a 3 spd trans, and a 3.73 rear end, my engine runs good but has miles on her, I get a little nervous driving her at speeds over 50 mph, afraid of blowing the engine up.

Am I being a little paranoid on this, do any of you know what I am talking about here................Fred

[greg g]

Most of that noise is coming from the fan. I drove mine 1400 miles last year with 60 + on the clock with no problems. We are just used to electric fans and engines loafing along at 2000RPM in our new cars. Besides your old buggie doesn't have half the noise insulation you contemproary car has.

You are only twisting it 3000 rpm or so. So as long as nothing's banging, clunking, knocking or squeeling, let her sing.

[55 Fargo]

Infact Greg, my old buggie has no headliner or door panels right now, it's not bad with the new exhaust.

I guess I am a little overprotective of my baby, cuz she has lots of miles on her..............Thanx Fred

[Guest rockabillybassman]

I know the feeling. I've got a 3 speed and 3.73 diff too, and around 55mph I'm starting to think.... hmmm, this is really as far as it wants to go for sustained driving.

[Jim Saraceno]

Mine has a 4.125 rear end and it will drive 55 all day long. By the time I'm up to 65, it starts to sound like one pissed off thresher but it still keeps on going. I've had it up to 70 just once just to see if I could. I can but I have no desire to do that again. I'm quite happy to cruise between 55 and 60.

[55 Fargo]

I was just looking at engine spec on allpar, most of you gents have the USA built of course 23.5 inch 218 it has a bore of 3.25 and stroke is 4.375, my Canadian engine is a 25 inch block 218, bore is 3.375, stroke is 3.75, my Chrysler originally had the 251, the 218 was put into it, in 1985, it came form a 1951 Plymouth.

Now because my engine is a shorter stroke 5/8 of an inch shorter, does this mean it can handle less rpm or more than the USA 218 which has a slightly longer stroke.........Fred

[greg g]

Conventional wisdom is shorter stroke more rpm. That is why formula 1 engines have about a 2 inch stroke and turn 18,000 rpms.

But Fred, methinks you obsess a bit much over this. These cars will do 55/60 all day long. Remember people used to travel cross country in them they are not just back road errand runners.

Thin in terms of your Brigs and stratton, other than air cooled vs liquid cooled there isn't much to call between them. Most of these are designed to runna full throttle. This works out to about 3200 with the governor giving 3600 when under load.

All this with splash oiling.

[JIPJOBXX]

The national speed average in the early 40's was just about 40-45 mph and so into day terms your old car if it was pre 1948 was set up to go that speed. I have somewhere in all my computer were I think the highest speed that at was authorized was in California and that would have been around 50. So I would not think to much if you keep-ed your old car at say around 45-50 on the freeway but you might be looking for big problems if you ran any faster than that for a long duration. And remember those old brakes were also made for slower speeds. My car is like a tank but it does run great (1800 dollars in the engine!) but I do treat it with respect. Jon

[TodFitch]

http://www.ply33.com/Misc/speed

[David Maxwell]

I can't recall if you published that in either our Golden State POC newsletter or the Plymouth Bulletin. If not, please consider either or both. If you have, can you provide the issue number? Thanks!

[TodFitch]

I can't recall if you published that in either our Golden State POC newsletter or the Plymouth Bulletin. If not, please consider either or both. If you have, can you provide the issue number? Thanks!

It has only been published on my web site. I guess I should proof edit it again and suggest to the new editor of the region that it could be used. . .

[Guest rockabillybassman]

TodFitch..... thanks for that link, very interestin. That calculator set my mind at ease!!

[bob westphal]

Many of us tend to be too protective of our pride and joys. Years ago when I was using these old buggers as everyday transportation, I never thought twice about cruising at 60-65 on the better highways. Today I have a '35 Pj sedan, a '47 DeSoto Custom sedan and my P-15 CC. to drive on occasion. Doing 60 in the PJ is very noticably a strain on the car and the inhabitants. The DeSoto criuses quite comfortably at 60 and likes to creep up to 65 if you don't watch it. The revs seem to be a bit high while getting up to 60 but seem to smooth out once there. The P-15 hums right along at 65 as my

P-15s did in the many years past. All in all I prefer driving the P-15.

[Normspeed]

Good stuff there Tod. Thanks for the link.

I've always felt my 53 with a 4.10 rear is happiest at 45-55 mph on the open road unless in OD. Even with the OD engaged, I think it prefers to run at 60 or below. Not only the exhaust note, but the overall handling and ride, are best in that "sweet spot". I agree that these rigs can handle sustained speeds of 65 or so forever, especially if equipped with the higher rear gears like 3.73. My 47 2 door, years ago, was a veteran of many runs up and down the east coast, back when Hwy 301 was wide open traveling.

[55 Fargo]

Hi Bob, yes we tend to be like old mother hens with our babies. I just came back from my first night ride on the highway, it dawned on me, a lot of my so-called noise is wind, my car has no headliner, or doorpanels right now, so the wind makes a lot of cab noise. I was only doing about 50 mph, hardly taxing the engine. I do know what you mean by revving till a certain speed, then it smooths out a bit.

My fear, is this, my engine has miles, I am not sure how many, she has decent compression and good oil pressure, but I have no idea how many miles are on her, so I do not know the shape of the bearings,rings timing chain etc.

I was on another website and posted this same question, these guys only drive there Chryslers at 55 to 60 mph, and very carefully, the Chryslers for 46 to 48 had a lot of 3.54 diffs, plus bigger engines with more hp.

One very learned guy told me I shouldn't go over 50 mph with my flattie as she is old with miles on her, he says I may brake a ring, if it hit the the cylinder ridge, first time I ever heard of that.

[bkahler]

http://www.ply33.com/Misc/speed

Tod, great article and thanks for sharing!

Brad

[mackster]

http://www.ply33.com/Misc/speed

Great article! thanks for posting it here!