Reg Evans Posted August 21, 2015 Share Posted August 21, 2015 Hello there,I just purchased a '39 Chrysler royal and wondered if anyone here knows what the standard rear end ratio would be.I'm hoping it's a little better than 4.11 for an occasional freeway run.Thanks in advance !Reg Link to comment Share on other sites More sharing options...
keiser31 Posted August 21, 2015 Share Posted August 21, 2015 The ratio for the Royal could be 4.1:1 or 4.3:1. 1 Link to comment Share on other sites More sharing options...
ScarredKnightfan Posted August 21, 2015 Share Posted August 21, 2015 Congrats, Reg! Cort www.oldcarsstronghearts.com1979 & 1989 Caprice Classics | pigValve, paceMaker, cowValve"My heart takes off on a high speed chase" __ Lifehouse __ 'Falling In' 1 Link to comment Share on other sites More sharing options...
keiser31 Posted August 21, 2015 Share Posted August 21, 2015 (edited) Gorgeous car. You could probably find some stock wheels, hubcaps and trim rings on this website. I have the trim rings. Some of the mounting tabs are missing.... Edited August 21, 2015 by keiser31 (see edit history) 1 Link to comment Share on other sites More sharing options...
trickydicky43richard Posted August 22, 2015 Share Posted August 22, 2015 The rear ratio is 4.1:1 for a standard transmission and 4.3:1 for an overdrive transmission. MIne has an after market 4.1:1 incorrectly fitted and makes it a bit "sluggish' with my overdrive engaged.Luckily I have been able to find a brand new 4.3:1 Crown and Pinion set for later fitment. 1 Link to comment Share on other sites More sharing options...
Reg Evans Posted September 2, 2015 Author Share Posted September 2, 2015 Wow, The car just arrived today and is better than expected. I also discovered it is equipped with an overdrive !!! The seller never mentioned that in his ad. I haven't driven the car yet so I don't know if the OD actually works. Got my fingers crossed though. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted September 2, 2015 Share Posted September 2, 2015 You should have no trouble with the occasional freeway run especially with OD. Your car is equipped with aluminum pistons and insert bearings with full pressure lubrication. Niceties not all cars had in those days. Also, the large diameter wheels make up for the low gearing to a certain extent. Do a compression test. That type engine is prone to broken pistons for reasons I have never been able to figure out but probably not connected to high speeds. As long as you have good compression and good oil pressure you should be good to go up to 60 - 70 MPH. 1 Link to comment Share on other sites More sharing options...
Reg Evans Posted September 2, 2015 Author Share Posted September 2, 2015 Today she's going up on my car lift for a brake bleed, adjust and inspection. After that I'll warm her up and do a compression test.I'm assuming somewhere around 90 to 100 psi would be healthy. Anybody know what the psi would be when new ? On another note the dash knobs have mostly crumbled away. Is anyone reproducing these. I tried the search function and nothing turned up. Thanks 1 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted September 2, 2015 Share Posted September 2, 2015 You are correct 90 - 100 PSI. Your compression ratio is only 6.5:1. 1 Link to comment Share on other sites More sharing options...
trickydicky43richard Posted September 4, 2015 Share Posted September 4, 2015 It's a wonder Wayne hasn't made a comment, Link to comment Share on other sites More sharing options...
Reg Evans Posted September 4, 2015 Author Share Posted September 4, 2015 Wayne ?....Who's Wayne ? Link to comment Share on other sites More sharing options...
Reg Evans Posted September 8, 2015 Author Share Posted September 8, 2015 ???Who is Wayne??? I did a compression test and they all range between 90 - 95 psi. Yahoo....Good news ! I'm going to have to buy new tires for the car. Right now it has some old polyester cord bias ply L78-15's on the "Truespoke" wire wheels. Too wide in my opinion. What would a narrower size be in a wide white wall radial ? The taller the better. Or ,better yet, who has a set of original 16" rims for sale for this car ? Link to comment Share on other sites More sharing options...
Rusty_OToole Posted September 9, 2015 Share Posted September 9, 2015 The closest to original size in a radial, would be the cheapest ones you can find. I used to buy Marshal 791 tires from Walmart in 205 75 R 15 size. They are nearly the same size as a 6.70 15 bias ply. The cheap tires are noticeably taller and narrower than the expensive name brands. Or you can go to a specialist like Coker. 1 Link to comment Share on other sites More sharing options...
trickydicky43richard Posted September 9, 2015 Share Posted September 9, 2015 There are some original 16" wheels on E bay now, well,.... last time I checked, or try Moores salvage yard.An almost correct radial replacement is a light truck radial 185 85 16, but it seems they are strangely not available in the States,but most every where else including Down Under.Rich 1 Link to comment Share on other sites More sharing options...
Reg Evans Posted September 16, 2015 Author Share Posted September 16, 2015 (edited) Another question.........?With the overdrive engaged what would the final drive ratio be ?A standard trans would be 1 to 1 final drive. I'm just trying to calculate the rpm's with my new 205/75-15 tires at 27.11" diameter when in overdrive. Edited September 16, 2015 by Reg Evans (see edit history) Link to comment Share on other sites More sharing options...
Reg Evans Posted September 18, 2015 Author Share Posted September 18, 2015 (edited) I found the answer thanks to FORDification.com of all places.When a 4.3 rear end car is in OD the ratio becomes 3.01. This is determined by simply multiplying the 4.3 x .7 ...... Yahoo ! Edited September 18, 2015 by Reg Evans (see edit history) Link to comment Share on other sites More sharing options...
JACK M Posted September 19, 2015 Share Posted September 19, 2015 (edited) Reg,Different trannys may have different OD ratios.Hi gear is 1 to 1 and an OD gear may be 1 to 1.15, 1 to 1.2 or 1.3 etc. out put from the transmission. (these numbers are just for an example)I suspect that the OD ratio of your tranny is listed in some manual somewhere. Maybe someone on this forum could determine that for you.You can divide the gear ratio in the rear end by the OD out put from the tranny to achieve a final ratio. In doing the math that you provided yours would be a 1.428 OD gear. This seems like a pretty high number to me. Although could be correct I don't know. If there is a way to lock your transmission in the OD gear and mark the drive line and the rear tires (or drums) if easier. Then turn the rear wheels TOGETHER and count the number of times that the driveline turns (it will be a few turns and a fraction of a turn) for one full revolution of the rear wheels it will result in a final ratio and give you some numbers to work with to determine your OD gear ratio. Just make sure that the wheels are rotated at the same speed as each other.So if your drive line turns 3.01 turns in the experiment then you indeed have a 1.428 OD gear.You could do this in high gear and the drive line should turn 4.3 times for one full revolution of the tires. Final drive is usually the revolutions of the wheel to revolutions of the engine. A transmission in high gear is indeed 1-1 but this is not considered the final drive ratio. Kind of fun figuring this stuff out. Edited September 19, 2015 by JACK M (see edit history) Link to comment Share on other sites More sharing options...
Reg Evans Posted September 19, 2015 Author Share Posted September 19, 2015 Thanks Jack. I'm going to do it the easy way and install my 6 volt tach and then do the math. Link to comment Share on other sites More sharing options...
Reg Evans Posted October 7, 2015 Author Share Posted October 7, 2015 Today I installed a Spitfire head on the '39 Royal. The average compression reading on the original head was 92psi. With this new head milled .050 the compression has gone up 13% to an average of 104psi. Anyone know what the higher reading did to the original 6.5 compression ratio ? 1 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 12, 2015 Share Posted October 12, 2015 (edited) My guess is, it raised it. Probably to about 7.34:1. You should feel a little more pep and get a little more mileage. Edited October 12, 2015 by Rusty_OToole (see edit history) 1 Link to comment Share on other sites More sharing options...
Reg Evans Posted October 12, 2015 Author Share Posted October 12, 2015 My wife I did notice that the car had an easier time climbing the hills around here on the way to town the other day. No down shifting where I had to before. Now I'm thinking I'll mill the original head with the Chrysler medallion riveted to it to -.80. I've heard they can be milled even more but I don't want to push it. Link to comment Share on other sites More sharing options...
Guest Bob Call Posted October 12, 2015 Share Posted October 12, 2015 (edited) If you have any doubt about how much the head can be milled you first to do a valve clearance check. Pull the head, don't damage or throwaway the gasket. Clean the combustion chambers in the head to remove all of the carbon build up. Get a package or two of modeling clay (yes the stuff kids used to play with). Press clay into the area of the combustion chamber that is above the valves, put enough to cover an area larger than the valves, make it a least 1/4 inch thick. Maybe rub some Vaseline or spray WD-40 on the valve heads to assure they won't stick to the clay. Put the gasket and head back on the engine and snug down the nuts on the head studs. Then rotate the engine by hand or by bumping the starter. Rotate it enough that all cylinders make a full cycle. Remove the head being careful not to disturb the clay. Finally, using a depth gauge of some type, like a tire tread depth gauge, or, some makeshift method of your own that can be measured with a caliper, and measure depths where the valves have squished the clay. The center of the valve impression should be the thinnest because that should be the high spot of the valve. Using the thinnest measurement you find you can do some ballpark arithmetic. Depth measurement of the clay less thickness of the head gasket, and less a few thousandths for heat expansion of the valve, should give you the number of thousandths to work with milling the head. Someone a little smarter than me should be able to tell you about how much to allow for heat expansion of the valve. Edited October 12, 2015 by Bob Call (see edit history) Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 13, 2015 Share Posted October 13, 2015 If you are serious see if you can find a head off a 1958 up Dodge truck. They used the 251 engine in 2 ton and larger trucks until 1962. They have the highest compression and best combustion chamber shape. If you live outside the US, Canadian made Plymouth and Dodge cars and light trucks used the same engine till 1959. Link to comment Share on other sites More sharing options...
c49er Posted October 13, 2015 Share Posted October 13, 2015 My wife I did notice that the car had an easier time climbing the hills around here on the way to town the other day. No down shifting where I had to before. Now I'm thinking I'll mill the original head with the Chrysler medallion riveted to it to -.80. I've heard they can be milled even more but I don't want to push it.I know of a head with the Chrysler cloisonne ribbon on it... a part # 635... IE...# 635987 or something close to that .What were these cloisonne Chrysler Ribbon heads off of?Two small brass pins staked the medallion ribbon to the head right behind the thermostat housing. Link to comment Share on other sites More sharing options...
Reg Evans Posted October 13, 2015 Author Share Posted October 13, 2015 The head on my 39 Chrysler had that medallion staked to it when I got the car. Not sure how many years they used that medallion or even if it's a factory head for my car. Link to comment Share on other sites More sharing options...
trickydicky43richard Posted October 16, 2015 Share Posted October 16, 2015 I was just sitting outside my garage having a beer and admiring my black 39 Royal, Geeeezzz their a big bulky car, aren't they ??R 1 Link to comment Share on other sites More sharing options...
Reg Evans Posted October 16, 2015 Author Share Posted October 16, 2015 (edited) Well, I would describe them as ...............BIG AND BEAUTIFUL !!!.........from every angle. Edited October 16, 2015 by Reg Evans (see edit history) Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 16, 2015 Share Posted October 16, 2015 (edited) K. T. Keller, head of Chrysler Corp from the mid thirties to the early fifties, weighed 280 pounds and was well over 6 feet tall. He would not approve a car for production unless he could get in and drive it comfortably, even the cheapest Plymouth. So yes, Chrysler made a big man's car. Oddly enough, today when people are supposed to be growing bigger than ever, you can't find a car nearly as roomy as an old Plymouth or Dodge no matter how much you spend. Edited October 16, 2015 by Rusty_OToole (see edit history) 1 Link to comment Share on other sites More sharing options...
Guest Bob Call Posted October 16, 2015 Share Posted October 16, 2015 I heard the story that the interior also had to accommodate him wearing his fedora. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 16, 2015 Share Posted October 16, 2015 I'm 6'3" tall and weigh 290, and I could drive my 52 New Yorker wearing a top hat if I had a top hat. Link to comment Share on other sites More sharing options...
Guest Bob Call Posted October 17, 2015 Share Posted October 17, 2015 (edited) Rusty, your comment about the size of the current crop of cars to meet government mandated gas mileage (or kiloage? for you Canadians) is spot on. I hate them. That's why my old car is a 52 Imperial and my daily driver is 2010 Mercury Marque. The 2011 models produced at Talbotville, ON, were the last of the Panther platform sedans after 33 years of production. The reason I chose to make the Merc my last new car was because it has a real bench seat, no useless space robbing center console and rear wheel drive. Edited October 17, 2015 by Bob Call (see edit history) Link to comment Share on other sites More sharing options...
Reg Evans Posted October 17, 2015 Author Share Posted October 17, 2015 WTF ? Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 17, 2015 Share Posted October 17, 2015 The funny thing is they save nothing. Today's cars are HEAVY. For example a Ford 500 or Taurus weighs more than a Ford Galaxie from the sixties but has half the room. With all the plastic, aluminum, and computer design they should be lighter. They are certainly flimsy enough. I don't know where all the weight goes. Link to comment Share on other sites More sharing options...
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