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View Full Version : 51 Champ top speed w/o OD



dong
07-25-2010, 10:12 AM
My 51 Champion has overdrive but the OD is not yet engaging. (that is the next project) It sounds and feels good when I shift to second at approximately 15 mph and into third at 25 mph and third up to 35 is good but after 40 it just doesn't sound or feel right. Is this normal and I just need to fix the OD or do I still have a problem with the engine. It starts, idles and accelerates just fine. All ignition components are new (including Pertronix module) carb has just been rebuilt, and I have tried it with various timing settings. It seems to me that it should get a little higher speed than this. I sure would appreciate hearing what your experience with this has been. Thanks

StudeRich
07-25-2010, 11:15 AM
If you are referring to the roaring sound of the engine racing, it should be fine up to about 55 to 60 and after that just sound like it is overworking it in direct gear. It should be able to do short bursts of around 70 MPH in direct and 80 or more in Overdrive.
If it lacks smooth power on take-off and labors at high speed that is a sure sign of a bad tune on the engine, failed vacuum advance unit, incorrect timing or Dwell etc, etc. or even low compression.

tbredehoft
07-25-2010, 12:53 PM
When I bought my '60 Lark 6 in 2002, it had no overdrive. I could get it up to 80, but it was really laboring.

Then I put in an OD transmission. It would still reach 80 in third, but struggled to do so in OD.

dong
07-25-2010, 02:37 PM
Rich, I guess I am referring to the roaring sound of the engine racing. It happens at 40-45 mph. I was afraid to take it any higher. It has smooth power at take off and through the gears. It has a newly rebuilt Cathcart Distributor with a Pertronix module so dwell isn't an issue and neither should the vacuum advance. I have tried it with the timing set at specs and also tried it with both advancing and retarding the timing. I haven't checked the compression but based on how it starts and shuts down I don't think compression is the issue. I don't what else to check but it just doesn't seem right.

okc63avanti
07-25-2010, 02:59 PM
Don,

It might be helpful to check the rear axle tag and see what gear ratio it is. With the 3 speed and OD it is possible this truck was ordered with 4.11 ratio axle and without the OD working that may be part of the issue.

StudeRich
07-25-2010, 03:00 PM
Is there any chance your brakes are too tight? It's easy enough to jack it up and find out if you are not sure.

studeclunker
07-25-2010, 04:45 PM
Don,

It might be helpful to check the rear axle tag and see what gear ratio it is. With the 3 speed and OD it is possible this truck was ordered with 4.11 ratio axle and without the OD working that may be part of the issue.

John, he's talking about a '51 Champion, the economy car of '51.

Don, your car (likely) has the 170 flathead (I would guess) and 55-60 is your top speed with the OverDrive, about forty-five to fifty without. You might be able to make seventy, though I wouldn't maintain that for any length of time. As to your top speed problems with O.D. out, it sounds about right. Often, they geared those Champs really low and they had some serious low-range grunt. Top speed, however, was not stellar.

If your differential is unmolested and you're lucky, there may be a tag still attached to it about the size of a postage stamp. This will tell you what the Differential's ratio is. Likely it's a low one. Fortuneately, the rear end's easy to switch out.

All the same, a Champion is an economy car, so it'll always be rather... leasurely in it's pace.

kurtruk
07-25-2010, 06:54 PM
No expert here but...Pertronix--12V and overdrive--6V? Could that be a problem still to be solved?

dong
07-25-2010, 08:08 PM
The brakes are not too tight, I have been through the system and all the wheels are adjusted properly. The Pertronix unit is 6 volts. The engine is (by the serial no.) a 51. The rear gears (I haven't found the tag) is very low geared. If as Studeclunker says, this is all I can expect then I will get to fixing the OD problem and just enjoy leisure drives. Thanks for your assistance.

pushrod63
07-25-2010, 09:20 PM
My 50 pickup with the 170 and overdrive (which is not yet hooked up) seems to be working hard at 43 mph but taking off without turning over the tires is a challenge.

brngarage
07-26-2010, 12:28 AM
I'm working on a friend's '50 Champion (3 speed overdrive). I've driven it at 65 or 70 MPH multiple times for 20 or 30 miles at a time (of course with the overdrive engaged). It seems very "comfortable" at those speeds. No excessive noise. According to everything I've read it probably has a 4:56 gear which in overdrive is about 3:2. I haven't put a tachometer on it but as I said it doesn't seem noisy or strained.

studeclunker
07-26-2010, 12:37 AM
My 50 pickup with the 170 and overdrive (which is not yet hooked up) seems to be working hard at 43 mph but taking off without turning over the tires is a challenge.

Yeah, those old trannys and clutches took a bit of skill to finesse.;) My '62 Champ pickup is comfortable cruising around fifty or possibly pushing double nickel. However, Ed doesn't like going any faster. Yet the truck has the 259 V8 and three speed tranny. I must admit though, the original 289 had a lot more power and ran a lot faster than this anemic 259. Also, now I have a new clutch plate again, it takes a bit of care for it not to jerk or chirp the tires when starting off. Hey, it's a real truck. Unlike these fru-fru things people drive now (LOL)!;):p

Ron Dame
07-26-2010, 06:40 AM
my '63 Champ with a 6 and OD and 4.27 rear CAN go 60 out of overdrive, but it's not pleasant. In overdrive, 70 is no an issue until I need to climb even the gentlest grade.

clonelark
07-26-2010, 07:16 AM
I've told this story several times but i bought this car in SanAngelo Tx, drove it home (Tulsa Ok) some 500 miles. when i got to the Oklahoma Turner turnpike in Okla.City, i put the gas to the floor and didnt lift till i got to Tulsa (99 to 102 miles)
Never missed a lick and 78 mph was the top speed on level ground. 3speed no OD.
Yes the car is for sale -less the aluminum wheels $2800 not a penny less. Show me a better 60 lark for less.
http://i29.tinypic.com/153md0l.jpg