Rob
Great looking Hollywood.
The exhaust is original style. The front and rear drive shaft appear to be out of phase. Yes a drive shaft out of phase can cause vibration.
Lee O'Dell

Thank you Lee!

Rob

Rob, just curious: do you have a shop manual for this car yet?

Lee what do you mean "front and rear drive shaft appear to be out of phase"? Is that the same as out of balance?

just curious

J

Hi Jon,

Yes, the manuals came on Friday from the club.

Am I asking too may questions... :blush:

I read through the manual about the propeller shaft, and the trouble shooting guide.
There are a number of possible causes for vibrations, the out of phase being just one.
However, I was hoping for some real world experience, especially regarding the transmission vibration, as some of the vibration is present while the car is running, but not moving.
The manual doesn't cover that scenario.

The transmission mounts look okay, from what you can see, does anyone know if they are the newer replacement style that are too hard.

Rob

[img] [/img]

Can't tell from the photo, but you can tell. Stick your thumbnail into it. Is it really tough, dense rubber like the tires on your car (excluding 200mph monsters or drag tires)? If so, they have been replaced. Most likely, they are not original.

I hate to ask an obvious question since you have already answered it, but......are you certain it's running on a healthy 6 at idle? Stick your ear next to the tailpipe (not on it!) and check for firing uniformity. A "ta, ta, ta, ta, ta" sound at 1/2 of rpm frequency is an indication of one hole not performing up to par for various reasons. That will cause a shake at idle, in gear or not, but more pronounced while in. I hope I'm wrong.
F

There is a splined slip coupling on the back end of the front shaft. Hidden by the cross member in the picture.It can be taken apart and realigned. That can cause vibration at speed. Not at idle though.

Russell,

Yes, it is pretty hard rubber. If it is the new, too hard style, what are my options?

Richard and David, thanks, we will get the drive shaft back to the way it is supposed to be.

Frank,

Never hurts to ask more questions...I've been wrong once or twice...[img] [/img]
I'm new to these flat head sixes, but it runs and idles pretty smooth.
When I come to a stoplight with the car in drive, it feels rough. When I shift up into neutral, it is as smooth as can be.
When I'm driving on the highway, at whatever speed, it feels a little rough. If I shift into neutral, the roughness goes away. Even if I rev the engine (while coasting at speed) the roughness is gone...until I drop it into drive.

Rob

Compression on each cyl. ?

I would inspect the drive shaft cushions more closely. The rubber part can sometimes look perfectly good, but the metal ends with the threaded stud may be beginning to separate from the rubber. Also, some Hudson mechanics have on occasion simply drilled out the rubber bushings and inserted a single bolt thru the bushing to hold the drive shaft in place - of course this would transmit any vibration from the cross member back to the body of the vehicle. Just some of things I've stumbled onto in my limited experiences with Hudson during my 66 plus years of playing with these cars.

Jerry's got good thoughts. I've often found that mechanics, who may be very good ones and just not Hudson mechanics simply don't know or understand the ins and outs of hudson automobiles. Every marque has their own unique quirks and engineering oddities and sometimes the Average Bear Mechanic simply is unaware. They sometimes think they are solving one problem by by-passing a problem and they inadvertently create one somewhere else. Case in point could be your center carrier bearing.

With very few exceptions, one rule I try very hard to adhere to is this: I know no matter what I do, or how much time I spend, or how much I study, I will NEVER know as much as Hudson engineers used to know, so don't try and re-invent something simply because you don't understand it's purpose. Again, case in point might be that carrier bearing.

Now, on to your tranny mounts. I have been searching off and on for some original tranny mounts to no avail. I'm pretty sure our reproductions are here to stay, different as they are. Now I'm referring to Hydra tranny mounts, only. Some of the hard shifting, especially downshifting can be eliminated by a smoother running engine and getting your TV cable set up properly. In doing that, I have been able to eliminate most of the hardness, but not all. One thing to remember is that all Hudson engines have a tremendous amount of torque-- way more torque than the horsepower, as far as balance goes. Especially 308's. Hydra-matics, also are a beast of a transmission. Have you found your transmission cooler, yet? How about the cooler lines coming off of the tranny? NO? That's because there isn't any. There is no transmission cooler. Hydra's are such monsters the fluid doesn't need cooling. Think about that for just a moment. Also realize that Hydras were used in WWII in tanks, one on each track.

O.k., all of that fluff to tell you that the Hornets, and especially the Hornets mated to a Hydra are beasts. They have more power and more torque than any other Hudson set-up. In your testing, did you get to experience a Hudson 8 with overdrive? Incredibly smooth, quiet, serene. Hornets, at least all of the ones I was ever in are not like that. Don't get me wrong, I'm as big a fan as anyone of the engineering that goes into them, it's just that you have a bigger tiger by the tail and it doesn't always want to play nice. Some leniency has to be given to the nature of the beast, but of course that doesn't mean that something that is not adjusted right or something else that is worn out does not need to be fixed, by any means.

Check your carrier bearing over very well (it also has to be greased). Check out your U-joints really well (they have to be greased, too). Maybe even take your driveshaft out and have it balanced. It never hurts, and driveshaft failure at 70mph is not fun, take it from me. Sounds like to me your problem is in the driveline itself, not the engine. Also, since you can take it out of gear when you are moving and it smooths out, that tends to eliminate tires, front end problems and wheel bearings. Has that car sat around a lot? When was the last time the chassis was lubed? Don't forget there's two places on the rear end on either side where you have to take out the plugs, insert grease fittings and grease the bearings back there. Lot of people miss those 'cause the grease fittings are not supposed to be left in place.

There's some food for thought!

Compression on each cyl. ?

Richard, from the front; 120-112-105-100-111-116

Rob