The ol 49 - 54 chevy front end debate

the words in bold were a quote from R pope. I love my FATMAN ultra low.

people who use "pinto" in thier explanation of why they don't like MII need to do a little research.

 

Old cars were setup different. they often ran at least 1-1/2 degrees negative caster (kingpins tilted foreward at the top) which was alleged to ***ist in steering effort while moving and to help the car track the ruts in some fashion I do not remember.

What the book recommended for high speed performance is to adjust in 1-2 degrees of positive caster (kingpins tilted back at the top).
I do know for certain that the negative caster was the stock recommendation as per motors repair manual.
(on some cars more-so the older kingpin independent fronts)
raking in positive camber will require slightly more steering effort but will result in a stronger return to center effect and more certain feel at high speed.

"Tolerance Stack" is the technical term for some small like .010 play in a system of seemingly tight components to add up into a large amount of slop

.050 slop at a radius of less than an inch could end up being a quarter turn of the wheel which is why you really can't blame your box until you get everything else right.

In a turn negative caster will do the shopping kart wheel thing if there's any play in the steering.
those steering components will be getting pushed around...like trying to push a wet noodle straight

Positive caster will have that suspension always trying to return to center and it will pull the steering slack tight like pulling a string straight

It is also recommended that you run some toe-in
any measurement across the front of the tires should be 1/16-1/8 tighter that at the rear.
Wont' that wear the tires out faster???
No, because once the slack in the steering and front end is taken up by road forces the tires will be turning parallel.
If you don't' have any toe in... your tires will actually be toed out when running even if perfectly parallel when measured and the front end will feel "findy" and will want to wander.

I remember why the neg kaster now...
Positive caster places the point at which the tire meets the road above and behind where the kingpin center intersects the tire.
The kingpin is dragging the tire behind it. and gravity directs the kingpin to pull the tire downhill
It will track straight, return to center and seek the low place in the road

negative caster also has the tire meeting the road above where the kingpin center meets the tire but in front of that kingpin center.
The kingpin is pushing the tire and while gravity is trying to straighten the tire to center... anything that strikes the tire causes it to deflect in the direction of the opposing force.
It will track straight and return to center on perfect pavement but will try to climb up anything offering resistance. This was so the car would track safely the higher ridge of the road where traction is good instead of running in the ruts.

The factory tune of negative caster had nothing to do with the superiority of the suspension design...It was a compromise to cope with inferior roads to today's standards

 

I wonder if anyone sets up their MII with anti-dive
Most aftermarket kits I've seen have the upper and lower control arms parallel looking from the side of the car.
The upper arm actually needs to be rotated several degrees up in front and down in back compared to the lower arm.
The rotation of the wheel pushing against the brakes forces the upper a-arm to push it's ball joint foreward a very small amount and down toward the pavement. this braking force actually lifts the front of the car against the dive created while braking.
If both A-arms are parallel to each other... there is no active anti-dive and the shocks (p***ive) are where anti-dive must be found if needed.

 

I've got two Chevys:

51 Coupe with a completely rebuilt stock front suspension, dropped spindles and disc brakes. 261 6 cyl + 5 speed S10 ******. This thing drives beautifully. I can do near 100 MPH on the freeway and it goes straight and feels great. The tires are Diamondback WW's (they are a great tire). It is not power steering but with the stock large steering wheel it has good leverage. This thing is a pleasure to drive. I actually like it better ON THE FREEWAY than my 53 Coupe with the power steering Mustang suspension. The Mustang is a touchy suspension. Yes, I can park WAY easier but I can also dart in the other lane much faster without knowing it but I gotta' say I really like the stock suspension...better no...I like it differently for different reasons.

Just my two cents...I mean Chevys

 

I also felt that if the front end was good enough for the Corvette to 62, it's good for me.

I redid my 54 210 a long time ago. All the bushings and pins except the lower inners, they were good. The idler arm pin and bushings. New drums and linings dropped spindles. Made my own kit to convert to roller bearings. Put a big sway bar on the front from a 76 Nova. Put an aftermarket sway bar on the rear. 2 inch blocks on the rear. Open drive line. Origonal Stock springs front and rear. New stock shocks.

One thing I found when fixing it was all the attaching bolts that hold the front end to the car was loose. This is important.

Reset the front end to get as much caster as I could in it, still not much. Tried to get the camber as close to neutral as I could. And one side is better than the other. I run Radial tires. 1/8 inch toe in.

The car is a dream to drive. It can lock the wheels if panic arrives.

I normally cruise at 70-75 on the I-States. and have been over 100 in it. It's very comfortable. and predictable.

235 with 2.93 rear and 1:1 trans.

Grease the front every 1000 miles or after running thru a rainstorm to flush the water out.

Frank

 

I daily drive my 54 and love it. Just rebuild it and enjoy. Dont forget the steering bellcrank bushings and pin, thats where most of the problems ive seen come from. My 54 is the nicest steering car ive ever owned. 1 finger it down the hiway at 75mph all day no problem. And you can get every part for it fairly cheep. Your dollar is around $0.90 US isnt it?

 

Torchmann, I found your tech really interesting, and I read it a few times, but I'm tired and not quite following. Do you suggest that I run the 1 1/2 degree negative caster as per the manual? One frightening occurrence for me is when I turn a corner and find the steering get away on me. I'm happy to keep the stock front end if I can make it super nice to drive. Ryan, that is a good point about the engineer, these projects can get frightfully expensive when engineers come into play.
The bellcrank (idler arm) bushings are always a sore point with these cars. I did get an engineer to rebuild mine, he did a thorough job of resleeving the device and giving it a new kingpin, alas it has found a way to move again. I do a whole lot of miles in my car. What about the corvette bearing loaded idler arms? Are they worth looking into?

 

Gas pumper, I'd like to hear more about your front end set up. How is your idler arm? By getting as much caster in the wheels as you could, do you mean tilting so the wheels sit further back? The whole caster angle thing is new to me.

 

49RF...sure, you have no actual "Pinto" parts on your MII setup, but the geometry is the same. It was still designed for a 60 mph 4 banger econobox that weighed in at half what a '54 Chev weighs. That stuff is great for impressing teenagers at a car show and rolling it on and off a trailer, but on a rough road and a mean side wind, I'll stick to the original suspension. The MII might work fine for years, but when it pays off and goes all squirrely on an unexpected fast maneuver, it's too late to change your mind. I wasn't kidding about them going end over end on a straight road! A side wind loaded the off wheel, it tucked under, and the car tripped over its own wheel.

 

there is a lot of information in the FATMAN catalog. I'd say get one and read.

you are just so incredibly wrong on this it is not even funny.

 

I'm with the rebuild the stock set-up bunch. Works great on mine. Williams bros sells the V-8 mounts to go right into the chasis.


Tim

 

my 50 chevy is a daily driver and I put minimal amounts on money into it. I think it handles fairly well. But if I could afford it. I would have gone with a late model clip of some kind. I am sure there are many good options out there for you. I have been told camaros are good candidates

 

I'm yet to have the time to set up the camber, toe in and caster angle on the stock set up. When I do I'll be sure to post my findings. I don't want to be too hasty to dis the front end without a proper set up. Hopefully get going on this on Saturday.

 

I'm with keeping the stock frontend also. IF you decide to keep yours, there's a sticky in the 49-54 forum over on ChevyTalk.Org on how to rebuild one of these front suspensions, by "DZauto". We kept our stock frontend on our 51 Bus Coupe, but blocked it up for a pseudo-g***er look. B utch/56sedandelivery.

 

I just installed a jag front end on my -51 this week. Its from a xj40, im very
happy with the result. Cant wait to test drive it

 

Hey everyone.
Well, yesterday I decided to get to work on the front end of the chev, moved the caster angle at the top as far back as it would go, got the camber sitting parallel with the back wheels, and gave it about 1/8 toe in. I can say that it drives really nicely. Dead straight and a good return to centre. The front end is largely pretty fresh except for the lower inner control arm bushings. Drums are worn though so I'll convert it to discs when I have a chance, but as far as it all goes I'm happy with how this car handles now.

 

bttt any more build pics?

 

I agonized over the same decision. Jag/MII/Clip it/stock.

In the end, I looked at my needs: lowering it now, maybe bags in the future, maybe discs in the future. Power steering isn't a big deal to me- granny handled these things just fine when they were in good condition, and without steamroller tires.

I rebuilt the stock front end. Just finished it up a couple of weeks ago. Still waiting on brake parts for getting it back together, so I can't give any feedback on driving it yet.

If I ever got the hair up my buitt to swap out the front suspension, I'd go with the Jag. Flame away, but I'm not paying 2-3K to put a Pinto front end under the car.