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MG MGB GT V8 Factory Originals Technical - Classic Conversion's front suspention
|I have been looking into changing out my stock front suspension with 460 lb springs. It rides like a brick. I have a chrome bumpered cross member in the shop and I may use it to get the geometry back in order for a new stock setup, but that is so normal. Anyway I like the setup that Bill Guzman has for his front suspension setup and was wondering if anyone is running it on there car? If so how does it ride? I am more concerned about ride then performance; even though both are important. I drive my MGBV8 from Shelby to Charleston every week, a 240 mile journey one way, and ride comfort is key. Any help would be great. Here is the link to the suspension setup http://www.classicconversionseng.com/front_end_kit.htm|
|If anyone is actually running this setup, sure would like to hear about it. Maybe Guzman will have a comment?|
What profile tyres are you using ?
I found when I changed wheels and tyres from 175x60x14 to 195x65x15 an incredible improvement in ride, no more thumping about at the rear, no loss of roadholding (slightly heavier steering perhaps), best improvement I ever made (apart from the V8 engine,of course)
|hello evan, i have been running this set up on my car for over a year now, i have driven the car alot, went to st louis and back last year, 1200 mile trip, and have put on probably 4000 miles on the kit, i am very happy with it, i like that fact that height is adjustable and have had no issues with steering geometry, i have a 1978 front end, with stock crossmember and i have lowered the car extensively, much lower than a stock chrome bumper car and i am running 16x7 panasports and 205/45/16 yokohama prada's. this front end kit in my opinion is much smoother and tighter than what i had before, which was shorter springs & rebuilt heavy duty lever shocks. the cost is very reasonable roughly a 1/3, when compared to an rv8 set up, i will be driving my car to grand rapids next week and you are welcome to drive it and see what you think, jim|
Do you have any photos of the 16" wheels on your car? I've been considering the same wheels. Also, what is your rear suspension setup? If stock, are the 45's stable on poor roads?
There are 2 kits, the first kit did not have any camber adjustment. Second batch came with camber adjustment. New kit will have Alden alloy adjustable shocks.
The ride quality can be adjusted by simply changing the coil spring, a very simple task, ride height is adjustable. The coil over is mounted close to the spindle thus eliminating the leverage advantage of the lower arm, this allows the use of lower rate springs and maintain a good road holding and smooth ride.
Sway bar links have to be extended if car is lowered over 1 1/2.
Soon, the rear 4 link suspension will be done to match the front.
At the moment I am running Continental Extreme Contact 205/65-15 tires. They are a bit big for the car but they really do handle well.
I havenít noticed the any heavier steering but the front end does shimmy from 65-70. My tires are balanced perfectly and the alignment is good.
Thanks guys for the input.
You may have perfectly balanced wheels, but they still may be out of balance on the car.
MG wheels are not hub-centric, they are lug-centric. Modern cars center the wheels on the hub, and the wheels really are centered. MG wheels are centered on the lug bolts & imprecise drilling of the wheels- hard to believe about British engineering, I know, wear from removing & installing the wheels, the amount of "slop" in lug size vs. hole size in the wheels all contribute to wheels mounted off center.
The tapered wheel nuts & care in installing the wheels help to center them, but they are often off center, none the less. I have a local shop mount & balance the wheels on my cars, then after a few hundred miles I come back & they balance them again while on the car. This is the only way I know of to really balance the wheels on an MG.
With slow speeds & stock tire sizes, the slight out of balance may not show up, but add 15 x 6 or larger wheels, 195/65/15 or 215/60/15 tires & the out of balance really shows over 60 mph.
Will worn out king pins cause this problem? I have a feeling mine have had it. The car only shakes from 65-70. 80 MPH to 120 is smooth as they come. The steering wheel shakes more than anything.
I have the same problem with shimmy on my 73, with original rostyle wheels. From 65 to 75 it shakes like crazy and then above 75 it smooths back out.
I have had the wheels balanced several times to try and address it, but no luck. If it is lug centric I will try to have the wheels balanced on the car.
The question for you is don't you have new mini lites on your car, and shouldn't they be centered?
|Shimmy & shake at certain speeds sounds more like a worn uni. in the drive shaft to me.In a sedan, this usually shows with vibration in the roof. No roof on a roadster. HTHs Barrie E|
|Interesting advice from Jim - here the tyre people say that as new tyres bed down they need periodic rebalancing.|
Evan - even modern cars with 195/205 low profiles tend to slam on potholes and bad repairs. I suspect part of the answer to your puzzle may be 70 profile tyres but if you redo your kingpins and front suspension in original form - use rubber bushes. They don't last but they give the quietest ride.
|New minilites or others will not help the concentricity as they are still lug centered.|
There are many causes for vibration & out of balance tires are only one cause. Out of round tires are another, usually caused by a panic stop & flat spotting the tire(s).
Worn front end parts are definitely a cause, & I suppose a bad U-joint could also be a cause, but when I had a bad U-joint, I felt the vibration at the floor, not the steering wheel. Being able to drive through a vibration has always been an out of balance tire for me.
Remember, the larger the tire, the more you will notice an out of balance. What you can get away with running 165/75/14 tires is not the same as using 195/65/15 or 205/60/14's.
|I've been slowly upgrading the suspension in my '72 V-6. I, too, had a tremendous amount of front end shake at 60 or so, and have been working to fix it by doing the following:|
Keeping in mind I'm running Joe Huffaker fiberglass flares all around, I'm running 14 x 7 Alum. Slotted Mags (ala Datsun Z) with 225/60-14 Yokohamas on the front. Glenn T. and I started with the Kingpins (only needed 1 2nd hand unit), replaced the front shocks, added the EVO II sway bar kit (front and rear), rebalanced the wheels 3 times, replaced the tire rod ends and finally took the stock rack out, and reshimmed it. Also, added the RB steering shaft to try to clear my headers (doesn't exactly clear it, but is much better than before). Once I got it all back together had it realigned (computer 4 wheel), it drives almost like new. Just a minor amount of 60 mph shake which disappears at higher speeds. And hardly any noticeable bump steer.
The alignment printout notes that my camber reads out to 0.4 pos. on both sides. Anyone had theirs read out and gotten a similar reading? Did you notice any abnormal tire wear? I haven't put that many miles on this set yet, so I can't see anything unusual.
Also, I'm thinking Bill's setup (ability to add some negative camber) will make a fair amount of improvement on my car considering the wide wheel/tire combo I have. Any comments.
FYI, I've seen hub centering rings advertised in the car mags. Anyone find any to fit our cars and notice any difference?
|Most of the hub cenetring rings in magazines are to adapt wheels with an wheel to an application it's not really designed for, usually aftermarket wheels use them because they can reduce the number of applications they stock to cover a variet of applications.|
The problem with MG's is they totally ignore the entire hub centering scheme. Look at w hub off any 'merkan car, and you'll find a machined cylinder surface on the hub anywhere from 1/4 to 3/4 of an inch long right up by where the back of the wheel sits (it's called a register). This hub register is usually just a couple thousanths smaller in diameter than the register in the wheel, so the wheel can only be mis-alighted 1/2 the difference of the clearance between the hub register and the wheel register. The register is (supposed to be) machined at the same time the bearing race seats are machined, so the hub cylinder runs concentric with the bearings. If the studs are a little off, no big deal- they are only used to provide clamping force.
MG's have no cylindical register for the wheel, it's just a taper. To add a registration for a hub-centric wheel, it woud be best to shrink a sleeve on the exterior of the hub, machine conical sections to match the taper of the bearing races and assemble an 'axle' using the tapers tocenter the hub on the shaft, then machine the shrunk-on sleeve to the diameter of the wheel register less a couple thousanths (just 2-3 thou, enough so you don't stuggle to put the wheel on.)
I had a set of B hubs machined for longer studs (had a larger splined diameter, and found that one of the stud holes was out 3/32- that's right, .09 inches. I'll beth the prior owner (bought em off e-bay) had a vibration.
IIRC (don't have a Bently here in Michigan yet) nominal camber for B's was 0-1 degree positive. Most modern tires like 1/2-1 degree negative. You can increase negative by re-drilling the hole in the lower arms a bit further out, or redrilling the hole in the shock in a bit, or a combination of the two. I've also seen offset upper bushes ( don't personally like them).
On the race car I'm running about 1 1/2 degree negative on the LH side and about 1 degree negative on the RH side.
|Greg, excuse me for saying that re-drilling the end of the A arms is not a safe way to get camber, neither alongating the shocks mounting holes.|
The easy way to increase camber without installing a new front end, is to make spacers for the lower A arm on the cross member. This mod will give about an added 1/2 degree of camber you will need longer bolts etc., it's an easy and safe way, if it's done correctly. It will also put the A arm parallel to the ground.
I cut out the the plate that the lower trunnion runs against, and weld in a new piece of .125" steel. I usually install a longer piece here so there's still p;enty of meat.
Other firnds have welded a washer offset from the factory hole and filed the ID of the washer to relocate the lower trunnion bolt.
Next plan is develop the lower arms to use offset bushes like Packard used on on levershocks for adjustable camber on the race car.
Not sure I suggested slotting the shock arms- i think i said redrill, which in my mind means plugging and redrilling. I've purchased new shocks with the upper trunnion hole differing in location 1/4 " between the two. I approach plugging and redrilling as a necessary corrective action due to factory inaccuracy.
Now i need to speak from memory- I haven't seen a front crossmember since I moved here in June...
You are suggesting shimming the inboard lower control arm pivot away from the crossmember to increase negative camber? Okay, i'm trying to remember where these pivots are located in the crossmember- I seem to recollect they are in the transition between the horizontal and diagonal on the crossmembr- but I'll say they are on the diagonal for the sake of not generating an argument i can't get data to support, and will suggest the diagonal is 45 degrees, again, nothing here to measure, so, based on these assumptions, any shim will move the pivot .707 times the thickness of the shim. I really have no disagreement that on a factory ride height car this is probably the easiest way to get static negative camber.
I haven't done any geometry, so cannot comment on the reduction in negative camber gain in roll that will occur, but I will make the general comment that I don't believe that a horizntal lower control arm is the panacea for handling woes that is generally believed. In my opinion, the relationship between a line between the centerline inboard pivots and the inner pivot of the rack, and a similiar line on the outbpard and the tie rod end, and relative vertical locations is more importatnt, and a higher inboard pivot may be a desirable feature, depending on the relationship of the links.
My comment on 1/2-1 degree static negative is, i guess, misleading. I really don't care what static is, as long as when the car body starts to roll, I get adequate camber gain to have the tire at 1/2-1 negative on the outboard tire and 1/2-1 positive on the inboard tire.
Bill- for a stock ride height car- I do like the shim idea for stock ride height cars- i'll need to look at this when I get some parts in the barn here.
|Greg," stud hole 3/32" out" I just dimantled a MGC hub and the outer bearing seating fell out! It had not spun and looks like it was factory done!|
|Greg, by adding the spacers and moving the lower A arm out and increasing camber will also change the roll center, since the pivot point is also lowered. Many moons ago it worked very nicely on our lowered 65 race car. It also helps on camber changes during hard turn in. The real problem is the angle of the steering rod, which it can be corrected and put back in the normal angle 5 degrees. The stock A arm produces allot of twist due to the design. If you want a A arm that will not deflect as much then box in the arm, weld one side of the spring perch to the arm. When the a arm is boxed hole saw holes on the new welded plate so that the two bolts can be installed on the other side. If you want a better control of the camber, then relocate the lower a arm pivot points and make longer a arms, at this point you can make a device to adjust the camber.|
Just my two cents worht.
|greg, look at the A arms in my web page.|
This thread was discussed between 02/08/2004 and 11/08/2004
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