Thread: irs suspension

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Hi,
I have been reading some of your advice on the web as i am concerned about how my suspension has been fitted.
My vehicle is a 1939 Chev truck that will have a 350 fuel injected motor.
My springs are angled outwards . Will it ride ok ?
Do you forsee any problems with the spring angles and should the chassis have been boxed near the crossmembers ?


Regards
Trevor Scullard
tvscullard@bigfoot.com

extra pic

Springs should be angled outwards, the further the better but 30 degrees at full compression is the recomended maximum. I would suggest boxing at least the back of the frame, but first you may want to narrow the rear of the frame and move the top mounting locations inboard to get the desired angle on the shocks. I would recomend boxing the frame it's entire length with 10 ga. steel. One other thing, those rivets may have been adequate in the low horsepower original car, but with modern horsepower and traction the rivets should be replaced with welded joints. JMO

To go along with Daves comments, envision the axle movement up and down. The lower arm pivots on the bottom of the center section, the axle at the inner u-joint. That lower arm strikes an arc moving in at top and bottom of its outter end. Your shocks, as they are now, point in the opposite direction which will cause a bind to upper movement.

whats the rate of those springs scully? looks like a lot of spring.

What was the source of this rear suspension arrangement, a 'Vette or what???

This one's a jag Richard, except for the orientation of the coilovers.

Another wee word of advice Scully, (you most probably know this already, but,) while you can still get at them, ensure your brake pads are in tip-top condition. The pads on those are real pigs to replace. Believe me.I've had the skinned knuckles and conversation with God to prove it.
johnboy

Originally posted by Bob Parmenter
This one's a jag Richard, except for the orientation of the coilovers.

thanks BBB

scully, ideally, the centerline of the shock should be at a right (90 degree) angle to the control arm at full bump as viewed from the rear of the truck. That will insure increasing spring rate as the control arm goes into bump. What you have now is a decreasing spring rate arrangement (not good). It looks to me like you're gonna have to cut the frame out and rebuild it to make room for the top shock mounts if you want to continue using the bottom mounts as they are.

Like Mike, I'm also wondering about the rate of the springs you're using. I'd start with something in the range of 150-170 pounds per inch on each side (2 springs on each side at 75-85 lbs each). If you get it sprung too heavily, that light truck rear end is gonna be real skiddish on bumps.

Little bit more info on those coil springs. I am running only two Jaguar coil-over springs in the back of my A model. Tin body duece chassis supra box and small block chev, not to heavy but not to light either. What I am trying to say is; With only two standard jag coilovers my rearend is still stiff! I am contemplating getting a rate change once I have bedded in all the suspension. (I also have the gas tank mounted in the rear.)

Good luck to you and welcome to CHR.

Andy.

This is a modified Jag unit (Ford, Jag, and Chevy slpiced) from Heidts for a 32 Ford

Next photo shows the rear view with spring angles.

Also notice the lower link arms and extra pinion links to an additional cross member. Might be very desireable for a heavier, high horse application.

I'm running a very light ride with a modified ZZ502/502. May be a little overkill but I really like the engineering Heidts put into this ..........

Best Regards

OOps ...........

I'll try to reduce the next one a little ...........

Hi Guys, thanks for all the advice. I have lots to think about.

I may have too much spring for a relatively light truck, but it is easy enough to get thinner springs made up. Or run it with only one spring and 2 shocks per side. The setup has been overhauled with new pads, disks and brake pistons and shocks.
I will be adding additional pinion support.

I feel i need to alter the angle of the coilovers closer to the original Jag configuration. Which is my biggest concern and original question.
Is there much difference connecting the rear radius rods directly from the lower arm to the chassis as per brackets in my pic(parallel). Or should the rods be connected to an additional cross member and angled in towards the center as in the pic Kitz has shown ?

Regards Scully

Okay...I'll take a different view. It looks like you can move the lower mount outwards instead of moving the upper mounts inwards.
This way you can drive the car as is to see how it does. If you are not happy you only could move the mounts outwards by removing the wheels & coil overs.& welding in new mounts. My guess is that it will be fine as is.

Because the spring/shock is almost straight up you will new less in/lb springs & a roll bar(sway bar).

Let us know how it turns out.

Don