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John Morralee

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I have just got my '63BJ7 'frame-up'restoration on the road all is going much better than I deserve 'cept for a very hard/bumpy ride.The orig.springs were shot: an autospring dealer and my self tried to guestimate a pair of rebuild replacements,seems like we got it wrong,much too hard.When the snow falls and I crawl under to replace these I assume a leaf or two removal will do.Is there a measure (spring rate?) which I can work too?Thank you in advance.John M.
 
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I assume a leaf or two removal will do.Is there a measure (spring rate?) which I can work too?Thank you in advance.John M.

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John,
Somewhere between 350 & 420 pounds per inch spring rate. If the rate is too high or the arch is too much the axle will be in the full rebound position, touching the frame. There should be about two inches of rebound travel with normal weight in the car. If its just the arch that is too much, a couple of people sitting on the rear bumper should lower the car an inch or two. This is in addition to the allowed for rebound static setting or now four inches of rebound travel. If the rate is too high the extra weight will not move things at all or less than the two inches. Kind of a balance between arch & spring rate.

Standard ride height is 27" from lower center fender wheel opening to ground. 28" on phase 2 BJ8's.

It's surprising what a good spring shop can do without even disconnecting the main leaves.
D
 
Dave, thanks for all your help. You truly have a gift and a wealth of knowledge.
Now the question: I have a 60'BN7 and it truly is too low to the ground. I have replaced all springs with new ones from Moss Motors. The muffler drags over the slightest imperfection in the road surface. I know the early model Healey's were very low, and since I added the new SS muffler it seems even lower. Is their a way to raise the ride height, particularly in the front?
Thanks.
 
Johnny; Basically the early cars do not offer much in the way of improving ride heigth.However, based on my experiences and observations the mufflers generally are the culprits in most SS exhaust system applications.Because most of the mufflers are round, they set lower underneath the car.-FWIW---Keoke
 
Johnny,

Changing the front ride height is not quite as easy as changing the rear. The numbers used below are ARBITRARY for illustration purposes ONLY.

Due to the front suspension leverage ratio (the spring is located somewhat inboard from the wheel attaching point) the wheel rate will be about 1.4 less than the spring rate.


Springs are rated by the number of pounds of force required to compress the spring one inch. Eg. 400 lb/inch requires 400 lb to compress the spring one inch, 800 lb to compress it two inches etc. When the spring is installed, it may start out at 12" long free length. When installed it may be eight inches long. This four inches of preload would give 1600 lb of spring support at this installed length. 1600/1.4 = 1143 lb at the wheel. If we assume that there is eight inches of total wheel travel available, this spring combination would place the suspension at the center of it's up/down travel with four inches available for rebound & four inches for compression.

A 13" free length spring of the same rating would compress to 9 inches for the same weight on the wheel. This would raise the static ride height by one inch. Leaving about three inches for rebound travel & five inches available for compression travel. If you use up too much of the rebound travel in an attempt to raise the car, the suspension will top out with a jolt each time it rebounds. This can be partially compensated by increasing the shock rebound damping.

I know what you mean about muffler clearance. They just didn't leave any place for the muffler when they designed the car. Mine has 4.5" of muffler clearance. At this point, a couple of questions come to mind. Is your muffler fatter or mounted lower than it could be? Does your car presently have the standard ride height of 27" from center fender wheel opening to ground? Maybe Moss sent the wrong springs, back to the 27" height question again.

There are a couple of ways to raise the front, none easy;

Install longer springs of a similar rate. There is some variation of spring lengths & rates between the various Healey models. Unfortunately I have never been able to find the exact numbers anywhere. Maybe someone can help?

Install springs of the same length but of a higher rate. This will raise the car but make it ride harder.

Install 3/4 inch spacers between the existing springs & their seats. This will raise the car about one inch. This would be my personal CHOICE, since spacers should be readily available from spring shops.

The phase two BJ8's finally addressed this problem & revised suspension & springs to raise the car about one inch front & rear.

Since I have never personally had this problem, you will have to rely on the input from others to find an exact solution. I'm mostly talking generalities. I have found Denis Welch UK to be very helpful with email advice. I know that they offer spring rates from 400 to 1000 lbs/inch. https://www.bighealey.co.uk/

If you wanted to lower the front there is a quick & cheap solution. Not the case this time.
D
 
"Install 3/4 inch spacers between the existing springs & their seats. This will raise the car about one inch. This would be my personal CHOICE, since spacers should be readily available from spring shops."
Thanks again Dave. I'm going to give this a try. I don't know why BMC didn't think of it. This might be a ridiculous question, but are the spacers mounted on the lower seat, or the upper seat? Or does it really matter?
Oh, BTW I've mounted the new SS exhaust system (incl. muffler) as close to the body as possible.
 
Looking at the side of the car, at 12 o'clock above the front to rear center of the tire - the wheel opening edge. About 7.5" down from the chrome bead. Same for the front.
D
 
John, you didn't really mean to list this post an an event in the calendar? (that's one of the checkboxes when you make a post, but it's usually for posts that are about British car events, shows, etc).
Basil
 
Just how close can the exhaust system be to the underside of the cars. Can they be raised especially in the rear? There are spacers on the bolts that could be cut down. Or am I just going to increase the heat inside exchanging one problem for another?
 
/ubbthreads/images/graemlins/savewave.gif Hi T.H., I think the limiting factor in raising the exhaust system up is that the pipes should not[impact] rattle at the outrigger cross over points.Additional thermal insulation can be placed behind the heatshield under the car and under the front floor mats to ward off potential heat buildup in the cockpit.-FWIW---Keoke
 
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Just how close can the exhaust system be to the underside of the cars. Can they be raised especially in the rear? There are spacers on the bolts that could be cut down. Or am I just going to increase the heat inside exchanging one problem for another?

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It is kind of a compromise all the way around. The parts must be somewhat flexibly mounted to reduce strain on the joints. Additionally air space makes a very effective insulator. If you reduce the spaces, there will be more heat inside which should be somehow shielded. Fires in the passenger compartment or boot are not fun & have been known to happen.

If you don't care about originality, the more simple the system, the less problems. EG. two into one, into one with a straight out exit is much easier to fit in & to insulate. A side exit tail pipe can eliminate some of the rear drag problems, but has it's own shortcomings. Is it worth all the trouble to gain 1/2" of clearance? Only you can decide.

To go way far out, the rallye cars often use a radically reworked body in which the muffler is mounted vertically in the bottom of the door opening & uses a side exit. It gets the parts completely out from under the car.

I have not investigated the Jag system of straight pipes back to rear mounted mufflers, but it appears the underside of the Healey body doesn't allow much room for mufflers in this location.

I don't think there is is an easy way to solve the problem, & most folks just live with it.
D
 
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