Aerostar Coil Clarification

[YukonJack]

Been thinking about doing the Aerostar coil springs on my 47 Plymouth. Other than being cheaper is there any other advantage over stock replacements? I've also done a search on this topic recently and found a lot of contradictory information regarding installed height. Some say it raised the front of the car up like a gasser, I saw some that said slightly higher than stock while someone else said a slightly lower stance. Also some have said they cut part of a coil off or a whole coil. My goal is stock height or a little lower. Any advise? I would like this to be the last time I have my front end apart. Currently using stock springs with 1 coil removed and not happy with the ride quality. 

Edited July 9, 2020 by YukonJack

[greg g]

Can't speak to the spring swap issues but you can accomplish a apx 2 inch drop by moving the spring pockets to the underside of the lower A arms.  If you are going to be pullingstuff apart it's worth a look.

[48ply1stcar]

I did front and rear springs at the same time, using Aerostar coils and rear springs from Andy Bernbaum.  The car was higher and level when I was finished.  Had I only done the coil springs I sure the car would look like it was squatting.  I when I replaced the rear springs I commented on here that the old springs had the shape of a handlebar mustache

Edited July 11, 2020 by 48ply1stcar

[Dartgame]

I installed the aerostar springs on my 52 and new rear leafs. Car sat level. I wanted to lower the front end slightly, so I cut off 2/3 of a coil on each, from the non progessive end (bottom coils). Dropped the front end about 1 to 1.5 inches, I dont recall exact amount, but was perfect for what I was seeking. The aerostar coils are a progressive rate spring and will improve the handling & stability of the front end - I like it. These are cheap and easy to swap (about 45 for a pair) i'd try them out if I were you. If you dont like it - its only $45 and you can swap in stockers in that case. It took me about an hour to swap the springs in and out per side - not taking into account time I spent cleaning the lower control arms and painting them.

[milo9rat]

Used them on my 53 coupe with one coil cut and gave it a nice little rake...

[pontiacray]

good afternoon everyone i have a 47 plymouth what year aerostar springs are you using ,i would appreciate any info thank you in advance

[casper50]

I used them here's the result.  No cutting.  47 Dodge

[Sniper]

1 hour ago, pontiacray said:

good afternoon everyone i have a 47 plymouth what year aerostar springs are you using ,i would appreciate any info thank you in advance

 

 

They all use the same spring as far as the aftermarket has available, I have a set I will put in, but will do a serious comparison between the two setups and write it up.

[belvedere666]

I used them on my 50. They are a thicker spring and they don’t compress as much. Overall, my car was a little lower than stock when installed. Maybe an inch.

i think the old ones were just stretchy and bouncy and worn out.

heres a pic of the height difference.

Aerostar on the left. Stock on the right.

[Loren]

As a general rule cutting coil springs will make the ride stiffer.

The reason is suspension movement is spread over fewer coils and they get stiffer the more they are compressed. So in selecting springs more coils = softer ride.

If you want the same comfy Plymouth ride then lower the car by other means such as the spring plate trick.

Leaf springs can be lowered with blocks or having a spring shop reverse the eyes (what they actually do is re-arch the main leaf the other way).

Do not sand blast your springs. Sand blasting heats the surface and the springs lose their strength. (don't ask me how I know that tid-bit)

 

I am not real keen on cutting springs because of the ride issue. An early Plymouth was never meant to be a race car (apologies to NASCAR pioneer Lee Petty) they are cruisers. That said the best compromise seems to be Aerostar springs with lower mounted spring plates, then put a level on the door sill and add spacers under the rear axle spring plates til you get the car level.

I will say one thing, new stock springs (on any car) will improve the ride and are worth the effort. You wouldn't think it possible but I've seen it many times.

[pontiacray]

thank you all so much for the info on the coil spring issue , i am rebuilding the suspension  & i am adding the a cavalier rack & pinion set up ,disc brakes , 318 - 727 combo , again i really want to thank you all Ray.

[Sniper]

If you look at the pics above comparing the old spring to the Aerostar spring you would think that the Aerostar would sit lower. The reason it may not is spring rate.  I do not know what the rate is for the original spring but the Aerostar's are 605 lbs/in.  What this means is that it takes 605 lbs to compress the spring one inch.

 

The load design rate of the Aerostar springs is 997lbs at 10.0 inches.  What this means is that at 10 inches of compression the Aerostar is designed to carry 997 lbs.  So this set the stock ride height when installed in an Aerostar. 

 

How do we determine the spring rate of the old spring?  Well, I weight 240, if I measure the freestanding height of the sping and it's 14", to toss a number out there, and then I sit on it and it's now 13" the spring rate is 240 lbs/in.

 

Mind you all these values are talking about each coil spring, if the total front end weight is 1200lbs then you are only going to compress the springs roughly 1", assuming equal left/right distribution.  Which might be why they ride high as the older springs do have a lower spring rate, compare the spring diameters as a rule of thumb.

 

I did find the spring rate for the rears, 100lbs/in.  but no info on the fronts. 

 

[Dartgame]

The Aerostars are progressive as well, so they are non linear. So when cutting anything off of them be sure to cut the non-progessive end of the spring. 

[Sniper]

I left the variable part out simply because it was starting to get too technical, even my eyes were crossing, lol.  But you are correct. 

 

the tighter the spacing of the coils the softer the part of the spring, so if you cut there you stiffen up the variable rate (or remove it if you cut enough). 

 

But, before you cut anything you need to look at how the ends of the coil are cut, if you look closely at either of the above and you will see the bottoms are cut to sit flat, but the tops are not, do not cut the bottom in this case.  Of the spring will not sit right in the spring cup.  As it sets, the part we most likely want to cut is the part we can cut. 

[rallyace]

The Aerostar front springs are available from O'Reilly's. Part number SP08160.  Price is about $71 per pair.

[Sniper]

Just got done doing this very swap today.

 

My car sits 1 inch higher than it did when I started.

 

Took if for a jaunt around the neighborhood, less  boaty feeling in corners.  Probably need new shocks though.

 

I'll remeasure the heights in a month to give it time to settle.