1967 BB Trim Heights
My 1967 L36 Coupe sits lower than the dimensions listed in the AIM on UPC 3 & 4. The LF is 0.92" and the RF is 0.73" less than the low limit of the "Z" dimension in the AIM. The LR is 0.19" and the RR is 0.32" less than the low limit of the "D" dimension in the AIM. This is a 30K mile Calif car with a rust free under carriage. The coil springs, leaf spring and spring cushions are all original. My questions are, how would this effect judging and is there any corrective action besides replacing springs? Thanks in advance for your comments.
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Re: 1967 BB Trim Heights
Most judges would do nothing. I would take a 20 - 30% deduct in overall chassis section for car sitting too low. I feel the over all appearance is important reflection on the condition of the pieces that comprise it. Regardless if replacement parts or original. Also car should sit level front to rear and side to side. -
Re: 1967 BB Trim Heights
My 1967 L36 Coupe sits lower than the dimensions listed in the AIM on UPC 3 & 4. The LF is 0.92" and the RF is 0.73" less than the low limit of the "Z" dimension in the AIM. The LR is 0.19" and the RR is 0.32" less than the low limit of the "D" dimension in the AIM. This is a 30K mile Calif car with a rust free under carriage. The coil springs, leaf spring and spring cushions are all original. My questions are, how would this effect judging and is there any corrective action besides replacing springs? Thanks in advance for your comments.
John-------
I'd definitely replace the rear spring cushions. If they're original (or, even if they are not), they almost certainly need replacement. These things are almost what could be called a "maintenance item". The downside of this is that it likely will exacerbate the difference in front-to-rear ride height. Other than replacing springs, there's really nothing you can do to increase ride height.
As far as side-to-side ride height as measured to body points (e.g. apex of the wheel opening or bumper height), my 1969 was 3/4" "off" the day it was new. I have seen many other Corvettes, including C2's, that were similarly "off". You could change every suspension piece in the car with NOS parts and you won't change this one bit. In fact, you could do it 5 times with all NOS pieces and you won't change it one bit.In Appreciation of John HinckleyComment
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Re: 1967 BB Trim Heights
John,
There is a couple of ways to improve the ride height without replacing the springs. One not so desirable as it involves placing a screw type spacer in between the coils on the front springs. Another one is to place a spacer under the springs on the lower a-arm. This will raise the front about an inch and is not noticeable unless closely inspected. These spacers are supplied in both hard rubber and metal.
As far as the rear is concerned the outside spring bolts have some adjustment and I suspect if you balance the rear right to left it will improve the front specs.
Usually removing the rear spring and replacing the plastic liners and the cushions (4) on each end of the springs will improve ride height.
A corvette that is 50 years old with a BB is going to have some issues but they can be taken care of carefully without replacing the springs however that is what I would recommend (replacing the front springs). Eaton does have the correct springs for your 67.
JRComment
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Re: 1967 BB Trim Heights
Gene, Joe and Joe. Thanks for the reply and suggestions. Gene, not sure what you meant by "overall chassis section." Were you referring to the total 35 condition points in item #7 (Front Suspension) or the 4 condition points for the front springs in the same item? Or is there another item I am missing?
JohnComment
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Re: 1967 BB Trim Heights
John, it does not matter where the judge spells out the description for the deduction but your suggestion to put it with the front and rear suspension area is a good one. But makes correlation between the parts and car's sitting on it's suspension difficult to spell out. So I use the overall cleanliness #15 to describe the car not sitting on the over all suspension as it should. True it is not a cleanliness thing but is a condition thing which is in the condition column. Where ever ya put it be sure to score it completely so the owner understands the reason it was deducted.
The leaf spring may appear very straight and no arch and the front coils may exhibit coils extremely close to one another. As mentioned the cushions will in most situations of this nature look flattened out. Each of these has condition issues. But if these parts were replaced and the car still sits as presented there could be more issues in the originality column.Comment
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Re: 1967 BB Trim Heights
John------
One more thing I should have mentioned: the primary reason that automotive springs, both coil and leaf, degrade is due to erosion of metal caused by corrosion. If your car lived its whole life in California, corrosion damage should not be a big problem. However, even in California there can be corrosion damage to the leaf springs. Water and salts (not sodium chloride, of course, but other naturally occurring salts) get between the leaves and corrosion begins and proceeds inexorably. Usually, this will be found on the non-tension (upper) surface of the leaves which were not coated with Ionoklad. If the car has been driven much in winter months, you might find this problem is quite significant in terms of leaf damage. The only way to determine it, though, is to remove the spring and disassemble it.
I might also comment on the coil spring "revivers" that JR mentioned. The twist-in coil spring spacers are easy to install. However, they are a very poor way to increase spring height. Many years ago when I was a real knucklehead I installed them in a 1966 Chevelle SS 396 I bought new. "Jacked up" front ends were a trendy thing to do in those days. I didn't leave them in long, though. It made for a rough ride and lots of front end noises. They can also fall out if you hit a pothole. NEVER again. The spacers installed under the coil springs will work well. In fact, GM may have used these in SERVICE on some 1965-E66 Corvette big blocks to resolve owner complaints of low front ride height. However, to install these you have to do pretty much everything that you would have to do to replace the springs. So, in that case, you might as well just replace the springs and be done with it.In Appreciation of John HinckleyComment
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Re: 1967 BB Trim Heights
Thanks again Guys. I can't yet speak to the rear leaf spring, but I know for certain the coil springs had only minor surface rust and no pitting (see attached pictures). Joe, you and many others on this forum have mentioned that the primary reason for spring fatigue is corrosion. Since that does not appear to be the case, wouldn't there be a possibility that replacing the springs might not solve the front height condition? It sounds like the installation of spacers under the springs would result in a known result, but would also result in a possible point deduction.
Maybe I'm putting to much emphasis on the possible point deduction as the ride and appearance are both acceptable to me. And just maybe as suggested, the car has "always" been like this. Thoughts?Comment
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Re: 1967 BB Trim Heights
John, When I restored my 67BB I installed new NOS front springs. This brought the front height dimensions in spec....for about 6 months, after which the front again had the "BB droop". I went back in and installed some GM spring donuts that I found at YearOne for a Pontiac. This solved the problem and has lasted for years. As stated earlier, a rebuild of the rear spring rubbers, inserts etc. will bring the rear into spec.Comment
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Re: 1967 BB Trim Heights
John------Thanks again Guys. I can't yet speak to the rear leaf spring, but I know for certain the coil springs had only minor surface rust and no pitting (see attached pictures). Joe, you and many others on this forum have mentioned that the primary reason for spring fatigue is corrosion. Since that does not appear to be the case, wouldn't there be a possibility that replacing the springs might not solve the front height condition? It sounds like the installation of spacers under the springs would result in a known result, but would also result in a possible point deduction.
Maybe I'm putting to much emphasis on the possible point deduction as the ride and appearance are both acceptable to me. And just maybe as suggested, the car has "always" been like this. Thoughts?
What is the FREE LENGTH of this spring measured from spring end to spring end?In Appreciation of John HinckleyComment
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Re: 1967 BB Trim Heights
I have looked high and low, but I cannot find my notes with the free length dimension. The wire size is .60".Comment
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