67 L79 Ride Height?
I am about to start a "sympathetic" restoration on a very original 67 coupe. I would like to reuse the original coil and leaf springs. Most people I have talked to have not been happy with repo coil springs or retempered rear leafs. The car looks right to me as it sits now but I am not sure how judges will view it, say at a regional meet (nothing was said at a recent chapter meet)- do they 'eye ball' it, measure it, or what? I've looked in the JG but don't see anything under front or rear suspension. I've attached a pic of the car and a drawing from the AIM. As an example the front "J" dimension should be 8.6" +-0.5, mine measures 6.75" so I am 0.35" low. The back "K" dimension should be 9.14" +-0.5 and mine measures 7.4" so I am 1.2" low. Variables- AIM measured with 2 gals. gas, I had above 1/4 tank, Radial height vs biased ply tires. will appreciate comments and advice. Thanks67ForForum.jpgAIMDwg.jpg
-
-
Re: 67 L79 Ride Height?
I have never seen any measuring being done. I think it would have to be way out for any deduction.Big Tanks In the High Mountains of New Mexico -
Re: 67 L79 Ride Height?
James,
IMO, you car sits very nice front to rear and I would not change anything.Comment
-
Re: 67 L79 Ride Height?
James,
To be honest your car looks great at it's current ride height. But as you measured it is below spec. If I were judging your car I would cover that in the chassis section as an overall. Being that it is a direct function of the springs and/or cushions (possibly body cushions too) A deduct of 20% is justified as it covers a number of parts. But understand I think it looks better, lower the way it is.
Be advised as the car settles the camber goes positive. If the camber looks excessive the point count would rise.Comment
-
Re: 67 L79 Ride Height?
I personally think your stance looks great! Nice. ARAComment
-
Re: 67 L79 Ride Height?
Your front ride height is not enough out of spec to eyeball as such, and the J and D dimensions are not measured during judging.
The most common cause of "rear sag" is compression of the spring link cushions. They cost about ten bucks, are easy to replace, and will bring the rear up much closer to spec. They compress and harden over time and should probably be replaced every five years, even if the car sits most of the time.
New cushions will also dramatically reduce rear ride harshness.
DukeComment
-
Re: 67 L79 Ride Height?
Your car ride height looks good. If you check the "C" and "D" dimensions you eliminate tire height, etc. as those dimensions are "differential" between two points of the suspension. If you had side pipes the "J" and "K" dimensions wouldn't apply. I'd check the height using "C" and "D" and see what the true height is....Comment
-
Re: 67 L79 Ride Height?
Jim, Chris Enstrom here. I believe it was you that I met last weekend at the WI Chapter Meet. If so, REALLY NEAT CAR!!! In terms of springs, I ordered the current day reproduction on the front coil springs. I believe I got them from Long Island, but it might have been Paragon. Not sure if that matters. The front ride height on my 67 L79 is right on. For the rear spring, I purchased an Eaton spring. I took it apart (it comes natural, and the springs were originally grey) and painted it grey. Pretty easy process, as long as you are careful and use some heavy duty C-clamps to slowly let things come apart. My car looks a little high in back but the measured spec is DEAD ON. I'm very happy with the Eaton spring. It did, however, take a few hundred miles to settle in. And, as others have already mentioned, ride height is not a part of Flight Judging. It is a key element of the Performance Verification (PV) test though, on the way to the Duntov Mark of Excellence.Chris Enstrom
North Central Chapter Judging Chairman
1967 Rally Red convertible, 327/350, 4 speed, Duntov @ Hampton in 2013, Founders @ KC in 2014, family owned since 1973
2011 Z06, red/redComment
-
Re: 67 L79 Ride Height?
Duke, good point and thanks, since I have almost no cushions left I am sure that is part of the problem. Could it also, in part, be the radial tires? Maybe the wheel center to ground dimension is slightly less with the 205/75 s vs original 7.75s.Comment
-
Re: 67 L79 Ride Height?
Yes, I am sure that would be more accurate. I will try that too (if I can get accurate measurements?).Comment
-
Re: 67 L79 Ride Height?
Chris, thanks for comments. If I decide I have to change springs will go to the sources you suggest. Jim BComment
-
Re: 67 L79 Ride Height?
Both tire sizes have about the same static loaded radius so that's not the issue, and the dimensions you should measure are Z and D, which are independent of tire dimensions.
Many springs are changed needlessly, and many replacement springs result it poor ride height - usually too high. Unless they are significantly corroded they should last virtually forever. "Spring sag" is somewhat of a myth though it can happen if the vehicle is constantly overloaded, which is rarely the case with a Corvette.
Do the easy job first. Install some new spring link cushions and go from there. If they are severely compressed and cracked around the OD - and MANY that I see are - they should receive a conditon deduction in Flight judging. From your description, I wouldn't be surprised if yours are original from St. Louis. I think a lot are on low mileage unrestored cars.
DukeComment
Comment