C4+3=/=C7

From the Corvette Central C4 suspension overhaul guide:

"All C4 Corvettes have short and long spacers to set the initial caster; 1984-1985 Corvettes will have long spacers at the rear (closer to the firewall) with short spacers at the front. 1986-1996 cars have the spacers reversed: short at the rear and long up front for increased caster. In the shop, we set all C4s up with the long spacer up front, short at the rear. The best policy is to record where the shims where and place them in the same position. Once the suspension service is completed, all C4s receive the same suspension alignment set-up specifications. The immediate result is a huge smile on the 1984-1985 C4 owners face."

Could anyone explain what's actually involved in changing the setup to the '86+ geometry? Would anything other than simply putting rear spacers on the front and fronts on the rear be necessary? The whole smile on owner's faces part sounds very appealing. Any advice would be appreciated.

WVZR-1

Can you actually confirm on your '85 that the spacers are arranged as that article implies?

C4+3=/=C7

I'm afraid not at the moment, but I will head over to the shop tomorrow morning to see whether the article's description of the early spacers is true of my car. I additionally found this excerpt in another article by the same author:

"In the shop, I swap the thick spacer to the front, placing the thin at the rear to achieve at least 6 degrees of positive caster for the best possible handling. If you look at any original 1986-1996 Corvette upper control arm, you will find the washers are thick at front thin at the rear."

I'm glad he elaborated here as the switch seems very straightforward. I will need to get to the shop somewhat early tomorrow so I should probably get some sleep in before then. I will post an update based on what I can gather from looking at my car. Thanks again!

WVZR-1

Straightforward seems to imply easy/simple and I doubt that. You've got your spring replacement yet to do so you could roll it all into the same labor operation so maybe straightforward could apply.

Measure, measure and measure again.

C4+3=/=C7

I didn't manage to get to the shop today (closes at 11:00 or 12:00 on Saturdays), so I can't say for sure whether I was speaking too soon in my assumption that it will be a simple swap. With everything disassembled and just taking up space, though, I'll definitely be heading over the first thing on Monday. I'll be making sure that everything is as described, though, as this suspension has obviously been apart at least once. Really nothing much to do between now and Monday. Let's see if I manage to not screw up royally on at least one thing...

Sorry to digress, but I was planning on heading over to WV for some nice mountain roads once this job on the car is done... would you know of anywhere to look for good driving roads aside from route 15?

WVZR-1

You would be fortunate to just maintain the 'legal limit' on 15 anytime, day, night or what ever. There's some better MD roads out and about where you can see 'thorough the corners' and I did those on Sunday AM as close to the break of daylight as possible and planned on being DONE before 7:30 - 8:00 AM.

We've got some great roads here in WV but if you don't know them you're much better off staying away. Summit Point has as many twists & turns as you would care for. As fast as you dare and 'legal too".

C4+3=/=C7

Thanks for the insight; it's definitely preferable to be able to be able to anticipate the next section of road when you're not familiar with it. However, grandparents are in Winchester and I should probably visit pretty soon anyways given that situation, so WV roads seem like a logical option for me because of convenience. I'll probably do a Friday At The Track next year... always wanted to do on-track driving. I still will get around to finding MD roads as well. But as for the lack of familiarity with the roads, I'll be taking it easy--it's not that I want to drive faster than would be advisable--I just want to enjoy some twisty roads and get away from the unenjoyable task of dodging potholes in heavy traffic that comes with living in the D.C. area. The one good driving road within 30 minutes is two miles long, and isn't all that entertaining after several traffic ridden trips to and from there through Route 1 either.

C4+3=/=C7

I made it to the shop this morning and it seemed that the switch was already made to thick front spacers, thin rears. Here they are (right and left upper control arms were set up the same way):
Front:



Width of the washers.is 2:1 (front to rear... and about the right 3mm and 6mm), so if these are actually the correct spacers, everything is luckily set up ideally.

Rear:



I'm honestly not completely sure whether or not these were the spacers being referred to by the guide, but it's as close as I could find.