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Got a couple small things accomplished today. In the process of replacing rear shocks, I was revisited by my delaminating spring. I can't tell if the cracking is getting worse, but it's probably time to replace it. I hear a lot about VBP stuff, but are there any other recommendations? I like the stock ride height, but it'd be nice if the suspension was a bit stiffer in the rear. Problem is, I don't know what the stock numbers are, so I have nothing to compare to when shopping. It seems like the front is really tight in comparison to the rear. It's especially annoying to have the exhaust pipes scrape on the road every time I drive over a small bump...
The composite base suspension 82 spring rate (gymkhana sport suspended 82's used an 8 leaf steel spring) is 183 LBS which is probably the softest spring rate ever used on a C3. As a comparison my original gymkhana sport 78 steel spring was 292lbs and I replaced it in 1986 with a VBP 360 composite which is still on the car and may someday go to a 420 composite. A 183lbs spring is way too soft, in my opinion, and you should look at least at a 300lb replacement since you have a base car to get rid of the floaty Cadillac like ride that the 81/82 base cars are known for.....
IF you had to "re-index" your lower shock bolt due to it was rotated incorrectly...and when you taped it out and looked at your splines on the bolt. IF those splines were really flat and worn out....do not be surprised that if one day you look at that lower shock bolt and it has moved again....that is telling you to put a new one in with really good splines that will lock that bolt in place.
IF when you re-installed that lower shock bolt and seated it and it did not take any effort to get it to seat and bottom out....that is an indicator for me that a new one needs to be installed. Becasue...when you install a NEW lower shock bolt...it is a process of tapping and tightening the castle nut to get it to pull in...much like a new wheel stud would do. Simply using the castle nut to draw in a new lower shock bolt is something I WOULD NOT do.
DUB
I should mention it was only off by a few degrees. Just enough to not allow the lower mount of the shock to slide on smoothly. When I tapped it it out a ways, I could adjust the mount up and down a few degrees. Is there another flat spot on the inside of the spindle support that prevents rotation more than a few degrees? Whoever installed this one, installed it at it's maximum upward position. I just rotated it downward a bit, and then pulled it back in.
Is the worry in pulling in a new mount damage to the spindle support? If the fit is indeed that tight, I could potentially see stripping out the threads on the nut/support if the part were new.
The composite base suspension 82 spring rate (gymkhana sport suspended 82's used an 8 leaf steel spring) is 183 LBS which is probably the softest spring rate ever used on a C3. As a comparison my original gymkhana sport 78 steel spring was 292lbs and I replaced it in 1986 with a VBP 360 composite which is still on the car and may someday go to a 420 composite. A 183lbs spring is way too soft, in my opinion, and you should look at least at a 300lb replacement since you have a base car to get rid of the floaty Cadillac like ride that the 81/82 base cars are known for.....
Awesome link. Thank you so much! I can't believe I've never seen that before. What's interesting is that the VBP site lists the 300 lb/in spring as the stock spring for 80-82 cars. I am thinking that's because the stock spring is more curved than the replacements. I'm sure it's a fine line between an enjoyable cruiser ride, and something close to racing stiffness. I'll have to talk to Gary on Tuesday. Either way, I think the new shocks will make a difference as well.
Awesome link. Thank you so much! I can't believe I've never seen that before. What's interesting is that the VBP site lists the 300 lb/in spring as the stock spring for 80-82 cars. I am thinking that's because the stock spring is more curved than the replacements. I'm sure it's a fine line between an enjoyable cruiser ride, and something close to racing stiffness. I'll have to talk to Gary on Tuesday. Either way, I think the new shocks will make a difference as well.
Most vendors selling composite springs have for 25+ years recommended the 300lb composite for base cars with the 460 replacement aftermarket front coils and the 360lbs composite with the 550lb front coil springs with the gymkhana sport suspension. I would not go less than 300lbs since as you have noticed the car will be too softly sprung, float down the road and will bottom out.
My 360lb composite rides better than my OEM 292 steel spring by a mile. The composite spring rates are not equivalent to a steel spring rate since the 2 materials are very different.
I should mention it was only off by a few degrees. Just enough to not allow the lower mount of the shock to slide on smoothly. When I tapped it it out a ways, I could adjust the mount up and down a few degrees. Is there another flat spot on the inside of the spindle support that prevents rotation more than a few degrees? Whoever installed this one, installed it at it's maximum upward position. I just rotated it downward a bit, and then pulled it back in.
Is the worry in pulling in a new mount damage to the spindle support? If the fit is indeed that tight, I could potentially see stripping out the threads on the nut/support if the part were new.
NO...I am not worrying about you rotating the lower shock bolt and putting it back in...it would not damage the casting.
NO...the flat spot at the back of the bearing support is what it is and I know that the lower shock bolts are not that precise.
The splines on the lower shock bolt is what I am more concerned about....and even with nut being tightened to 80 lbs/ft...I always have a concern that IF the splines are wiped out...I can not afford for the lower shock bolt to rotate and eat away at the stud of the lower shock bolt where the flat spot is and cause for the shock not to be correct....because I would have to hear about it from a customer.
SO...when I see the splines are shot and when I put it back into the bearing housing and I can get it to seat with a light tap...it gets a new one. And if the customer feels it is not needed...then they sign off on it NOT being replaced when advised....so I am not liable.
Am I being overly paranoid...maybe...but I have to warranty what I do and let people know what I find....and couple that with all the Corvettes I have worked on and seen what has happened.
Today is one of those days where I just wanted to throw in the towel after all this work. I got the dipstick tube today, and of course it wasn't packed well. Needless to say, at a minimum, the tube support got bent. Basically, I can't get it to fit, because I don't know what the support piece is supposed to look like. To add insult to injury, the torque converter is stuck and won't pull forward. It's like it's binding on something.
If anyone can get access to an original '82 car, I'd love to see how the support bracket is bent to allow for correct installation. I am at my wits end.
For what it is worth....IF I were having to deal with the dipstick tube..I would try to install it so I can see what I would needed to do. Mainly because for me....trying to move the tab to what I would see in a photo (even with measurements) more than likely would cause me to have problems and I would end up doing it the way I know works good for me.
AS for your torque converter...that one is a new one on me ...especially IF it will slide back and engage. I would have to look at the bolts on the flywheel at eh crankshaft and see if that area of the torque converter is not right...as in how the torque converter was made in that area.
I know torque converters can have a hard time to engage in all the way...but I have not run into a case where I could not get it to pull forward and bolt to the flywheel
Dub, thanks for the reply. I basically had to do exactly what you described. I ended up rotating the tube in a way to allow it to be the closest it could be to the transmission itself without touching. Then I bent the bracket to match. Everything is fitting so much better now!
As for the torque converter, I feel pretty dumb. There was a little too much paint on the end of the converter for it to fit into the crank. I gave it a good sand and put some transgel on both surfaces. Sure enough it slid right on and rotated freely. Torquing the three bolts was a little tricky with the flywheel trying to turn, but I got it done.
Transmission cooler lines are now in as well. I ordered from The Right Stuff. Very friendly service, and the lines fit very well with extremely minimal bending. I ended up using 5/16" flexible line for the joints between the lines and radiator elbows (VERY tight fit). The underside of the car is dirty, yes. I have a new transmission pan though, which will help to clean things up. I'll paint the engine oil pan when I replace the engine gaskets and seals.
I just got done replacing the driveshaft universal joints. Unfortunately, the new ones I ordered a few months ago didn't fit (but I didn't find out until now). Turns out that the ones listed for a 1981 manual transmission car fit just fine. I wanted to use the OEM Spicer joints (the originals lasted 35 years!), but all the store had in stock was MOOG, which will be good enough. I went with the non-greasable type for increased durability.
Next is to set my TV cable. I'm going to slide the sheath all the way back, open the butterflies all the way, and hope the thing ratchets out! I also hope tomorrow I'll be taking a test drive.
Those were the joints I wanted, but they weren't in stock anywhere local. The MOOG joints I ended up using look closer to the original Spicers I removed. By this I mean that the casting is the same for both the no maintenance type and the greaseable; only difference being the no maintenance ones are not cross drilled and tapped for a zerk. I know it probably seems trivial, but when I installed them I installed both ends "mirrored" as to not upset driveshaft balance. If the nub in the body faced the upper right corner on one joint, I installed the other joint with the nub facing the lower left corner. Did the same with the C clips, although I doubt that will affect the rotating inertia like the actual joint will. Regardless, it's in, and if I ever find myself replacing them again in my lifetime I'll use the Spicers. I think they were 51310X models or something like that.
When I took the distributer out to change the rotor and cap, I forgot to account for the fact that I was turning the engine over when I bolted down the TC to the flex plate. Oops. There is a 50-50 chance the spark will be off by 180º when I try to start it. It's easier to flip the rotor if I need to, than do the procedure in the manual which involves cranking the motor and placing a finger over the #1 plug hole. Lesson learned!
With the exhaust reinstalled, all that remains is adjusting the TV cable, which has proved itself to be more of a challenge than expected. It turns out my cable doesn't ratchet, and I am unable to fully depress the TV plunger flush with the bushing at WOT. I thought something was binding in the actual valve itself, so I took it apart. Everything was fine. The cable is also smooth and has more than enough travel without the linkage connected, so I am stuck at this point. I posted in the C4 forum where I may get more 4L60 owners, but if anyone following the thread knows where I am going wrong, please don't be shy. I'm eager to road test this rig.
You are aware that you can not flip the rotor. It is made to go on the distributor only one way...which means the distributor needs to be pulled back out. Just saying.
Unless what you wrote was a typo...and you meant to write that you were going to take the distributor back out.
You are aware that you can not flip the rotor. It is made to go on the distributor only one way...which means the distributor needs to be pulled back out. Just saying.
Unless what you wrote was a typo...and you meant to write that you were going to take the distributor back out.
DUB
Yes. Bad wording on my part. The small tang on one end only allows the rotor to be installed one way. What I meant was removing the distributer to rotate and not flip the rotor.
Lots of updates to share. I hope you find some or all of it as interesting as I do.
Long story short, the TV plunger spring was a heavy aftermarket spring. I stopped by a local trans shop, and they set me up with an OE spring. It's slightly shorter than the aftermarket spring. I finally achieved the proper WOT TV setting. Put the new pan on, torqued bolts, done.
Moving on to the car. I cranked it, and after it backfired I knew I had the rotor 180º off. Oh well, I had a 50% chance of putting it on wrong! Repositioned the rotor, repositioned the distributer to make it more or less "parallel" to the firewall. Hit the key, and it fired right up.
Move back to the transmission. With the engine running, I topped off the rest of the fluid. Here comes the test, putting it into gear. I moved the shifter from P to R, and the engine stalled. Weird, but I restarted, and tried D. No dice. Frustrated, I took a step back and slept on it.
Fast forward to today, I decided I'd actually open up the timing light I've had for two or three years and never used. I disconnected the ESC wire, connected the light, and started the engine. Right from the get go, no mark was visible on the balancer. I cranked on the distributer one way, and I still couldn't find the mark. Finally, after rotating the distributer in the opposite direction, the mark finally showed itself. I can't believe how much the engine smoothed out after the timing was corrected. Next, I tried shifting the trans again, and what do you know- it goes into all gears smoothly. I can't believe how much an incorrectly timed engine can seemingly run and idle well, but then drop off when a load is demanded.
With the car moving under its own power, I connected the pressure gauge I bought from BTO. The readings were all within specification, except for the "manual second" 1000 RPM, and at minimum TV. I was showing 180 PSI. This is something I still need to look into.
The car drove well overall, and shifted into all gears no problem. The TC was able to lock up as well. Cruising on the freeway at 1500 RPM was really nice! One strange thing I noticed when slowing down, was that the TC was still locked up at lower speeds. When coasting at around 45 MPH, the trans was in 4th with the TC locked up, and upon light acceleration, the whole car shuddered because the converter was still locked and the engine was barely above 1000 RPM. Pressing the brake, or a heavier acceleration made the TC unlock, but it was a weird thing to experience nonetheless. Maybe this is just the way the car was designed?
One other thing I noticed was a really soft 2-3 shift, regardless of throttle. I called Dana at ProBuilt, and he is setting me up with a "corvette" servo to help improve the 2 to 3 shift. He did warn me before I drove the car that I may experience this phenomenon. If the servo doesn't do the job, I'll upgrade the boost valves too. With a 200 horse engine, you wouldn't think the trans would be overly stressed!
I am really happy so far, mainly that nothing catastrophic has happened! I think with a few tweaks, I'll have this thing dialed right in. Oh, and I started rebuilding my front calipers today. No stainless sleeves, but the pistons and bores were excellent with no signs of wear. One side is almost done. Tomorrow I'll be balancing my throttle bodies. I've never had an idle this consistent, and it's hard to believe it will get better, but I know it can. That's all for now!
Are you using GM outline in the service manual on balancing the throttle bodies??? Meaning ...using the rubber plugs for the IAC ports and a manometer and keeping the rear drive wheels from turning when it is in gear???
That was the procedure I was attempting to follow, but upon connecting my manometer, the engine vacuum sucked all the water right into the balancing port. I have some troubleshooting to do in my adjustment setup.
Yesterday I ended up installing a new master cylinder, because the original one was really rusty, and leaked. When I removed it, I was immediately glad I bought a new one, because the rear seal had failed, allowing brake fluid all over the booster, and onto the CC servo and rag joint below. I flushed the entire system with new fluid, using my Mityvac. As much as I tried to get a firm pedal with just the vacuum pump, too much air was being pulled in through the threads of the bleeder ports. I was able to suck fluid until it turned clear, but then I had dad get in the car and manually press the pedal while I operated the bleeders. Very firm pedal after that! My front rotors were both at 5 thousandths runout, which is in spec. I left it for now (because I have no shims), but when I inevitably do more brake work, I'll shim them properly. I also never had issues with the proportioning valve. Using only light pressure on the pedal during bleeding seems to have prevented the valve from stopping flow. Either that or the valve is stuck!
I also mentioned earlier that I thought I had an issue with transmission pressure in manual low, but it turns out I was looking at the wrong model 700R4. Using the chart below (mine is an MZM), it turns out I am right within spec. Good news! I ended up buying the larger boost valves along with the Corvette servo, but may only do the servo for now. Looking back, I wish I would have just bought that servo from the start. I'll probably have to drop the exhaust again to install it...
It's been a while since I've posted, but now I finally have something new to share. I bought a couple used differentials from forum members. One has a 2.87 ratio, and the other is a 3.08. I have been consulting my owner's manual to see what kind of specialty tools I'll need for this rebuild. I haven't been able to find any DIY thread for the Dana 44, so I will be largely using my manual for the job. I did pick up a 0-80 in lb beam torque wrench for setting pinion preload.
As far as ordering parts/other required tools, what is my best course of action? I see kits on Ecklers, Rock Auto, etc. I haven't taken my original unit from the car yet, but I am almost certain it will need a new center pin, and potentially side yolks (the yolks from the ones I bought won't work). My plan is to use the best parts from each of the differentials in my final build.
I have to admit I am a little excited to tear these apart (maybe more excited to get rid of noises and leaks)!
I prefer to use Timken bearings. Federal Mogul bca are good also. Just stay away from the bearings from the land of rice. Or at least I do.
If you feel you are getting to a point of no return..STOP and contact 'GTR1999' here on the forum. If there is anyone who is the guru of gearboxes and differentials. Gary is it.
Thanks guys, I appreciate the comments. I'll check out those sites you've mentioned, Dub. Do you have any experience with Tom's? I was looking over their catalog, and found that they might have everything I'd need in one place.
In regards to the set up bearings, has anyone used a brake cylinder hone to remove a little material from the inner race, allowing a slip-fit? I am thinking this may be the easiest option, because I haven't found any reasonably priced set-up kits for this application.
Also, should I have any concern over supporting the rear of the vehicle on jack stands while I take the back end apart? I don't want to cause damage from the flex of the frame while the weight of the back is off of the rear tires. Maybe this isn't an issue, I just figured I'd check.
I have dealt with Tom's in the past...but not recently. I had no problems with Tom's.
I know I would not hone out the bearings so it is a slip fit. I know for a fact that bearings are not 100% perfect. So...The bearings I would use would be installed as per design so the set-up is correct.
As for where I put the jack stand where there is no rear suspension. I know that temporarily I will put it near the #3 body mount in front of the rear tires...then...when parts are out of the car and the car is going to sit for days on end...I use one of my taller jack stands and place it on the frame where the differential is mounted.
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
Bad wording on my part. The small tang on one end only allows the rotor to be installed one way. What I meant was removing the distributer to rotate and not flip the rotor.
