1966 Corsa Convertible

[Project65]

I like the look of those lower strut rods. Congrats on completing the suspension rebuild. Looks like a quality job done right.

[JohnDB]

I like the look of those lower strut rods. Congrats on completing the suspension rebuild. Looks like a quality job done right.

Thanks! I have an alignment scheduled for Friday and then I'm looking forward to putting some miles on it! The weather is getting better and it should be a lot nicer to drive now.

I realized earlier this week that it's been about a year since the Corsa moved into my garage. I'm also glad that I've recorded a lot of the work I've done in this thread, there is a lot in here that I've already forgotten about.

[JohnDB]

The weather was perfect today for a nice drive to a PCA club member's house for alignment. Overall nothing was too far out of line, but it certainly drives better afterwards!

Next on the list is probably the alternator/oil filter mount gasket to see if that stops the oil leak, and it looks like I'm also dripping some gear oil from the transmission. Maybe the shift selector shaft seal didn't go in as well as I thought it had? Seems to be coming from that end of the trans (front), not sure there is much else to leak at that end?

[gbullman]

Hi John,

Can you get the specs he used on your car? I’ll be getting my aligned after the next round of suspension work and could use what works for modern tires.

Gary

[JohnDB]

Hi John,

Can you get the specs he used on your car? I’ll be getting my aligned after the next round of suspension work and could use what works for modern tires.

Gary

Hey Gary,

Here is a screenshot of where everything landed. We used the 1965 specs in his alignment setup (Hunter) - the specs for 66-69 call for more negative camber in the rear that isn’t really necessary for radials.

It is also important that the rear gets aligned first. Good luck!

[gbullman]

Thanks!

[JohnDB]

Was hoping to get some miles on the Corsa this week, but the gear oil leak from the trans is a little worse than I thought:

I wiped everything off the bottom of the trans and ran the shifter through the gears a few times, it seems to be the shift selector shaft seal. Almost looks like it backed out a little bit, but I'm just going to replace it again as soon as the parts get here. At the rate it's leaking I think the seal might have gotten cut going in, I'll try to polish up the shift shaft a bit more before putting the next seal in.

Decided to do the valve cover gaskets while I was under it. I cleaned up a spare set of covers that are in better shape than the ones coming off. The old gaskets were very stiff and brittle, a few sections broke when I removed the covers:

Everything looked good under the valve covers:

All back together:

Should have some parts this week to take care of the transmission. Hopefully this seal comes out easier than the last one...

[bbodie52]

Regular rubber gaskets and O-rings tend to "cook" and get hard and brittle at cylinder head temperatures. Viton rubber gaskets handle the high cylinder head temperatures much-better.

If you have to add or change the gear lube in the transmission and differential, be sure to use GL-4 Gear Lubricant.

The selected lubricant for the Corvair transaxle must also be rated for use in API/GL-4 applications. GL-5 lubricants are not to be used in Corvair transaxles, as the GL-5 formulation will cause damage and corrosion to the internal "yellow metal" synchro's in the manual transmission. GL-4 Gear Oil lacks the reactive sulfurs found in most GL-5 oils that cause damage.


Multi-Purpose Gear Oil SAE 75W-90 is shared internally between the differential and the manual transmission. To be compatible with both, the gear oil must be compatible with HYPOID differentials. Some manual transmission lubricants do not support hypoid gears.

Why do the hypoid gears require special lubricant? Explanation: Hypoid gears require special lubricant because of the extreme pressure between the teeth. The sliding motion of the teeth is effective due to the use of special lubricant.

Special gear oils are required for hypoid gears found in Corvair differentials because the sliding action requires effective lubrication under extreme pressure between the teeth. ... They are considerably stronger in that any load is conveyed through multiple teeth simultaneously. By contrast, bevel gears are loaded through one tooth at a time. Hypoid gear oil is formulated with extreme-pressure (EP) additives to protect and operate effectively with hypoid gears.

Tue Nov 07, 2017 11:32 am

... DO NOT USE Redline MT-90 in a Corvair transaxle. Redline's site specifically states that MT-90 is NOT approved for hypoid gears (differential). So it is NOT acceptable for use in a Corvair transaxle since protection for the ring and pinion differential gears is inadequate. Redline does make a modified GL-5 lube that is suppose to work with brass synchronizers called - 75W90 NS GL-5 and states it's approved for transaxles with brass parts. NOTE: Redline NS GL-5 is different vs. their GL-5 which is NOT approved for transaxle use.

To cover the guiding rules applicable to the Corvair transaxle for BOTH the hypoid gear-based differential and to protect the yellow metal synchromesh gears in the manual transmission, I decided to use the following...

HIGH PERFORMANCE GEAR OIL (WITH SYNERLEC®)

Max Gear is recommended for truck and automotive differentials, outboard motor lower units or in rear axles or manual transmissions requiring an API fluid. Max Gear is a high performance automotive gear oil designed to provide maximum protection to heavily loaded gears while increasing power throughput through the drive train. Max Gear virtually eliminates both gear and bearing wear—even under severe squeeze film conditions caused by extremely high loads, sudden shock loads or low RPMs. Slippery, synthetic molecules not only reduce wear and friction but significantly increase Max Gear’s cold weather fluidity and lubricity, making it the ideal choice for vehicles operating in cold climates. Gears run smoother, quieter, cooler and longer without overhauls. It is noncorrosive to both ferrous and nonferrous metals.

PERFORMANCE ADVANTAGES

• Maximizes horsepower
• Extends gear and bearing life
• Reduces operating temperature
• Lower coefficient of friction
• Superior corrosion protection
• Separates rapidly from water
• For use with open, limited-slip and locking differential
• Contains limited-slip friction modifier

https://www.royalpurple.com/product/max_gear/


This synthetic gear lubricant appears to support both hypoid differentials and, unlike GL-5 lubricants, is safe for "yellow metal" synchro's.

[gbullman]

John,

That is some transmission leak, hopefully the shifter seal takes care of it.

I’ve been putting some miles on my 66, really happy with the way it is running and driving. I bumped up the tire pressures just a little and feel like the steering responds just a little more positively. I had been running 22 front, 32 rear and now I’m running 23 front, 34 rear.

I’ll eventually get to the suspension work I have planned but the way it is driving there isn’t much sense of urgency.

Haven’t ruled out Corvair Ranch Open house but it is a pretty good hike for me. More manageable if I stay at my daughter’s before or after.

[JohnDB]

John,

That is some transmission leak, hopefully the shifter seal takes care of it.

I’ve been putting some miles on my 66, really happy with the way it is running and driving. I bumped up the tire pressures just a little and feel like the steering responds just a little more positively. I had been running 22 front, 32 rear and now I’m running 23 front, 34 rear.

I’ll eventually get to the suspension work I have planned but the way it is driving there isn’t much sense of urgency.

Haven’t ruled out Corvair Ranch Open house but it is a pretty good hike for me. More manageable if I stay at my daughter’s before or after.

I think the cardboard made the leak look a lot worse, I checked the level in the trans and it is still about a 1/4” below the fill hole. Pretty much where I filled it to last summer when I changed the fluid (Amsoil MTG GL4)

Got some time to work on it yesterday and got the seal swapped out. Old one came out fine, and I cleaned up the selector shaft with emory cloth. A wrap of electrical tape over the hole to make sure nothing catches the lip, and then I bent the new one trying to install it. Really glad I bought 2 in the last order - the second one went in fine.

Also got the left side shield for the oil cooler in this Clark’s order. It came bare metal so I got my paint booth setup and hit it with some primer and black paint.

Should be pretty easy to install when I do the alternator mount gasket.

[JohnDB]

Put some miles on the Corsa today and met a lot of great folks at the Corvair Ranch:

Still need to do the alternator mount gasket, but the valve covers and shifter shaft seal are all good and the car is running great!

[gbullman]

Great meeting up with you, fun to finally get our twin cars together.

Had a great time yesterday, it was worth the 440 miles I drove in the Corvair round trip. Oil mileage overall was better than it is on shorter trips and it is still trending upwards so I'm planning to stay the course for now.

Attaching a couple of photos from yesterday.

[JohnDB]

Put some more miles on the Corsa over the past few weeks and it is still running well. Had some things to return to AutoZone and took a chance on some touch-up paint to try to match my non stock paint color. Since my rear air outlet grill was already in primer I cleaned it up with some mineral spirits and hit it with some paint.

Before:

After:

Still a little wet in the after photo, but it's not a bad match for a wild guess and way closer than anything else I've tried so far.

Looks much better than the primer:

I have another grill in better shape that I'm going to sand, prime, and paint at some point and swap. I was also able to get a pretty good used Corsa trim to finish it off.

[JohnDB]

We had some really nice weather today, and it would have been an excellent day for a long drive, but it was also great weather to be out in the garage. I was due for an oil change and decided to swap the alternator/oil filter mount since I had to remove the filter anyway - and I'd really like this leak to be resolved.

Alternator out, plenty of oil pooling on the edge of the top cover - oil cooler still looks really dry:

Mount removed from engine, cleanup doesn't look too bad:

Swapping to a different mount, sanded the bottom on oiled 400 grit sandpaper to make sure it is flat - old and new getting acquainted:

Mounting surface on engine looking good after cleanup:

For this install I used a new gasket and new bolts - I smeared both sides of the gasket with Ultra Black, we'll see if it all seals up. Bolts went in finger tight for an hour and then torqued to 11 lb./ft. - all tightened up fine and there was no squeeze out the edges. Letting it sit until tomorrow before putting the fuel pump, alternator, and oil filter back on. Yup, used the same touch-up paint on the fill tube since I had it out

Also put the oil cooler side cover on:

[JohnDB]

The rest of the reassembly went pretty quickly this morning - fuel pump, fuel lines, alternator, and oil filter back on

And out in the driveway a little while later with the belt back on ready to fire up and check for leaks:

It started right up and no leaks found. I let it idle in the driveway for a few minutes and can't see any oil coming from anywhere. Had to stop a few places and put about 20 miles on the car. Sadly, when I got home I found this:

My current guess is that the oil pressure sender is no good despite being less than a year old. I looked it over very carefully while it was out and couldn't find any evidence that it was leaking. It still doesn't seem like it is leaking out the seam where the plastic and metal join, but maybe it has a small crack somewhere? I've only ever used the correct sending unit socket on it, so not sure what happened. Can't tell if it leaks all of the time or only when pressure is over a certain amount - maybe I'll rig up a test with compressed air to find the leak?

Oh well, at least the gasket under the oil filter adapter seems good at this point, there is nothing coming from under the fuel pump, and nothing from the oil fill tube or cap. Looks like I need to pull the alternator again and swap out the sender, looking at maybe moving the sender and adding a gauge "while I'm in there".

[gbullman]

Well, that stinks! Any chance it is coming up around the bolts (seems wettest by the bolt to the right of the sender)? Don’t know if this is true for the bolts of the oil filter adapter / alternator mount but I’ve had other GM engines where bolt threads were in areas wet with oil, ended up applying permatex to threads after cleaning as best I could. Really slowed down the leak but didn’t quite stop it completely.

Also that seems like enough that a few minutes at fast idle after wiping it down should reveal the source.

I’ve heard that replacement oil pressure switches can be a bit hit or miss, I definitely got lucky with mine.