1966 Corsa Convertible

[terribleted]

The oil fill caps often get loose. The seal in them can also get poor. Using a pliers to tighten the catches in the cap and a new seal often stop fill cap leaks. the fill cap will leak oil of it is loose at all or the seal is bad as oil get slung up against it during operation from the fuel pump eccentric, so leakage here may or may not be blowby. If the cap is sealing blowby will not show up here but as oil in the air filter. The cap should be snug fit when turned all the way to the stops.

I changed the gasket in my oil cap and I believe it stopped any leak that was coming from there. At first it was really hard to twist the cap closed but a few months of use and it is just very firm, kind of hard. Engine is definitely drier than when I bought the car. There is only a slight mist of oil in the general area of the distributor and the cardboard I keep under it in the garage has just a few small spots that barely grow over months and many miles.

Something I don’t seem to see mentioned much about Corvairs is valve stem seals. I know the valves are up top in the valve covers so no oil sitting near them. By now I expect any stem seal that may be there is long ago hardened, probably disintegrated. Is that typically a source of oil consumption in Corvairs?

Since this last change with Penn Grade semi synthetic I’m approaching a 1/2 quart down after around 300 mixed driving miles. Most relatively calm, a few pretty spirited. I’m told those following me don’t see smoke so it is a mystery where the oil is going.

Bad or missing exhaust valve stem seals will cause some burning of oil. 1/2 quart in 300 miles sounds like a little more than is ideal. You sure you are not losing more than you think through leakage? That said I would not be terribly concerned. I would say anything under a quart per thousand is fairly normal for a worn engine. Rebuilt engines I have had after break-in may burn a quart every 2-3k miles. Most talk to me with some start up valve noise when they get down 1/2 quart. I just check them fairly often and top them up as needed.

[JohnDB]

The oil fill caps often get loose. The seal in them can also get poor. Using a pliers to tighten the catches in the cap and a new seal often stop fill cap leaks. the fill cap will leak oil of it is loose at all or the seal is bad as oil get slung up against it during operation from the fuel pump eccentric, so leakage here may or may not be blowby. If the cap is sealing blowby will not show up here but as oil in the air filter. The cap should be snug fit when turned all the way to the stops.

I've replaced the seal in this cap, tightened the catches, and bent the "soup can lid" spring to try to add pressure to the seal. Maybe the cap or the fill pipe or both aren't flat? I also have another cap and alternator mount with a fill pipe, maybe I'll try to find the best combination and see if I can get it to seal up. It isn't a really bad leak, I think I've only added about 1/2 quart in almost 2000 miles. It sure does make a mess though!

I did almost 50 miles of running around today trying to chase down exhaust parts that were listed "in stock", along with other errands. I still need some clamps and one piece of pipe that should be available tomorrow. Still have to wait on the hangers and packings to get delivered anyway, so hopefully next weekend I can do the install.

[JohnDB]

Got caught out in the rain while making a grocery run this morning - oh well, at least it makes the paint look really good!

Made a few adjustments to the oil fill cap and the top of the fill tube. Still wiping up oil, but hard to say yet if it was leftover or newly spilled.

[JohnDB]

Exhaust upgrade, part 1:

Since I had the day off, and the weather is terrible, I figured I might as well get some work done on my exhaust upgrade.

Mufflers off, some interesting pipes:

Not sure what this driver side muffler mount was from, but I'm glad I got a new one:

Exhaust logs were in pretty rough shape, the studs on the driver side were pretty bad and all studs had been "welded" back into place. The really short stud didn't break when I took it apart, it was that short and had a nut on it by maybe 2 threads:

Everything looks pretty good on the bottom, starting to see a slight weep from the bottom of the valve cover gaskets, but all the push rod tubes are good:

All nuts and bolts came apart nicely, seems like the manifold nuts were upgraded to stainless at some point in the past. I've got some cleanup to do on the exhaust tubes, and then I can start putting things back together.

[JohnDB]

Exhaust upgrade, part 2 - forgot to take much in the way of pictures:

I was able to clean up the threads on the spare manifolds that were in Dad's garage and get new collars on them:

All of the exhaust tubes cleaned up well:

I ran a die over all of the manifold studs, and used new locking tabs and stainless nuts. Everything went back together nicely with new packings, and a "new" thermostat for the passenger side. New U-pipes on each side into a 1 7/8" ID to 2" OD pipe adaptor, then into a Thrush Turbo muffler, and out a chrome slash cut tip. I'm pretty happy with how it came out - it's a little louder, but not terrible and it doesn't seem to drone too badly. We'll see how it goes after I get a few more miles on it. Might need a few adjustments to fitment, but there don't seem to be any leaks.

Before:

After:

[gbullman]

Still so many parallels with our cars. Your exhaust tubes all seemed to be in good shape, I had one that was really bad but I managed to change it. Not easy on a 140 head but doable. My passenger side manifold was really bad, driver's side bad enough I just got both from Clark's.

Somewhere I have a few more in progress pictures, just not finding them right now.

[JohnDB]

It's been a quiet few weeks, just keep putting miles on the Corsa. The oil drips are less since the last round of messing with the oil cap, and it just keeps running really well. The exhaust is pretty good, still need to make another adjustment on the driver side but nothing major.

Had to run to Lowe's today for various small things, great weather for a ride:

Noticed this on the left front wheel after I got home:

I'll have to pull the wheel and see what's going on, seems like a line of grease coming from under the center cap. It's been about 1000 miles since it was PA inspected, the wheel was off and everything was good at that point. Maybe the dust cap got knocked loose? Nothing like that showing on any other wheels at this point.

[JohnDB]

Pulled the LF wheel and everything looks ok. Dust cap is there and all the way on, seems to be some thin "oil" or leftover grease working its way out but nothing past the hub and into the brakes:

Seems like I didn't get a picture inside the dust cap. I cleaned up the outside of the hub and the wheel and put everything back together. Will keep an eye on things in the next few weeks.

[gbullman]

Those dust caps are not perfect seals, not unusual for some leakage like that. Hopefully turns out to be nothing.

[JohnDB]

Put the car up on the QuickJack yesterday and pulled all the wheels, it was bugging me that the studs on the LF all had an M stamped in the end. It was messing with my head a bit since most everything I could find online says the metric studs are stamped like that. But I have 7/16 - 20 lugnuts on them and they torque down fine. RF has the same studs with the M stamp, but none of the rears have the stamp. The rears are also about 1/4" shorter than the fronts, but they all measure out the same diameter with a micrometer. Best I can figure is that the front studs were changed sometime before 1985 and the M is a manufacturer stamp, nothing to do with metric at all. RF dust cap had about the same amount of "oil" seeping out as the LF, so that got wiped up a bit as well. Doesn't seem to be an issue at all, the front wheel bearings all feel good.

Did what I think are the final adjustments to the exhaust and tailpipes, needed to get the driver side muffler rotated a bit more to better match the passenger side. So far so good, we'll see if any other changes are needed after I get more miles on it. I was also able to replace some missing screws from the rear wheel trims on both sides while the wheels weren't in the way. Was able to get about 25 miles on it again this afternoon, and it really seems to like to run. Heat output is good and I don't have any exhaust smells in the cabin.

Next will be pulling the shift tube for a rebuild - hopefully I can get that on the schedule for next weekend, the coupler on the car is pretty worn and I can see that there is no busing at the rear end of the tube - from the feel of things there probably isn't much at the front either.

[k24556]

If you haven’t resolved your oil consumption issue, try checking the PCV system, if the orifice is plugged, the crankcase pressure will be out of balance and can suck oil even on a tight engine with no blow-by. You may see a little oil residue on your air cleaner surfaces as a clue.

[JohnDB]

So much for getting to the shifter rebuild a month ago, but that seems to be how it goes sometimes. On the plus side, the weather hasn't been too bad and I've still been able to get the Corsa out 2 or 3 times a week :)

Small cosmetic update, I found some new decals for my center caps - I never liked the generic stickers that came on the ebay special centers I'm running:
Before

After

And I finally got the car in the air today to start on the shifter rebuild:

I think there were only 6 different fasteners holding the tunnel covers on, so it looks like a run to the hardware store to get a matching set. The clutch cable has some slack in it, so I need to check into that adjustment as well. Tomorrow (hopefully) I can pull the shift tube out and get everything cleaned and re-bushed.

[gbullman]

Hope you enjoy your winter projects, I expect to be starting mine in the next couple of weeks. Lots of salt on the roads around here so no driving for a while. My driver side muffler got very loose so that will be the first mini project, then expect to install the XR700, then onto springs and shocks.

[JohnDB]

Hope you enjoy your winter projects, I expect to be starting mine in the next couple of weeks. Lots of salt on the roads around here so no driving for a while. My driver side muffler got very loose so that will be the first mini project, then expect to install the XR700, then onto springs and shocks.

So far so good, we've had a few cold days and 1 day with a few slippery spots, but no salt thrown yet.

Got the shift tube out of the car this morning and found some interesting things:

The piece of aluminum is part of the "bushing" at the front.

Also found the inner shaft is a bit bent:

Got the inner shaft much closer to straight and was able to remove it from the outer tube:

I guess the aluminum wasn't enough "bushing" by itself, so why not add some duct and electrical tape in 3 places on the inner shaft?

Cleaned all the old and solid grease out of the shifter cup:

I decided to use a Hillman bronze flange bearing (part number 58105) for the bushings at each end - 20 or 30 seconds on the inside diameter with a dremel and they fit well. I also decided to use the aluminum piece I found as a bushing retainer, looks like its going to work nicely:

At the far end I had to tap the bushing into the tube, and I'll stake it in place before it goes into the car:

Next I decided to change out the shift selector shaft seal as there has been a small leak there for a while. The old seal did not want to come out, but I finally got it:

New seal in place and I'm done for today:

Might get some time for reassembly tomorrow, but maybe not until Wednesday. Also need to run to the hardware store for some sheet metal screws for the tunnel covers, will be nice to only need 1 tool to remove/install them again.

[gbullman]

Wow, interesting set of issues and quickie fixes. I’m sure you will love the improved shifting when you’re done.

[County98]

Nice job on all the troubleshooting. I've got to do the shift tube in my future as well.