1966 Corsa Convertible

[gbullman]

Expecting others will chime in but I remember one possible cause of a bouncing tach is points plate in distributor is not consistently grounded. That would also contribute to your miss if I’m remembering correctly.

Oil leak is a bit more of a mystery being up so high. Even that wet bolt sort of threw me. Location is close to oil cooler but can’t see oil running up hill.

[joelsplace]

Don't forget air pressure leaks between the block and shroud. That will make oil leaks do strange things.

[JohnDB]

Pulled the PCV orifice tube out today and found a really old GM hose - original or really old replacement I guess:

Need to get a new hose for that spot, it's almost solid and started to break apart trying to remove it - you can see some of the chunks missing on the end still on the pipe. Once I got that end off, I used a 1/16" drill bit to check the hole - it seemed to be open at the end, but it was actually clogged where it meets the other tube. Some cleaning with the drill bit, some brake cleaner, and compressed air and it seems to be flowing again.

I pulled the oil cap again and tried to take the gasket out to check the round spring behind it - bad move, the gasket is now in about 5 pieces. There was also a lot of fresh oil inside the cap, so maybe the clogged PCV was the problem combined with a weak oil cap seal. I think I can get some gasket material at work tomorrow, so I'll cut a circle out and see how that works for now. I cleaned up the oil on the top side, will need to clean the bottom again. Hopefully tomorrow afternoon I can put some more miles on it and see if the leak is stopped.

Don't forget air pressure leaks between the block and shroud. That will make oil leaks do strange things.

I've been thinking about this as well - if I still have a leak up top I think pulling the shroud will need to happen soon.

[JohnDB]

Got some rubber I was able to cut into an oil cap gasket (for now at least) and put a few miles on it again tonight. Sadly, cleaning out the PCV tube didn't seem to do anything, the same amount of oil was still freshly all over the engine number when I got home. Need to see if I have the gasket for the alternator/fuel pump mount, I think that one makes sense to replace next.

And the temp/press light started blinking again during this drive. I'm going to disconnect the temp sensor and run only the oil pressure sensor for now to test, maybe the temp switch is going bad and grounding itself?

Also need to check for tune up parts in Dad's garage - don't want to pull the cap/rotor/points/etc. without having good parts to re-install.

[azdave]

Another question - is this part of the shroud under the distributor from a car with AIR?
Any reason I can't cover that hole with a small piece of sheet metal?

Yes. That hole is where the A.I.R. (SMOG SYSTEM) air injection hose went down from the smog pump and into the exhaust manifold. No harm to block it off.

The flickering oil/temp light is unlikely to be a bad temperature switch but any place that long wire might accidentally touch a ground point would also cause a flicker. If the light only flickers when the engine is warmed up and idling really low then you should verify the oil pressure with a trusted gauge.

Also, be sure your oil is the proper grade for the season and not diluted accidentally with fuel or other contaminates that would lower the viscosity. There have been many fuel pump failures (leaks) that go undetected because the leaking fuel drains down inside the pump shaft and slowly fills the crankcase without you knowing it is happening. Is your oil level increasing? Does the oil smell very strongly of fuel?

Also, be aware that a new oil pressure switch is not always a good switch. I've had them bad out of the box and chased a low oil pressure issue that wasn't there. I check oil pressure by installing a special bolt and gauge in place of the oil filter bolt. This location taps the same flow path as the oil pressure switch location. You can install the bolt/gauge for as long as you need and either leave it there or remove it when done. I make and sell these with a gauge ready to install for $35. Clarks also sell a similar bolt (no gauge) part number C7521.

[JohnDB]

Yes. That hole is where the A.I.R. (SMOG SYSTEM) air injection hose went down from the smog pump and into the exhaust manifold. No harm to block it off.

The flickering oil/temp light is unlikely to be a bad temperature switch but any place that long wire might accidentally touch a ground point would also cause a flicker. If the light only flickers when the engine is warmed up and idling really low then you should verify the oil pressure with a trusted gauge.

Awesome, I got a piece of stainless scrap from work and will make a cover for the AIR hole.

The flicker of the temp/press light happens randomly, not only at low idle. Sometimes it seems related to throttle position like something is moving around, other times nothing seems to make a difference. I like your gauge on the oil filter bolt, might be in touch with you later about that.

Tonight what I did as a basic test was to make a short jumper wire to go from the oil pressure sender to the engine wiring harness. The temp sensor is disconnected for now and hopefully this will help me isolate the issue. Didn't get to take a drive yet, but key on engine off testing was as expected with the wire connected (bulb lit) and disconnected (bulb out). Hopefully I'll know more next time I take a ride.

I was also checking some wiring to the distributor and coil, so far that all seems ok. The points plate looks pretty good and I had good connectivity to ground as I moved it around. Need to borrow a vac pump and test the vacuum advance, when I pushed the lever all the way in and held my finger on the port it didn't hold. Not sure if it should or not so the vac pump should help test it for sure. Need to test the voltage at the coil when it is running cold vs. hot and see if there might be a problem with the resistor wire.

The other thing I found is that it might be the wrong distributor - the number on it is 1110311 which may have come from a 95hp PG. I suppose all the internals could have been changed, but not looking to pull it apart yet to find out. Need to check the other engine to see if it has a 140 distributor and maybe swap them.

[JohnDB]

Also, be sure your oil is the proper grade for the season and not diluted accidentally with fuel or other contaminates that would lower the viscosity. There have been many fuel pump failures (leaks) that go undetected because the leaking fuel drains down inside the pump shaft and slowly fills the crankcase without you knowing it is happening. Is your oil level increasing? Does the oil smell very strongly of fuel?

Just checked and the oil is still oil and the level is not increasing. No fuel smell and it is fresh Rotella T4 10w30. Hope to take a drive later today and see if my jumper wire helped.

[azdave]

Just checked and the oil is still oil and the level is not increasing. No fuel smell and it is fresh Rotella T4 10w30. Hope to take a drive later today and see if my jumper wire helped.

Great! It's probably not truly low oil pressure if you see the light flickering at RPM's other than idle. Still could be a bad switch with the cheap stuff they sell these days. I'm guessing a bad (exposed) wire might be found. Seems like you know how to find that...just takes some time to sort it all out.

[JohnDB]

Got a chance to do about 10 miles tonight with a few stops in between. So far so good on the temp/press light, but time will tell. Also had a minute to block the hole in the shroud under the distributor with a piece of sheet metal. Nothing fancy, but it should keep the hot air away from the distributor a little better.

[Gregory_Miller]

The vacuum advance should hold in when you plug off the moving it in manually. Sounds like yours is bad which can also cause a vacuum leak on that side if it's a big leak.

[JohnDB]

The vacuum advance should hold in when you plug off the moving it in manually. Sounds like yours is bad which can also cause a vacuum leak on that side if it's a big leak.

Thanks! I thought I had read that somewhere before, and it made sense that if the diaphragm was good that it should hold. When I started the car yesterday I let it idle for a minute and then cracked the throttle a little bit while watching the vacuum advance - it only moved about a very small amount, maybe 1/8" or so. I've got at least one other distributor that I need to check out, hopefully it is the right part number for a 140 manual trans and in good shape with a working vacuum advance.

[JohnDB]

I was lucky to find pretty much all the spares I was looking for in Dad's garage - cap, rotor, points, condenser, coil, vacuum advance, and a bunch of other stuff I'll need at some point like the gasket for the alt/fuel pump mount.

I also borrowed a vacuum pump, and when I hooked it up to the advance on the car it opened and held 15" of vacuum fine. I let it sit there for about 5 minutes and it didn't drop, so I guess I don't need to change that right now.

After some thought, I decided to change one thing at a time so I would know what fixed the misfire. I started with the condenser as it seemed to be the easiest, and I've read reports on various boards about bad ones causing strange misfires. Went for a ride to get 3/8" ID hose for new PCV lines and the miss was as bad or worse than before when it got hot. I guess now I know the condenser I took out should be good.

Next I went after the coil. The car has had a Judson Electronic Magneto installed for years and it's up on the firewall to keep it cool. I hit it with a temp gun when I got home and the outer case was over 140 degrees. No idea if that is a problem or not, but I have another coil and it's a quick swap. When I pulled the high tension lead out of the Judson, the metal end pulled off the wire. Don't think that was the overall issue, but I'm sure it didn't help. Got that crimped back on and finished swapping the coil. Did a last check for tools around the engine bay and noticed the belt didn't look right. Turns out it flipped at some point, probably earlier today, and was actually on the wrong side of the guard on the idler pulley. Pulled it off and it's in pretty bad shape with 2 pretty bad kinks stuck in it. Put another new belt on and will have to keep an eye on tension - I suspect I didn't have it tight enough when I had the alternator on/off last week.

Took another ride and this time it seems to be better! I think there is still room for improvement, but progress at least. Was able to get it fully up to temp and had no real issues. I think I'll do a set of plugs next to see how they look and have a good baseline for going forward. As an added bonus the temp/press light didn't flicker at all today!

[viewmaster]

Also, these distributor bodies of ours are old and the bushing wears out reletively quickly. I would check your distributor shaft for play, because that is a big source of spark scatter, and will give you a miss.

Forgive me if you had already mentioned that you had a rebuilt distributor body.

-m

[gbullman]

Sounds like you are making progress! I was also in Delaware County, PA this weekend but totally doing family things.

When we got home today managed to take a nice long ride and all went well. Very happy where my car is at the moment. I expect there will be more to come but getting a little break at the moment.

Gary

[JohnDB]

Also, these distributor bodies of ours are old and the bushing wears out reletively quickly. I would check your distributor shaft for play, because that is a big source of spark scatter, and will give you a miss.

Forgive me if you had already mentioned that you had a rebuilt distributor body.

-m

Without pulling it out of the car it seems pretty good, no real side to side play that I can detect. I've got an Allison/Crane unit on the shelf and I'll probably swap it in soon. Wanted to make sure it was all good with points first to minimize issues. I've got plugs to put in but will wait until later this week when new wires arrive, no need to touch it all twice. Then I need to play with the carbs a little and get the idle speed down some, it's up around 900 or so at the moment which won't help me get accurate timing from what I've seen.

[JohnDB]

Had a chance to get a few miles on it today and it ran pretty well. No unusual behavior from the temp/press light and it didn't miss when it got up to temp. New plug wires should be here tomorrow I think, so I'll probably get a chance to swap plugs and wires over the weekend. Even the oil leak didn't seem too bad today, but I need to wipe everything down again to know for sure.

Found a couple of pictures on my phone of some stuff I worked on about a month ago. The rear cove trim is banged up a bit, especially on the driver's corner where the casting is bent and one mount is broken off. I figured it was worth a try to get this one to fit better - I have another cast piece but it needs to be painted, I'll probably do that when I'm ready to repaint the entire cove.

Here is the before picture:

I was able to get it apart and separate the stainless from the casting. Some gentile hits with a small hammer and various dull chisels and the big dent in the stainless came out pretty well. A bit of gentle bending and I was able to get the casting to fit the body better. I drilled a hole where the broken mounting post used to be and tapped it for 8-32 - a piece of all-thread a couple inches long worked pretty well to pull it back to the body better. Didn't polish the stainless yet, but that'll be easy enough to do another time.

The after picture - a little different angle that showed the improvement to the stainless better:

I noticed then that the trim on the deck lid didn't line up very well. I took it off and tried to adjust it a little, but it seemed to want to go back to the same spot - the long plastic nuts hit the body under the weatherstrip and pushed the trim out of alignment. After some online research, it seems that someone had all the trim off the back of the car sometime long ago and managed to swap the clips in the top and bottom long stainless strips. I was able to slide them all out and swap the clips back to the proper stainless - It lines up much better now and doesn't hit the body when the deck lid is closed!