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This is a first step, of course. I do have a dial back timing light and i will plot the curve.
BUT....IF your notch on the outer ring of your balancer is off....then your reading will be....incorrect...so-to-speak.
I know the notch can give the rate of advance..but the overall correct timing value will be subjective UNTIL the notch is verified to be correct....in my opinion.
And this also has to do with what you can live with and not worry about. If you get it running great...then I guess all is good.
In my world I have to know this for information. Due to I normally get customers cars in on a regular basis for service and I need that data so I am not chasing my tail.
While the spark plugs were out, I accurately confirmed TDC. I am slowly getting there... there is a bog on acceleration; the next step is to carefully go over the timing.
Nonetheless, I do take it for short drives and must admit... it is becoming a fun ride.
I put a relay on both the line to the coil/distributor and to the starter solenoid and that seems to have cleared things up dramatically. The starter no longer seems to hang and spins nice and fast. No more detectable high RPM misses.
I took the corvette out for a series of test drives and, it seems that I have a sticky thermostat: temp spikes and slow or erratic behavior. I'll replace that within the next few days taking care to drill some holes in the thermostat flange.
Soon I will start looking into tuning what I have... which isn't much: 882 heads, headers, who-knows-what cam, Torker intake and 750CFM Performer carb. I have good compression and oil pressure; I am happy about that.
The idle quality is good - I'll check this weekend how many inches of vacuum I am getting. But from experience, I'd say at least 15. I don't know if it is the cam or the burble of the twin Flowmasters that give the car a feeling of vibration at 2500-3000 rpm. The sound might be misleading me. It almost feels like the rotating assembly was not properly balanced. I'll need to focus my senses the next time I take this for a drive (after I swap the thermostat.)
I rebuilt the carb; it has the original Performer tuning on it. The ignition curve, I still have to check. I am going to double-check TDC. (Anyone have a tutorial on converting a spark plug into a piston stop?)
There is significant bogging when I get on the gas. Peak torque feels around 2800-3000 rpm. Beyond that is seems to run out of steam.
Once I get the basics done, I will take it down to a dyno. I also have a dual wideband O2 sensor... I just need to get a couple of bungs welded in. We shall see what I can find out there.
I also have to remember that I have at least one cam lobe that is worn... that might be a factor; number 8 intake barely rocked over when setting lash.
. (Anyone have a tutorial on converting a spark plug into a piston stop?)
All I did was bust out the porcelain. Grind off the tang. and use a tap and I believe it is a 3/8-16 tap and tapped out the metal portion of the plug an put in a long bolt that I ground and polished round so it would not nick or gouge the top of the piston when it makes light contact with it.
I will post a photo of mine tomorrow.
Just keep in mind and I do not know if it has been mentioned before...but I would remove and cap off all unneeded vacuum hoses from the intake vacuum fitting and tune your engine without them attached.
Originally Posted by DorianC3
Once I get the basics done, I will take it down to a dyno. I also have a dual wideband O2 sensor... I just need to get a couple of bungs welded in. We shall see what I can find out there.
I also have to remember that I have at least one cam lobe that is worn... that might be a factor; number 8 intake barely rocked over when setting lash.
Refresh my memory...why are you using an 02 sensor???
...Feeling of vibration at 2500-3000 rpm. The sound might be misleading me. It almost feels like the rotating assembly was not properly balanced. I'll need to focus my senses the next time I take this for a drive (after I swap the thermostat.) .
Right, well I think I might have found where the vibration is coming from: the mounts. At the rear, I could literally lift the back of the Muncie nearly an inch and see the bolts through the torn rubber. Completely shot. I will replace the motor mounts figuring that they may be as old.
What are typical symptoms of a shot trans mount on a manual?
Oil pan gasket is leaking: rats! i think I will get one of those one piece deals.
However, once I took it for a drive, the steady drip started. #annoying
I reset the ignition. Carb had a base tune and I must say, it ran quite well. I have 18 inches of vacuum and the power comes on steadily without hesitation. However... that pesky vibration was there. My guess is, as said above: trans mount.
I also replaced ALL the vacuum hoses. The headlights work well (maybe need some grease) the wiper door as well - now it is a matter of reinstalling an original 1969 wiper motor that I got from Wilcox... I am looking FW to this weeekend.
Hi Dorian.
Fellow Blue '69 Coupe owner here, and been watching this thread since your acquisition last fall.
Wondering if you have any specifics on the Blue color of your car? Like mine, it's clearly NOT the LeMans Blue that came from the factory in '69.
To me, it looks close to my Blue, which I've theorized is actually Bridgehampton Blue from '71+. What does your trim tag say the original color was?
Also - regarding your higher RPM sluggishness. Take a look at your accelerator pedal pivot system on the floor. You had mentioned this as being one of your early issues. I found mine to have a loose clinch bolt, which caused it never to actually open the throttle fully, even when mashed to the floor. Needed to make sure all the slack was out of the system with the pedal at "rest" by tightening that bolt where it clinches around the pedal rod. Then adjusted the cable until you can SEE the throttle opening fully when the pedal is floored.
I had driven mine for about 6 months before I discovered this, and it was like I had installed a super charger after I fixed it!!!
YES...a bad transmission mount is NOT good and a new one can help greatly. Not saying that it will fix it entirely...but you have to start with the obvious.
While you are there you might want to drop down your rear main cap and check and see if the real main seal is leaking. NOTHING is worse that putting in a new oil pan gasket and it still leaks ...only to find out after going back into again that it was also the rear main seal.
***REAL WORLD EXPERIENCE***
On a 1967 big block I did many months ago. Thee engine was rebuilt. The engine had about 1000+miles on it add it was leaking at the back of the engine. So I took my borescope and looked the best I could to see if I could see if the rear main was leaking.
So I installed a new oil pan gasket and let it idle for about 30 minuses...revving it from time to time....and WHAM...it began to leak oil. SO I took the pan back off and did it again...and it leaked again. It took about 30 minutes for it to show up. Do not ask me why...but it did.. So I took off the pan and rear main cap and WHAM...there it was. The rear main seal was leaking. When I replaced all seals/gaskets. It did not leak a drop.
Point is. I ASSUMED that due to the engine being fresh. That there was no way the rear main was leaking due to how long it took to leak.
Hi Dorian.
Fellow Blue '69 Coupe owner here, and been watching this thread since your acquisition last fall.
Wondering if you have any specifics on the Blue color of your car? Like mine, it's clearly NOT the LeMans Blue that came from the factory in '69.
To me, it looks close to my Blue, which I've theorized is actually Bridgehampton Blue from '71+. What does your trim tag say the original color was?
Also - regarding your higher RPM sluggishness. Take a look at your accelerator pedal pivot system on the floor. You had mentioned this as being one of your early issues. I found mine to have a loose clinch bolt, which caused it never to actually open the throttle fully, even when mashed to the floor. Needed to make sure all the slack was out of the system with the pedal at "rest" by tightening that bolt where it clinches around the pedal rod. Then adjusted the cable until you can SEE the throttle opening fully when the pedal is floored.
I had driven mine for about 6 months before I discovered this, and it was like I had installed a super charger after I fixed it!!!
WOW !!!!! That car is stunning.
The car is indeed "tagged" as LeMans Blue (I love that name), but many have told me that it is not the right shade. With no experience, I can't tell the difference anyway. But I am pleased that it is blue.
As for the gas pedal, I think you are onto something... but on the other side of the spectrum. When the pedal is if fully down, the carb is at WOT. However, I think I noticed that there is slack in the gas pedal so that at tip-in the input is not relayed to the carb. That would make moving off the line more difficult. This weekend, if I am not sent out on some damned fool-mission, I'll get a closer look.
Ever hear of the car known as "La Jamais Contente"? Built in 1899 in Belgium, it was purportedly the first car to break 100kph (62mph). It was battery powered and shaped like a torpedo. https://en.wikipedia.org/wiki/La_Jamais_Contente
La Jamais Contente means: 'The Never Satisfied'. Which pretty much sums up my feelings about my C3 for the moment.
I have had it a few months and have yet to reach fully daily driver status. There always seems to be some ****ling detail that keeps any of my projects for being 100% complete. That pesky oil pan drip, post cam swap, is a good example. It is not a big drip but enough that little wisps of smoke emanate from the "gills". This drives me nuts!
I know. I know. I am spoiled. With a couple of wiped cam lobes, it could have been much worse.
Well, I replaced all the vacuum hoses and switches. (Freezing here but fortunately dry... note the Belgian cobblestone, or 'pavé', driveway) Fortunately, most of the vacuum circuit seemed to be intact; very little Bubba there. Even better, the behind-the-tach solenoid and headlight switch work fine and did not require replacement.
I also replaced the wiper-motor. It turns out the motor that was on there was from a later model not designed to be used with a wiper-door. It had no independent power provision.
OEM, the wiper motor only gets power once the wiper-door is fully open. In my case the inhibiting switch was still there but bypassed and then led... nowhere. This in addition to having no independent power provision on the wiper-motor.
This led to the wipers slamming into the door before it could open, thereby destroying the wiper transmission. PO must have been using the under dash bypass prior to engaging the wipers.
Well... all that is fixed... sorta. Enter La Jamais Contente. The dash switch is very crappy and not working well. I had replaced the defective one that was on there, but the replacement one is as bad. Its operation is vague and inconsistent. No clear slide-click-engage. (Anybody can recommend a good source that works!?)
Other than that, I am very pleased to see my headlights AND wipers working and not requiring the override switch. As a bonus, if it rains, I now no longer have to pull over.
It sounds like you are making good progress.
Your updates and photos are always good it see.
Unfortunately I've been so busy, mine hasn't even been out of the garage or even uncovered for over a month.
It is good to recap, from time to time, what one has covered that way you know you are making progress and avoid getting discouraged... La Jamais Contente's journey so far
Covered:
Gas tank - had to be rebuilt as it had rusted out in several places and developed serious leaks. These only appeared after driving a few days.
Front end harness - lots of bubba wiring twisted together with major cable sheaths that suffered heat damage. All replaced with fresh wires and fuses. All gauges seem to work... including the clock
Battery - connectors were melted and holding by a strand; replaced and installed a batt disconnect
Starter - solenoid contacts had to be freshened up. Put solenoid IGN cable on a relay to give full batt. It works very well now.
Ignition - timing was severely off and there was no timing tab. Found TDC, installed a timing tab and gave is a street tune.
Carb - rebuilt 100% and converted to an electric choke; the choke was wired open. Cold starts are now excellent.
Cam - had a few worn lobes. Swapped in a standard GM cam; pesky oil pan leak
Headers - were leaking, Replaced the gasket.
Steering - tightened steering box lash and significantly improved the steering experience.
Rear lights - had a trailer hitch harness twisted in (!). Debubbafied and now working properly
Wipers and Door - replaced the wiper motor with correct one and replaced damaged wiper arms and transmission. Now working well (except for the dash switch)
To Do to reach my standard of daily driver
Front end control arm bushings - replacing fuel pump gaskets I noticed that these bushing were seriously compromised. Man I hate removing springs.
Horn - 90% of the work is done. Replaced the contact spring and button and discovered that there was an insulating piece missing... which I have now. I may install this weekend. On the other hand the horn emblem rivets broke... I'll need to epoxy that, but only once the circuit is fixed. I only want to have to do that epoxy job once.
Foot-well draft - There seem to be some holes and steering column bolts missing leading to severe, freezing drafts at 60mph.
Mounts - rear trans mount is shot. I might replace motor mounts as well.
Weather sealing - some looks ok, but I really want this car (pipe dream) 100% dry inside.
Go through climate control - maybe it is just the draft, but it feels like the climate control is completely ineffective
Power brake conversion - I have all the parts. That will be a fin project ! The first real upgrade. The breaks work fine as it is... this should be so much nicer
Oil pan leak - a priority. Those little wisps of smoke are very distracting for one who is alert to all odd noises and tells this early in the acquisition
Shifter loose - it looks like a loos mounting bracket and otherwise seems to shift well
Rear right brake - slight rhythmic noise to be investigated.
Upcoming projects:
OD conversion - a daily driver/touring definitely needs an OD trans.
Storage compartments - wood is in bad shape: replace and rebuild
Gymkana - Need to have a reasonably modern feeling suspension at the very least worthy of the "Corvette" moniker.
More grunt -See above
Borgeson conversion - See above
Hot-swappable wheels and tires - I like the OEM look with rally wheels but would like to swap back and forth between a more performance oriented and contemporary look
Lower pulley - has a "wobble"
Alternator bracket - in poor shape
Keyed ignition - restore and get rid of the push button start on console
Dash and gauges - restore original look and radio. Get rid of boxy bubba speakers in rear.
Rear window - restore operability of removing.
Lock-outs - restore steering and reverse lock-outs
Detailing engine bay - yank engine, clean up wiring, etc.
Well, I have been overseas for three weeks and finally got home.
I think the vibration was related to the transmission mount. The rear of the trans is slightly raised and, if you look carefully, you can see the tear in the rubber. Comparing to the new part - the mount was almost completely perished; it was pretty much worn flat. Can't have been good for the driveshaft geometry. Installed, the ride is muuuuch smoother...
Well, I have been overseas for three weeks and finally got home.
I think the vibration was related to the transmission mount. The rear of the trans is slightly raised and, if you look carefully, you can see the tear in the rubber. Comparing to the new part - the mount was almost completely perished; it was pretty much worn flat. Can't have been good for the driveshaft geometry. Installed, the ride is muuuuch smoother...
Soooo, it has been a while, but I have not been idle (no pun intended)
I just fixed (knock on wood) a persistent oil leak. I like very much the FelPro one piece oil pan gasket, but drops seemed to be squeezing through between the timing cover and the gasket at the front. Researching led me to the conclusion that it was possibly a cheap non-OEM timing cover with a spot welded lower lip. I managed to source a vintage OEM cover - not only was the steel thicker, but the lower lip was indeed radius welded. I bit the bullet and undertook the tedious job of swapping.
After a few short drives, there is not indication of an oil leak.
At this point we are at the next step of "The Force Awakens" saga.
I am finally open to more sustained testing and improving and ...trying to decide what to do next.
I do want to keep it some what of a driver; so nothing radical will be undertaken like new heads or a cam swap.
The door and various other rattles bother me. But perhaps that can wait a bit.
I do have a power brake conversion kit. I am considering that.
The front control arm bushing are clearly perished. I am postponing doing an alignment job until that is sorted.
I think I need to get the following sorted:
I find the car to be uncomfortable to drive at 60 mph. I am not sure what it is. My 1973 Malibu felt smooth as glass cruising at 70 or 80. Granted, (the rotating assembly was balanced to perfection and) it did have a 200-4R keeping the RPM in the low 2000's. On the corvette, 60 MPH is at about 3000.
Now to be clear, I do not know exactly what I am sensing.
It could be, I guess, the exhaust muffs bumping against the plastic body. I noticed that the clearance there is minimal, it might even be touching. (Loud, but cool, Flowmasters do not help diagnosis.) I have to revisit how the piping was actually hung. I don't seem to recall any rubber insulators.
The timing tab on the OEM cover is about an inch away from the harmonic damper. Could this damper be too small for the application?
Is the clutch properly aligned? I suspect is isn't. I need to rule everything else out be for digging in there.
The timing tab on the OEM cover is about an inch away from the harmonic damper. Could this damper be too small for the application?
.
YES....about every harmonic balacner I have seen from the factory for your era of Corvette...the air space between the tab and the outer ring of the balancer is so close.... that it is no more than 1/4" apart.
YES....about every harmonic balacner I have seen from the factory for your era of Corvette...the air space between the tab and the outer ring of the balancer is so close.... that it is no more than 1/4" apart.
DUB
Hmmmm, I will measure when I get home this evening but... my damper is significantly smaller than that...
01-07-2018, 06:26 PM
BUT....IF your notch on the outer ring of your balancer is off....then your reading will be....incorrect...so-to-speak.
That car is stunning. 
But I am pleased that it is blue.
