couple of questions.. - Corvette Forum : DigitalCorvettes.com Corvette Forums

graphicjunki · 01-05-2013, 10:53 AM

So I took the vette out on it's first highway run this morning. It was awesome! Still haven't gotten the timing dialed in perfect, but that probably won't happen until Lars rebuilds the carb...it's running a little rich. But that's ok.

Q1)
After getting gas, I was going through the gears at low speed to test the shifting as discussed in the transmission thread...

D - acted as figured.
Down shifted to 2 and the RPM's increased....as figured.
Down shifted to 1 and the RPM's dropped considerably. Almost like going into an over drive.

Not sure what to think about that. To me a reverse valve body would go 1 2 3. This almost feels like a 2 1 3.

At 60, I was hitting about 2300 RPM. That seems high to me with 3:08 rear gears.

Q2)
I don't remember what it was called, but my vacuum sucks. I can barely get the headlights to open/close. If someone can remind me what it's called so I can research it, I need to get that vacuum magnifier...

C3C6 Norm · 01-05-2013, 08:17 PM

Sorry, can't help you out much, on my '75, I'm a puzzie, it's an auto. Auto's a three speed, at 60mph, I'm pulling about 2800 rpm with I think 318 or 323 gears. See, I told you I couldn't help you out much.

TimAT · 01-05-2013, 09:38 PM

Full manual valve body or just a reverse pattern? Could it be at the speed you were travelling and downshifted to 1st, that the overrun clutch did exactly what it's supposed to do? If it went into low at a high enough speed, the rear wheels would lock. And that could get real ugly real quick.

72SBVet · 01-05-2013, 09:49 PM

Quote:

Originally Posted by graphicjunki

So I took the vette out on it's first highway run this morning. It was awesome! Still haven't gotten the timing dialed in perfect, but that probably won't happen until Lars rebuilds the carb...it's running a little rich. But that's ok.

Q1)
After getting gas, I was going through the gears at low speed to test the shifting as discussed in the transmission thread...

D - acted as figured.
Down shifted to 2 and the RPM's increased....as figured.
Down shifted to 1 and the RPM's dropped considerably. Almost like going into an over drive.

Not sure what to think about that. To me a reverse valve body would go 1 2 3. This almost feels like a 2 1 3.

At 60, I was hitting about 2300 RPM. That seems high to me with 3:08 rear gears.

Q2)
I don't remember what it was called, but my vacuum sucks. I can barely get the headlights to open/close. If someone can remind me what it's called so I can research it, I need to get that vacuum magnifier...

Actually your rpm at 60 is correct. Mine runs 3k at 70-80 and it has a TH400 with 3.08 gears.

graphicjunki · 01-05-2013, 11:01 PM

No, I did the 1st gear shift at like 10 mph......should have been able to easily handle that.

But now its developed a back fire on the passenger side of the engine.....GREMLINS! So no driving until thats figured out.......

diehrd · 01-07-2013, 04:12 PM

Check ignition connections for that back fire

graphicjunki · 01-07-2013, 04:24 PM

It was running fine, then started to back fire. I haven't taken off the valve covers, but I'm guessing I have a valve rocker still not right.

To add to it, since it doesn't ping, it just back fires, I'm somewhat voiding out lean condition.

slofut · 01-07-2013, 06:56 PM

Quote:

Originally Posted by graphicjunki

It was running fine, then started to back fire. I haven't taken off the valve covers, but I'm guessing I have a valve rocker still not right.

To add to it, since it doesn't ping, it just back fires, I'm somewhat voiding out lean condition.

Unless It's a vacuum port open somewhere.
And you said your vacuum sucked...

graphicjunki · 01-07-2013, 07:04 PM

lol...

diehrd · 01-09-2013, 02:49 PM

Quote:

Originally Posted by graphicjunki

It was running fine, then started to back fire. I haven't taken off the valve covers, but I'm guessing I have a valve rocker still not right.

To add to it, since it doesn't ping, it just back fires, I'm somewhat voiding out lean condition.

is it backfiring out of carb or exhaust

graphicjunki · 01-09-2013, 03:23 PM

Its backfiring out of the passenger side exhaust.

diehrd · 01-10-2013, 07:53 AM

Check ignition usually exhaust back fires are related to it , what happens is un-burned fuel ignites in the hot exhaust as that cylinder pushes it into the exhaust system.

graphicjunki · 01-11-2013, 10:51 PM

Checked out all the plugs and everything. All was well. Since it was loading up, decided to tune down the fuel. Go the timing set at 31 degrees, and turned each of the front screws in one turn. DID WONDERS! Must have been just dumping fuel into the carb!

Either way, back fire is gone, it's idling better now. Too bad we got 6" of snow today! !@#$!$%!@#$!$%!!