[dataway]

The GTO went out for the first drive in 40+ years on Sat.

Basically just about 3 miles of driving on the roads around my house.
I found it to be suspiciously problem free.

My home rebuilt TH400 shifted and operated normally ... although I feel the 1st 2nd shift is a few hundred rpm early. (Using original to car modulator)

No surprises with the engine temps (190 +/- 2 degrees), oil pressure at idle 23-25 fully warmed up, 55-60 psi at 2000 rpm (VR-1 20-50), saw it run up to 69 psi blipping the throttle. No detectable leaks yet, cooling system pressurized nicely. No pinging, very quiet valve train (91 octane ethanol free).

Power drum brakes work considerably better than I expected. Firm pedal, very good progressive feel.

I'd say the only thing annoying me is it's got a bit of a rough, "running on 7 cylinders" feel at low rpm acceleration. And a bit of a whine off throttle at cruising speed, not sure if it's the rear end (untouched 100k mile, 2.93) or the trans.

Starts and idles fine, idle drops normally after warm up, but I have a feeling the choke is not opening all the way (driver side of cross over is blocked). Only once did I think I got the back barrels to open .... or it could have just been the trans kicking down. Still taking it kind of easy until I'm confident it's reasonable sorted.

DIY front end alignment seems suitable for this testing, not doing anything unusual except a tiny bit of wandering, tire temps felt fine.

[dataway]

Just spent some time under the car, not a single drop on the floor .. did have one "hanger" drop on the base of the tail shaft .. looks like it might be coming from the Speedo cable hookup.

Checked the diff fluid just in case I happened to forget to fill it .. all good.

Gave the front brakes about five clicks of adjustment on each side, shoes just skimming the drums now.

I see nothing amiss in the ignition, plug wires all in place nicely. I'll check the timing today. I'm running 9 initial, stock iron heads, typical speed-pro pistons with added 6cc dish, about .005 in the hole, typical .037" head gasket (heads cc'd right at 72cc), 068 melling cam, OEM dist internals, and I think an OEM vacuum can.

After many years of only driving late model vehicles it's hard remember what these older cars SHOULD feel like.

[Half-Inch Stud]

Definitely "check the Timing", yet properly; Time for 34* Total ADV at ~2600 rmp, vac adv hose disconnected, and see what the initial Adv ends up to be. Keep initial under 18* (455).

After that, consider setting up an HEI for best results.

[tempest1964]

That is awesome. Congratulations! Enjoy it now.

[Shiny]

How fun this must be for you..

Congratulations

[Jim Moshier]

Congratulations! Enjoy it now. find the little things along the way!

[dataway]

Here is a boring video of the first drive.

You can hear the whine in the drivetrain. At about 6:30 I stop in front of the house ... drive to the corner and turn around, I come to a stop and move off ... you can hear how quickly the trans is shifting.

The rear end is original to the car, I replaced the axle bearings and seals, replaced the oil. There was a lot of banging and yanking to get the axles out, but I did nothing with the diff (one legged) ... could have harmed something I guess. The rear end sat for about 40 years unused, sometimes inside, sometimes outside, so I'm sure there was some condensation inside. When I had it apart I didn't see anything that looked bad, nothing broken, no metal parts in the oil.

I did noticed that the trans fluid is at least a quart low, can that effect shifting? But I don't think it's trans pump whine, but could be far as I know, I'm not a auto trans guy by any means.

Jeez, after driving modern vehicles with overdrive transmissions this 2.93 feels like a 4.11.

https://www.youtube.com/watch?v=sjt4EtVkiNY

[Shiny]

Excellent

Had to be rewarding!

[Verdoro 68]

I bet it feels good and probably a little surreal to get it back out on the road. I also know that the first few drives come with a lot of nerves, but don’t let that get in the way of enjoying this milestone!

Funny that the 2.93s feel steep. I was cruising in the Trans Am the other day and noticed it was 1/2 the RPMs of my ‘68 at 70mph. Those extra three speeds really make a difference!

[dataway]

I should have said it feels like a 4.11 in third gear compared to my truck with it's six speed with an overdrive final ratio. From a start the GTO feels pretty normal. I found the hesitancy for it open the rear barrels was more my like of pedal pressure, again use to the fly by wire of most modern vehicles.

Tomorrow I check the timing and point dwell. I suspect it's somehow considerably less than the 9 degrees I originally set it at ... I can really lug it and not a hint of ping. I don't recall that I ever set the timing with the engine in the car ... so I could have moved things around during installation.

If the whine doesn't go away with the addition of more trans fluid then I might end up opening up the rear end.

That another thing ... these old vehicles aren't exactly quiet compared to new ones. More road noise, more wind noise, engine noise etc.

[jhein]

Originally Posted by dataway

Here is a boring video of the first drive.

You can hear the whine in the drivetrain. At about 6:30 I stop in front of the house ... drive to the corner and turn around, I come to a stop and move off ... you can hear how quickly the trans is shifting.

The rear end is original to the car, I replaced the axle bearings and seals, replaced the oil. There was a lot of banging and yanking to get the axles out, but I did nothing with the diff (one legged) ... could have harmed something I guess. The rear end sat for about 40 years unused, sometimes inside, sometimes outside, so I'm sure there was some condensation inside. When I had it apart I didn't see anything that looked bad, nothing broken, no metal parts in the oil.

I did noticed that the trans fluid is at least a quart low, can that effect shifting? But I don't think it's trans pump whine, but could be far as I know, I'm not a auto trans guy by any means.

Jeez, after driving modern vehicles with overdrive transmissions this 2.93 feels like a 4.11.

https://www.youtube.com/watch?v=sjt4EtVkiNY

Looks like a really fun project. Great video..

[dataway]

I've had a couple more outings. The initial timing was at 6 degrees, bumped it up to 10 and felt a nice improvement, much crisper on the throttle. Bumped it up to 12 after that, I'll let it sit there for a while. Vacuum advance is kicking in 20 degrees. Starts nicely, idles nicely both in gear and neutral. Starts well when up to temp also. Engine still seems just a tad tight, stops rotating very quickly when shut down. Pressures and temps still where they should be, no dripping so far.

Still whining ... but if I had to make a bet, I'd say it's a bit less ... could just be getting used to it.

And I'm remembering why when I was a kid I removed the hood hinges and used pins on four corners.

[NeighborsComplaint]

Car sounds great. Congrats on getting another legendary car back on the road!

[dataway]

Another Shake Down update ...

So among a few things annoying me I felt the car was a bit more wallowy than I remember, even accounting for the yet to be aligned front end.

So doing my usual late night examination I figured I'd check the body mount bushings. How about this ... with the exception of one on each side just to the rear of the front wheels .... they were all just finger tight, I don't mean hand tight, I mean finger tight, I could unscrew them all with my fingers.

Evidently when I finished adjusting the body position and all the front body panels I for some reason only tightened the ones behind the front wheels.

Test drive will have to wait till tomorrow ... wondering if I will notice a difference.

Bit by bit I'll get it right

[Greg Reid]

That 068 sounds good. Congratulations on reaching this milestone!

[dataway]

If anyone ever wondered .... having 80% of the body mount bushings bolts so loose they could almost fall out makes little difference in daily driving

Car runs better with the initial timing bumped up to 12. Topping up the trans fluid made no detectable difference. I manually shifted the car and it shifts wonderfully, firm but not harsh.

Are OEM modulators adjustable at all? Still seems to be shifting too early by at least 300 rpm.

[Greg Reid]

I've never done it but I believe they are adjustable. What are the shift points supposed to be? Mine is set up just as it was when I got it and I have no idea whether it's right.
My initial timing is set to 14* if I recall correctly.

[PunchT37]

Cool deal. 40 years, huh? Run that thing. You`ll figure that thing out.


Late model cars? Yeah but, how many eyes does that car get?

[OG68]

Originally Posted by dataway

Are OEM modulators adjustable at all? Still seems to be shifting too early by at least 300 rpm.

I think the shift points are in the service manual (TH400 Chapter) and IIRC they were quite low under minimal throttle.

[Greg Reid]

I know mine shifts 1-2 very quickly on normal takeoff from a stop but since the change to the 3.55 rear, if I goose it immediately after the shift it'll chirp the tires in the downshift back to 1.