1965F85_scholten

My buddy and I just finished rebuilding the 330 that's in a 65 F85. Running it with a Junkaway, um I mean Jetaway tranny.

We've got the timing down, 7.5 degrees at 850 RPM and adjusted the carburetor to an idle at about 700 rpm. We just finished break-in and took er for a spin. It's still running a little hot but haven't really had it on the road yet.

3 things, related or not going on.

1. The engine purrs at idle, in park, but when I put the engine under load, I can get it going, but it's hit and miss and will usually stall

2. We took it out onto the highway, and it doesn't want to shift from 1st to 2nd. We never got up to more than 40-45.

3.The oil pressure light came on about the time we took it out onto the highway and now doesn't want to turn off.

The motor was completely rebuilt but the tranny was not touched but had no issues when we pulled the motor. New cam/lifter set, valve set, rings, push rods, oil pump, journals polished, gasket set, and on and on.

I'm thinking on the shifting, I need to check to see if it's the vacuum modulator line. I know it's connected on the intake I know when I connected the line it to the modulator on the the until itself I could rotate the modulator, it was not in a fixed position.

For the oil pressure, I'll put it on a guage to see if the sensor is failing. Other than that, I've got full oil and all the innards of the engine are new, no leaks. What else could be causing that light to come on ?

The stalling has me stumped, but I really haven't had time to look into it.

Thoughts on what may be going on or what I need to do to troubleshoot?

MDchanic

Good heavens, get an oil pressure gauge on it before you even think of doing anything else.

After that, we can talk.

- Eric

firefrost gold

what oil filter did you use ? I had one block up on me i gota lifter tick and I was close to home i pulled valve covers no oil out pushrods, dropped oil and filter all came back That was about 150 to 200 miles after break in oil was changed and new filter . Did you put on new wres and plugs I would check the order a week spark or jumping will sometimes do same thing as far as idle good but buck and choke when getting on the gas good luck and post up some vacation pics or vids even.

joe_padavano

The lack of upshift is most likely a vacuum modulator problem, with the most obvious cause being the line came off the modulator. Less likely but possible is a problem with the kickdown wiring that is causing the solenoid valve to be held in the downshift position.

I'm not sure what you are describing in No. 1, exactly. Are you saying that the car won't run when you give it gas? If so, could be any one of a number of things, from ignition to carb to fuel delivery.

oldcutlass

I think you forgot to connect the vacuum modulator and possibly have a vacuum leak causing your operating issues. Make sure your carb linkage is set correct as the ST300 is a variable pitch torque convertor which also effect your drivability. It also controls passing gear shifting and will have a dramatic effect on how it downshifts.

1965F85_scholten

Joe, I double and triple checked to make sure the vacuum modulator on the ST300 is connected. It appears to be the original modulator and line with just a rubber seal over the modulator.
What I don't know is there an adjustment on the modulator? When I had the tranny out, that thing spun around and the only adjustment I made to it was to rotate it so it would mate with my vacuum line that I connected to the intake.

1965F85_scholten

Thanks, the plan is to put it on a oil pressure gauge. Don't have one but will be picking one up today.

Octania

Sounds a bit like the 1st drive of my rebuilt 403- I had set the timing to factory specs but with HEI and a decidedly non factory engine it overheated rapidly and maxed out at about 50 mph. Advancing the timing helped- A LOT.

When you go to a Dr., they like to ck your status- weight, blood pressure, respiration.... right?

You need to instrument that engine. ANY freshly built engine.
1) REAL [Bourdon tube] oil pressure gage.
2) Vacuum gage to show manifold vacuum.

Beyond that some basics like temperature instrument such as handheld IR meter would be nice. Timing light, of course. Dwell meter if running points.

Don't run it again w/o verifying Oil Pressure with a real gage.

1965F85_scholten

Carb was rebuilt by a local shop, so I assume they knew what they were doing with the linkage. Runs fine in park, it stalls though when I put it in gear. Throttle linkage was never changed. The only thing that came apart on the throttle were the springs just to clean off some gunk. Modulator is connected but the rubber housing just slides over the tube on the modulator, no clamp. Is there an adjustment on the modulator? It just rotates.

oldcutlass

Make sure the modulator is connected to manifold vacuum.

joe_padavano

The stock modulator is not adjustable (aftermarket versions are), and turning it has no effect. Verify that the modulator holds vacuum and also verify that you have manifold vacuum at the trans end of the modulator tube. If all is good, look to the kickdown switch. You can temporarily disconnect the wires from the trans and see if it upshifts.

1970-W30

My advice, get a mecanical gauge on it right away, don't fire up the engine again until you get the gauge on. No pressure or real low pressure, replace the oil filter, it could be clogged. If it still has no oil pressure, forget about the other problems, you will have to open up the engine and determine what is wrong. That is number one priority!

droldsmorland

I wonder if the infamous oil galley plug was left out in the back of the block??? Which would cause low oil psi!
X10!!! on the two test gauges, the oil psi gauge being the most important. Once you've verified the blood pressure is good then use the vacuum gauge to tune and verify the port you're hooked into for the modulator has vacuum. I'm not sure if a ST300 needs full un-ported vacuum, likely? I can check the book when home if needed. I always run the modulator directly off the nipple on the intake.
If you have vacuum down at the modulator (pull the line while its running and see, unless its ported?) and it still isnt shifting then Id suspect a bad modulator diaphragm. This can be hand tested several ways. Pull it out and test it with a hand held vac pump or hook it to vacuum source on a running car to see if it moves with direct vacuum applied. If the modulator tests good then its time to, once again, use a pressure gauge. But that needs to be a high pressure gauge to check the trans pressures. A good trans shop will be able to diagnose fluid bypass and kick down solenoid problems and verify if a rebuild is in your future etc...
FYI verify the modulator metal tube (if so equipped) doesn't have a kink or is obstructed with carbon or debris.

1965F85_scholten

I sure hope the oil galley plugs were not left out, but it did have pressure for the first 45 minutes or so that we were breaking it in and tweaking the timing and carburetor. If it was, the machine shop is going to hear from me in a big way.

I will pull the metal modulator tubing off go through the vacuum tests on both ends to see where it may be failing. Picked up an oil pressure gauge today. Just gotta find time to do it now.

Octania

You can verify the presence of the hole in the LH oil passage plug [and of course the presence of the plug itself] with an inspection mirror thru the distributor hole.

While you are in there you can spin the oil pump drive rod and see what kind of oil pressure the pump builds...

Sampson

Just curious but wouldn't there be oil pouring out of the bell housing if this plug was left out?

jag1886

The oil pressure is your #1 priority. You know what they say about assume (it makes and *** out of U and Me).
Worry about 1 problem at a time. No oil pressure, engine wasted. If no oil pressure is confirmed with gauge I'd be draining the oil and cutting the oil filer open to investigate. Not to be doom and gloom but that is most important. The other stuff is secondary.

droldsmorland

No this isn't a welch plug on the outside of the block. It is a restrictor plug internal to the rear of the block on the left lifter oil galley. You pull a freeze (welch) plug to gain access to it on the rear of the block with the bell housing off. The restrictor holes jobs to sprays oil on to the dist shaft area. If this is left out you will have oil pressure at higher RPM (such as break in periods) but very little at idle. If its replaced by a standard plug w/o the hole the distributor will be starved for oil.

1965F85_scholten

Well I've got the best possible outcome. Traced the problems to 1) a faulty oil pressure sensor. Put the motor on a pressure gauge and it holds a steady 60 lbs. couldn't be happier with that and 2) a simple vacuum leak at the connection to the modulator. Cleaned that up and the junkaway is happy as ever, shifting like it always has.

The third problem, stalling, was fixed because I had my carb adjusted way too to rich. It didn't seem rich I think because of the vacuum leak.

Once again, all of you olds faithfuls, have come to the rescue. Your help and knowledge is greatly appreciated. Some day, hopefully, I'll have enough knowledge to pay forward myself. Thanks!

oldcutlass

Great, glad it was the simple things and nothing major.

MDchanic

Good to hear!

- Eric