Large RPM drop when car is put in gear

I had a similiar problem. After much screwing around, I installed a fresh set of spark plugs and shazam, it fixed it.

 

I had a problem like what you have.High idle put in gear stall.
Had to use both feet to drive at low speed.I changed carb,dist,plugs,wires.
The engine run good when moving,plenty of power.
I bought the truck this way.
I also did the timing chain thing first.
I thought it was the cam or leak in maniflod.
NO LEAK i could see.
I bought a Elelbrock cam kit with good idle.
I had no more problems with new cam.

 

Whew, I just read this whole thing. Unfortunately there are a lot of variables to check, but you just have to go through them one by one. Compression, timing mark, check vacuum lines, all that and more. The motor must be in good tune first.

I have suspected since page one that the trans converter is pulling the motor down. I don't know a lot about lockup converters, but I think the converter is just not matched to the motor right. The symptoms you describe are cl***ic too much cam/ too little (too big in diameter) converter. Even if the motor idles calmly, which points to a mild cam, you may have a converter designed for a much bigger motor.

If the problem goes away after your trans swap, this was likely the reason.

 

This is a problem? My boat (a '54 Chris Craft with a small block Chev, a 350 with 283 heads and marine conversion from a '63 CC 283, manual Paragon trans), idles at 600 rpm, in gear it drops to 350. I use this as an example only because it's the only vehicle I have with a small block running points and carb. My other cars are all EFI, they drop RPM at idle in gear as well.

 

Can too much fluid in the trans cause the converter to be too much filled and stall at low RPM instead of 1200 / 1500 or whatever ?
This may be a stupid question, I m just wondering

 

I had a similar issue. I know 10 degrees of time does not seem like alot. I backed mine timing off to 4-6 degrees BTDC and it ran like a whole different engine -- and I mean that in a good way.

 

No too much fluid in the trans would not cause the converter to stall differant

 

All great suggestions. Right now, the engine is ready to be pulled after Christmas to do the trans swap. While its out, I'm going to pull the intake since I can do it without throwing my back out if the engine is out if the car. I'll check it closely for cracks and leaks.

That Chris Craft sounds awesome! I'm into vintage boats too. But, while my car will idle at 400 RPM for awhile, it starts to sputter after awhile. I discovered this at a long stoplight.

I'll report back after the trans swap. Thanks for all the help so far.

 

Got the TH350 out and the 200R4 partially swapped in. (I have to finish dealing with moving the crossmember, not a fun task. So its sitting in the car with the transmission being supported by a jack)

Anyway, I'm not sure if this means anything, but the torque converter that came out of the TH350 had a "blackened" look compared to the clean appearance of the 200R4's converter. I was wondering if maybe this torque converter got overheated or had some other failure/damage?

http://i79.photobucket.com/albums/j152/V8PunkRocket/torqueconverter002_zpsfff36013.jpg

http://i79.photobucket.com/albums/j152/V8PunkRocket/torqueconverter001_zpsafa6c893.jpg

Or, does the color not mean anything at all?

I'll also post what happens after the 200R4 swap after its done. Thanks again for all the help so far.

 

I doubt heat could change the color. It s full of trans liquid. If it overheat, oil would be boiling. This may no happen so often . Unless you have a major problem

 

On a 283 engine, any cylinder with less then 90 psi is a dead cylinder. Ya its firing, but it isnt making power. I am intrested to see if the 200r4 and converter swap makes a differnce.

I had a 283 n my 40, did the same thing, swapped it for a low milage 350 still did the same thing, I did not abandon the compression and power issue, turns out the 350 had 2 mushroomed valves cuz of a plugged egr system, got rid of the egr did a valve job, compression back to 150 across the board, problem solved.

283's are small engines and need rpms to make power. I doubt its the ****** since the TQ converter (fluid coupler) isnt even flashed yet. To me it sounds like the slightest HP or TQ loaded is more then the engines 3 good cylinders can over come, and turn the rest of the engine.

 

Well, I'm not completely finished with the trans swap, but I did do enough to fire the car up. Yeah, nothing changed with regards to how it idles in gear. So it looks like you guys are right - the engine is just tired.

So I'm keeping my eyes open for a useable SBC for the time being, until I can afford to rebuild this 283 properly. Until I do, I guess I'll just idle it up a bit for now.

 

I knew from past experience. My 283 is also sitting. I got a 350 from a buddy with low miles. Its a GM crate engine. I wouldnt buy one new though. GM doesnt build-um, they are out sourced to the cheapest builder, hence cheap parts. My valves where sunk in the heads, so I had to invest in a valve job at 10000 miles.

I also learned, most engine shops will rebuild your 283 not to pricey.

Mine needs punched, and the price complete was $1800. I didnt think that was to bad. Good luck.

 

Quick update, got the rebuilt motor put in, and the problem went away. So it was an old, tired engine after all. Thanks guys.

 

Good news now get out there and burn a tire.