V6 Torque Converter stalling out my v8...

[Guest alphamale1906]

Quick questions. I did a V6 to V8 swap and was wondering if the torque converter from the 6 could be stalling out my 8? The cam isn't what I would think is too aggressive. It's 350 from a 69 Camaro, stock 260Hp (From what I can tell). Anyway, I pulled a shot 6 from my 84 El Camino and dropped in the 8 without upgrading the torque converter, figuring it wouldn't be a problem. However, everytime I drop it in gear the engine stalls out. If I rev it high enough then she feels bogged down, but stays running. Is there any way that the trans (a TH350) is stuck in an upper gear? I know this isn't a Monte question, but you guys have helped me so much with her, that she's running like a champ and I've taken on an ElCo project (at least until I drop the Gen VI BBC into my 400 Monte).

 

Any thoughts would be greatly appreciated!

[Sam (Bones)]

most V6 torque converter have a higher stall, check your timing, sounds like it's retarted

[kc8oye]

check your idle mixtures too.. that will cause problems with it stalling when you go into gear.

 

[Heckeng]

Or Vacuum leak.

[Sam (Bones)]

all of the above

[Guest alphamale1906]

Is there anyway that a weak coil and too cool spark plug could make this happen? The coil was one of unknown origin I just had laying around the garage, and I'm running R43T and the recommended plug is a R45TS.

 

I used a FelPro intake manifold gasket set and torqued everything to spec in sequence. I'll use the carb cleaner test method tonight to check for vacuum leaks, but otherwise everthing is buttoned up well.

 

I just advanced the timing to where the starter could barely turn the engine over, and backed it up a few degrees.

 

She'll idle around 1200, but once in gear...Ka-chug, ka-chug...Cough. Then stopped. I haven't taken it on the road to see if she'll stay running when floored in gear.

[stangeba]

Left field here, when you put it in gear, I assume your foot is on the brake and I assume you have power brakes. Try applying the parking brake first or if it doesn't work try blocking the wheels then shift into Drive. The power brake booster could have a huge vacuum leak causing the problem.

What happens if you shift into Reverse?

Good luck.

Bruce

[Guest alphamale1906]

I've checked and checked again, and I can't seem to find a vacuum leak. At least not in the places I would suspect (i.e. trans module hose, carb gasket, intake manifold gasket, etc.) However, when this engine was in another car, I think I ran it with a breather vent in each of the valve covers and not a PCV valve connected to the carb (which is a Holley 750 DP). This was the same carb I ran on this block when in the other car and it ran fine. However, it has been sitting in the corner of the garage for some years so my memory is skethcy on the exact set up. However, could the wrong PCV valve cause the vacuum leak? Is it common to just run two vents as opposed to a vent and PCV valve?

[Sam (Bones)]

just plug the PVC and try, if this carb was on it before with no PVC, it will need to be re-tuned

[Guest alphamale1906]

Prior to plugging the PVC, I've adjusted the idle mixture screws and idle adjustment screw. Otherwise, I am not sure how to go about any other tuning of the carb. I've replaced jets and some gaskets before, but not really a full rebuild. What is entailed in tuning the idle circuit?

[wallaby]

Yea, I've had PCV valves give me idle problems like that. I've had PCV valves that worked great if they were positioned horizontal, but didn't work if they were mounted vertical, and I've had PCV valves that were new but wrong for the aplication that wouldn't work with my engine. I thought they were all the same but one that works for a V8 might be different than one for a 4cyl.

 

My gut reaction to your problem is the idle speed being too high. It would seem that more throttle opening would keep the engine from stalling, but it also greatly increases the shock the engine sees when it's put into gear: it will try to lurch the car forward and load down the engine, etc.

 

Do your best to slow down the engine speed and still get a favorable idle. Most stock engines will idle happy around 500rpm. If you have a cam you might not be able idle that slowly, but the goal is to aim for as slow as you can. You might have to readjust the mixture screws as you slow things down, but experiment with it to make it slow and happy.

 

Once that is done, if it still needs help, try plugging the PCV hose or putting your thumb over the end of the valve while the engine idles. If there is a big change in engine speed then something isn't right. You should be able to notice the speed go up & down as you put your thumb on/off the valve, but it shouldn't be a radical change. Also listen to the valve itself as you do this to make sure the pellet inside is moving freely.

The PCV system is a good thing.