Possibly too small of a torque converter?

[Onewildcat54]

Hi All, recently I just upgraded my 350 to a comp cams 12-601-04 cam with 1.6 rockers which now makes it a .510 lift cam. When attempting to drive this car it goes in to gear, and will roll slowly. If any attempt is made to cut the wheel hard or fully the engine will stall HARD. I also put a summit 2200-2800 stall converter with long tubes. Is it possible that the converter needs a higher stall? Car is reluctant to accelerate as well.

 

[Onewildcat54]

Hi All, recently I just upgraded my 350 to a comp cams 12-601-04 cam with 1.6 rockers which now makes it a .510 lift cam. When attempting to drive this car it goes in to gear, and will roll slowly. If any attempt is made to cut the wheel hard or fully the engine will stall HARD. I also put a summit 2200-2800 stall converter with long tubes. Is it possible that the converter needs a higher stall? Car is reluctant to accelerate as well.

Let me add that to even make it possible to drive it has to be idling around 1100-1200 rpm. When driving low speed rpms are around 3000 as well.

 

[rotinrob]

Not much of a small block expert but this is what the catalogue says about the cam

Also says 2200-6100 rpm range. Idle may be about the best you can get you didn't say anything about the intake/head/carb combination.
Might need some more converter especially with the rockers. You could try going back down on the rockers and seeing if the drivability improves. What gears are in it? Are the mixture screws responsive when you turn them? Idle vacuum? I would say that the drivetrain setup is a bit off for that cam (maybe the intake as well). There is no substitute for 4.56 gears and a small (high stall) converter.

rotin

 

[Onewildcat54]

So the heads are stock with the addition of dual springs and the 1.6 roller rockers like I mentioned, also the heads are fitted with guide plates and push rods. The carb is a basic edlebrock 500 cfm and the intake is an edlebrock performer. The car has notibly less idle vacuum by just the power brakes alone. It has a 3.73 posi rear end. Mixture screws are honestly not very responsive until all the way backed down or backed out. My thoughts exactly were maybe to pull the rockers back off and go back down to the 1.5 stock ratio. Would make more sense to do this then pull the tranny back of and change the converter to an even higher stall. I daily this car around town in the spring and summer so honestly the excessive top end power isn't needed.

 

[muscl car]

IMHO this is the best way to get a torque converter that is built / spec'd to your combo . Is to either talk to a tech / salesman from a Torque converter mfg or fill out a form such as this

Coan Racing Car Specification Form

Default Description

www.coanracing.com

I never buy an off the shelf converter as it will not perform and have symptoms as you're experiencing

When I had my Shafiroff 427sbc built , I had the transmission and especially the Torque converter spec'd to the new engine . Originally I was just going to go with an off the shelf 3k rpm to 3500 stall converter . After talking with Mike's Racing transmissions who is a very well known transmission builder in the High Desert of Socal

He recommended after I gave him my 427 sbc engine specs that I go with a 4500 stall 9" converter and it is very streetable but will easily flash to 4500rpm when hit the loud pedal

 

[Twisted_Metal]

Before you throw expensive parts at it... Make sure the timing/advance is set and working properly.

 

[tom3]

When I saw the "car is reluctant to accelerate" we need more info. Does the engine rev up and not go, or does the engine bog down and has no power? With the trans in park does the motor idle right, rev easy, run smooth at 3000 rpm? Something is out of whack here I think.

 

[Twisted_Metal]

When I saw the "car is reluctant to accelerate" we need more info. Does the engine rev up and not go, or does the engine bog down and has no power? With the trans in park does the motor idle right, rev easy, run smooth at 3000 rpm? Something is out of whack here I think.

Cam installed correctly?
Compression readings might help if that's the problem.

 

[Onewildcat54]

When I saw the "car is reluctant to accelerate" we need more info. Does the engine rev up and not go, or does the engine bog down and has no power? With the trans in park does the motor idle right, rev easy, run smooth at 3000 rpm? Something is out of whack here I think.

When I drove it yesterday, it seemingly shot to around 3000 and didn't get much power. In park the motor idles OK, or neutral, in drive it can idle around 900, this is if I have the idle mixture screw set to 1100-1200 rpm. When idling in drive though, the motor tends to cut out if the wheel is cut hard in any way.

 

[Onewildcat54]

Cam installed correctly?
Compression readings might help if that's the problem.

Cam was installed fine itself, but the mechanic who did it didn’t use any washers or red loc tite in the 3 bolts. Car has great compression last time I checked, that was right after the cam was in.