Torque convertor swap
#1
Torque convertor swap
Since we are still socked into winter i thought i might swap out my old original torque convertor(th350 trans) in my 72 convertible with a 2200 stall unit i picked up from jegs.Ive tuned this thing as far as it will go and im hoping it will help with a little off the line performance. I used to swap transmissions in my driveway in january laying on 2 inches of ice with like 3 tools .Now a heated garage with all the stuff i need and it still seems harder! I guess it must be because im 35 years older.Of course the test drive is still at least a month or so away .
#2
You are looking at a lot of work for little to no return. Liken it to installing an 1100 Holly without doing anything else.
What's your rear gear? 2 or low 3 series? That's where Id put the T&M first...time materials. That and upgrading the trans to Hi-Perf specs. Then a converter makes sense.
What's your rear gear? 2 or low 3 series? That's where Id put the T&M first...time materials. That and upgrading the trans to Hi-Perf specs. Then a converter makes sense.
#3
I guess we’ll see when it’s done if it helps . I have 273 peg leg rear and i like that for cruising , it’s just such a pig until it gets rolling .trans is rebuilt with a shift kit but I retained the original torque convertor. It’s a factory original 350 motor so it’s by no means a power house in its current state .
#4
A good converter will help the get up and go feeling. I wouldn’t consider it a waste of time to install one. If your considering engine upgrades, make sure the converter is going to work with the future upgrades. Buying a different converter and the effort to install it would be a waste.
When I was 17, I swapped the engine in my car on my parents gravel driveway. No garage, in the dead of winter. Didn’t bother me. Now that I’m almost 50, crawling around on the floor for a couple hours hurts for days after. I knew the time would come when I got old, it just got here much quicker than I expected.
When I’m 70, I’ll look back and remember fondly how young I felt at 50.
When I was 17, I swapped the engine in my car on my parents gravel driveway. No garage, in the dead of winter. Didn’t bother me. Now that I’m almost 50, crawling around on the floor for a couple hours hurts for days after. I knew the time would come when I got old, it just got here much quicker than I expected.
When I’m 70, I’ll look back and remember fondly how young I felt at 50.
#5
Back in around 1982 I swapped the factory converter in my 1970 Cutlass for a 2200 RPM stall and it sure made a big difference. That was with a 350-4bbl, TH350, dual exhaust, 2.56 anti-spin rearend.
#7
I guess the question would be "how much is too much stall?" I do not think that something in the low-mid 2000 RPM range would too much for even a stock engine. Keep in mind that the G-Body 442 with a 307 and TH200-4R had something like 2600 RPM stall.
#8
I’ll let everyone know about my experience when the weather is nice . Been prepping for the job tonight my son comes tomorrow to give me a hand. Turn on the radio and turn up the heater and it’ll be a good time .
#10
i have an interesting scenario after topping off the trans fluid .I started and ran the car a couple weeks ago got the everything up to temp and filled the trans to the proper level. climbed under the car and checked for leaks and all was good.I checked under the car over the next several days and all was dry.after about a week i see a big puddle of trans fluid under the car. it looks like its coming from the kick down cable. why would it take almost a week to show up there?will have to disconnect the cable and check the o ring seal on it and go from there
#11
Your leak scenario seems a not uncommon condition on TH350. Converter gradually drains back into case/pan/sump and fluid level overcomes seal of kick down cable. I’m thinking run car to refill converter, jack from passenger side to move fluid away from cable, install new O-ring, maybe a dab of rtv around the flange, cross fingers, recheck in a few days.
#12
Your leak scenario seems a not uncommon condition on TH350. Converter gradually drains back into case/pan/sump and fluid level overcomes seal of kick down cable. I’m thinking run car to refill converter, jack from passenger side to move fluid away from cable, install new O-ring, maybe a dab of rtv around the flange, cross fingers, recheck in a few days.
#13
X2 on converter draining back causing the level to rise in the pan and then leak out.
Put some time into diagnosing the leak, it can be the o-ring but it can also be the fitting on the end of the cable. The leak may be between the cable casing and the plastic fitting that goes into the transmission.
Good luck!!!
Put some time into diagnosing the leak, it can be the o-ring but it can also be the fitting on the end of the cable. The leak may be between the cable casing and the plastic fitting that goes into the transmission.
Good luck!!!
#14
I fixed the leak it was at the kick down cable.A little extra silicone around the o-ring did the trick.I was able to take the car out for a good cruise last weekend it drove and ran great ,but sadly the new torque convertor made absolutely no difference. I thought it might help coming out of the hole since its a 2200 stall vs 50 year old factory convertor.No complaints about the engine its just lazy off the line .So imo i see no reason anyone should get a higher stall convertor for a basically factory olds 350.In my case i already had the new convertor so i figured it was worth a try
#15
Can you elaborate on that? My Supreme back in high school had a 2.56 rear and it would launch hard, then with the 2200 RPM converter it would smoke the tires through first gear. Your car has a bit better rear gear so I would expect it to launch a bit better.
#16
I agree ive had many 350 oldsmobile motors that would rip it up ,but for whatever reason this car isn't one of them.If i stomp it to the floor from a dead stop it just kinda takes off slow until the rpms get to about 2500 rpms then she'll wind up and go like hell.Ive done several jet changes in the carb as well as secondary rods always end up back to the original setup .i added and hei a couple years ago and tried various timing settings with light springs and heavy springs and that whole routine but no real changes no matter what i did there either.Im just going of memory here but ,i think where i stand now is total timing at about 36 degrees and all in around 3000 thats where it seems to be the best .A said before its a beautiful starting ,running and driving car just a slob off the line. i dont need it to sizzle the tires to go get ice cream, i have 2 455 cars for that so ill just enjoy it for what it is
#17
What is the converter flashing too? The factory TH350 flashes around 1600, maybe your replacement is flashing at the bottom of the advertised range. Usually they have a 500 rpm spread, top to bottom. Step on it from a stop, see where it flashes to. Mine usually stall mid range, a 2000 to 2600, flashed at 2400. My current 2200 to 2500 flashes at 2300 to 2350, give or take. A Hughes I had flash stalled exactly at the 2500 rpm rating.
#18
What is the converter flashing too? The factory TH350 flashes around 1600, maybe your replacement is flashing at the bottom of the advertised range. Usually they have a 500 rpm spread, top to bottom. Step on it from a stop, see where it flashes to. Mine usually stall mid range, a 2000 to 2600, flashed at 2400. My current 2200 to 2500 flashes at 2300 to 2350, give or take. A Hughes I had flash stalled exactly at the 2500 rpm rating.
#22
You say you have tuned the engine, and it still feels lazy? What is the condition of the engine? It’s it’s got a lot of miles on it, a stretched timing chain will make the engine feel sluggish.
Make sure the outer ping on the balancer hasn’t moved. You may think the timing is set correctly, but if the timing marks are off as far as the engine is concerned it’s not right. Put a few ecm tea degrees of timing in it, if it runs better you know something is screwed up with the distributor or balancer.
Make sure the outer ping on the balancer hasn’t moved. You may think the timing is set correctly, but if the timing marks are off as far as the engine is concerned it’s not right. Put a few ecm tea degrees of timing in it, if it runs better you know something is screwed up with the distributor or balancer.
Thread
Thread Starter
Forum
Replies
Last Post