I've got a th350 im bolting up to the back of an ls1. the trans came from a 71 chevelle, using stock ls1 flexplate, the torque converter I don't know naything about, I had it laying around. when I go to bolt up the trans to the motor the TC mount pads are physically flexing the flexplate, in other words a negative gap. I figured this was wrong so took it back out, rotated the tc triple and quadruple checking to see it was in all the way.which it felt so, although im going to say I dont think it was near an inch like its supposed to be. any ideas. is it just some wrong converter that happens to almost work?

 

Installed my Yank tonight. Got 1 and 1/8 from front of trans to mounting pad. That seems right on par. From the converter pad to flexplate, I could fit a 1/4 bit but could not fit a 5/16ths. So I would estimate it to be between 0.25 - 0.31. Suggestion on shim size and where to get them? So lets say its .28 and I need to get to at least .18 I would need at least a .1 shim correct?

 

anyone wanna chime in on this one?

 

It really does not matter where the manual lever is when you install the converter. I have never paid attention to where it is when doing this. Also as far as which way to turn it I do not think it makes a difference. I usually spin the converter clockwise but it really does not matter. Being right handed that is just the way I do it! Good questions never hurts to ask. Vince Bielanski

I have found that the th350 and th400 measurements in this thread are a bit off when not using a PI converter. I recently received some more info on converter spec's and need to update the thread.

Depending on the the converter that you have i would suspect a couple things. If this is a factory converter it might be that what ever it came out off used a flex plate with a different offset. You might not have the converter all the way into the pump gears. Pump gears installed in the wrong direction.

With an after market converter the build height might be taller than spec. This would lead me to believe that it might have been built for a combo using a mid plate. Or as mentioned above....You might not have the converter all the way into the pump gears. Pump gears installed in the wrong direction.

When I get some time I will look at the info that I have and update the thread. Sorry not to have the exact answer but I figured I could throw out a few ideas for you. Vince Bielanski


I like to see .125 or 1/8" of converter spacing. That to me is ideal. Remember the spec's I have posted here are no looser than 3/16 and no tighter than 1/16. So if I was setting this up and you say that you have a 1/4(.250), we want to get to 1/8(.125). With that being said you need a .125 shim or less to achieve the 1/16-3/16 we are looking for. .250-.125=.125. Make sense?

Now for the washers. I believe if you look through the thread it has been covered.

To add to this I think any grade 8 washer will be fine. I would suggest contacting the converter company to get what they recommend but I'm pretty sure they will tell you basically what I have already. Vince Bielanski

Very good point. I have always followed an old timer rule that was taught to me years ago. That at 5-6 threads need to be in the mounting pad to be safe. When properly torqued this more than enough. Good point on the bolt length and it is just as important as the spacing so you do not wreck the threads. Thank you for adding this. Vince Bielanski

 

bump for a good informational post.

i was installin my fresh trans from performabuilt, but hurt myself while doin it(always have a friend). i let a shop finish it. needless to say they didnt check clearances. broke my pump gear. and cracked my fresh yank converter.(barely even 3/16'' of the converter snout was on the pump gear!!!)...

when i told them that they should have checked the clearances and used shims to fit , they got really mad and started BS'in at me that they have never heard of such a thing and that why would i need shims for a "direct drop in" for my specific make& model.

i know that 90% of you dont need it but the other 10% some times do.

sad to say they are not doin any of my work anymore cause they wont take responsibility and the shop thats fixing it now will let ME check my clearance and make sure its up to par

 

Bump again as I am preparing to take my transmission out that isnt doing well.
What happens if the the converter is pulled to far forward to the flexplate?

 

You end up breaking the pump within the transmission.

 

I figured it would be more damaging if it was in to far.
Learn something new everyday.

 

Well after getting everything in tonight, I came up with 3/16 I believe using the drillbit technique. From what ive read this is at the max it should be. Will this be fine to bolt up? im guessin when I tighten down the bolts it will pull the converter out the correct distance? Sorry if these are noobish, but first time accually messing with an auto.

Its a ckperformance th400 and a fuddle converter if that matters

 

^^^yes you're good. You can just pull the converter close with your fingers. It should slide easily.

 

Goood....Gooood

Thanks man, just wanted to make sure everything was right

 

When I installed mine, there was a crazy gap, about an inch. I used a half inch thick nut as a washer on each bolt and everything works fine. I guess the build height was a bit off, being it was custom built (TH350 converter bolting up to a stock LT1 flexplate). But numerous track passes and over 7 months of daily driving and not one issue.

 

The measurements stated in this thread aren't something to worry about. here's the best way to go about checking the clearence yourself.

measure from the edge of the flexplate to the mating surface of the motor. then measure from the edge of the bellhousing to the converter. the distance on the trans should be slightly more than the one you measured on the motor side. I'll see if I can get a good pic to repesent this soon.

 

Vince I think you miss the point of what I originally posted. There are measurements from the face of the bell to the converter pads. This insures us that the converter is fully installed. Then once you get the trans bolted up you need to check the distance between the flex-plate and the converter pads.

Not saying that your method will not work but the key point of this thread is the distance between the flex-plate and the converter pads. I can appreciate what you said and it is a valid point. Mainly because many installers are using after market flex plates. With the measurement of the engine side of things this will insure the flex-plate/engine side of things.

When installing the trans and checking the spacing, if it is more than 3/16 of an inch then we need to do some shimming. I personally like 1/8 of an inch.

Please feel free to add your input with pic's so myself and others have it to review.

Thanks Vince @ FLT

 

Newbe here:Question about the steps in how to add oil. how Important Is it adding that one qt of oil into ths cenverter before installing it. The reason why I ask is because I just finished installing everything and was ready for start up. I mean can the qt be add any other way or do I have to take everything Down add a qt to the cenverter then bolt everything back up? :/

 

Did you install a brand new converter???

 

No but IT was drained a good amount

 

Personally in your case I would not worry about it because the converter you are using has already been run. It has had some oil in it to lube all components. I would make sure to dump 4-5 qts in the trans before starting it up. After you start your vehicle start dumping the rest of the oil in as quick as possible. Another way is to fill the trans with 4-5 qts and start it for a short time. Meaning like 20-30 seconds and then shut it down. Refill trans and continue until full. Hope this helps. Vince

 

Thanks a lot guys.. Ton of help. I did what you guys said, car's running great.

 

Good thread here guys! I am installing mine in the morning!