Torque Converter Install Problems

[Strawdawg]

Over the past year, I have been helping my son install a 440/727 in place of 318/904.  It would have been a lot cheaper to build a good sb in retrospect but....

Okay, he came up over the holiday and we made a push to finish the job but we ran into a problem trying to bolt up the converter as there seems to be zero clearance between the converter and 440Source Flexplate.

Previously, when the engine was out of the car, we installed the converter and it appeared to be seated.  Then we installed the transmission on the engine and the bellhousing went right into place and the converter was not binding.

BUT, i made a mistake and did not bolt the converter to the flexplate for some reason.  This meant that I did not check the fore/aft clearance on the converter to the flexplate.

We dropped the engine/transmission into the car and proceeded to install everything else.  This weekend , we started to bolt up the converter and discovered that it was binding  just as it rotated where the mounting pads started to move over the bolt holes in the flexplate.  There was no fore/aft movement on the converter.

In order to get the converter to rotate, we had to loosen the transmission bolts a little to let it it move back about 50 thousandths.   So we bolted it up but did not tighten the bellhousing bolts back up.

Today, I looked at Munroe's book on the A727 and it says the mounting lugs should be 0.500" below the bellhousing mounting surfaces and it should move forward an 1/8" to bolt to the flexplate.

I will have to measure another ten times to be certain, but it appears that the lugs are the correct distance behind the bellhousing mounting surfaces (0.500") but that is touching the flexplate without any clearance.  In other words, my first impression is that the flexplate is sticking too far into the bellhousing.

The flexplate is one of those hd round ones, one size fits all. it cannot be mounted but one way due to the offset holes and the recessed side is over the end of the crank as it should be.  As it is the round style, it is very difficult, if not impossible to see what is going on around the crank mounting area.  It appears to be flat against the crank.

When loosening the bellhousing, the converter seemed to be hitting a high spot on the flexplate up toward the top as it was rotated.

Given that the converter is the specified 0.500" below the bellhousing face, it would seem the flexplate is sticking too far into the bellhousing which seems unlikely...but that is what my measuring would indicate.

I will pull the transmission back some more and see if something becomes obvious but, I wonder if anyone has seen something like this before.  I see some say the converter should be over an inch back in the bellhousing but I am pretty sure Munroe is right..and that if it had not dropped all the way in, it would not allow the transmission to bolt up without resistance from the pump ears.

[7212Mopar]

From any torque converter manufacturers, B&M, TCI. Dim A is trans case to converter pad, about 0.5". Dim B is engine mating surface to flex plate bolt hole. A need to be greater than B.

[MoparLeo]

I know this may sound obvious but did you install the torque converter correctly ?  Rotate it slowly until it seated ? The notches in the torque converter snout must line up with the front pump ears or it won't seat and if you force it you will break the front pump.

[FE5CUDA]

The converter isn't in all the way.  I did that over 40 years ago and the result was I broke the ears off the pump in the trans.  You should have plenty of clearance between the converter and flex plate where you have to slide the converter out to the flex plate.  The other thing you want to do is line up the holes on the flex plate and converter and paint one of the ears, it only goes on one way and a PITA if you have to rotate the converter only to get a couple bolts started and the last doesn't line up.

[Rich G.]

When you put the converter in it will slide in and engage the splines of the trans. Then you push in while turning the converter ( possibly wiggle it a bit ) and keep turning and pushing until you feel it engage and slide in the rest of the way. You'll definitely feel it move all the way back in the trans.

[Strawdawg]

When I installed the converter, I recall at least two "clunks" as I installed the converter.  It felt bottomed out to me and I did not get it to go any further.

My son and it picked the transmission up and slid it over the dowel pins and it mated flush with the rear of the engine without any resistance.

The converter turned freely altho I don't recall if I spun it any distance or just verified it was not under pressure at that point.  I DID NOT check for fore and aft movement which was a big mistake on my part as I would rather have messed with it out of the car.

The distance to the converter from the face of the bellhousing measured 0.500" which is what Munroe says in his book.  That measurement is with the converter bolted to the flexplate and the transmission and engine are in the car. 

NOW, with the engine and transmission bolted together, the converter no longer wanted to turn after the converter was rotated and the mounting lugs were about half way over the mounting holes in the flexplate.  Loosening the bellhousing bolts so that the bellhousing moved away from the engine about 40-50 thousandths allowed the converter to move to line up the mounting holes.  As I mentioned I still heard a slight rub from somewhere toward the top of the plate.

Yes, the holes in the plate and in the converter are not symmetrical but they lined up on the second turn of the converter and all four are now installed and torqued down.  No, I did not tighten up the bellhousing bolts because I knew something did not make sense.

My first round of measurements yesterday indicated that the mounting lugs of the converter were the correct? 0.500" below the bellhousing face.  BUT, the flexplate appears to be about 0.530" below the  bellhousing face.  I believe it should be about 0.375" to provide for the desired gap between.  I would not bet money on that measurement as of yet (how far the flexplate is protruding into the bellhousing).

I doubt the flexplate could be that far out of spec which means something else is wrong and the wrong is probably me LOL   But so far, nothing seems to be wrong.

Logic tells me the converter is not seated all the way in, but the measurement seems to disagree.  What I don't know is how far the converter moves when it properly engages the pump.  Given that the converter did not initially bind until rotated enough that the mounting lugs hit something is what puzzles me.

[Strawdawg]

It must not be all the way in...and the measurements are probably throwing me because it will definitely be somewhat more than 0.500" from the face of the bellhousing.  I need to find a transmission jack as I may be a bit too old to bench press it by myself anymore.

I don't see how the flexplate could be off that much so....

[floorit426]

Is it possible to unbolt the convertor (after marking the bolt, for easier reassembly), and try to spin, wiggle, and finagle it back the remaining 3/8", or so?

[Strawdawg]

Is it possible to unbolt the convertor (after marking the bolt, for easier reassembly), and try to spin, wiggle, and finagle it back the remaining 3/8", or so?

I am going to try, but I don't think there is room...my current plan is to go into town tomorrow and grab some long bolts to use as guide pins to keep the transmission line up...then pull the driveshaft and pull the transmission to the rear a few inches to make some room.  Hopefully that will give me enough room to better grab the converter and have some wiggle room.  I won't need any help or jack to do that.