[hurryinhoosier62]

Originally Posted by chiphead

Got the car up on jackstands today.

IF THE CONVERTER'S KNOCKING, DON'T GO ROCKING.

Whoever said loose converter gets the prize. Yup, the converter is loose on the flexplate! Check out the video below. One of the flexplate holes is elongated and the threads in one of the converter mounting feet are boogered up. Check out the mounting bolt from that hole.

I'll have to take a closer look at the flexplate itself to see if there's damage beyond that one bolt hole. What should I look for, it's hard to see in front of the converter?

Onward, party people! I'm just happy it's not in the engine.

https://youtu.be/wPabvV0lCVE

A little bit of blue LocTite goes a long way in securing converter bolts. I
had a couple come loose when I changed out the 350 SBC in Mom’s Suburban years ago. The LocTite cured the problem. BTW…I torqued the converter bolts to factory spec; they still came loose.

[chiphead]

Should I use lockwashers under the bolt heads AND loctite?

[b-man]

Originally Posted by chiphead

Should I use lockwashers under the bolt heads AND loctite?

No.

I would never use a lock washer under a highly stressed bolt like that.

Maybe a hardened flat washer but no lock washer.

[Half-Inch Stud]

Replace them 3 bolts with crispy looking bolts with builtin Shoulder washers.

[25stevem]

I am very happy to hear that it was not a internal issue with your motor!

While you have the converter backed off take a good look around the damaged flexplate holes for signs of cracks starting off due to a sharp edge.
If need be you might as well replace the flexplate now as opposed to getting stuck somewhere and needing a expensive tow home.

[Formulas]

"One of the flexplate holes is elongated and the threads in one of the converter mounting feet are boogered up"

Next step is to make sure these two parts can live on or not, no threads no workie.

I always thought the three bolt attach there was a weak spot

[25stevem]

The start of the whole root of problem can be just like with a manual trans and main shaft alignment issues that the trans locating dowel pins can be off enough to wobble the converter, and this over time can back off the these bolts if there not set in with thread locker.

[chiphead]

The elongated bolt hole isn't too bad. I checked around the crank flange and didn't see any cracks. I did see where it looks like some moron went after the flexplate mounting bolt area with a chisel or something during a previous disassembly.

I chased the boogered threads in the converter with a tap. Had to remove the starter and run the tap through the flexplate bolt hole. That was lots of fun, let me tell you. The last 2 threads in all the holes were really tight. The old bolts were hand cut to not pass through those threads, really weird? I put it back together with hardened washers, grade 5 bolts and red loctite. Torque to 45 ft/lbs. Yeah, I know, I went to 2 hardware stores and could only find grade 5 in 7/16-20 bolts. All 3 new bolts felt like they torqued up securely.

It doesn't have to stay together forever. I just need this engine to last long enough to sort the car. A few of you may remember the 434 stroker I built just before covid. Its going in this car eventually. The janky flexplate will be a wall hanger soon enough.

Looking at the damage, its been loose like this for awhile. I wonder if this is why the PO sold the car? He didn't have it long, and I wonder if he heard the racket and figured the engine was about to let go?

[Half-Inch Stud]

Grade 5 is fine.

Hope you seated the converter fully into the Trans Pump, then pulled it forward about 3/16", and shimmed with Washers, THEN bolted with bolts of proper length.

[mgarblik]

If you are uncomfortable with the grade 5 bolts, PM me and I will send you some ARP bolts. I will need the underhead length. Pretty sure I have some that will work. You pay postage only. Let me know. Personally, grade 5 is probably OK.

[bluejudge]

Originally Posted by 66beaumont

I had a similar noise in mine. Found loose bolts on crank pulley.

I would check this too, it is a quick check. Had a noise that sounded like the front of the motor, I changed the water pump, and was not the problem. All four bolts were loose and ready to break. As someone on this sight said it sounded like marbles in a can. Marc

[wakesupremo]

Originally Posted by Half-Inch Stud

Grade 5 is fine.

Hope you seated the converter fully into the Trans Pump, then pulled it forward about 3/16", and shimmed with Washers, THEN bolted with bolts of proper length.

Do these need to be 'special' washers?

[b-man]

Originally Posted by wakesupremo

Do these need to be 'special' washers?

Hardened washers, all of the same thickness.

[chiphead]

Wait, you're supposed to put washers between the converter and the flex plate? I just pulled it back forward and bolted it back up like it was. What is the purpose of these washers? Front pump engagement or what?

[Formulajones]

Originally Posted by chiphead

Wait, you're supposed to put washers between the converter and the flex plate? I just pulled it back forward and bolted it back up like it was. What is the purpose of these washers? Front pump engagement or what?

Well, that's only if they are needed to keep the distance at 3/16" or less.
Easiest way to check is pull the converter back and stick a 3/16" drill bit between a mounting pad and flex plate. If it doesn't go, your fine on the big side of the scale, if it's snug your fine, if it's loose you'll need to shim it with washers.

Keep in mind you also need a minimum clearance of 1/8" so if a 3/16" bit doesn't go grab an 1/8" bit and make sure you at least have that.

[Formulas]

Another thing that may trip up some people
is after a converter bolt has been pounding the wall of a hole in a flexplate it can peen a riser on the flexplate around the bolt hole creating a smaller surface area for the next torque up lending the situation to get loose again easier