Putting my motor back in the car. I have a fresh build 400 going on a c6, rebuilt by someone local.
Old motor was a 351m, using same starter, motor plate and flex plate as well as the old C6 that was in the truck.
Over the weekend, was able to mate up the engine and trans. Got the motor plate and flex plate on.
Pretty sure I had oriented one of the torque converter studs at 6 o'clock and made sure the TC went in 3 clicks to ensure proper depth.

Here's the interesting part. Reinstalled starter and tried turning the motor over to start moving the flex plate around to find the TC bolts/studs.
Couldn't turn the motor. First thought was did I somehow bind something up by putting on the flexplate incorrectly.
Removed the starter and engine turns again. Again, same starter, same engine plate and same bellhousing.
Not sure what's different about the set up.
next question...I don't see the TC stud at 6 oclock anymore. not sure if it moved when I was installing the engine, but also can't seem to freely turn the TC when reaching into the starter hole in the bellhousing. And how am I supposed to get the TC moved forward to start the bolts?

I realize what iI really need to do is have a helper turn the engine as I watch what's going on. Not sure if the flexplate and TC are binding, spinning both as I turn the crank.
also can't explain why the starter installed seems to be binding on the flexplate, hoping I didn't install it backwards.

for what it's worth, I can see the witness marks from the TC nuts on the forward side of the flexplate and also had witness marks on rear from the flexplate bolts when I mounted it to the block. the flexplate has a lip on one side and a counterweight on the same side and that side is facing the block and visible through the inspection plate opening.

any reassurance would be helpful, but not above pulling the engine again if necessary. fingers crossed, hopefully not.

 

In thought the 351 and 400 took different balancers and flex plates? maybe not but someone here should know.

Usually the flex plate has a lip around the center opening that always goes towards the transmission. I don't think you could get it backwards without noticing something is wrong.

You never put the starter on until the transmission is bolted to the block. it would be binding and jamming on the flex plate so that seems normal. you have to get the TC into the flex plate holes before you're going any farther.

 

I found some pics of a flex plate on Jegs and Summit website showing both sides of the plate and to my relief, the counterweight faces the block , which is what I'm seeing from the inspection plate hole. Plus, looking at the pic of the flexplate, it can really only go on one way or else it'll seriously bind to the motor plate. Oh, and it appears that the same flexplate works for 289/302/351m/400 engines.
I didnt try installing the starter until the block was mated to the bellhousing/trans.
I'll check again later, but almost seems as if the bendix on the starter is catching the teeth of the flexplate, but not sure why since I'm using the same motor plate, flex plate and bellhousing. The new block isn't anywhere in that equation. Bendix is also not stuck in an extended position.

It is possible that the rotating portion of the crank that the flexplate bolts to is sitting too far forward, causing the flexplate to sit more forward, interfering w/ the bendix on the starter?

 

Not sure how it plays to you, but the TC had studs and uses nuts ... correct? If you are easing an engine with flexplate into position, I think that you are gonna need someone to align the studs with the holes in the flexplate as it goes together. I don't know if the TC will go deep enough into the trans to allow you to move it once the engine is all the way in.

With some cars, trucks, Chevrolets, etc ... they use bolts that thread into the TC through the flexplate so as long as you get the TC in deep enough, you can turn the TC to put bolts in after you get the engine in as I recall.

I did this once on a Chevrolet I had, but the T400 transmission had a big lower TC access cover that gave access that is not possible with a C-6.

 

I guess I'm not sure exactly where you're at in the process, but on every rig I've done you have to get the studs through the flex plate before you bolt the transmission to the block. if the TC uses bolts that's different of course.

I'm thinking you have the flex plate bound to the TC and you'll have to back the bolts out a way on the transmission to free it up. not sure if you could have damaged anything or not, but it's possible.

 

If you reach through the starter hole and the TC won't wiggle back and forth. You missed the holes or TC not all the way in.

 

thanks guys
I was under the impression that the TC had enough fore/aft play to allow the studs to clear the flexplate if the TC was pushed back far enough. makes sense now that the studs on the TC are likely binding to the flexplate, pushing it foward and interfering w/ the bendix on the starter, not allowing me to crank the engine w/ the starter in place.
I'll loosen the TC bolts and start separating the two, seeing if I can get the TC to spin again freely. Then line up the studs to the flexplate.

 

Make sure, double sure even ... that the TC recesses into the front of the transmission far enough that it allows room for the flex plate on the engine before starting to install the engine. Then as the engine goes in, someone needs to align those studs with the holes so that they don't get tight with the FP ... but go through the holes. Once the studs are into the holes, then you can close up the gap block to bell housing. If the studs are aligned, the TC hub will be in line with the crankshaft. Go slow, there's fingers involved.

 

Last question (for now).
Will I have enough room just loosening the bellhousing bolts to take enough pressure off the flex plate or do I need to completely remove the bolts? I was hoping to just loosen the motor mount nuts as well and not remove everything.

 

I think that if you get the pressure off and can rotate the TC so the studs align with the holes, if all the several studs go in their holes, my experience is that the snout or hub is aligned as well. It should be an easy thing to get the TC a little forwards once those studs are lined up, as long as the engine and trans are in line. If you then gradually tighten the bolts from bell housing to block. Once there, the engine should rotate (easier if plugs are out) and the TC with it. I'd test by using a wrench on the crankshaft bolt at front.

Starter after all bolts and TC nuts tight on studs. I think you will have 4 studs and a little round short "key" beside one, they all need a hole.

I also see that some aftermarket TCs use 4 bolts rather than studs?

It's been a long number of years, but this is my memory. I'll say it was easier on a old school Mopar or Chevrolet, those were a piece of cake. Those TC studs and no easy access are the PITA ... IMHO.

 

Guess I’ll have to go look at mine again. But I thought my 79 C6 had an inspection plate you could remove to do all this work.
I hope it did, or else I was much more clever when I was younger!
Not sure I could do all that by myself now.🙄

 

I think I know what I need to do. The challenge is I've put on a lot of other stuff (headers) and hope I won't need to pull these. Also, had to remove the motor mounts to initially get the block/bellhousing aligned and had to remove the oil filter to get to the motor mounts. Hoping I can just loosen the motor mounts (keeping nuts on), loosen all the bell housing bolts and gently lift the block up an inch or so, separating the bellhousing, then crawl under and rotate the TC studs to line up. Put a nut on one of the studs loosely, then start to tighten up the bellhousing bolts slowly again.

 

My '77 has a small flat inspection plate (secures to the "block plate" with two self threading bolts that have 3/8" hex heads) and the ring gear/flexplate will not let even a finger past it. It'll let you see a little bit & tighten / check the 4 TC nuts if needed ... but that is about all. I don't know that lifting the block is the answer ... unless it lets you keep the crank shaft pilot hole in line with the TC hub.

I was ... and still am ... hoping someone more recently going through this will jump in ... for my own desire to learn a tip or two maybe. Partly why that 400 is still on my stand.

 

i was going to lift up, then pull back. basically reverse the installation process. we were able to get all the dowel pins lined up using a leveler, after removing the motor mounts as they were hitting the perches on the initial approach in.
I'm not above removing the motor mounts if needed. but hope I can get er done without doing so.

 

Got it sorted out tonight. Details on my build thread. Thanks for the help!