360 Starter Problems

[NSdartSW]

I’m trying to wrap up swapping a junkyard 318 for a ‘72 J head 360 and I’ve ran into problems trying to start it and finish up this project. I left the stock 727 trans in the car with stock converter but I bought a B&M weighted converter,BMM-10236, with a summit brand weighted balancer. I first installed the starter from the 318 and when I hit the ignition the starter would spin at what sounded like a million miles an hour. I figured the solenoid wasn’t firing so I tried hitting the solenoid a few times and it didn’t change anything. After some more hitting it sounded like the solenoid was firing but not spinning. I work part time and a full time student so my dad pulled that old starter for me and bench tested it and found out it wasn’t working. I bought a remanned starter from O’Reillys and got it all installed and buttoned up but got the same results. Hit the key and it just spins. Hitting the starter does nothing no matter how much I do and I’m out of ideas. So just looking for help and knowledge cause I’m out of ideas and I’d rather not have to pay a shop to figure it out for me but that’s about where I’m at. Thank you in advance.

 

[Professor Fate]

Are you SURE you've got a 727, and not a 904? Most 318s came with a 904.
Using a B&M 10236 in a 904 will result in the Bendix gear being blocked from engaging the ring gear on the convertor, which is exactly what it sounds like is happening to you.
A 904 requires the use of B&M 10239, which will give you the clearance you need.
Easy way to tell the difference between a 727 and a 904 is the shape and bolt pattern of the transmission pan:

 

[NSdartSW]

Are you SURE you've got a 727, and not a 904? Most 318s came with a 904.
Using a B&M 10236 in a 904 will result in the Bendix gear being blocked from engaging the ring gear on the convertor, which is exactly what it sounds like is happening to you.
A 904 requires the use of B&M 10239, which will give you the clearance you need.
Easy way to tell the difference between a 727 and a 904 is the shape and bolt pattern of the transmission pan:
View attachment 1716396105

I thought it was a 904 but I bought a gasket kit and filter for a 904 and the gasket doesn’t fit so I assumed it’s a 727, guess I forgot to mention it the car came stock with a 273.

 

[Professor Fate]

Well, if the transmission was stock to a 273 (what year and car is this, anyway?), then it's definitely a 904 as I don't think a 273 ever came with a 727.
Compare the pic I posted to what you have.

 

[Projectile Dart]

If your came stock with a 273 and that is the original transmission then it is most likely a 904 but like what was stated before. Just take a peek at the pan and confirm 100%. These cars are old, with who knows how many owners, and who knows how many modifications have been done to them.

 

[NSdartSW]

Well, if the transmission was stock to a 273 (what year and car is this, anyway?), then it's definitely a 904 as I don't think a 273 ever came with a 727.
Compare the pic I posted to what you have.

Really oh ok that’s interesting then the gasket kit I bought for a 904 didn’t fit. I’ll get a pic up here shortly. It’s a ‘66 Dart 270 Wagon. As far as I’m aware it’s all stock past the engine.

 

[NSdartSW]

I think you’re right I do have a 904 which is what I thought at first so not sure why the gasket didn’t fit. Guess I’ll have to pull it out and again and get a different flex plate. Thank you for your help I would’ve never figured that out I’m new to the mopar world and everyone here I’ve talked to has been super helpful you guys are amazing thank you.

 

[Professor Fate]

Always happy to help out a fellow '66 wagon owner!

 

[Locomotion]

Is your car a '66 with the original trans?
I can never remember exactly what year they changed but the early 904s had a smaller converter snout to fit the corresponding smaller register in the crank.

If the 360 crank register is bigger than the 273 converter snout, you'll have to make/find a spacer ring or change the converter (which would have different converter splines so you can't just swap in a newer converter).

.....or is it a good year or you fixed the converter difference with the 318?

 

[NSdartSW]

Is your car a '66 with the original trans?
I can never remember exactly what year they changed but the early 904s had a smaller converter snout to fit the corresponding smaller register in the crank.

If the 360 crank register is bigger than the 273 converter snout, you'll have to make/find a spacer ring or change the converter (which would have different converter splines so you can't just swap in a newer converter).

I just used the converter that was on the 318 not sure if it’s the stock one or not but bolted up to the 360 and was working fine but the 318 gave out.

 

[Locomotion]

I just used the converter that was on the 318 not sure if it’s the stock one or not but bolted up to the 360 and was working fine but the 318 gave out.

Sounds like the 318 & trans are a later model.

But a small snout converter would bolt up to a bigger crank register and you wouldn't find out unless there was a vibration and/or the flexplate broke.

 

[NSdartSW]

Sounds like the 318 & trans are a later model.

But a small snout converter would bolt up to a bigger crank register and you wouldn't find out unless there was a vibration and/or the flexplate broke.

I’m not sure the guy I bought the car from put the 318 in it because the stock 273 was locked up solid. Not sure what he did to make it all work unfortunately.

 

[Oldmanmopar]

You need to put a bushing on the torque converter register or you will destroy the front pump on the transmission. The trans went in because the register is probably way to small on the torque converter then the hole in the crank. She'll be a wobbler if not perfect in size for the hole.

 

[NSdartSW]

I’m not sure I understand. Like I do but I also don’t, how do I know it’s not fitting in perfectly.

 

[Professor Fate]

I’m not sure I understand. Like I do but I also don’t, how do I know it’s not fitting in perfectly.

Here's the short and sweet explanation:
On the front of your torque convertor, there is a nub or "nose".

It rests in, and is supported by, a recess machined into the rear of your crankshaft flange.

The issue is that in 1968, the diameter of the convertor "nose", and therefore the size of the pocket machined into the crank flange, was increased.
This means that when a post '68 engine is mated to a '67 or earlier 904, the nose of the convertor is no longer rigidly supported by the crankshaft because of the differing diameters. This can cause all sorts of unusual vibrations that can result in a cracked flexpate or ultimately a trashed front pump as @Oldmanmopar mentioned. And no, a later torque convertor cannot be used on a '67 and earlier 904 because of input shaft differences in diameter and spline count.
The solution? A bushing seated into the later model crank flange to make up the difference in diameter, which will now properly support the nose of the early torque convertor.

Here is one source:
Chrysler Torque Converter Flexplate/Crankshaft Adapter | 1.81" OD x 1.55" ID | A904, A727 | OE | 1 Year
Welcome to the Wonderful World of Mopars.
Our motto is "It's always something. Why the Heck did they do that?"

 

[NSdartSW]

Oh ok thank you that makes more sense. Pictures are a big help for me thank you. I’ve only had the car about 6 months and I know I’ve said those exact words. I just had a thought, when the 318 was in the car and working it made a crazy racket from the back of the engine/front of trans the guy I bought it from told me it was a bad flexplate. I’m not sure what year the 318 is but if it’s post ‘68 and didn’t have a bushing like it should, could that have been the source of the noise? Could it have trashed the trans? It wouldn’t make the noise in park unless I gave it some rpms and would do it constantly in every other gear. We thought maybe it was a lose flexplate but bolts were all tight so I bought one to swap but then 318 gave out.

 

[JDMopar]

It would have made the noise anytime it was running. Chances are, if the previous owner ran it much like that, it has junked the front pump in the transmission, or it is well on its way. You can get that transmission rebuilt and use the adapter, or find a 68 & up 904 and rebuild it to avoid the problem without the need for the adapter. If you pull the transmission out, you can measure the nose of the converter, then measure the register in the crank and determine if they are way off. Does the B&M flexplate you bought have a cut out place on part of the outside edge? The ones they make to mate a 360 to a neutral balance converter do. That is how the balance stays true on the 360 with the neutral balance converter. 360's are externally balanced, as are late 72 and all 73 model 340's. 318's are internally, or to use another term...neutral balanced. Hope this wasn't too much info and confused you even more! You'll get it sorted out. A later model 904 will bolt right back in and all of your linkage and driveshaft will work right back if you go that route.

 

[NSdartSW]

Ok alright guess I’ll look to see what’s cheapest for me, minimum wage gives me kind of a tight budget. I did try and do as much research as I could before diving into this mess so I do have a weighted flex plate for a neutral converter. Guess I missed the part about the transmissions needing different ones. Kinda bummed to hear the trans will need a rebuild I was hoping to get it working and daily to finally have a car and wanted to get it to a local car show in May, guess I’ll do what she needs though. Thank you for your help, you gave me a lot of info I don’t think I’d only find out after the hard way I appreciate it. I know Mopar guys have a reputation of being kinda grouchy and sticklers but you guys have been super helpful me, being new to this whole mopar side of the big 3 I feel like sometimes I ask stupid questions and you all have been super helpful and kind about it I appreciate it.

 

[NSdartSW]

Another dumb question, would it drive poorly without the converter properly shimmed, if the front pump is trashed would it effect the drivability? I did drive it a little being a little giddy with my new car and it drove good just made a racket.

 

[318willrun]

I thought it was a 904 but I bought a gasket kit and filter for a 904 and the gasket doesn’t fit so I assumed it’s a 727, guess I forgot to mention it the car came stock with a 273.

Watch this and you'll never wonder if it's a 727 or 904 ever again. You'll know in less than 1.5 seconds. Be it in a car, truck, van, or on the garage floor from a marketplace seller, you'll know.

 

[JDMopar]

You could always pull the trans, check the measurements on the nose and register.....then add the adapter if needed. Stick it back together and see if the noise disappeared. If it does....you got lucky! A good bit of work to roll the dice and hope, but you might get it on the road sooner if it works out good, and only be out the price of the adapter ring.

 

[NSdartSW]

Ya either way it’s all coming out so I’ll figure it out. Thank you again I really appreciate it.

 

[NSdartSW]

I do have another question. What have you found to be the easiest way to do this kind of work, pull just the engine leaving the trans and do the work, leave the motor and drop the trans or just pull them both as one. Doing the engine swap my dad and I just pull the engine and the 360 was a fight to get in and everything aligned in the right spot. We’re debating what will be best and easiest/quickest. Thought could maybe just drop the trans but the top bell housing bolts would still kinda suck to get out with the firewall.

 

[JDMopar]

Trans will be easier at this point. Remove the starter and take the flex plate to converter bolts loose first. The bolts towards the top of the bellhousing are pretty easy to get with a 9/16 box end wrench. It won't be bad....just time consuming. Get the car up as high as you can on jack stands so the transmission will come out from under it. Be careful with the dip stick tube on the transmission so you don't knock it out and make a big red puddle in the floor...lol. Take the top bellhousing bolts out before you jack the car up, and take the distributor cap off so you don't break it if the motor tilts back. Support the motor with a block of wood under the oil pan and on top of the center link. It will be a good learning experience to do it.

 

[NSdartSW]

Ok thank you much appreciated