Would you notch a 727 bell that already has an inspection port in it?

[Z88Z]

So, this is pretty much the same as a lot of the swaps you guys are doing - running 98 OBD2 EFI and sticking with an old school 3spd 727.

Notching the bell for the crank sensor should be pretty straight forward, except in this case the 727 came out of a motor home and has some kind of inspection port cast into the bell.
It's about a 1 inch hole, top center, and (IIRC) maybe about 3 to 4 inches back from the front lip of the bell.

With a stroker rebuild and a few other goodies, this thing should make some fairly serious power - and I'm concerned that having two holes that close together could compromise the integrity of the bell.

And ya, I'm pretty much married to using that tranny at this point and staying with the OBD2 PCM as opposed to going aftermarket like FAST etc. The build's been set up around that tranny and it's measurements so it's there to stay.

What do you guys think? I know - or at least I think I know, lol! - that it's not going to instantly explode when I start it up, but do you think there are limitations to the power I can or should put through that?


I'd much prefer to leave it intact and fab a damper mounted setup for the factory CKPS.
It seems like you guys have bounced that idea around - but so far I don't think anyone has done that yet? Is that correct?

I have a few ideas, and I've heard a few things - but I'm thinking that subject might be worth asking in it's own thread. In the meantime I'll do a search on the subject.

Thanks for any replies - Z/John

 

[jbc426]

It will be fine. Just use a good torque wrench and the longest grade 8 bolts that will properly fit and hardened washers to clamp it to the block.

How do you normally notch them? I used one of those hole saws with a small pilot drill in the center that's normally used for cutting holes in doors for the handles being sure to start the pilot hole about half the pilot bit width away from the edge of the block mounting face. I then smooth out any stress risers with a burr bit.

 

[ssba]

The existing hole is used for timing the engine.
I wouldn't be worried about adding another hole for the sensor.

 

[Z88Z]

Thanks for the replies!

Are you guys pretty sure about that? LOL I hope so as it looks like the direction I'm going in.

Seems weird they'd have that for timing as they already had the hole for the magnetic pickup on the front cover for checking timing

I looked at that inspection hole again. Seems a tad raggedy for something the factory put there. It's also a tad off center towards the passenger side, which puts it closer to where the CKPS hole needs to be - really not feeling warm and fuzzy about this! LOL.

Like I said, wanted to do the front mounted CKPS but after really looking it over again it looked like the less reasonable of the two approaches - once my miserable fabbing skills are taken into account, ha ha.

Got the engine and trans back out of the project yesterday and got them apart.

First big problem is that the weight on the torque converter interferes with the Magnum flexplate sitting flat against the the face of the 727's converter.


And ya, if you're wondering about that... I'll just say that this is "some miscellaneous older setup".
It's external balance, but they put the weights on the converter instead of on the flexplate.

More fun. Of course I also noticed last night that I used my 5.2 neutral balance FP on another project, and the only ones I have are weighted 5.9 flexplates. And of course the weighting isn't compatible with what's on than the converter.

I'm thinking I can drill through the spot welds on the weights themselves from the back, without getting into the flexplate itself and compromising it's integrity. Any thoughts?
I may be better off just hunting down another 5.2 flexplate

I may see about having the window wheel portion of the Magnum plate welded to the 727 style flexplate - that's if it will clear the weight.
Or I may see if I can remove the weight from the converter and have it tacked to the flexplate instead. That would be the better option, assuming I can somehow get the weight off without cutting to much which would affect the weight of the weight. LOL!


That's where I left off. Today I'll be looking into the best solutions to see which if any of these ideas will work.

 

[Infecteddog]

Vans with MPFI came with 3spds. If you're so worried about cutting the hole- get one of transmissions. I'd imagine one of the 5.9 3spd vans MAY have a 727 but they may all be 904 based.

If you're rebuilding as a stroker why are you externally balancing- much less doing so on the converter? Is this a 5.7 stroker build?

 

[Z88Z]

Hi ID! I believe I just saw your name in some of the threads about the CKPS and the manual trans flywheels, yes?

Very interesting read! I have a 5.9 Magnum with a manual trans added on - no help to you guys though as it's on an OBD2 Jeep and uses a combination of the Dodge and Jeep stuff.
(Ram 5.9 flywheel under the 3.9 bell, connected to an NV3550)

Anyway - all good questions...
For which I don't necessarily have any answers that will make sense right now...

Like I said above, I'm pretty much married to this combo. It's a shorty 727 and the mounting and custom length d/shaft are already set up around it.

And yes, it would be a ton easier if I was doing the stroker part of this build first.
I'd be able to go neutral balance and I'd be getting a stall TC which would also be set up neutral...

Unfortunately that's not in the cards right now.

Without going into too much detail, Ill just say it's a bit unconventional and I'm just wanting to get any bugs sorted out before I go back and do the stroker/performance bit.


EDIT: I have heard of the van boxes you mentioned.

I have it on pretty good authority they were 727s and heard they were probably only available on 94s, or maybe 93s and 94s. Something like that.

 

[jbc426]

I found an inexpensive 5.2 neutral balanced flexplate for my 5.9 strokes on eBay.

 

[Infecteddog]

Hi ID! I believe I just saw your name in some of the threads about the CKPS and the manual trans flywheels, yes?

Very interesting read! I have a 5.9 Magnum with a manual trans added on - no help to you guys though as it's on an OBD2 Jeep and uses a combination of the Dodge and Jeep stuff.
(Ram 5.9 flywheel under the 3.9 bell, connected to an NV3550)

Definitely possible- wouldn't think too many mentions into it- maybe just a handful.

I have it on pretty good authority they were 727s and heard they were probably only available on 94s, or maybe 93s and 94s. Something like that.

My buddy's got a '96 3.9 with a 904 based trans. I've seen '98 5.9 3spds and I think I may've even seen later than that too. They had the vans with 3spds into OBD2 years- only the trucks went to ODs standard with the Mags.

We did the same with the holesaw for the 904- the bell's one of the latter places that'd be on my list of worries so long as there's at least several inches between the holes.

 

[Z88Z]

.... I've seen '98 5.9 3spds and I think I may've even seen later than that too. They had the vans with 3spds into OBD2 years- only the trucks went to ODs standard with the Mags....

Oh wow. That's good to know.

I was misinformed that it was OBD1 only. I don't know as much about Dodges - primarily a Jeep ZJ guy.



Wanted to thank you all again for your help. So busy on the project that I hadn't had a chance to post back! I guess that's a good thing, lol.

Ya I finally made peace with the idea of notching the bell.

Between you guys and my tuner, who's tuned a few serious 727'd Dakotas - I guess it's not going to automatically disintegrate the first time I step on the gas.

Had a bit of "fun" with the flexplate though.

As said above, this particular combo had the balance weight on the face of the converter, which would not allow the flexplate to sit flat. Didn't think to take a pic until after I drilled it off.





I took a look at various flexplates I had. Left to right: 93 5.2, 98 5.2, both neutral balance. Weighted 98 5.9.






Closeup. Note the 93 5.2 has the elongated tombstone shaped bolt surfaces versus the simpler dimple on the 98 FPs. Best part is, the 93 FP has the offset bolt pattern that matched the 727's pattern. 98 FP were both 90 degree patterns.
Just to make it interesting, they all have exactly the same part number. Thanks Mopar! lol.




Using this super ultra hi-tech scientific procedure, ROFL! - I determined the 5.9 FP's balancing weight was extremely close to matching the 727's weight. (I'm almost ashamed to share that pic but it was too funny not to!)
So I was thinking of notching the offset hole and using that 5.9 FP. For anyone not familiar with that, the Offset vs 90 degree holes only miss by a hair. Like maybe a millimeter or probably less that 1/10 the diameter of the FP to TC bolt. It's a fairly common practice to do that notching when putting a ate 5.9 into an early ZJ/Grand Cherokee for instance and will still handle some pretty good horsepower per various tranny building folks I've talked to...




Gave that some thought and decided, rather than rely on my half baked backyard physics I'd be better off going with this approach....

Since the weight was going to be a little close to one of the 'windows' the CKPS uses and I don't know exactly how deep the CKPS 'sees', I decided to flip the weight upside down so the tapered edge was to the outside instead. Positioned the flexplate on the TC with the weight behind it. Got the weight positioned, marked it up and took it to a local welder.


727's weight on the (formerly) NB 93 FP.

Yes the weld adds a tiny bit of weight, but I lost a bit drilling through the spot welds so I figure it's still pretty darn close. If it was going to stay like this forever I would have worried more about the precision, but this stuff would all be replaced during the stroker build anyway





So after handling that part, I was finally able to get the bell notched and the CKPS set up.

There's a bit more to this project that I won't bother going into at the moment. I'll put up some pics when I'm done.

Thanks again folks!

 

[Abodybomber]

Interesting work,best of luck!

 

[jbc426]

The flex plate needs to be from the 5.9 to match your 5.9 engine, as it is externally balanced. The torque converter needs to be neutrally balanced, so as not to affect the 5.9 engine's factory flexplate balance. If you add that weight from the torque converter, you will have thrown off the balance provided by the 5.9 flexplate and harmonic balancer.

I had to file on the side one of the 4 mounting holes on my 5.9 flex plate to bolt it up a neutrally balanced torque converter for my old 727.

Once I built a neutrally balanced Magnum based 408" stoker, I used the neutrally balanced 5.2 Magnum flex plate and had my custom converter made with the pads in the correct place so I didn't have to file one of the mounting holes for it to fit.

 

[Z88Z]

Interesting work,best of luck!

Thanks!

This part turned out to be a piece of cake compared to setting up the Edelbrock 4bbl TB to accept factory throttle and TV cables. Didn't really want to go the Lokar route.

On that note, to make sense of that statement....
I have a small confession to make - this isn't really an A body! lol. Although this drivetrain may very well end up in one. Thinking 67 to 69 Dart or notchback Cuda.

I came here for help cuz I know you guys tend to get creative with the transmission stuff, so thanks to all who responded

The flex plate needs to be from the 5.9 to match your 5.9 engine, as it is externally balanced. The torque converter needs to be neutrally balanced, so as not to affect the 5.9 engine's factory flexplate balance. If you add that weight from the torque converter, you will have thrown off the balance provided by the 5.9 flexplate and harmonic balancer.

I had to file on the side one of the 4 mounting holes on my 5.9 flex plate to bolt it up a neutrally balanced torque converter for my old 727.

Once I built a neutrally balanced Magnum based 408" stoker, I used the neutrally balanced 5.2 Magnum flex plate and had my custom converter made with the pads in the correct place so I didn't have to file one of the mounting holes for it to fit.

I figured somebody might catch that


Under normal circumstances you would be 101% correct. I'm not normal though, so you're only 97% correct. (nah j/k - you remain at 100% correct)

I guess if you want to get technical the torque converter is neutral balance now that the weight has been removed, lol.
And per my scientific super hi-tech balancing test (I'm still laughing at that...) that TC's original weighting was pretty close to the factory 5.9 weighting.
Which makes me wonder - since the factory motors aren't ultra precision manufactured, I wonder how many grams off it would have to be before you'd really notice it?

But yes, I didn't trust my method and decided to stick with the original weight.

I was lucky in that I had all three flexplates available. The 5.9 90 degree FP's weighting was close enough that I almost used it, but decided not to. The 93 NB/offset flexplate happened to fit the 727 TC's offset so I went with that one.
When the stroking gets done the whole thing goes to neutral balance, with the 98 5.2's 90 degree/NB flexplate and a converter with some stall, built with 90 degree pads to match the flexplate - as you said.


So, I'm not trying to go all secret squirrel jerkiness on this, but there's a few things going on that I'd rather not go into at the moment.


In closing I will just say this.....

I'm aware of the balance issues you mentioned and I agree with you absolutely. However, I also believe this setup is correct. (Try and make sense of that! lol)


I will definitely be posting up the results. I figure it needs about a weeks worth of work - which as we all know means two months in real life! rofl!


Thanks again for all the help

 

[krazykuda]

Depends on if it's going into a fastback or notchback...

 

[Z88Z]

Depends on if it's going into a fastback or notchback...

It pretty much has to be a gold 1967 fastback 273 4bbl car that was in Colorado at some point in it's life!
Just kidding. I had to go through a few posts to figure out what you had

Man, seeing the pics of jaws gold fastback in that '273 Commando pics' thread brings back some memories. Back in the day one of the more serious street/strip builds in my town was a gold fastback 440 car. Pretty sure it was a 69 but I have no idea if it was one of the original 440 cars or a transplant motor.

Had a 67 Dart, so I'm leaning towards a notchback next time around.