Bell housing runout

[Kern Dog]

It is a '74 block....

I've had it since 2004. It was standard bore when I got it. No signs of having a pilot bushing so it was mated to a 727 from the start.
In 1974, the 440s were only available in the Coronet/Satellite Police cars, C bodies, trucks and RVs if I recall. I don't recall hearing of a Charger or Road Runner in 74 having a 440. If they did, I don't know of any.
This didn't have the 7 to 1 RV pistons in it so I figured it was most likely from a C body.

 

[Kern Dog]

The topic of bell housing runout has gained a lot of attention the last few years with the rise in popularity of the aftermarket overdrive manual transmission kits.
What is it about these new transmissions that the vendors require such precise alignment?
.005 is the limit for the SST kit. If you’re at .006 they won’t honor the warranty??

Here is a screen shot of a YouTube video showing the tapered roller bearing used on the input shaft of the Tremec transmissions.

That explains why the runout has to be so small...The bearing can't tolerate much misalignment.

 

[Cranky]

Here is a screen shot of a YouTube video showing the tapered roller bearing used on the input shaft of the Tremec transmissions.

View attachment 1538198

That explains why the runout has to be so small...The bearing can't tolerate much misalignment.

It's not just the bearing.....look at how wide the gear is. I would think it needs to mesh as flat as possible if it's expected to last for a long time.

 

[Runner 68]

First the bell is located by dowels, second I can tell you from personal experience there's maybe.025-.03 bolt clearance... Not .05 Greg has already seen that he doesn't have clearance either....

Ok, .025-.03, 2 hundredths difference. The point is that by merely bolting the thing on, despite the dowels, can cause a mis-alignment by more than .005".

 

[fourgearsavoy]

If it has a stock bell then you are stuck with the factory dowel locations. I have removed the factory dowels to align a Lakewood bell before. I don't know if they still offer the alignment kit anymore but is does work. You need to drill new dowel holes and enlarge the bolt holes as well.
Gus

 

[4406bbl]

Ahhh...I can't do that. The vendor requires documentation of measuring the runout to no more than .005 or less to warranty the transmission. When you spend $7000 on one of these kits, you're inclined to do what it takes to get it right.
I have one friend that set aside a bellhousing for me to use. I wouldn't mind another though. If the other bells also have excessive runout in the same direction, it seems that would indicate an indexing issue with the crank not being centered or the mounting surface of the block being drilled out of spec.
Sometimes weird stuff happens and you have to find a way around it.
To the topic of automatic transmissions...
I noticed during my 5 speed swap when I pulled the flex plate off of my 440/493, it had 2 cracked ears.

View attachment 1538132View attachment 1538133

I had a buddy that cracked the hubs on 2 different flexplates within a couple of months on this car:

View attachment 1538134

It was just a mild 360.

What about you? Have you accidently found broken parts like this and didn't know what caused it?
What if all along it was excessive runout?

The thicker and more solid the flex plate is, sfi stuff, the more likely it will crack if the trans is misaligned, and wear the front pump bushing and convertor hub.

 

[4406bbl]

The original dowels in my 440/495 during my Tremec installation:


View attachment 1538162

View attachment 1538163

View attachment 1538164

Those look really short to me. I wonder if the holes in bellhousings are tapered at all at the edges. If so, these dowels are almost useless!

View attachment 1538165

You're looking at the ends that were in the block. I welded lug nuts to the face side to crank them out.

The new ones were much longer:

View attachment 1538166

Look how much they stick out past the bell:

View attachment 1538167
View attachment 1538168

The dowels get pushed deep in the block at machine shops, or in storage when the block is stood on its backside and moved around.

 

[4406bbl]

Ahh, missed the auto tranny part. I'm speaking from a manual perspective. Grab the input shaft on freshly rebuilt 833 and wiggle it. 1/16" of play or more. They were designed that way because of bellhousing alignment issues out of the factory (I believe).
Not an auto guy here. I need three pedals.

No they were not designed that way from the factory. You are forgetting the needle bearings at the rear of the input shaft, it will destroy the output shaft bearing surface in short order if it is that far out. From the factory they were perfect, and the service manual calls for .008 max. I have been in hundreds of a-833s and it is easy to tell if one was misaligned, input nub on both shafts will show heavy wear, along with the input gear and cluster gear. I had transmissions returned for warranty and boom, they were pissed when I said no, your bellhousing is way off, almost always a lakewood back then. I am not trying to dog this poster but anyone that tells you this is not important is wrong, it must be done if the original factory bellhousing is changed. My boss at the gas station I worked at taught me how important this is and how to do it. His camaro ran 10s in the mid 70s so I never questioned what he said.

 

[steve340]

The factory service manuals for the three brands I have read which includes Mopar describe bell housing alignment procedures. Indicating the factories worked to tolerances.
98% were probably close enough but 2% were not and gave trouble. I made up those numbers in case you are wondering.
I have done alignments on steel or fabricated bell housings and found them quite a long way off centre and parallel. I don't like the Lakewood brand myself.
If the bell housing is aligned properly the clutch works better and the transmission is generally quieter.

 

[4406bbl]

I think the factory was 100% perfect with the centerline because of the way they finish machined the hole, parallel could still be off. The problem comes in when the bell is removed or changed for another, or even careless mechanics that get dirt/caked grease/sand between the bell and the block. In any case unless you know the bell and block are original it should be checked. I just did a 90,000 mile 340 4-speed, one owner car and the input shaft of the transmission almost looked like it had never been ran, pilot bearing area was absolutely mint, along with the pilot bearing, trans was out for leaks only. You can almost guarantee a worn input shaft in the pilot bearing area means the bell is out of alignment. Somewhere on u-tube there is an assembly line video of a small block chevy getting the bellhousing hole machine after it is installed on the block, so I think all brands were done that way. I also agree lakewoods were out the worst of anything else I ever checked.

 

[CoronetDarter]

.005 is not hard to achieve.

Then I'd like to know the secret because I'm the one with the TKX that Greg is helping. The car is on his 2 post lift. The first time we measured, it was .082", or .041" TIR. Removed the bell and found some metal boogers on the block mating surface, along with paint from the rebuild. Removed the paint and filed down the protrusions. Last night we got to .048, or .024" TIR. The runout could be brought into spec using the Robb Mc .021" offset dowels, but that's the hairy edge of spec. We came back this morning and remeasured and this time we couldn't get closer than .056" / .028" TIR; uncorrectable.
Last night we installed an OEM cast iron BH and the TIR was .004".
This past week we've spent countless hours on a 20 minute procedure with nothing to show for it.
The .003" was the high spot; after zeroing out the indicator we did a 180° sweep and stopped at -.048". The other numbers was us measuring different 180° data points. If we had been able to replicate the .048" this morning, I probably would've ordered the .021" dowel set and dialed in the BH.

As the GH bolts are being tightened there is quite a bit of wiggle room. But once the bolts are torqued down, I would think the BH would always wind up in the same place. The order in which the bolts are torqued down shouldn't materially affect runout, should it?
Now we're questioning the current dowels that are in the block. Maybe they're offset dowels. The 440 is a transplant, we have no idea what it in prior to the Coronet or what its been used for. A lot of questions and its killing me because Greg and I are spending waaaay too much time trying to dial in this BH.
Here's the TKX project thread if anyone is interested:

Tremec TKX 5-Speed Conversion

As much as I enjoy driving the Coronet, whenever we take long trips, like to the Mopar Spring Fling in Van Nuys, I take the Dart because it has an ancient Keisler Engineering Tremec 5-speed and I can cruise at 65 and 2,100 rpm. I've been mulling over converting to the Tremec for years but there...

www.forbbodiesonly.com

 

[Kern Dog]

I know that when I am doing something new and encountering problems, it is extremely frustrating. The unknown is what makes my blood boil.
If I'm doing something that is giving me trouble BUT I know what is wrong and HOW to fix it.....even if it is a difficult thing, I am able to handle that better.
I have confidence that by tomorrow, we should have it figured out.

 

[padam]

Then I'd like to know the secret because I'm the one with the TKX that Greg is helping. The car is on his 2 post lift. The first time we measured, it was .082", or .041" TIR. Removed the bell and found some metal boogers on the block mating surface, along with paint from the rebuild. Removed the paint and filed down the protrusions. Last night we got to .048, or .024" TIR. The runout could be brought into spec using the Robb Mc .021" offset dowels, but that's the hairy edge of spec. We came back this morning and remeasured and this time we couldn't get closer than .056" / .028" TIR; uncorrectable.
Last night we installed an OEM cast iron BH and the TIR was .004".
This past week we've spent countless hours on a 20 minute procedure with nothing to show for it.
The .003" was the high spot; after zeroing out the indicator we did a 180° sweep and stopped at -.048". The other numbers was us measuring different 180° data points. If we had been able to replicate the .048" this morning, I probably would've ordered the .021" dowel set and dialed in the BH.
View attachment 1540186
As the GH bolts are being tightened there is quite a bit of wiggle room. But once the bolts are torqued down, I would think the BH would always wind up in the same place. The order in which the bolts are torqued down shouldn't materially affect runout, should it?
Now we're questioning the current dowels that are in the block. Maybe they're offset dowels. The 440 is a transplant, we have no idea what it in prior to the Coronet or what its been used for. A lot of questions and its killing me because Greg and I are spending waaaay too much time trying to dial in this BH.
Here's the TKX project thread if anyone is interested:

Tremec TKX 5-Speed Conversion

As much as I enjoy driving the Coronet, whenever we take long trips, like to the Mopar Spring Fling in Van Nuys, I take the Dart because it has an ancient Keisler Engineering Tremec 5-speed and I can cruise at 65 and 2,100 rpm. I've been mulling over converting to the Tremec for years but there...

www.forbbodiesonly.com

What you need is in post 25.
Drill the holes out in the bell, knock it into line, weld on the bushings.

 

[AR67GTX]

QuickTime bellhousings have developed a reputation for being far more accurate out of the box than the old Lakewoods. At least the one I used in my Cobra replica dialed in good. They now own Lakewood too but I doubt any of this precision out of the box has rubbed off on them.

 

[Fran Blacker]

Have a machine shop make offset bushings for bellhousing? Don't known if you the room to oversize the dowel holes? Return bellhousing to vendor for another.

 

[CoronetDarter]

Have a machine shop make offset bushings for bellhousing? Don't known if you the room to oversize the dowel holes? Return bellhousing to vendor for another.

Yes, that is the answer. If the bell falls in spec on the shop engine, the bell goes back to SST.

 

[1 Wild R/T]

QuickTime bellhousings have developed a reputation for being far more accurate out of the box than the old Lakewoods. At least the one I used in my Cobra replica dialed in good. They now own Lakewood too but I doubt any of this precision out of the box has rubbed off on them.

I don't know why that is...

I refer you to post 25... Tremec TKX 5-Speed Conversion

 

[murfman]

It is a '74 block....

View attachment 1538170

I've had it since 2004. It was standard bore when I got it. No signs of having a pilot bushing so it was mated to a 727 from the start.
In 1974, the 440s were only available in the Coronet/Satellite Police cars, C bodies, trucks and RVs if I recall. I don't recall hearing of a Charger or Road Runner in 74 having a 440. If they did, I don't know of any.
This didn't have the 7 to 1 RV pistons in it so I figured it was most likely from a C body.

440 was available in the 74 Road Runner and Dodge Charger Rallye or SE with a 727 onlyView attachment 1540503

 

[AR67GTX]

I don't know why that is...

I refer you to post 25... Tremec TKX 5-Speed Conversion

That‘s the first one I remember hearing of trouble with one like that. Just about all the Cobra builders use aftermarket bell housing and most swear by (not at) QuickTime. Maybe Mopars are their archilles heel.

 

[RemCharger]

440 was available in the 74 Road Runner GTX and Dodge Charger Rallye or SE with a 727 onlyView attachment 1540503View attachment 1540519