Slant Six Forum
https://slantsix.org/forum/

Another Broken Flex Plate....HELP
https://slantsix.org/forum/viewtopic.php?t=26481		 Page 1 of 2
Author:  64A100 [ Tue Jan 01, 2008 11:45 am ]
Post subject:  Another Broken Flex Plate....HELP
Ok, So This is the second broken flex plate in my '64 A100 in less than six months. What could possibly be causing this?

Some history... It's a '64 A100, 225 with 727 auto. The 225 is not original, but was an upgrade put in sometime in the early '70's.

I bought the van and drove it for about 8 months. The trans. decided it was time for a rebuild. I pulled it and had a reputable guy rebuild it. I put it back in with a new torque converter and the old flex plate which was in great shape. Everything lined up nice & there was the right amt. of clearance bet. the converter and plate going in.

About six months of happy driving goes by and the flex plate breaks on one of the outside holes where it bolts up to the converter. I had also have developed a leaky rear trans seal. I pull the trans. and put in a new flex plate. I also replace the rear seal (which was new from the rebuild) and send my driveshaft out to be balanced.

Another 3 or 4 months of happy driving and I have another broken flex plate. It broke on one of the outside holes again.

Any help would be greatly appreciated. I plan to pull the trans. again and ckeck the crankshaft end float. any other thoughts?

One weird thing I did notice while it was in the air last time is that the diff. seems to be offset to one side from the output shaft of the trans. Is this normal in a '64 A100 van? Should it be a straightline from the motor, trans., driveshaft, diff.?

Thanks,
Tom
Author:  slantzilla [ Tue Jan 01, 2008 12:38 pm ]
Post subject: 
What year is the trans/converter? If it is a pre 68 trans it may have the small pilot on the converter, and you have the large register in the crank. That will break flew plates for sure.

www.wildcatmopars.com sells a spacer to fix the problem if that is what is happening.
Author:  SlantSixDan [ Tue Jan 01, 2008 12:56 pm ]
Post subject: 
Yep, I was going to guess you're missing the adaptor ring, too. You can also get it (and perhaps a flex plate) from Pat Blais, tflitepatty@verizon.net
Author:  64A100 [ Tue Jan 01, 2008 1:57 pm ]
Post subject: 
Thanks guys,
I'm pretty sure the trans. is original to the van. '64. I'm guessing the motor is a little newer. How can I tell the true ages of the motor and trans.? #'s etc...? What exactly should I look for Re: the end of crank and converter to know if I need an adapter/ spacer?
Author:  Jeffc [ Tue Jan 01, 2008 2:35 pm ]
Post subject: 
Org. trans in a 64 A100 should be rear case short shaft 727
with cable shift dash shifter and cable should enter the case
below the kickdown lever.
May, or may not, have the 2 cable type shifter with
the 2nd cable running to park sprag at rear of main case.
Should not have a slip joint yoke at rear of case/driveline
and should use a (detroit ball) ball and trunion at rear of trans
or slip joint built into driveline.
May or may not have a e-brake drum on rear of trans,
if no e-brake drum on trans, then axle rear brakes should have cable
running to them for the e-brake.

If trans has a slip yoke that enters rear case, it is at least a
65 or later trans, if it has the single cable shifter and
cable does not enter the case,
it is likely a 66, and later trans.
Author:  66aCUDA [ Wed Jan 02, 2008 7:04 am ]
Post subject: 
To see the age of the engine look at the freeze plugs 3 is old style, 5 is new style. This should let you know whether you need the adaptor or not.
Frank
Author:  64A100 [ Wed Jan 02, 2008 8:02 am ]
Post subject: 
What does the adapter look like & where does it go?
Author:  SlantSixDan [ Wed Jan 02, 2008 9:18 am ]
Post subject: 
Quote:
To see the age of the engine look at the freeze plugs 3 is old style, 5 is new style. This should let you know whether you need the adaptor or not.
All that'll do is tell you the age range of the block itself. Since the '60-'67 and '68-'76 cranks are completely interchangeable across '60-'67 and '68-'76 blocks, at this late date (with 4 decades' worth of potential engine swaps) the year of the block doesn't necessarily correspond to the year of the crank. Much better to check the engine ID number (stamped at the top right corner of the block, facing the sky, below the frontmost spark plug, inboard of the ignition coil). These still aren't perfect (for the same reason -- rebuilds, etc.) but give an approximation much more likely to be accurate, particularly if the engine's history is at least partially known.

64A100: The adaptor is a 1/8" annular ring (that is, a ring with a 1/8" wall thickness). It goes in the crankshaft rear counterbore to take up the extra space between the '67-down small-nose torque converter and the '68-up large-bore crankshaft.
Author:  Charrlie_S [ Thu Jan 03, 2008 7:59 am ]
Post subject: 
I may be wrong, so don't take this as gospell. Didn't the 64 van use the V-8 727 trans, with the adapter plate and special crankshaft adapter?
Is the trans used in 64A100's van the V-8 727 trans or the slant six 727 trans? This would need to be determined, first. So does the starter mount, above the oil pan flange (slant six trans), or below the oil pan flange (V-8 trans)?
Author:  SlantSixDan [ Thu Jan 03, 2008 8:05 am ]
Post subject: 
Quote:
I may be wrong, so don't take this as gospell. Didn't the 64 van use the V-8 727 trans, with the adapter plate and special crankshaft adapter?
The A727s used in the A100s were indeed V8 items. However, the large/small torque converter nose issue still applies. It's just that the changeover from small to large took place one year earlier with the V8s than with the slant-6s.
Author:  Charrlie_S [ Thu Jan 03, 2008 8:42 am ]
Post subject: 
The point, I was trying to make is, what trans is actually being used in the particular vehicle? Then we need to find out if the crank is the large bore or small bore. This will then determine what adapters are required, if any. The V-8 727 used a special crank adapter, in the original installs, which had the small bore crank. I don't think the factory 727 crank adapter will fit with the large bore crank. The crank adapter, from Pat Blaise, and Wildcat, is not the correct adapter for the V-8 727 trans install. If I remember correctly the proper adapter actually spaces the flexplate closer to the trans, to make up for the thickness of the trans adapter plate, and the nose of the converter fits into the crank adapter, for support.
If this is missing, it could be the cause of his flexplate problems.
Lou Madsen has this setup on one of his cars, and could shed more light on it. I think he is even using the late crank.
Author:  Jeffc [ Thu Jan 03, 2008 10:41 am ]
Post subject: 
The only adapter used in the van 727 to \6 was for the bell mount,
no spec crank adapter was used, flex plate is nothing special other
than \6 only, however, the converter was
special to this application of the slant/727 in trucks and taxi application.
As per my truck parts book and my experance.

Yes, A727A (small block v8) with a short rear case/shaft was used in
vans and 4x4's in the 100(1/2 ton) weight ranges.
At this point in time a \6 type 727 was not made, that came
long after 68.
There should be no reason why a adapter for the crank should not
work to fill the void if the crank is the later type and the trans
is pre 68.
Author:  SlantSixDan [ Thu Jan 03, 2008 12:10 pm ]
Post subject: 
Quote:
The only adapter used in the van 727 to \6 was for the bell mount, no spec crank adapter was used
An adaptor (or spacer, if you prefer) was bolted to the crank flange in this setup. It needed to be there, because the thickness of the bell housing adaptor moved the entire transmission rearward.
Quote:
At this point in time a \6 type 727 was not made, that came
long after 68
From the FPCs I see, the 727RG (727 with slant-6 bellhousing pattern) was introduced in '69.
Quote:
The point, I was trying to make is, what trans is actually being used in the particular vehicle?
Yep, that's a critical question. Best way to tell, short of tearing everything all apart, will be to find and post the transmission ID numbers, which are stamped into the case on the driver's side above the pan rail:

Image
Author:  64A100 [ Thu Jan 03, 2008 1:22 pm ]
Post subject: 
The transmission is now out. Its number is "E2508475...1384334. There are three freezeplugs on the engine beneath the manifolds.

There is a cast iron bellhousing adapterplate between the engine block and the transmission. It is about 1.112" thick, has a circular hole at 6 o clock for drainplug access. Starter motor mounts in this plate below the engine oilpan flange.

The crankshaft has an adapter/spacer- 1.125" thick, 4.162 circular diameter with a counterbore on the torque converter side 1 .802"in dia. and .665" deep. Bolts go through the flexplate, this adapter/spacer and into the crankshaft end.

Torque converter nose is 1.800" in dia., .882" tall to the surface of the converter.
There was evidence of contact between the face of the torque converter nose and the bottom of the crankshaft adapter/ spacer counterbore.

The adapter/ spacer sits .647" above the face of the cast iron bellhousing adapterplate when installed.

NOTE: When we had the trnsmission rebuilt, the rebuilder replaced the torque converter- could we have a converter with a incompatable nose?

Any more ideas? Do you think this adapter ring is necessary given this jumble of parts? We'd like to nail this down before we break another one.
Thanks
Author:  SlantSixDan [ Thu Jan 03, 2008 1:59 pm ]
Post subject: 
Quote:
There is a cast iron bellhousing adapterplate between the engine block and the transmission. It is about 1.112" thick, has a circular hole at 6 o clock for drainplug access. Starter motor mounts in this plate below the engine oilpan flange.
OK, so an A727A transmission (V8 type). As expected.
Quote:
The crankshaft has an adapter/spacer- 1.125" thick, 4.162 circular diameter with a counterbore on the torque converter side 1 .802"in dia. and .665" deep. Bolts go through the flexplate, this adapter/spacer and into the crankshaft end.
...goes with the bellhousing adaptor...
Quote:
Torque converter nose is 1.800" in dia., .882" tall to the surface of the converter.
So, no mismatch between the torque converter nose and the rear of the adaptor. I can't remember if the crank adaptor has a "nose" (like the torque converter nose) that fits in the crankshaft flange's central counterbore. Does it? If so, what is the OD of the adaptor nose? And what is the ID of the crank flange's counterbore?
Quote:
There was evidence of contact between the face of the torque converter nose and the bottom of the crankshaft adapter/ spacer counterbore.
Probably not problematic.
Quote:
When we had the trnsmission rebuilt, the rebuilder replaced the torque converter- could we have a converter with a incompatable nose
It doesn't sound like it, given the TC nose OD and the adaptor counterbore ID you cite.
Page 1 of 2 All times are UTC-07:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/