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Flex Plate [message #353039] Sun, 22 March 2020 16:37 Go to next message
Husker92592 is currently offline  Husker92592   
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GMC'Ers
so I have ordered tWO flexplates so far ATP Z116 AND PIONEER FRA 102, I also tried a buick just because and nothing is matching up to the bolt patterns on the crank. Does anyone have an idea where to get one? Is there a used one out there? its quite difficult to break in an engine if you cant start it?

thanks
Grant


1974 GMC Sequoia 26'
Re: Flex Plate [message #353041 is a reply to message #353039] Sun, 22 March 2020 17:19 Go to previous messageGo to next message
lqqkatjon is currently offline  lqqkatjon   United States
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Hmmm. I bought one with my engine from s&j. ? Box is in my storage unit.

From my invoice:


Part-PIO-FRA-102
Description: FLEXPLATE
Manufacturer: Pioneer



Jon Roche 75 palm beach EBL EFI, manny headers, Micro Level, rebuilt most of coach now. St. Cloud, MN http://lqqkatjon.blogspot.com/
Re: Flex Plate [message #353046 is a reply to message #353039] Sun, 22 March 2020 19:11 Go to previous messageGo to next message
C Boyd is currently offline  C Boyd   United States
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Sir, Have you tried rotating the flexplate? IIRC it will only fit in one position as 1 hole is a little off. I do have a used one if you can't find one closer than Tennessee.




Husker92592 wrote on Sun, 22 March 2020 17:37
GMC'Ers
so I have ordered tWO flexplates so far ATP Z116 AND PIONEER FRA 102, I also tried a buick just because and nothing is matching up to the bolt patterns on the crank. Does anyone have an idea where to get one? Is there a used one out there? its quite difficult to break in an engine if you cant start it?

thanks
Grant


C. Boyd
76 Crestmont
East Tennessee
Re: Flex Plate [message #353054 is a reply to message #353039] Mon, 23 March 2020 07:23 Go to previous messageGo to next message
bobby5832708 is currently offline  bobby5832708   United States
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I used an ATP Z-116 flexplate purchased from Amazon on my spare 455 engine. Works fine.

Bob Heller
2017 Winnebago 29VE
Winter Springs FL
Re: Flex Plate [message #353061 is a reply to message #353046] Mon, 23 March 2020 09:52 Go to previous messageGo to next message
Husker92592 is currently offline  Husker92592   
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Yes that was the frustrating part, I rotated to where all lined up except 1. 5 out of 6 is not a bad thing but i really dont want to alter the holes on the plate. maybe I have bad holes on the plate?

1974 GMC Sequoia 26'
Re: Flex Plate [message #353062 is a reply to message #353046] Mon, 23 March 2020 09:55 Go to previous messageGo to next message
Husker92592 is currently offline  Husker92592   
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Mr. Boyd,
Thanks. I have one more heading to me in the mail. I will let you know, thansk


1974 GMC Sequoia 26'
Re: Flex Plate [message #353065 is a reply to message #353062] Mon, 23 March 2020 10:46 Go to previous messageGo to next message
C Boyd is currently offline  C Boyd   United States
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Sir, just a note.. the welded on weight on the flywheel goes toward the torque converter. If one hole is off, rotate to next hole and so on till all 6 line up. It will only go 1 way as the engine is externally balanced. I am surprised the engine builder did not include the flexplate as it is needed to balance the engine, unless he did not balance lt?






Husker92592 wrote on Mon, 23 March 2020 10:55
Mr. Boyd,
Thanks. I have one more heading to me in the mail. I will let you know, thansk


C. Boyd
76 Crestmont
East Tennessee
Re: Flex Plate [message #353066 is a reply to message #353061] Mon, 23 March 2020 10:47 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Husker92592 wrote on Mon, 23 March 2020 10:52
Yes that was the frustrating part, I rotated to where all lined up except 1. 5 out of 6 is not a bad thing but i really dont want to alter the holes on the plate. maybe I have bad holes on the plate?
Grant,

Did you try turning the plate over? Maybe you are trying it the wrong way.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: Flex Plate [message #353139 is a reply to message #353066] Wed, 25 March 2020 22:11 Go to previous messageGo to next message
Husker92592 is currently offline  Husker92592   
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http://www.gmcmhphotos.com/photos/data/7287/IMG_1444.pdf

http://www.gmcmhphotos.com/photos/data/7287/IMG_6542.pdf

So here is my last try and all of the flex plates I have ordered are the same. the alignment of the holes are off.

any ideas?


1974 GMC Sequoia 26'
Re: Flex Plate [message #353140 is a reply to message #353065] Wed, 25 March 2020 22:13 Go to previous messageGo to next message
Husker92592 is currently offline  Husker92592   
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Mr. Boyd,
Yes the weight goes out towards the torque converter. on a post recently i added some pictures so everyone can see. it is awfully frustrating as I cant dyno my engine and get it installed with out a flex plate.
any ideas?

Thanks
Grant


1974 GMC Sequoia 26'
Re: Flex Plate [message #353141 is a reply to message #353140] Wed, 25 March 2020 22:17 Go to previous messageGo to next message
Husker92592 is currently offline  Husker92592   
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my engine block on the back in the casting says 396021 fa does that make a difference if the engine block is not a motor home block? it also has a 68 F4 on the back which is a 1968 high nickle content engine, will this have a different flex plate?
thanks
Grant


1974 GMC Sequoia 26'

[Updated on: Wed, 25 March 2020 22:35]

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Re: Flex Plate [message #353143 is a reply to message #353141] Wed, 25 March 2020 23:49 Go to previous messageGo to next message
Rick Staples is currently offline  Rick Staples   United States
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Husker 92592 wrote:
" 396021 fa does that make a difference if the engine block is not a motor home block? it also has a 68 F4 on the back which is a 1968...."

According to the late Joe Mondello ("Dr. Olds"), crankshafts changed in 1968. Earlier cranks used an old/odd bolt pattern flex plate which, (as of 1996) were "...no longer available anywhere except Mondello Performance Products and junkyards." I hear Mondello Performance has deteriorated a bit since Joe's death, so I don't know if they still carry this part.

But first, you need to get the casting number off of the CRANKSHAFT, as the block doesn't really matter. If it is 384722, used on 400 and 425 cu. in. engines or 390370, it is a short stroke (3.975") steel crank with the earlier bolt pattern. I think Mondello's "Technical Reference Manual" is still available. To be safe, you might try to get hold of a copy, I may be barking up the wrong tree. Remember, Olds engines since ~1957 have external balancing, so they must be balanced with the flex plate and vibration damper installed.

Don't know if this applies to you, but hope it helps.

Rick Staples.


Rick Staples, '75 Eleganza, Johnstown, CO "Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
Re: Flex Plate [message #353145 is a reply to message #353140] Thu, 26 March 2020 07:59 Go to previous messageGo to next message
C Boyd is currently offline  C Boyd   United States
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Sir, I can't tell anything from your pics. Back up a little so the whole flexplate can be seen. Mark 1 hole with paint spot and take 6 pictures of the flexplate in the 6 possible combinations with the weight showing.
Where did the engine come from? Was it a running engine or assembled from floor parts?
Do you have the flexplate that came with engine?
Have you checked with the engine builder? If he is clueless you better check to see if it has the correct oil galley plugs with holes to spray oil on timing chain and distributor gear.
What heads are on engine? Are rocker attachment bolts 5/16 or 3/8?
Here are some specs.. https://oldsjunction.classicoldsmobile.com/oldsfaq/ofblk.htm#BB%201965%20-%201976%20Identifying%20a%20Big%20Block%20Block
Table of contents at bottom of page.

Early 68 is when Olds changed flexplate mounting holes but I have never heard of a true 455 with early bolt pattern. Was the engine originally red? Did it have a 2 bbl or 4 bbl carb?
All flexplate pre 68 have 1 mounting hole offset 5* ccw and 68 and later 1 hole is offset 5* cw.

You may have to remove oil pan and work off the crank numbers.
https://oldsjunction.classicoldsmobile.com/oldsfaq/ofcrk.htm#Cranks



Husker92592 wrote on Wed, 25 March 2020 23:13
Mr. Boyd,
Yes the weight goes out towards the torque converter. on a post recently i added some pictures so everyone can see. it is awfully frustrating as I cant dyno my engine and get it installed with out a flex plate.
any ideas?

Thanks
Grant


C. Boyd
76 Crestmont
East Tennessee
Re: Flex Plate [message #353157 is a reply to message #353145] Thu, 26 March 2020 12:54 Go to previous messageGo to next message
Husker92592 is currently offline  Husker92592   
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Not sure on any of these as my engine builder is supposed to be a BOAT guy. I picked up the engine from a local GMC'er and quickly took it to get built. So relaying on my builder probably is not a good idea. there was not and origianal flex plate so this is where I am at. I suppose it is time to remove the engine pan again and do some research.

396021 fa is the casting number next to the oil filler tube, according to the "oldsmobile FAQ site The block is "common" but the back casting is a 1968 not a 72 on, obviously there is something wrong.

ID/ Casting
Code Year(s) CID Number Notes
A '65 425 381917?? 1st year, big cars.
386525
B '65 400 389298 442 only, one year only.
D '66 - '67 425 389244 Big-car engine. Toro is different internally.
E '66 - '67 400 390925 442 engine [VERY rare].
F '68 - '70 455 396021 Common big block. Stick type F (sans serif).
F '70 - '72 455 396021 Common big block. Serif type F. Two vertical
and a base serif.
Fa '72 - '76 455 396021 Very common big block. Marine also (L VIN derivative).
G '68 - '69 400 396026 442/Vista/etc. engine.
L '76 455 231788 Motorhome, marine and irrigation. GM made motorhomes
from '73-8, maybe in all? Casting number appears
as "231 [tiny 'L'] 788" on the block.


so much for a solid rebuild. seems I need to find a new crank. and who knows what else. I will do some research and be in touch. thanks

I could have put a diesel in my coach by now.\


New photos:

http://www.gmcmhphotos.com/photos/engine/p67122-engine-castings.html

http://www.gmcmhphotos.com/photos/engine/p67123-engine-castings.html

http://www.gmcmhphotos.com/photos/engine/p67121-engine-castings.html


block casting under heads: 33M730673

3= oldsmobile
3= 1973
M = Lansing
730673= vin of car block comes from

Crank?


1974 GMC Sequoia 26'

[Updated on: Thu, 26 March 2020 13:48]

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Re: Flex Plate [message #353160 is a reply to message #353157] Thu, 26 March 2020 15:16 Go to previous messageGo to next message
C Boyd is currently offline  C Boyd   United States
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Sir, the 68 cast in the rear of the block is the Julian date (1-365) of the year the block was cast. Since yours is Fa it is 72-76 nothing strange there. It looks like if you were to rotate the flywheel about 5* ccw on the crank then 5 bolts would line up and one would be off center 5* cw which it should be and you should have the correct flywheel according to the #'s.. I still think you just need to rotate the flywheel on the crank till all 6 bolt holes line up. Just keep turning it to a new hole and somewhere all 6 will line up. Make sure the welded weight is facing outside toward / against the torque converter.
On the date built it is on some cars stamped with VIN number on oil fill spout then painted over. I have not found any on motorhome build engines as the oil fill tube end is motorhome only. Has a fill hose instead of spin on fill cap. If you do find a number the first # is the year, should be 2-6.


Husker92592 wrote on Thu, 26 March 2020 13:54
Not sure on any of these as my engine builder is supposed to be a BOAT guy. I picked up the engine from a local GMC'er and quickly took it to get built. So relaying on my builder probably is not a good idea. there was not and origianal flex plate so this is where I am at. I suppose it is time to remove the engine pan again and do some research.

396021 fa is the casting number next to the oil filler tube, according to the "oldsmobile FAQ site The block is "common" but the back casting is a 1968 not a 72 on, obviously there is something wrong.

ID/ Casting
Code Year(s) CID Number Notes
A '65 425 381917?? 1st year, big cars.
386525
B '65 400 389298 442 only, one year only.
D '66 - '67 425 389244 Big-car engine. Toro is different internally.
E '66 - '67 400 390925 442 engine [VERY rare].
F '68 - '70 455 396021 Common big block. Stick type F (sans serif).
F '70 - '72 455 396021 Common big block. Serif type F. Two vertical
and a base serif.
Fa '72 - '76 455 396021 Very common big block. Marine also (L VIN derivative).
G '68 - '69 400 396026 442/Vista/etc. engine.
L '76 455 231788 Motorhome, marine and irrigation. GM made motorhomes
from '73-8, maybe in all? Casting number appears
as "231 [tiny 'L'] 788" on the block.


so much for a solid rebuild. seems I need to find a new crank. and who knows what else. I will do some research and be in touch. thanks

I could have put a diesel in my coach by now.\


New photos:

http://www.gmcmhphotos.com/photos/engine/p67122-engine-castings.html

http://www.gmcmhphotos.com/photos/engine/p67123-engine-castings.html

http://www.gmcmhphotos.com/photos/engine/p67121-engine-castings.html


block casting under heads: 33M730673

3= oldsmobile
3= 1973
M = Lansing
730673= vin of car block comes from

Crank?


C. Boyd
76 Crestmont
East Tennessee
Re: Flex Plate [message #353172 is a reply to message #353160] Fri, 27 March 2020 12:00 Go to previous messageGo to next message
Husker92592 is currently offline  Husker92592   
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Location: Temecula ca
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Thanks I will check it again.
Thanks for everyone's help.


1974 GMC Sequoia 26'
Re: Flex Plate [message #354353 is a reply to message #353172] Sat, 02 May 2020 02:00 Go to previous messageGo to next message
Husker92592 is currently offline  Husker92592   
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So, here is what I found on the crank, I had to remove the pan and the oil as well as the crank as it needed to get balanced with the late model off hole location flexplate. reason for some reason in my 1972 455 block there is installed a 1968 -1969 odd ball nodular iron crankshaft that was only made for two years. Isn't that just my luck. so odd ball crack in a 1972 455 block, and now balanced with a flex plate with two hole drilled oversized as the only flex plate available for this crank is a sfi racing flexplate that is $350.00


1" wide.
397363 455 '68 - '70 Nodular iron. 'N' on front weight

so word to the wise not everything is what is should be and yes for some reason there are some engines out there that have mis matched parts.
so another $400.00 added to the engine build as it has to balance between the flexplate crank and balancer. $10,000 and climbing and no end to the bleeding. one of these days ill be able to drive my coach again.


1974 GMC Sequoia 26'
Re: Flex Plate [message #354362 is a reply to message #354353] Sat, 02 May 2020 10:10 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Husker92592 wrote on Sat, 02 May 2020 03:00
So, here is what I found on the crank, I had to remove the pan and the oil as well as the crank as it needed to get balanced with the late model off hole location flexplate. reason for some reason in my 1972 455 block there is installed a 1968 -1969 odd ball nodular iron crankshaft that was only made for two years. Isn't that just my luck. so odd ball crack in a 1972 455 block, and now balanced with a flex plate with two hole drilled oversized as the only flex plate available for this crank is a sfi racing flexplate that is $350.00

1" wide.
397363 455 '68 - '70 Nodular iron. 'N' on front weight

so word to the wise not everything is what is should be and yes for some reason there are some engines out there that have mis matched parts.
so another $400.00 added to the engine build as it has to balance between the flexplate crank and balancer. $10,000 and climbing and no end to the bleeding. one of these days ill be able to drive my coach again.
An issue like this in my early engine building is why I always keep a damper/crank/flywheel as a set.

There is a local guy that took an engine from me for evaluation. He brought it back and I gave him back his deposit, then I noticed that the flexplate was missing. He has refused to return that or the lube oil pump. He is on my Shix list.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: Flex Plate [message #354364 is a reply to message #353039] Sat, 02 May 2020 10:27 Go to previous messageGo to next message
jhbridges is currently offline  jhbridges   United States
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Matt, is this asshole a GMC Person or just a local turd?

--johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
Re: Flex Plate [message #354379 is a reply to message #354364] Sat, 02 May 2020 17:35 Go to previous messageGo to previous message
Matt Colie is currently offline  Matt Colie   United States
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Johnny Bridges wrote on Sat, 02 May 2020 11:27
Matt, is this asshole a GMC Person or just a local turd?

--johnny
Just a local guy. If I heard he was looking for a coach, I would do my best to discourage him.
Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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