Flex Plate [message #353039] |
Sun, 22 March 2020 16:37 |
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Husker92592
Messages: 137 Registered: August 2013 Location: Temecula ca
Karma: -4
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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'
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Re: Flex Plate [message #353041 is a reply to message #353039] |
Sun, 22 March 2020 17:19 |
lqqkatjon
Messages: 2324 Registered: October 2010 Location: St. Cloud, MN
Karma: 5
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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/
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Re: Flex Plate [message #353046 is a reply to message #353039] |
Sun, 22 March 2020 19:11 |
C Boyd
Messages: 2629 Registered: April 2006
Karma: 18
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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 17:37GMC'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
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Re: Flex Plate [message #353054 is a reply to message #353039] |
Mon, 23 March 2020 07:23 |
bobby5832708
Messages: 237 Registered: November 2006 Location: Winter Springs FL
Karma: 3
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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
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Re: Flex Plate [message #353065 is a reply to message #353062] |
Mon, 23 March 2020 10:46 |
C Boyd
Messages: 2629 Registered: April 2006
Karma: 18
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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 10:55Mr. Boyd,
Thanks. I have one more heading to me in the mail. I will let you know, thansk
C. Boyd
76 Crestmont
East Tennessee
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Re: Flex Plate [message #353141 is a reply to message #353140] |
Wed, 25 March 2020 22:17 |
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Husker92592
Messages: 137 Registered: August 2013 Location: Temecula ca
Karma: -4
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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] Report message to a moderator
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Re: Flex Plate [message #353143 is a reply to message #353141] |
Wed, 25 March 2020 23:49 |
Rick Staples
Messages: 126 Registered: May 2014 Location: Johnstown, Colorado, USA
Karma: -1
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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
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Re: Flex Plate [message #353145 is a reply to message #353140] |
Thu, 26 March 2020 07:59 |
C Boyd
Messages: 2629 Registered: April 2006
Karma: 18
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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 23:13Mr. 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
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Re: Flex Plate [message #353157 is a reply to message #353145] |
Thu, 26 March 2020 12:54 |
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Husker92592
Messages: 137 Registered: August 2013 Location: Temecula ca
Karma: -4
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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] Report message to a moderator
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Re: Flex Plate [message #353160 is a reply to message #353157] |
Thu, 26 March 2020 15:16 |
C Boyd
Messages: 2629 Registered: April 2006
Karma: 18
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Senior Member |
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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 13:54Not 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
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Re: Flex Plate [message #354364 is a reply to message #353039] |
Sat, 02 May 2020 10:27 |
jhbridges
Messages: 8412 Registered: May 2011 Location: Braselton ga
Karma: -74
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Senior Member |
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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
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