Flexplate/converter bolts/converter tabs

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by AJ FED, Jan 2, 2017.

  1. AJ FED

    AJ FED New Member

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    Hello and Happy New Year!

    By way of introduction I have just joined however I have been reading the forum on and off for a while. What a great resource and I think it is terrific that it has been going for so many years. Great to see these days!

    I have been 'de-bugging" my roots blown hemi front engine dragster for a while. I am having recurring issues regarding converter bolts loosening and causing the usual damage to the flexplate etc. Rather than re hashing what's wrong I would like to ask the members what's right. Having said that I have been around drag racing long enough to know that what works for one might not work for another. I am looking forward at running reliably for a while before cranking it up.

    I have read all/most previous posts regarding this problem and there is a strong recommendation for the meziere flexplates. I have noted this.

    What size/grade bolts are "best" used for the flexplate to the converter?

    How many bolts used for the flexplate to converter. I see some use 3, 4 and 6

    Does anyone have threaded converter tabs or only nuts on the back of the tabs?

    Have others made access in the rear motor plate, directly behind the sump, in order to get a decent torque wrench enough clearance to torque the converter bolts to specification?

    Any input would be appreciated.

    Thanks AJ
     
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  2. jody stroud

    jody stroud ZOMBIE Top Dragster

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    On my old Convertor with a power glide style open bottom Bellhousing I used all 6 bolts and a nylon lock nut. Never had one loosen. Make sure the the bolt length is correct and that the threads are not carrying any shear load. When I switched to a chance Convertor and full closed Bellhousing I now have to remove my oil pan to access the bolts ( before I could remove the starter for access) and I use red locktite on the bolts. Never had one loosen. Same thing about threads carrying no shear load. I had to use a longer grade 8 bolt and cut it down to the proper length.
     
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  3. Mike Canter

    Mike Canter Top Dragster

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    I agree with Jody. We use nothing but ARP converter bolts and never have a problem. We use CSR flex plate
     
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  4. BEDNAR1320

    BEDNAR1320 Member

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    Six bolts here, red Loctite they stay tight.

    When I ran only three bolts, they would loosen even with Loctite..........
     
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  5. AJ FED

    AJ FED New Member

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    Thanks Jody, Mike and Bednar. I really appreciate your experience. 6 bolts it is with nylon lock nuts.

    I see the CSR flex plates use 1/2" bolts and the Meziere use 7/16" bolts. With 6 bolts it probably doesn't really matter. Any comments for the bolt size?

    Are the holes in the tabs/lugs on the converter tapped to suit the 6 bolts as well?

    cheers

    AJ
     
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  6. BEDNAR1320

    BEDNAR1320 Member

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    You have to have a converter with six lugs. Mine are 7/16", the converter lugs are threaded so no nuts. FWIW, I prefer the Meziere billet flywheel.
     
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  7. Mike Canter

    Mike Canter Top Dragster

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    AJ the size of the bolts is dependent on the converter and not dependent on the flex plate. When you buy a flex plate you have to tell them if you have a 10.5" pattern such as with a Chance converter or a dual 10.5" and 11.0" as with a Coan converter. Now flexplates are offered with a dual pattern. The Coan converter doesn't use nuts but the Chance does. There is no way I would run anything less than six bolts with a blown application.
     
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  8. BEDNAR1320

    BEDNAR1320 Member

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    Good explanation, Mike. Didn't know some converters have all six holes in the same bolt circle. Mine is an Abruzzi and it has two different patterns.
     
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  9. lucky devil

    lucky devil Member

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    We had a blown Chevrolet that ran 6.6s in a door car with a 3 bolt converter that worked. As soon as we went with the HEMI we needed 6 bolt and we upgraded to 1/2 inch too.
     
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  10. jody stroud

    jody stroud ZOMBIE Top Dragster

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    My chance Convertor is drilled and tapped for bolts. Since I run a full 360 bellhousing that is a requirement. The only way you can run nuts is with an open bottom, power glide, style bellhousing.
     
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  11. AJ FED

    AJ FED New Member

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    Thanks all for the input. My "new" converter only has 1 1/2 runs on it before converter bolt damage to the converter lugs (and flexplate and seal etc etc :)) I will be getting those 3 lugs replaced with 6 new ones.

    It certainly seems that some cars don't have problems with 3 bolts yet others have all the drama. Don't you love drag racing!

    It now comes to mind about the machined spacers sometimes necessary, between the flexplate and converter lugs, to locate the converter. Do you guys have the lug thickness designed to eliminate the need for the spacers or do you still use them?

    cheers

    AJ
     
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  12. Mike Canter

    Mike Canter Top Dragster

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    You try and design it to have thin ones so you can move it back and forth to get it right. I think it is better to have thin spacers for mounting but that is just my opinion.
     
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  13. AJ FED

    AJ FED New Member

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    Thanks Mike. My current set up uses a 1/8 spacer. I guess this may change once I replace the existing crank adaptor and flexplate with a new one piece flexplate. As I am getting new converter lugs I will keep the spacer requirement to a minimum to give a bit of set up room. Cheers
     
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  14. secondwindracing

    secondwindracing top alcohol

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    one question I have for you...what are you using for spacers?
     
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  15. AJ FED

    AJ FED New Member

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    The spacers are 1/8 thick x about 3/4 OD machined steel.
     
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  16. secondwindracing

    secondwindracing top alcohol

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    Text me your number..620 249 5909
    I'll send you a pic of my spacers..this cured my problem
     
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