700R4 Torque Converter Flexplate Question - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Transmission - Rearend
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 02-29-2008, 06:37 PM
Registered User
 

Last journal entry: 1965/66 Impala body lines.
Join Date: Nov 2006
Location: Northern New York
Age: 63
Posts: 55
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
700R4 Torque Converter Flexplate Question

I think I may have a problem. I am installing a "86" 700R4 tranny behind a "70" SBC 350 with a two piece seal. The engine has been completely re-built with a new Scat crank and all. I also purchased a new flex plate and B&M 2600 stall torque converter for this installation. Everything seemed fine till I installed the new high torque starter that I got on eBay from Skip White. Once the starter was installed I noticed it was almost impossible to turn the engine with the harmonic balancer bolt in order to bring it up to TDC. Upon investigation I found that the "bendix" drive was engaged in the flex plate by just a few thousandths. I attributed this to the fact that the flex plate had not been bolted to the torque converter yet. So I went ahead and installed the flex plate bolts and found that this drew the plate back away from the bendix drive. However once all the bolts were in and torqued I noticed that as I manually turned the engine, the areas between the flex plate bolts still wanted to rub on the bendix. So what I am saying is that where the bolts are, the plate clears the bendix and in between it wants to just knick the end of the drive gear. So do I have an incompatible combination (700R4 torque Converter and "old" style crank) or is the flex plate supposed to be "warped" like that? Do I need to shim the starter motor back away from the plate? I'm confused!! Sorry if I confused you, it's kind of hard to explain.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 02-29-2008, 07:31 PM
Crosley's Avatar
Hotrodders.com Moderator
 
Last wiki edit: T-350 rebuild tech
Last journal entry: Morris update 9-28-2014
Last photo:
Join Date: Nov 2002
Location: ... USA
Posts: 8,173
Wiki Edits: 1659

Thanks: 409
Thanked 106 Times in 102 Posts
Quote:
Originally Posted by fosterdl
I think I may have a problem. I am installing a "86" 700R4 tranny behind a "70" SBC 350 with a two piece seal. The engine has been completely re-built with a new Scat crank and all. I also purchased a new flex plate and B&M 2600 stall torque converter for this installation. Everything seemed fine till I installed the new high torque starter that I got on eBay from Skip White. Once the starter was installed I noticed it was almost impossible to turn the engine with the harmonic balancer bolt in order to bring it up to TDC. Upon investigation I found that the "bendix" drive was engaged in the flex plate by just a few thousandths. I attributed this to the fact that the flex plate had not been bolted to the torque converter yet. So I went ahead and installed the flex plate bolts and found that this drew the plate back away from the bendix drive. However once all the bolts were in and torqued I noticed that as I manually turned the engine, the areas between the flex plate bolts still wanted to rub on the bendix. So what I am saying is that where the bolts are, the plate clears the bendix and in between it wants to just knick the end of the drive gear. So do I have an incompatible combination (700R4 torque Converter and "old" style crank) or is the flex plate supposed to be "warped" like that? Do I need to shim the starter motor back away from the plate? I'm confused!! Sorry if I confused you, it's kind of hard to explain.

early crank shaft and the converter are fully compatible. 700 type of trans was released in early 1980's


Is the flex plate on backwards?

Was the end of the crank shaft clean where the converter alignment hub slides in?

Was there a manual trans bushing in the end of the crank shaft?

__________________
Some people are like Slinkies... Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 02-29-2008, 09:30 PM
NEW INTERIORS's Avatar
Believe in yourself !!!!!!
 

Last journal entry: 41 WILLYS FRAME
Last photo:
Join Date: Jul 2007
Location: In My Shop..
Age: 49
Posts: 10,299
Wiki Edits: 0

Thanks: 1,440
Thanked 691 Times in 508 Posts
I have to agree,If there is a bushing in the end of the crank shaft It's not going to work.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-01-2008, 07:25 AM
Registered User
 

Last journal entry: 1965/66 Impala body lines.
Join Date: Nov 2006
Location: Northern New York
Age: 63
Posts: 55
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
700R4 Torque Converter Flexplate Question

Good thoughts and at first I thought that the plate MIGHT have been on backward, but I've checked it against a 305 I just removed and it looks OK. The crank is a NEW Scat and I'm almost positive that there is no bushing as I came sealed in the box from the supplier. Again as to the cleanliness of the crank, it is brand new. I suppose there is a possibility that the converter had a burr on it as these are all rebuilt items, but I'd hope that B&M would check that out first. At any rate if any of the above situations existed all that would do id to help straighten the flex plate and it would still be bumping the bendix. After posting I found a post from back a while and some responder recommended installing three washers between the converter mounting tabs and the flex plate to allow the converter to engage the front pump drive further and prevent damaging it, but that too would not solve the starter problem. Supposedly there needs to be a spacer there to set the converter back, but I've never fond one on a factory install. Maybe it's time for a tear down?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 03-01-2008, 07:54 AM
31 five window
 

Last journal entry: grill and rear end
Last photo:
Join Date: Oct 2007
Location: louisiana
Age: 57
Posts: 1,579
Wiki Edits: 0

Thanks: 1
Thanked 16 Times in 16 Posts
If the converter is not fitting all the way into the crank this would pull the flex plate away from the starter drive gear.So it has to be something else.Is the flex plate new? I don't remember the exact years but at one time GM had a run of flex plates that where out of round.Sorry, after posting I re read and noticed your flex plate is new. Maybe it is defective.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-01-2008, 08:34 AM
Registered User
 

Last journal entry: 1965/66 Impala body lines.
Join Date: Nov 2006
Location: Northern New York
Age: 63
Posts: 55
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
700R4 Torque Converter Flexplate Question

It's starting to sound like I may have more than one issue here. One, that the converter isn't going into the crank far enough and two, the starter isn't lining up correctly.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 03-02-2008, 07:10 AM
Member
 
Last photo:
Join Date: Feb 2005
Location: chillicothe oh
Age: 47
Posts: 1,445
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
were you able to spin the convertor in the trans or did it bind on the flexplate before you bolted it up? If you could spin it that eliminates the convertor causing the starter problem.Would have to be flexplate or starter issue.As to the spacers I used them on my boys v8 s10 with a 700r4 after reading about it here worked great just used a couple washers between the convertor and plate.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 03-02-2008, 09:47 AM
Registered User
 

Last journal entry: 1965/66 Impala body lines.
Join Date: Nov 2006
Location: Northern New York
Age: 63
Posts: 55
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
700R4 Torque Converter Flexplate Question

The converter spun well on the input shaft before we installed the tranny, and also spun OK before I moved it forward to line up the centering hub to the back of the crank. I have a feeling that the hub isn't going all the way into the crank for what ever reason, but I suspect the the paint applied by B&M may be the cause. Once the hub engages the crank I think the "warped" flex plate problem will be solved. I was on Powermaster's (starter) site last night and they offer a shim to set the starter further away from the ring gear. I just don't know where to lay my hands on one of those.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 03-23-2008, 01:03 PM
Registered User
 

Last journal entry: 1965/66 Impala body lines.
Join Date: Nov 2006
Location: Northern New York
Age: 63
Posts: 55
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Follow-up on 700R4 converter/flexplate problem

I read with interest all the replies to my question, and decided that shimming the converter back with washers was out of the question. This solution still wouldn't solve my starter engagement issue and in fact might make it worse. I jumped over to Summit and looked at all the starters and found that some starters have shims that would move the bendix further away from the flexplate, but I couldn't find any shims for my starter. As I looked around the site I ran across .030 Flywheel shims supplied by TCI that are intended to mount between the flange on the back of the crankshaft and the flywheel or flexplate. Now, I knew these were available since I remembered (after finding them) installing them when I worked as a mechanic. I ordered all that Summit had and then jumped over to Jegs and ordered 6 more. I just got done with the adjustments and using 5x.030 shims did the trick. That brought the flexplate back far enough to allow the torque converter bolts to install through the flexplate without any warpage and also gave me the desired bendix/flexplate clearance I needed. Thanks for all your replies. They were a big help.
Reply With Quote Quick reply to this message

Recent Transmission - Rearend posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
TH350 converter and flexplate cisco57 Transmission - Rearend 1 03-26-2007 07:37 AM
Torque converter drain plug 700r4 blacklabzeke Transmission - Rearend 2 03-21-2007 09:22 AM
Torque Converter Application BMRIde85 Transmission - Rearend 4 06-17-2004 03:57 PM
Torque Converter Question 79 Malibu327 Transmission - Rearend 2 05-27-2004 01:44 PM
C5 or Torque Converter Bad? k2mooch Transmission - Rearend 2 11-30-2003 09:27 PM


All times are GMT -6. The time now is 05:49 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.