78 gmc with 454 & turbo 400 breaking starter nosecones

sure could use some help. my 78 gmc truck 2 wheeldrive,454 with t400 auto. has broken 3 starter nosecones as fast as i can install them. never had any
problems untill i had to change the old one out. flexplate has a slight rounding at gear, but don't see anything real bad. maybe warped? I've got a new one but never have changed one before. after unbolting converter do i need to unbolt bell housing and pull tranny out or just back to get to bolts or maybe thats not prob. at all. any advice would be forever appreciated maybe i should get gear reduction starter????? please help this rookie, i love my truck! thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Shims/clearance...
The front (rear of starter, but facing the front of the truck) starter mount missing?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 15 Aug 2005 09:38:00 -0400, Peter D. Hipson

yeah - the shims - wich are thin pieces of metal that go between the starter and where the starter mounts to the block - they come in different thicknesses - it is a trail and error kind of thing as to how close or near it needs to be.
Good luck.
-W
p.s. some sites to check out:
http://www.chevytalk.com 73-87 trucks section
http://www.67-72chevytrucks.com <- started for 67-72 now covers '47 - current chevy/gmc
-Woogeroo
------------------------------------------------ snipped-for-privacy@yahoo.com <- remove NOBS to send email. ------------------------------------------------
Woogeroo's Simple Smoking Page:
http://woogeroo.home.mindspring.com/wsp /
smokin' along with an old style Big Green Egg...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

It is a lot of things, but trial and error is not one. There is a procedure to measure gear tooth clearance, compute the shims needed, and then you get it right. Guessing gets you broken starters, stripped flywheels/flexplates, and other nasty things.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Peter D. Hipson" wrote:

stripped
Not really, you can tell by listening to it if it is too tight and if it was much over .030 interferance fit the starte would likely grind when engaging. This was fairly common on some GM engine in late 60s thriugh mid 70s or so. I have never seen one shimed more than .030 and usually around .015 to.020 at most.
--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Maybe you can tell by listening. Maybe I can tell by listening. But that doesn't mean the poster can tell, and judging from the post I'd say not. <g>
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Peter D. Hipson" wrote:

starter
I agree, the starter nose it to close to flywheel. You need to shim it about 20 to 30 thousands to begin with.
--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.