Info: Lets talk starter bolts - Diesel Place : Chevrolet and GMC Diesel Truck Forums
 
Home Forum Market Place Garage Tuning Library DTC Tool Register Vendors
Go Back   Diesel Place : Chevrolet and GMC Diesel Truck Forums > GM Diesel Engines > 6.2L Diesel Engine
Register FAQ Forum Rules My Replies My Threads Mark Forums Read Advertise

6.2L Diesel Engine Discuss the 6.2 GM diesel engine & associated components.

DieselPlace.com is the premier Duramax Diesel Forum on the internet. Registered Users do not see the above ads.
Like Tree24Likes

Reply
 
LinkBack Thread Tools
Old 10-14-2017, 11:43 PM   #1 (permalink)
roadhog0
Diesel Specialist
 
roadhog0's Avatar
 
Join Date: Dec 2011
Location: Washington
Posts: 3,488
iTrader Score: 1 reviews

Old School Oil Burners (Old SOBs) Member

Lets talk starter bolts

OK, we've had a bunch of talk about starter bolts lately and it's largely known that GM bolts are the only way to go. I've personally never looked into this past breaking one years ago before I had a brace. As I'm getting ready to install my starter I noticed some things. This is what I found, there is a quick summary at the bottom:



So as I'm pulling parts together I looked at my starter bolts. The one on the very left I bought about five years ago from Chevy when I broke one prior to having a starter brace (I had the truck for like a month and it came that way....). Here I am wondering, which one of these is really the right bolt. I went out to my parts stash and found one of the spare sets of bolts I have, but confusingly both of them had a very good fitting washer. That washer is really what got me wondering and is what prompted this photo heavy post.



Lets start by looking at bolt length to figure out which is correct. The correct bolt for this application is PN 15544950, an M10x1.5x110 Grade 9.8 bolt. 110mm is approximately 4.331". Below are what each bolt measures.

***Side note, a grade 9.8 is roughly equivalent to a Grade 5 SAE bolt. Grade 9.8 has a minimum tensile strength of 900MPa, Grade 5 is 825MPa. This is why you do not use a higher strength bolt, this bolt is the designed failure point of the system.***




That answers the first question of which bolt is correct. Not the long one! What about that washer then? Is that suppose to be there?? A quick look to some GM parts diagrams answers this question. Upper right hand side is the starter for the diesel. The direct drive and the gear reduction starter diagrams both call out this washer. So I have been wrong about this in the past it looks like (Sorry joeq!)




Now, since I'm a mechanical engineer, I can't leave well enough alone, and I like to know how things work/why they are the way they are I come to my next question. What's up with the knurling? Knurling is largely used to either create a grip point on something (it's rougher) or it's used to make the outside diameter of something larger. To show my point here, a few more visuals! First, knurling on the spare bolt, second shank on the spare bolt, third knurling on newer gm bolt, fourth shank on newer GM bolt, fifth knurling on the unknown bolt that came with the truck, sixth shank on the unknown bolt, seventh knurling on all the bolts.








OK, yeah, the bolt is enlarged. What's the point we ask? Well, lets take a wander over to the block. Here you will see that the block is about the same size as the bolt knurling, roughly .003-.004" difference in size. I do not know the original engineers intention on this, but it would appear to aide in strengthening to the bolt so it doesn't bend as much (cyclical loading) and is more rigid (less distance it can bend/move).






My last question I wanted to explore was a point I have heard before that the bolt seats into the block (sort of like a head stud seating into a head bolt hole). I screwed the bolt into the block as far as it would go, theoretically seating it all the way, then measured with and without the washer.





Check, we've got some measurements with and without the washer now. We can toss the measurements without the washer since we now know that is not the correct configuration. So if the bolt was to seat in the block the starter should be roughly 3.000" tall at the bolt hole right? Well, here is the starter at the bolt hole.




Well then, 3.3". That proves that wrong too. The starter bolt does not seat down into the block. It only engages part of the way and uses the knurling for support as mentioned earlier.


There you have it! Everything you ever wanted to know about starter bolts! Hopefully this didn't bore any of y'all too much and proved to be some valuable information!



Summary: Buy the right GM bolt (PN 15544950), use washers, the bolts don't seat down into the block, the knurling is there to make the bolt fit tighter in the hole.

__________________
-Nathan
1986 Chevy K20 6.2TD NV4500!! 4.10's (Name: POS Truck)
6.2 Turbo Diesel (HX40 CKO), 6.5 Serp, 6.5 Lift Pump, intercooler (to come), more broken or missing parts than you can shake a fist at, balls.
Offline  
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 10-15-2017, 02:14 AM   #2 (permalink)
Bigboytoys
Diesel Veteran
 
Bigboytoys's Avatar
 
Join Date: May 2007
Location: Manitoba, Canada
Posts: 5,877
iTrader Score: 1 reviews

Old School Oil Burners (Old SOBs) Member

Well, I'll give you a golf clap for that post!!!

Awesome Job!! Stuff like this is usually done in the dead of winter when we don't wana go outside and find other things to keep our selves busy at.

I will agree that washers are used but not the cheapo stuff, use grade 8 washers, the cheapo's will deform from the 6.X starter abuse.



__________________
90 Burb 1500 Silverado 4x4, 6.x in the shop, ATS Turbo on the bench . Open plenum intake. 700 R4 Now Rebuilt + 241, 10,000lb Trany Cooler With 10in pusher Fan and gauge. 8,000 LB Warn Multi Mount. TCC lock up control, 60 + 14b 4" Lift and 285 16's. ΜΟΛΩΝ ΛΑΒΕ
Quote:
Originally Posted by happypunch View Post
it would be nice if it could deflect a deer or a prius...
Quote:
Originally Posted by Livelli View Post
Mine ate about 6ft of paper towel once. It idled funny for a minute, then let out one big black firey fart and smoothed right out.
Quote:
Originally Posted by ManyStepsKY View Post
My being able to set at the computer and type is evidence that my wife has not cut off both my arms and used them to beat me into a coma, so no, I did not buy it!
Post up pics of your carnage!!!! and timing ....Click Here
To bleed or find an air leak, simply, here’s a few different ways..
https://www.dieselplace.com/forum/8492425-post11.html
https://www.dieselplace.com/forum/63...leak-6-2l.html
https://www.dieselplace.com/forum/63...ht-turn-3.html
Offline   Reply With Quote Quick reply to this message
Old 10-15-2017, 03:27 AM   #3 (permalink)
RatsMC
Diesel Boss
 
RatsMC's Avatar
 
Join Date: Nov 2015
Location: Oakland, CA
Posts: 1,299
iTrader Score: 0 reviews

Old School Oil Burners (Old SOBs) Member

Nice work. I just went through the washer/no washer ordeal and decided at the least, the seating of the bolt without the washer could not be uniform.
__________________
--
jerry

82 GMC K1500 6.2l

Banks Sidewinder Turbo
TH400 Transmission
Rebuilt 10 Bolt 3.42 Diffs
NP208
Electric Lift Pump relocated to the frame
Manual Glow Plug Set up
Offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 10-15-2017, 11:09 AM   #4 (permalink)
DieselPro
Diesel Guru
 
DieselPro's Avatar
 
Join Date: Mar 2004
Posts: 7,060
iTrader Score: 0 reviews

Never mentioned here >ARP starter bolts > http://arpcatalog.com/releases/ARPrelease_184.pdf
Offline   Reply With Quote Quick reply to this message
Old 10-15-2017, 08:27 PM   #5 (permalink)
DieselPro
Diesel Guru
 
DieselPro's Avatar
 
Join Date: Mar 2004
Posts: 7,060
iTrader Score: 0 reviews

Nice pic! Can you also show a pic of knurled protrusion through the starter housing and perhaps clearance between knurled part of bolt and the housing. My thinking is some of the worn housings are culprit to failure and some aftermarket housings may not be in spec. Perhaps the starter housing can be peened in to reduce starter hole clearance.
Offline   Reply With Quote Quick reply to this message
Old 10-15-2017, 10:25 PM   #6 (permalink)
roadhog0
Diesel Specialist
 
roadhog0's Avatar
 
Join Date: Dec 2011
Location: Washington
Posts: 3,488
iTrader Score: 1 reviews

Old School Oil Burners (Old SOBs) Member

Never seen ARP starter bolts before. Those are cool! Probably too hard for a 6.2 though. I figure they wont break.

I put the starter in the truck today, so I won't on that one, but I have a spare I will try to pull out and get pictures of the bolt in the starter with the knurling.

Also a funny side note. I went to put the starter in the truck today, grabbed the bolts and washers, and wouldn't you know it, the washers dont fit! I must have a starter that is machined different than OEM. So I dug around and got smaller OD washers that do fit....
__________________
-Nathan
1986 Chevy K20 6.2TD NV4500!! 4.10's (Name: POS Truck)
6.2 Turbo Diesel (HX40 CKO), 6.5 Serp, 6.5 Lift Pump, intercooler (to come), more broken or missing parts than you can shake a fist at, balls.
Offline   Reply With Quote Quick reply to this message
Old 10-15-2017, 11:17 PM   #7 (permalink)
joeq
Diesel Boss
 
joeq's Avatar
 
Join Date: Jun 2015
Location: Northern Ct
Posts: 1,202
iTrader Score: 0 reviews

Very thorough examination and explanation of your starter inventory Nate. But you neglected to touch on one note, that was explained to me, by not just you, but more than a few of our members. I was under the impression that...(let's see how I can explain this so it makes sense), where the knurling on the bolts terminates at the thread, there's a tapered "seat?", that is fitted to the block hole, where the threads begin. Know what I mean? (the knurl is wider than the bolt thread). "Theoretically", the washer kept this bolt seat(?), from seating into the block hole, causing a vertical gap, which was the reason for my bolts shearing. But that confuses me too, because you can't reliably have "2" pressure points on a bolt, IE the tapered seat at the knurling end, and also under the bolt head against the nose housing.
I do know that because of the light you guys have shed on this subject, I wasn't aware of how much penetration the knurl went into the block, until I measured it myself. I thank you for that. But now my worries will return to the reasoning for my continued bolt failures. I thought by removing those washers, I was eliminating the gap in the bolt hole. Now I'm not so sure.
__________________
Oil Burner
83 C-30 dually. Stock anemic N/A 6.2, SM465, 4.10s
93 2500 stake bed, stock J code 6.2, 4L80E, 3.73s

Last edited by joeq; 10-15-2017 at 11:19 PM.
Offline   Reply With Quote Quick reply to this message
Old 10-16-2017, 06:38 PM   #8 (permalink)
DieselPro
Diesel Guru
 
DieselPro's Avatar
 
Join Date: Mar 2004
Posts: 7,060
iTrader Score: 0 reviews

Quote:
Originally Posted by joeq View Post
But now my worries will return to the reasoning for my continued bolt failures. I thought by removing those washers, I was eliminating the gap in the bolt hole. Now I'm not so sure.
I would check the clearance between the bolt knurl and the starter housing hole. I imagine it should be somewhat tight.
Offline   Reply With Quote Quick reply to this message
Old 10-16-2017, 07:26 PM   #9 (permalink)
joeq
Diesel Boss
 
joeq's Avatar
 
Join Date: Jun 2015
Location: Northern Ct
Posts: 1,202
iTrader Score: 0 reviews

Already did DP. The knurl is tight in both the holes in the starter, and the block.
__________________
Oil Burner
83 C-30 dually. Stock anemic N/A 6.2, SM465, 4.10s
93 2500 stake bed, stock J code 6.2, 4L80E, 3.73s
Offline   Reply With Quote Quick reply to this message
Old 10-16-2017, 08:04 PM   #10 (permalink)
highdesertrange
Diesel Starter
 
Join Date: Aug 2013
Posts: 163
iTrader Score: 0 reviews

I got my starter bolts from real4WD. highdesertranger

Offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Diesel Place : Chevrolet and GMC Diesel Truck Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

PLEASE READ! You must check your email inbox for the confirmation link to complete registration. Please check your spam box if you do not see the email in your inbox.

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:
Insurance
Please select your insurance company (Optional)

Log-in


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
Starter Bolts joeq 6.2L Diesel Engine 16 10-10-2017 11:46 PM
Starter bracket bolts AmomentsLife 6.2L Diesel Engine 3 09-27-2017 10:28 PM
K5 Blazer Starter Install Problem 65creedmoor 6.2L Diesel Engine 15 08-02-2016 04:32 PM
Starter bolts broken - how to get ends out? dseal1983 6.2L Diesel Engine 10 01-08-2016 07:02 PM
Starter Jam up from flywheel bolts?? Redheadsoxfan5 6.5L Diesel Engine 12 10-19-2015 11:49 AM


All times are GMT -4. The time now is 07:34 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Shoutbox provided by vBShout v6.2.1 (Lite) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd. Runs best on HiVelocity Hosting.
© AutoGuide