grade 8 allthread in motor mounts? - 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> General Rodding Tech
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 09-05-2011, 05:59 PM
Member
 
Last wiki edit: Ford axle ratio codes
Last journal entry: Rear Suspension
Last photo:
Join Date: Aug 2005
Location: Prattsville
Posts: 6,387
Wiki Edits: 31

Thanks: 2
Thanked 57 Times in 53 Posts
grade 8 allthread in motor mounts?

Went to the nearest open hardware yesterday ( sunday ) to get grade 5 or 8 7/16"-14 bolts for my custom motor mounts, to hold the 2 1/2's togther. being that they needed to be 6" long, and they didn't have any. I ended up with some allthread and a couple nuts. I figured this stuff was good enough for mock up purposes.. As it turns out, due to the orientation to the frame mount 1/2 not being flipped like the actual engine mounts are ( 1 left, 1 right ), the nut insert on it ( inner plate ) has to thread thru it on 1 side, and thus the bolt would have to be fully threadded, and seems like a hard thing to find.. Didn't think grade 8 allthread existed, but I searched and it does.. Is grade 8 allthread as strong as a grade 8 bolt?

if anyone is wondering. The mounts are correct for a 1975 Ford Elite or Lincoln Continental, and the lower 1/2's are the top plate to a 1974 Plymouth barracuda mount. The spacer is a 3/8"x1 1/2" pipe nipple, which puts the engine at 1 1/2" setback. This could be adjusted any way with different spacers. The allthread needs trimmed, but being it's just the mock up allthread/ bolt, I wasn't worried, and just cut it as close as I could with the small chop saw



    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 09-05-2011, 06:09 PM
35terraplane's Avatar
Registered User
 
Last photo:
Join Date: Sep 2010
Location: MN, ON THE DARK SIDE OF THE MOON
Age: 70
Posts: 1,325
Wiki Edits: 0

Thanks: 2
Thanked 60 Times in 51 Posts
grade 8 thread

Quote:
Originally Posted by matt167
Went to the nearest open hardware yesterday ( sunday ) to get grade 5 or 8 7/16"-14 bolts for my custom motor mounts, to hold the 2 1/2's togther. being that they needed to be 6" long, and they didn't have any. I ended up with some allthread and a couple nuts. I figured this stuff was good enough for mock up purposes.. As it turns out, due to the orientation to the frame mount 1/2 not being flipped like the actual engine mounts are ( 1 left, 1 right ), the nut insert on it ( inner plate ) has to thread thru it on 1 side, and thus the bolt would have to be fully threadded, and seems like a hard thing to find.. Didn't think grade 8 allthread existed, but I searched and it does.. Is grade 8 allthread as strong as a grade 8 bolt?

if anyone is wondering. The mounts are correct for a 1975 Ford Elite or Lincoln Continental, and the lower 1/2's are the top plate to a 1974 Plymouth barracuda mount. The spacer is a 3/8"x1 1/2" pipe nipple, which puts the engine at 1 1/2" setback. This could be adjusted any way with different spacers. The allthread needs trimmed, but being it's just the mock up allthread/ bolt, I wasn't worried, and just cut it as close as I could with the small chop saw


Matt grade 8 threaded all the way is just as strong, they are rolled threads that is a much stronger thread than a cut thread, also that is how they get up to the head.
With a rolled thread you remove no metal just move it around, cut threads of course you remove metal.

Bob
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 09-05-2011, 07:34 PM
MRTS33's Avatar
33 Pontiac 3W Sport Coupe
 
Join Date: Aug 2010
Location: Albany, NY
Posts: 117
Wiki Edits: 0

Thanks: 1
Thanked 2 Times in 2 Posts
I have little experience with Ford and even less with Mopar motor mounts. It looks to me that those motor mounts aren't going to take to much torque to snap that bolt. I think I'd look for a better setup. Please correct me if I'm wrong.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 09-05-2011, 08:01 PM
Member
 
Last wiki edit: Ford axle ratio codes
Last journal entry: Rear Suspension
Last photo:
Join Date: Aug 2005
Location: Prattsville
Posts: 6,387
Wiki Edits: 31

Thanks: 2
Thanked 57 Times in 53 Posts
It shouldn't be any weaker than the setup the Lincoln it came out of had, which used the same engine mounts. The only diffrence is the mount sat over top of a saddle with a locator pin. I don't see it snapping a grade 8 bolt, altho I could weld a thick steel washer to each side of the mopar mount, so it doesn't rip out the metal, just to be sure.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 09-06-2011, 02:29 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 55
Posts: 13,200
Wiki Edits: 0

Thanks: 1,336
Thanked 1,167 Times in 1,029 Posts
That is WAY wrong, it WILL break. The mount ears need to be next to one an other. With that one floating out in space it WILL break or at least bend that bolt. Grade 8 means nothing when you have those forces, zero grade garden gate bolts would hold just as good.

Correct the design and don't try to make up for what you have with "stronger" bolts.

Brian
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 09-06-2011, 03:02 PM
da34guy's Avatar
Registered User
 
Last photo:
Join Date: Sep 2008
Location: Bumfork, OK
Posts: 481
Wiki Edits: 0

Thanks: 21
Thanked 36 Times in 33 Posts
4 words ---
THAT AIN"T GONNA WORK !!!!!!!!!!!!
Sumthin Mickey Mouse would do.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 09-06-2011, 03:05 PM
Member
 
Last wiki edit: Ford axle ratio codes
Last journal entry: Rear Suspension
Last photo:
Join Date: Aug 2005
Location: Prattsville
Posts: 6,387
Wiki Edits: 31

Thanks: 2
Thanked 57 Times in 53 Posts
I was just looking at/ going by the listed bolt strengths. But I see what your saying, and after thinking about it, I would tend to agree.. I'm thinking, if weld the spacers to the inside plate, then it would eliminate the load forces on the bolt. Or I could get another set of the 460 mounts, and seperate them from the rubber and use those for the bottom plates. that would put both ears side by side, and probably work best... I have the mount towers for the 4cyl, which I was hoping I could get the engine to bolt onto them and into the chassis. I might fabricate a saddle on the towers, just like the lincoln had
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 09-06-2011, 03:23 PM
Member
 
Last wiki edit: Ford axle ratio codes
Last journal entry: Rear Suspension
Last photo:
Join Date: Aug 2005
Location: Prattsville
Posts: 6,387
Wiki Edits: 31

Thanks: 2
Thanked 57 Times in 53 Posts
Quote:
Originally Posted by da34guy
4 words ---
THAT AIN"T GONNA WORK !!!!!!!!!!!!
Sumthin Mickey Mouse would do.
Lol yea. I'll figure somthing out tho. The Mopar mounts were $6/ each so it's no big deal to chuck them. make good brackets for somthing or other anyway.. I was trying to do it cheap. but cheap and good doesn't always work out
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 09-06-2011, 03:35 PM
da34guy's Avatar
Registered User
 
Last photo:
Join Date: Sep 2008
Location: Bumfork, OK
Posts: 481
Wiki Edits: 0

Thanks: 21
Thanked 36 Times in 33 Posts
Now yer thinkin right.
Leave the MM stuff to Disneyland
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 09-06-2011, 03:37 PM
Member
 
Last photo:
Join Date: Jan 2003
Location: tennessee
Posts: 5,912
Wiki Edits: 0

Thanks: 0
Thanked 7 Times in 7 Posts
Quote:
Originally Posted by 35terraplane
grade 8 threaded all the way is just as strong, they are rolled threads that is a much stronger thread than a cut thread,Bob


True and an often misunderstood factor. I think extending the thread by cutting on a lathe or with a thread die loses about 20% to, in some cases, as much 30% in strength as opposed to the correct rolled threads. Basically if a thread die is used to extend the threads on a grade 8 bolt shank it can no longer be considered as a grade 8.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 09-06-2011, 03:52 PM
boatbob2
 
Join Date: Dec 2005
Location: north florida
Age: 76
Posts: 1,374
Wiki Edits: 0

Thanks: 6
Thanked 24 Times in 21 Posts
grade 8 bolts.

Hi,basically what everyone is trying to tell you is,the 2 motor mounts (engine half,and chassis half) need to fit inside each other,then the bolt holds the 2 halves together,,, thats the way the factory designed them,dont try to re-invent the wheel.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 09-08-2011, 04:16 PM
Member
 
Last wiki edit: Ford axle ratio codes
Last journal entry: Rear Suspension
Last photo:
Join Date: Aug 2005
Location: Prattsville
Posts: 6,387
Wiki Edits: 31

Thanks: 2
Thanked 57 Times in 53 Posts
Ok, trying to find somthing else to work.. I thought about splitting the Mopar mounts in the center and making them wider. It could work but would need fish plated to retain the strength, and by the time I got done splitting and welding, I could have just fabbed somthing.. I don't want to use another set of 460 car mounts and try to cook them, as I'm only 50% sure they would work once I seperated the 'hoop/ear' half from the engine mount 1/2. There a bit too expensive for a 50% chance at $30/ each just about everywhere.

If I bend a bracket out of steel stock, what is a good way to keep the holes equal when drilling both sides equal? my drill bits are not that long.. Otherwise is it kosher to weld the right size mount tab to a base plate cut to the right width?
Reply With Quote Quick reply to this message

Recent General Rodding Tech 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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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
Grade 8 bolt with grade 8 washers STUDE55DOG Engine 11 07-11-2011 06:21 PM
S10 V8 Motor Mounts callmej75 Engine 9 04-09-2011 02:43 PM
MOTOR MOUNTS (Engine Mounts) PackMule General Rodding Tech 2 08-28-2009 09:52 AM
motor mounts mayday3045 Engine 4 04-19-2006 11:15 PM
Motor Mounts MHenricks Engine 4 10-10-2002 06:42 AM


All times are GMT -6. The time now is 10:05 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.