Author |
Message |
![Top of page](http://au.rrforums.net/forum/icons/mark_top.gif) ![Previous message](http://au.rrforums.net/forum/icons/mark_up.gif) ![Next message](http://au.rrforums.net/forum/icons/mark_down.gif) ![Link to this message](http://au.rrforums.net/forum/icons/tree_m.gif)
Mark Aldridge
Frequent User Username: mark_aldridge
Post Number: 871 Registered: 10-2008
| Posted on Saturday, 25 May, 2024 - 08:35: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
What thread is the exhaust manifold to block stud thread. I have a new manifold to replace mine which has cracked and it seems that I will have to slit the nuts to remove them. I will then have to run a die nut up the threads. To access the nuts it appears I will have to cut the manifold up in situ.The nuts do not wish to turn ! Thanks |
![Top of page](http://au.rrforums.net/forum/icons/mark_top.gif) ![Previous message](http://au.rrforums.net/forum/icons/mark_up.gif) ![Next message](http://au.rrforums.net/forum/icons/mark_down.gif) ![Link to this message](http://au.rrforums.net/forum/icons/tree_m.gif)
Jason Watson
Experienced User Username: crikeydawn
Post Number: 162 Registered: 07-2023
| Posted on Saturday, 25 May, 2024 - 10:02: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Have you tried putting diesel on the nuts, or studs into the block. Let it sit for a day, then try and turn with a well fitting socket. If no movement re apply diesel, wait another day. Repeat until success. I now it sounds dumb, but it can tae up to a couple weeks. |
![Top of page](http://au.rrforums.net/forum/icons/mark_top.gif) ![Previous message](http://au.rrforums.net/forum/icons/mark_up.gif) ![Next message](http://au.rrforums.net/forum/icons/mark_down.gif) ![Link to this message](http://au.rrforums.net/forum/icons/tree_m.gif)
Jeff Martin
Frequent User Username: jeff_r_1
Post Number: 640 Registered: 07-2018
| Posted on Saturday, 25 May, 2024 - 10:15: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Oxy/Acetylene torch always works. Heat one nut a time until it just starts to turn orange, try to move it at this point. If it wants to budge, even a little, don't keep reefing on it, let cool completely with your favourite penetrating oil. Once it's completely cooled, it should come right off. Repeat as necessary. I use lots of layers of aluminum foil to protect surrounding areas with the torch. The car should be standard SAE, to answer your question, so 1/4 inch is either 20 or 28 tpi. for course and fine. And 5/16 is 18 or 24 tpi. Probably fine thread. It will be either 1/4 or 5/16 inches. Use stainless nuts, not brass. I find brass nuts swell too much under manifold heat, and I have to be constantly snugging them up when things cool down. |
![Top of page](http://au.rrforums.net/forum/icons/mark_top.gif) ![Previous message](http://au.rrforums.net/forum/icons/mark_up.gif) ![Next message](http://au.rrforums.net/forum/icons/mark_down.gif) ![Link to this message](http://au.rrforums.net/forum/icons/tree_m.gif)
ChristopherCarnley
Unregistered guest Posted From: 3.8.155.170
| Posted on Saturday, 25 May, 2024 - 19:23: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
They are UNF threads.
(Message approved by david_gore) |
![Top of page](http://au.rrforums.net/forum/icons/mark_top.gif) ![Previous message](http://au.rrforums.net/forum/icons/mark_up.gif) ![Next message](http://au.rrforums.net/forum/icons/mark_down.gif) ![Link to this message](http://au.rrforums.net/forum/icons/tree_m.gif)
Mark Aldridge
Frequent User Username: mark_aldridge
Post Number: 872 Registered: 10-2008
| Posted on Monday, 27 May, 2024 - 06:39: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Thanks all, I will try heating and soaking with atf/acetone mix and diesel and see if they will turn. Would certainly be better than slitting the nuts. I have UNF die nuts to clean up the threads and will fit new nuts. |
![Top of page](http://au.rrforums.net/forum/icons/mark_top.gif) ![Previous message](http://au.rrforums.net/forum/icons/mark_up.gif) ![Next message](http://au.rrforums.net/forum/icons/mark_down.gif) ![Link to this message](http://au.rrforums.net/forum/icons/tree_m.gif)
Jason Watson
Experienced User Username: crikeydawn
Post Number: 164 Registered: 07-2023
| Posted on Monday, 27 May, 2024 - 16:45: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Mark, at it would have it I was looking for some suspension bolts today and found these. If you can make sense of the note well done. They are definitely fine thread both ends. Think others have covered it but will report back tomorrow with what sized threads they are. exhaust manifold studs for 4.9 Long is 68mm Med is 59mm Short is 51.5mm
![](http://au.rrforums.net/forum/messages/17000/45148.jpg) |
![Top of page](http://au.rrforums.net/forum/icons/mark_top.gif) ![Previous message](http://au.rrforums.net/forum/icons/mark_up.gif) ![Next message](http://au.rrforums.net/forum/icons/mark_down.gif) ![Link to this message](http://au.rrforums.net/forum/icons/tree_m.gif)
Robert J. Sprauer
Frequent User Username: wraithman
Post Number: 853 Registered: 11-2017
| Posted on Tuesday, 28 May, 2024 - 00:01: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
When exhaust manifold nuts are tightened beyond the suggested torque, they inhibit the expansion of the cast iron. Once this happens the cast iron cannot expand and often results in cracks. Exhaust manifolds usually have elongated holes and torqued to a low figure. A heavy hand is not in not needed. A micro torch will eventually break the bond with ATF/acetone mix. Give it time and constantly check. |
![Top of page](http://au.rrforums.net/forum/icons/mark_top.gif) ![Previous message](http://au.rrforums.net/forum/icons/mark_up.gif) ![Next message](http://au.rrforums.net/forum/icons/mark_down.gif) ![Link to this message](http://au.rrforums.net/forum/icons/tree_m.gif)
Jason Watson
Experienced User Username: crikeydawn
Post Number: 166 Registered: 07-2023
| Posted on Tuesday, 28 May, 2024 - 11:05: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
studs are 5/16, 24 thread, UNF |
![Top of page](http://au.rrforums.net/forum/icons/mark_top.gif) ![Previous message](http://au.rrforums.net/forum/icons/mark_up.gif) ![Next message](http://au.rrforums.net/forum/icons/mark_down.gif) ![Link to this message](http://au.rrforums.net/forum/icons/tree_m.gif)
NormanGeeson
Unregistered guest Posted From: 81.98.117.162
| Posted on Tuesday, 04 June, 2024 - 00:28: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Jason Now all you need are the correct bronze nuts to fit.
(Message approved by david_gore) |