|
Author |
Message |
Miken
Joined: 24 Dec 2012 Posts: 544
|
Posted: Tue May 16, 2017 9:53 pm Post subject: cylinder head studs |
|
|
Thoughts please;
When fitting cylinder head studs to an iron cylinder block, some of the threaded holes in the block break into the water gallery.
So, something is required on the threads of the studs to both seal the water in and prevent the studs rusting to the block in case they ever have to be removed again.
Could use ordinary mineral grease, silicon grease, copper grease, Hylomar gasket goo (or similar), loctite hydraulic thread sealant (easily dismantles).
But maybe not silicone sealant as acetic acid can cause corrosion.
Discuss.
Mike |
|
Back to top |
|
|
billysugga
Joined: 01 Jan 2017 Posts: 55 Location: Carlisle
|
Posted: Wed May 17, 2017 6:54 am Post subject: |
|
|
I Went with loctite on mine but I haven't ran it more than in the garage. Loctite breaks down at high temperature but that is very high normally. We used to use it on steam pipes so I think it should be ok. _________________ Volvo Sugga ,Volvo Trygge
I just wish one was working! |
|
Back to top |
|
|
Kenham
Joined: 12 Mar 2012 Posts: 209 Location: Kent
|
Posted: Wed May 17, 2017 9:10 am Post subject: |
|
|
Is it the bottom of the stud that goes into the gallery or down the side of the thread? Side valve or overhead? |
|
Back to top |
|
|
MikeG
Joined: 16 Sep 2013 Posts: 56 Location: Cheshire/Staffordshire Border
|
Posted: Wed May 17, 2017 9:35 am Post subject: |
|
|
My Engine restorer used PTFE tape on the studs.
Hope this helps
Mike |
|
Back to top |
|
|
Kleftiwallah
Joined: 27 Oct 2016 Posts: 222 Location: North Wiltshire
|
Posted: Wed May 17, 2017 12:51 pm Post subject: |
|
|
And to follow the P.T.F.E. idea, how about Boss white and hemp as used by plumbers of yore?
Cheers, Tony. |
|
Back to top |
|
|
Miken
Joined: 24 Dec 2012 Posts: 544
|
Posted: Wed May 17, 2017 3:30 pm Post subject: |
|
|
Kenham wrote: | Is it the bottom of the stud that goes into the gallery or down the side of the thread? Side valve or overhead? |
All interesting suggestions, thanks.
Kenham, it is the bottom end of the thread and a SV engine. |
|
Back to top |
|
|
colwyn500
Joined: 21 Oct 2012 Posts: 1745 Location: Nairn, Scotland
|
Posted: Wed May 17, 2017 4:07 pm Post subject: |
|
|
Clean the threads in the block and the stud really well with a good solvent such as panel-wipe and then use stud-grade Loctite or similar.
All the other suggestions may work for a time but aren't designed with that specific purpose in mind; and as far as I know, none of them have the added benefits of the Loctite in resisting the stud loosening and in helping to transfer the torque more evenly throughout the threads. |
|
Back to top |
|
|
alastairq
Joined: 14 Oct 2016 Posts: 1954 Location: East Yorkshire
|
Posted: Wed May 17, 2017 5:23 pm Post subject: |
|
|
What was used originally? {Assuming an ancient engine?] |
|
Back to top |
|
|
colwyn500
Joined: 21 Oct 2012 Posts: 1745 Location: Nairn, Scotland
|
Posted: Wed May 17, 2017 6:42 pm Post subject: |
|
|
alastairq wrote: | What was used originally? {Assuming an ancient engine?] |
The original idea was that the studs had a slight tapered waist where the threads stopped. This "chamfer" would create an interference fit when the stud was torqued into the block. Therefore no precaution was taken to seal the threads against moisture. This creates the nightmare that many people face when the studs are eventually attemped to be removed.
Last edited by colwyn500 on Thu May 18, 2017 12:41 pm; edited 1 time in total |
|
Back to top |
|
|
Farmer John
Joined: 18 Feb 2010 Posts: 181 Location: Manawatu NZ
|
Posted: Thu May 18, 2017 2:29 am Post subject: Head studs. |
|
|
Hi Mike. You are right to be concerned, but the proper Loctite will take care of movement and sealing. There are makes of block where the top surface is swollen around the head studs from repeated or over tightening of the studs. (Some top plates are pretty thin in places.)
Get both threads perfectly clean and screw them in until only just tight, the Loctite will keep them there.
The matter of corrosion of the end of the stud should be taken care of by using coolant from somewhere they supply industrial or heavy vehicles. Buy the best they have, so many worries about classic engines just vanish when you use top quality coolant.
John |
|
Back to top |
|
|
MikeEdwards
Joined: 25 May 2011 Posts: 2470 Location: South Cheshire
|
Posted: Thu May 18, 2017 10:38 am Post subject: |
|
|
I'm sure you all know, but keep in mind there is Loctite and there is Loctite. I have a bottle of Loctite that I bought because I thought it was a bargain. Fortunately - and due to a conversation I was having with a mate who bought a Jaguar XK8 project car and found suspension bolts that are fixed using the same stuff - I noticed before I used it that the specific one I had bought is described as a "permanent" lock, not just the usual medium strength that I intended. I forget exactly what is required to undo it, but it's quite extreme.
Like I said, I'm sure that isn't news to you. |
|
Back to top |
|
|
Ray White
Joined: 02 Dec 2014 Posts: 6314 Location: Derby
|
Posted: Thu May 18, 2017 11:39 am Post subject: |
|
|
I am with Colwyn 500 on this; 100%. I was recently advised by the engineer who has been working on my Dodge engine that a couple of the studs in the block have pushed through into the water jacket. He recommended Loctite.
The PTFE tape also works. My Dad was the engineer who built the first PTFE tape making machines and used it extensively over the years but when Loctite began being used in industry he also went over to it. |
|
Back to top |
|
|
Miken
Joined: 24 Dec 2012 Posts: 544
|
Posted: Thu May 18, 2017 4:07 pm Post subject: |
|
|
OK, So i've done a bit of an experiment today.
I tapped a thread in a bit of cast iron bar .
Degreased a high tensile bolt and wound it in by hand with some Loctite 270 threadlocker which the manufacturer produce for "the securing AND sealing of bolts , nuts and studs".
Which sounds just the job.
After 8 hours I attempted to dismantle it with a socket spanner.
After fitting a long tube extension I merely succeeded in shearing the bolt off.
So I wont be using this as i may want to dismantle it again and i wont want to heat it up to 300deg.C to break the bond.
|
|
Back to top |
|
|
Ray White
Joined: 02 Dec 2014 Posts: 6314 Location: Derby
|
Posted: Thu May 18, 2017 4:16 pm Post subject: |
|
|
If you want to be able to get it apart again then maybe PTFE tape would be your best option. |
|
Back to top |
|
|
Kenham
Joined: 12 Mar 2012 Posts: 209 Location: Kent
|
Posted: Thu May 18, 2017 6:22 pm Post subject: |
|
|
I think I would do what they did when they built the car, put a bit of grease on it. PTFE would be good, Its lasted many years without such stuff as Loctite and if it were mine it would do many more. No great pressure in the system so just a bit of copper grease so the studs will undo later. |
|
Back to top |
|
|
|