As I work through my 71 Pre-HE V-12, I’ve been tying to make sure that it is assembled properly and that it look good.
A local shop put the heads through their cleaning tank and I need to get some scale off of them. It shouldn’t be there, but that’s neither here nor there. Looking at the plugs in the head, they look like crap. I measured them at 3/4" and 1 3/8". That is the same that SNG shows them.
Has anyone gotten any from their local car parts places?
Any tricks or best sealants to use when reassembling them?
Dorman makes some brass plugs that are readily available. I always like to get a bit of a sanity check prior to doing something related the the engine. Oftentimes, someone has had a good or bad experience one way or another.
It often is good to tank the head with all core plugs removed, giving better access to removing unwanted built up material and further inspection capability. Brass plugs can cost more than some steel plugs, I favor Dorman brass plugs, https://www.dormanproducts.com/c-238-concave-expansion-plugs.aspx . Installation directions for common applications are at http://www.hubbardspring.com/index.php since Hubbard has been in this business since about the beginning.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
6
I’d like to hear opinions on sealants. It would seem that Loctite 518 would be ideal, but perhaps it might cause the plug to pop out too easily? Are the installation instructions different for whacking these things into an aluminum block than a cast iron block? What kinda prep work do you need to do to the hole before installing?
I’ve not removed the old ones yet to see if they had any sealant behind them. In most cases, they are just a press fit. Myself, I’d be prone to put some kind of sealant around the lip in the head to ensure that any light gaps would be sealed.I’m going to pick up some Dorman brass ones today from one of our local parts houses. I’m still waiting on some other parts to finish off the heads so I’ve got plenty of time. AND other engine parts to get cleaned and installed.
I got home tonight and had some time on my hands so I went about pulling the old plugs. EGAD what a PITA. On most engines, you can tap one side in and they rotate and can be pulled right out.
I believe that Kibert is right that bars leak was used at some point in the past as there was a brown residue around the periphery of the plugs. I will certainly be sealing them in place with something. I know that 518 is one of the preferred options, but I might go with something with a little more adhesion. I would hate for any of these to pop out if the temp and pressure got too hat.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
9
I haven’t played with a lot of freeze plugs, but I didn’t think punching one side in was a recommended removal procedure. There’s supposed to be a step behind it, so punching one side would presumably mess up that step.
Anyone know the actual recommended removal procedure? I can think of two ways that might work. One would be to use a hammer and drift to dish the center in, which should make them loose and they’ll either fall out or you could get them out with a magnet. The other idea would be to drill a hole in the center and screw in a self-tapping screw and use it to pull it out.
If you watch the youtube videos, when they punch them in on one side, they rotate and can be easily removed.
On the intake side of the block, the one with 4 plugs, there was a ledge behind them, but on the exhaust side, the one with 3 plugs, there was no ledge. I did manage to get one of those knocked into the head, but fished it out fairly easily.
What I expected to be an easy task turned into one that tested my patience. A lag bolt screwed into the middle didn’t work well. With the small ones, I eventually drilled 2 holes into them and cut the metal between the holes. This relieved side pressure and gave me a leverage point to lift them out of the cavity.
One of the local auto stores has Dorman plugs coming today, so I’ll get them buttoned back up this evening.
It has been a lot of effort just to make something look better.
The first 2 plugs, I used a punch to make a hole and used a large diameter lag bolt to get some bite in order to pry it out. Didn’t go well. But… They are out and new shiny brass will go back in later today.