A65 Spark Plug Bushings

[gusc]

Today I screwed out a bottom plug and knew it didn't feel right. I had screwed out the plug along with a copper bushing of a type I have never seen before. I've seen aluminum ones for autos but this it the first copper one I ever saw?

There is a log entry in '05 for replacement of two bushings, p/n 2002. My AI had never seen these either so I decided to ask the experts.

Where do I find a new one? It is pretty obvious that I can't remove the plug from the bushing without destroying the bushing and I'll need some new ones for spares. I suppose I could reinsert the bushing and plug together but it will have to come out eventually.

I can't tell what holds them in the cyl. There are some very small spots which indicate maybe some type of staking but the spots look too small for that. So, I assume they are held in by some type of thread locker?

Tell me about these things!

[Paul Agaliotis]

Gus,
Fresno Airparts has them listed but the last time I tried to order they were out of stock. They also come in oversize if required.
The inserts are pinned in the cylinder with a brass pin. The overhaul manual has the proceedure.
Paul

[joea]

Gus,

Have had that happen to me one time. Got an oversized bushing and put it back in and it held.

Look around and see if you can find one.

Joe

[Mnflyer]

Hi Gus its happened to me several times when doing annuals never a happy moment , as Paul posted they are screwed in tight and locked with a brass pin like a piece of brazing rod. If you can get them the best is to go over sized as Joe posted, I have gotten them off of the spark plug by putting the plug in a vice and heating the bushing a using a pipe wrench on the collar of the bushing. That is why it is extremely important to use anti-seize on the plug threads and to torque the plugs properly. I never ever install plugs with out anti-seize and a torque wrench even when I'm in a hurry. The newer cylinders with the SS helicoil insert are not as critical for needing anti-seize but even with them sooner or later the time will come when one will wish anti-seize had been used.

[gusc]

Thanks guys, I knew you would come through.

Those small spots I saw must be the tops of the brass pins? I don't have the bottom cowl off so didn't look at the cyl yet. The pins are so small it is no surprise they sheared.

Questions; how do I know what oversize to order or is there only one?

Can locktite be used?

How are bushings torqued into the cyl, there is very little space on the bushing or at the cyl hole for tools. Don't tell me, it is a special, expensive tool!!

I thought about the vise-heat method but the bushing is so soft it must be very difficult to keep from distorting it?

Obviously once a bushing is used there is no choice but to keep using them.

Amen, to anti-seize but it is too late for this case.

Didn't think to look at my OH Manual because I assumed it was something new since my AI had never seen one.

[Paul Agaliotis]

Gus,
The insert should go in a couple of threads and start to tighten. If this is the case the size of the insert is correct. The head should be heated for installation and lock tite is good to use. The sleeve lock works well here ( its green). You can make an installation tool using a 18MM bolt and a jamb nut. Be sure to pin the insert after installation it needs to be pinned.
Paul

[joea]

As Paul says but you also might put the bushing in between two pieces of dry ice for a couple of hours. Chill the bushing, and heat the head and it usually will screw in just fine. Then when the temps normalize the head will shrink and bushing grows a bit and both bits should stay together.

Also chill the socket you will be using to install the bushing so it does not heat the bushing up while installing it. Just make sure you use gloves when picking everything up.

Rest of everyone's comments are spot on as per my little experience.

[Ron Babos]

gusc: These things can be a pain or go in good. A few years ago I had to weld up a head and retap for the spark plug bushing. I purchased two .009 over inserts, because it's all I could get. No friggin way to get these into a standard hole. Had a special tap made up at .009 over. Wasn't cheap but, a lot cheaper than pulling a cylinder and having someone else do it.

Even with a freshly tapped hole the insert will have some drag on it when it's torqued in. I just use a spark plug for the insertion tool and coat the bushing threads with 680 Loctite.

If you heat the head first you may not get it in before the Loctite sets. Dry ice for the bushing is best, or at least the freezer. Torque to 30 ft. pounds and wait 10 minutes and then remove the plug. Drill for the retaining pin and Loctite it in as well. Carefully level the slightly longer pin down to the face of the bushing and you're done. Use a drill stop for depth and make sure you drill in the thread area like the original. If you get rammy and drill too far and into the combustion chamber, I have a fix for that too

You are fortunate that it came out that easy in the first place. Most of the time the plug threads are stripped out. Then you have to tap over size and loctite a larger bolt in there for the extraction tool after drilling the pin out.

Ron

[gusc]

Thanks again guys, now we're getting down to details;

I tried to screw it back by hand and it didn't go in very far before it got tight so that sounds good. It had a bunch of black unhardned goop on it, don't know if it was oil or some kind of sealer.

What is green sleeve lock?

How far in does the pin go?

What do you use for the pin?

The bushing appears to be copper or bronze, can't tell for sure?

This will be an interesting experience!!

[joea]

Gus,

What do you think this is, an informational forum just giving out information out for free??? Suppose you want us to stop by next weekend and help??!! Truthfully if I was closer would love to come and lend a hand. Grew up in the Ozarks and its a nice part of the country.

Those of us who are over 30 or so can remember what it was like in the "old days" when there was no internet. These days you post something on the net and receive a reply in minutes or an hour or two, versus sending a letter off (if it was not too important) and waiting several weeks for the reply or picking up the phone calling, thus financing MaBell's next retirement project for the bosses and costing you an arm and a leg.

Was the goo on the bushing like carbon that could have come from the combustion process or more like a sealing material? If it was difficult to screw back in the jug then you may have lucked out.

One thing, someone suggested screwing it back in using an old spark plug. You might try taking an old spark plug and knocking or drilling the guts out of it then using it to install the new bushing. Have heard that using a hollowed out version that the "installation plug" is easier to remove after screwing the bushing into the jug.

Joe

[Ron Babos]

Thanks again guys, now we're getting down to details;

I tried to screw it back by hand and it didn't go in very far before it got tight so that sounds good. It had a bunch of black unhardned goop on it, don't know if it was oil or some kind of sealer.

What is green sleeve lock?

How far in does the pin go?

What do you use for the pin?

The bushing appears to be copper or bronze, can't tell for sure?

This will be an interesting experience!!

gusc:If you plan on using the same insert clean the threads off in the area of the bushing where the pin hole is. It there are burs in this area the insert will act like a tap and chew the threads up in the head more than they already are. The shavings could jam it, and then you will bi in deep poop. A light touch with a fine file will do it. Did you remove the part of the pin that was left in the head? 680 Loctite is green and is used for sleeves , bearings and so on. If you clean the threads inside the head and the bushing a pin is nothing more than a secondary retention device. That mother will never come out without a good torch to burn the Loctite out. Normal head temps wont fizz on it. It will create a totally leak proof seaal as well.The pin is 1/8 brazing rod and only needs to be about 3/16" into the aluminum of the head. The bushing is bronze, as copper is too soft to do the job. It closely matches the expansion rates of the aluminum when the engine heats and cools.
Ron

[Mikek]

There is a log entry in '05 for replacement of two bushings, p/n 2002. My AI had never seen these either so I decided to ask the experts.

Tell me about these things!

Gusc, do not forget to share this info you are getting with your AI.

Mikek

[Tugaske2]

Preferred airparts have several 1000 of these inserts(NOS)..standard size and several oversizes...about $15 each if I remember right..

[gusc]

Again, thanks to all. Yeah, this net is a wonderful thing. I resisted a computer for years but finally broke down and now don't know what I would do without it! I was planning to to dazzle my AI with my newfound knowledge of bushings next time I see him!

Good thing I didn't try to screw it back in before cleaning the threads. I don't think I got it in one thread, was just trying to close up the cyl.

From what all of you have told me I'm not sure the pin is worth the effort to replace since it didn't hold this time. I'm really tempted to just go with the Loctite. It seems to me that the chance of hitting the exact pin spot is almost impossible anyway so I just assumed I would have to drill
another hole?


The stuff on the threads was dark sticky stuff, I think it might be non-hardening gasket sealer! I don't think it was loose until I tried to remove the plug because it sure didn't come out easily.

I'm in the boonies of the Ozarks, neither of my nearby airports even has a maintenance operation but I'll find some bushings somewhere.

Ron, thanks for all the details, that's what I like, details!

[Ron Babos]

gusc: I would use the pin, even if it's wimpy . Definition of repair (as good as or better than original) Normal procedure is to drill a new hole. I've seen these heads with so many holes in them, there is practically no threads left in the aluminum. The original first time pin is usually at 12 oclock, or towards the tappet cover.
Ron