Keep up the good work Silber ,New ideas are great for all .
An idea , if you want the pressure in the ims tube to equalize either negative or positive, with the pressure on the other side of the bearing , just punch a SMALL hole in the sealing cap inside the hex drive at the oil pump end of the shaft . This is what the EPS folk suggest as an oil feed for their roller bearing conversion , although they do groove the hex drive as well. General leakage will take care of the equalization which is what you want
Peter

I really like the freeze plug idea. Don't know ok if the pressures work out but it sounds like a cost effective way around the problem. Also gets around the problem of having an open bearing.

Markus, your posts are always so exceptionally helpful, thank you for all your input on this!

14.4 psi is almost ideal for a freeze plug. Automotive cooling systems usually are designed to operate at a pressure of between 14 and 15 psi. Freeze plugs are designed to stay put and hold pressure in this application, I would assume there is a wide margin of safety, but will be testing to make sure.

I still plan to do some research to find out what the previous retrofit was that used one and what happened with peoples engines.

Silber

But freeze plugs are hammered in to a cast iron block usually. Very different from a flimsy sheet metal IMS tube

Here's some photographic proof that it's been done before, the ones that did it was a company called Casper.

http://986forum.com/forums/526229-post29.html

IMS solution uses a plug is well, I hear it is patented, but I'm not sure that that would hold up if it's just freeze plug, as it was done before by Casper.

Regards,

Silber

But, that tube is supported by the sprocket casting where are you are driving into it, so essentially you're driving into a casting. The tube will do nothing but be an intermediate layer between the casting and the freeze plug it will not have to support any load.

As soon as I find a dead intermediate shaft I will be testing this.

Silber

It is patented, and is not a freeze plug. And the "Casper" system was a failure....

It would be a lot more helpful to say why it was a failure.

This sample calculation was done by using 1 litre as the inner volume of the tube and a max. temperature of 200 degrees Celsius. As said, the volume will be higher. So measure an IMS tube and recalculate. I suspect the pressure will be much higher than 14,4 PSI, because i think the inner volume of the IMS tube higher.

Besides that in a crankcase you have a negative pressure, but in an closed IMS tube you have positive pressure – as said before.

So the freeze plug handles negative pressure, not positive pressure. So to say it isn't pressed to the outside, it is sucked in. ;)

And if you have 14 psi negative pressure in a crankcase and you have 14 psi positive pressure in the IMS tube, the pressure difference is 28 PSI.

Casper Labs IMS: just do a google search. ;)

Regards, Markus

This ancient history thread explains some of the twists an turns in this story and mentions Casper:
Different Approach to DIY IMSB Retro / Parts and Pics
The problem with the freeze plug idea is the interference fit,the tool to install it, the lubricant(Bearing Seal?) -the issue is not axial of course.It is linear. If you force a very tight freeze plug into flimsy tube and it goes in like some RMS seals do,so you push harder ......
Try to adapt on of the IMSB insertion tools to do this gently & square ?
Recall that the IMS tubes are often oor so that may complicate the interference issue.
* Why do you think most IMSB kits use 1RS and no plug ?
Even the kits designed by JR and sold by LN. And those guys know all about the freeze plug concept. They deliberately do not use it with ball bearings but they do with the plain bearing. The cost issue is trivial.

I have googled Casper labs, and their IMS retrofit.

It seems like they just sort of disappeared, I haven't been able to find any reports of failures, or any other reason why they apparently stopped existing.

Silber

In that case, I'll try to fill in the blanks for you: Bill Ryan of Casper (who were involved in aircraft components) came out of nowhere in late 2011, claiming to have a "low cost alternative to the over priced LN ceramic bearing" (the Casper kit sold for around $325). They cobbled together a kit using an off the shelf ceramic bearing, a center bolt either from Pelican or reuse your own (was never really clear on this), a plugged shaft, and which used the OEM flange from your original bearing. They sold a couple of kits off fleabay, which apparently did not fare very well, and they folded their tent in the IMS retrofit market in early 2012. End of story.........

I am thinking this is not a problem, freeze plugs are often used in oil galleries and oil pressure can be higher than that.

I cannot seem to find any engineering data for freeze plugs on the web as far as what kind of pressures they can hold. I may have to experiment. I have feelers out for a damaged IMS shaft that I can plug and pressure test, hopefully I will find one before too long.

Silber

The problem is not the freeze plug itself, it's the overall situation.

You have an IMS tube that rotates axial, horizontal and vertical at very different frequencies and is accelerated and decelerated. Just think about that this thing is part of the valvetrain and every time the cam moves / hits a valve it vibrates a little bit. Also the IMS tube connects both valvetrains. One in the front and one in the back. So you have torsional forces within the IMS tube.

Next thing is that if the freeze plug starts moving, because the air in the IMS tube expands in worst case it will be pressed against the IMSB main bolt. The freeze plug rotates, the bolt is in a fixed position. Think about if you want that and what can happen to the bolt, screw and plug and in the end to the IMSB and IMS tube. Keep in mind that you have horizontal, vertical and axial forces and vibration. And you have vibration caused by combustion.

If you install the freeze plug like Casper Labs installed their "patented thing", the edge of the freeze plug can rub against the circlip that holds the IMSB in position. This might be a less bad situation as if the plug rubs against the center bolt at first sight. But if the circlip fails, everything will fail sooner or later.

As said before, the problem is to fix the freeze plug or anything else without harming the IMS tube (temperature, expansion levels, balancing, weight, maybe engine oil in the Ims tube to the bearing side) in a defined and fixed position.

That is why i said come up with a more sophisticated solution than a freeze plug. ;)

And to be honest, i did like the freeze plug idea too at first sight, but after thinking of it in detail, i don't think that it is a clever solution. The clever solution would be if you can make 100% shure that the "plug" can't move in any direction, doesn't harm the tube and doesn't cause any balancing problems.

But if you insist on using a freeze plug… it's your car, your engine, your money. ;)

Regards from Germany,
Markus

Casper does not hold the patent, Jake Raby does.

JFP: if you like to have a discussion about patents, laws, country regions… we can do that.

Besides that i think we all know what your interests are.

But i think here we just talk about ideas and if somebody decides to do an individual solution for a personal car. So…

Regards, Markus

My interest is keeping the conversation on point and factually correct...

Some previous freeze plug discussion.

http://986forum.com/forums/performance-technical-chat/59365-ims-bearing-upgrade-6.html

Silber