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12-15-2007
I'm looking at the shape od the TR water ports and how thin the deck is and not seeing a good o-ring option...I'm pretty sure I could get a 1/16" o-ring to stay sit in the block with vacuum grease or something, but a small cross-section like that wants about .010" compression, which isn't much.

What popped into my head was permatex 518. I could o-ring the oil feed and copper ring the heads then 518 the water....maybe???? I've sealed all kinds of things with 518 over the years with excellent results.

Last night was a night of Lana said, so this morning I finish the drilling on the 1st oil feed and did in fact find an oil feed. Now I need to plug the 3 open ends of the holes. On to the oil retun holes.....while I continue to ponder the water o-ring/sealant issue.

12-15-2007
I used it for all the sealing on my 2 blower set-ups and the last one was 22-23 psi, well above the water pressure. It's a pain to break loose and scrape off when stuff has to come apart, but I have never had it leak on anything I've tried it on....and it doesn't care a bit if there is a little cut-in at the edge of a weld or any other small surface defect that a gasket would hate.

I think 518 counts as an on-the-shelf gasket solution too. So that along with VW/Porsche copper rings and a couple o-rings and there would be no custom disposable parts on rebuild.

12-16-2007
Not a great weekend for working so far…baby duty most of the day yesterday and the power was out until 3pm today. Here’s what I’ve got so far though. The one side is pretty much done. It will need a finish cut on the deck and I still need to cut the bores but that has to wait until I actually see a 348 liner to know what I’m cutting.

I also gave some thought to the o-ring concept, but I don’t see a practical solution there. The reason is the tops of the liners do not seal to the block and there is no way to make them seal, so the o-ring would have to go around everything as I’ve drawn in the second picture….I’m really liking the 518 idea…..

Off to start the second side. Once I finish cutting what I cut on the machine, I'll get into the water passages with a die grind and smooth them out...they have to make a little bend at the bottom of the hole and I'll have to finish that by hand.

12-16-2007
Side 2 almost done. The oil feed hole is right where an old oil return hole was and I didn’t get it welded deep enough…I didn’t realize they where going to be in the same place. I’ll re-weld it all the way to the bottom tomorrow. Then re-drill the feed hole and hopefully no more break throughs. I also need to clean up the 2 oil return bungs I welded on, I didn’t do it tonight because I didn’t want to change the set-up and it’s late anyway.

I have a plan for the oil feed, but I need a longer drill bit than I have. I’ll get it on order and move on to the timing cover while I’m waiting.

A little progress anyway.

12-17-2007
It sounds like the spacer plate was there to raise the deck height to accommodate a longer stroke. I definitely could cut the o-rind groove into the block and make the length work out to some standard size….I see mcmaster has a 412mm OD, that would be 1294mm long and that would be right in the ball-park but it’s a 6mm cross-section an I think I would want 2-3mm . I’m sure I could find something but it seems like it would be a bugger to get it to sit in the groove and not pop out while I’m putting on the head. It think that will be the back-up plan if the 518 springs a leak.

I am planning to use 12 individual copper rings (vw bug is the right bore) to seal the combustion chambers. I think I will cut the groove into the liners only so they will sit nicely in the grooves.

12-17-2007
You’re probably right, 1/16th does sit pretty well, a little grease and it good to go. I’d be a bit nervous about anything that small for this job though. I was thinking 3/32nd or 1/8th…which would still probably stay in with a little grease, vacuum grease is about as sticky as it gets.

This would need to be a continuous o-ring or it would leak at the ends. I know they do glue the ends together, but that is pretty scary to me.

The o-ring will be the back-up plan. I think if this were a race engine that would be coming apart on a regular basis, I would move the o-ring to the top. In this case though I’m hoping the next time it comes apart is at about 100k miles 30 years from now and I think the 518 will give a better seal and I know it’s less work for me.... today anyway

12-17-2007
I just ordered 12 VW bug head gaskets, I think they will do the trick. It's an 85mm bore and they have 87mm overbore kits, so right in line with what I'm planing and they cost $1.85 each..right in budget

Also in budget is the free loaner extra-long drill bit I got hold of today so I can finish up the oil passege tonight if nothing else comes up.

12-17-2007
I got oil to the second side tonight. I was a little nervous drilling the hole...it was 4" deep, a compound angle and had to slip the deck, which isn't all that thick without breaking out, but it came out fine. Tomorrow I just need to weld shut the ends where I had to drill through the outside to get to the inside. Then on to the timing cover and head part.....where I though the project was going to be starting. Stupid head studs in the wrong places........

12-18-2007
That's still a good question. My experience with copper gaskets is that they need a very smooth surface and glue to seal. It's hard to get a nice surface finish on aluminum weld, so I'd really be relying on the glue part, which makes me think it might be best to just skip the copper gasket and go straight to the glue.

The advantage of a gasket on a non-drop-in liner engine in general over the rings and glue I'm planning is it's easier to grind/mill the deck flat and drop on a gasket then it is to mill 6 pockets per deck (nearly) exactly the same depth for the rings to work. On this engine through because of the drop in liners I need to machine the pockets for the liners perfect, so I have to do the hard work anyway. I figure I might as well save the extra effort of making the copper gasket on top of it all. Hopefully is won’t prove to be a mistake…..

12-18-2007
Quote:
Originally Posted by Verell View Post
518 should do the job, sealing metal flanges against pressure is what it's made for.

finally 1 vote in favor....I thought I was going this one alone

Quote:
Also, I've glued o-ring stock (nitrile) with crazy glue & the result was a very strong bond, as far as I can tell, the bond is as strong as the rest of the 0-ring. In one case, the o-ring was being used as a replacement for a broken drive belt. The belt broke again (eqpt problem), but the break was NOT along the bond.
Crazy glue or cyanoacrylate is great stuff, but it breaks down with exposure to water. In looses about ½ it’s strength in 2 hours at 100F and will generally be undone in 24 hours on the stuff I’ve ever tried to glue with it such as SS and assorted FDA approved polymers. I may try it on an o-ring that seals oil, but not water.