Has anyone located a suitable replacement for the $8 dowel o-rings? I can't help but think a nitrile o-ring of the same size could be sourced for a fraction of the cost and work just as well. Are the stock units nitrile? Am I missing something?

I realize it's not a huge deal but every little bit helps. I would prefer to spend the money elsewhere.

 

Check the Doman boxes at NAPA. THe big locations have "O" ring selections. Nitril or silicone are fine, and the old ones can be reused if they are still flexible.



Lynn E. Hanover

 

My sincere thanks as always!

On another note I just got through polishing my 12a e-shaft with your recommended 400 grit silicon carbide, kerosene, and 18ga hookup wire method. It honestly took me about 10 minutes before I was able to achieve a good rhythm but the results were better than I expected!

I have a set of very pliable outer water seals from a 13b-rew. They seem a bit too large. Do you see any reason I couldn't cut them at a 45 degree angle to shorten them, add silicone to union, and use them on my 12a? I know the part numbers are different. If I don't use those seals the motor is getting the 18ga hookup wire jobs

 

The outer "O" ring gets longer because it was crushed when it was installed. The material is taller than the groove, and spreads out when the pieces are assembled. The result is that the material just about fills the groove, so there is some pressure on the ring even before the coolant starts pushing on it.



I cut the ring at a long angle and install the seam at the top of the engine, so any leak would be be visible. A drop of silicon on the seam was used. Never had a leak. You can do this several times with the same "O" ring. When I have new rings I use them. My friend bought a spool of ring material and makes all of his own water rings, and uses Beldon wire from NAPA for compression "O" rings. He still does this because he is cheap to death and has no sponsor.



The wire in the compression groove was a gag to get through a weekend when I ran out of new rings.

I happened to have a spool of aircraft wire with a cloth sleeve and teflon insulation over silver tinned copper wire. Very nice stuff. I peeled the cloth sleeve off, and the diameter turned out to be just the right diameter. Once used the wire comes out nearly square. You don't want to fill the groove with the wire, as the groove will hydraulic and the housing will not close up solid on the iron.



A small bead of silicone goes into the groove before the ring material, and may have a great deal to do with this all working so well.



For the wire ring, the seam goes on the intake side of the engine where there is no load at all on it. I had quite a gap in the ring, as the big "J" port leave a big opening in the seal path. I stood up a barb in the seal groove in the rotor housing with a special punch I made. I cut the wire at a long angle so as to fit into that barb. Then added silicone at the wire end and along the water side of the groove wall.



There is a drawing on here somewhere shoing that, or, I can make another one..............



I did this in my race engines, at first as a means to get in a race weekend when money was short, and then just because we never had a failure in the system using Teflon wire. We did take engines apart either every weekend or every other weekend. I should point out that I also never had a failure with stock "O" rings. I have broken down many gift engines where the stock inner "O" ring had failed and caused that engine to be removed. I never did this on a customer engine. That would be tacky.



I think torqing up the stack is far more important than is understood by most builders. No two bolts are the same. No two threaded holes are the same. So when done by the book, the actual torque for each bolt would be a bit one way or the other from perfect.



So I put nickel antisieze on the threads and on the washer so that the differences between holes is minimized. Then torque to the low end of the spec. Like 23 to 25 pounds is then use 23 pounds. The actual clamping force would then be some value above what is called out in the manual for the highest dry thread torque. Then do the torque pattern 6 times. Wipe off the bolt heads. Use a sharpie to make a dot

on the bolt head and iron in the same location.

The next day break each bolt all the way loose (one bolt at a time) to get some antisieze on the loaded side of the threads, or, take each bolt out and add a bit more antisieze, then torque that bolt back to the minimum torque number. Notice that some of the bolts will move past where those dots are. So 6 times yesterday did not do the job did it?



Turn the engine over several times, and remove any excess silicone through the exhaust port.



Don't turn the engine backwards unless you have made the ramp cut at the bottom of the port for ported engines.



Lynn E. Hanover

 

Great advice! So when you say to do the torque pattern 6 times you mean I do a multi-stage sequence torquing all the bolts to spec, release them all in reverse order, then do the sequence again 5 times? I just want to make certain I understand correctly so that I don't damage the soft seals in any way.

I have some high-temp copper anti-sieze but no nickel. Should that work ok?

 

Just do the pattern as in the book with antisieze and let it sit a while. Then do the pattern again.



So, do the pattern to 10 pounds or whatever is called for.......then 15 pounds, then 23 pounds, whatever the book says. Then let it sit for a while, then do the pattern again at 23 pounds.



Just repeat the 23 pound check over several hours a total of 6 times.



Then wipe off the bolt heads and the iron around the bolt heads, and mark with a sharpie.



The next day, either loosen or remove and relube the threads, on the first bolt in the pattern. Retorque the first bolt.



Do not loosen all of the bolts at once. Just one at a time following the torque pattern. Torque the bolts up with one continious motion. If you have to stop to tie down the engine stand or because the shop is on fire, start over on the bolt you were doing. If you have to stop before the bolt is all the way to 23 (or whatever the lowest number is) start over at zero torque and go again in one motion.



Note where the sharpie dots end up...............In almost every case one or more will have moved to a tighter indication.



Isn't that interesting?



These engines are very flexible. Seems impossible but true. Notice the engine mount locations moving to the rear over the years. This was to take the torque load off of the stack. Like a deck of card in your hands as you twist in opposite directions. So the very high output (high torque) engines have extra dowels along the combustion side (to limit combustion chamber movement) and tight fitting oversize case bolts to control the twisting effect of housings going in the opposite direction from the rotors.



(Equal and opposite) According to Newton.



This is why the top dowel can shear off, or the dowel hole can crack open.



So pulling the stack down nice and square lets it run better and last longer, and does just a bit more to to keep the dowel from shearing off.



Lynn E. Hanover

 

Ok, understood. I was wrong in my initial understanding. Thank you for clarifying. I'm really looking forward to attempting my first assembly. I'm an old school "newb" in that I've been around and even assisted in multiple engine rebuilds but have yet to attempt one solo. I'm using 12a parts I've had sitting around in the garage for this build. The 12a will be fitted with the EGI components from my recent gsl-se acquisition. It's 13b seems to have worn oil control rings and there is considerable smoking now having gone over 213k. I'll be giving it a streetport and hopefully assemble soon after. I'm using the 13b intermediate in order to utilize the injector bungs. I have to order several soft seals such as front and rear mains, rear gear o-ring, front cover o-ring, fd corner seal springs, and tension bolt seals but the main thing I lack is a decent set of used apex seals within spec. This build is part of a "Top Gear" style challenge that myself and two friends have agreed to undergo and our cars were purchased for this reason. We have to stay within a very limited budget which rules out new apex seals. The competition is an 87 e30 bmw 325 and 90 honda prelude si. I have a set of seals but they are right at 7mm in height and according to the fsm that's the limit.

We have yet to determine all the "challenges" but so far they include some local auto-x as well as a trip to Deals Gap to run the dragon.