NoPistons -Mazda Rx7 & Rx8 Rotary Forum

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-   Rotary Engine Building, Porting & Swaps (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/)
-   -   Pinning Irons And Extra Dowels... (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/pinning-irons-extra-dowels-41650/)

l8t apex 12-17-2004 04:47 PM

Pinn this thread .

GMON 12-17-2004 06:08 PM

Im not understanding why you would place the dowels so low like in those pics.



I would think you would place one below and one above the stock Dowel by the Oil feed for the turbo and above an below the stock dowel by the oil filter pedistal.



To me I would think that since thats where it breaks thats where I would pin????

GMON 12-17-2004 06:24 PM

Also, is there really a need to dowel all the way through the rotor housing. Why not just use the same thing thats on the back of the rear iorn used to pin the tranny in place??

kahren 12-17-2004 06:59 PM

cant u guys tell me what u are doing with these motors no need all this doweling?

Lynn E. Hanover 12-17-2004 08:30 PM

93BlackFD,Dec 17 2004, 02:08 PM



this is actually frowned upon by most major engine builders, the concept behind loctite is that it is an anaerobic process by which the fluid begins to harden the minute it lacks oxygen, thus the process can be similar to pressing the bearing in with "shrapnel" behind the bearing between the rotor or gear and the bearing itself, this shrapnel can press through the bearing material as it is soft and pregnable, so the result is a compromised bearing surface



now, this may not be an issue for some because it relies on the loctite instantly or near instantly hardening, as some weaker and less commercial strengths tend to take longer as they aren't as pure or "exact" of a mixture



however, the "susbtance" is behind the bearing from day one until the bearing is removed, so whether or not you see these impressions immediately, or you notice them after a few thousand miles, a compromising element within your bearing does exist...



again, i would stick to using a press lubricant only (and perhaps freezing/heating), but no loctite- these are also issues that will come out of a motor that is built and then subjected to stress, so that could explain why some of you are able to get away with this- but i would think the purpose of using loctite is in anticipation of stress situations







I know I shouldn't say anything more about Locktite, and I am talking about Locktite not some other product.



There are few things that fit well in a sentance that includes the word "instantly".



If locktite hardened "instantly" in the absense of oxygen, there is little it could be used for. You would not get the bearing installed all of the way into the hole.



You could not get the stud screwed all the way into the hole and so on.



The outside of the rotor bearing is flash plated steel. The hole in the cast steel rotor is a rather poorly done course hone job. It has thousands of voids that will hold oxygen. The bearing is bigger than the hole. The crummy finish in the hole scrapes off some of the plating from the outside of the bearing. The amounts of material available to become "shrapnel" must be limited to the plating. I have never seen Locktite remove steel from any surface. If this is the case, I would like to see it demostrated. In most applications, it will take some amount of time for the locktite to set up. Or more correctly to cure once all of the oxygen has migrated away from the junction. It may take 10 minutes or an hour or 2 minutes, but time it does take.



Even when removing Loctited bearings (heating destroys the locktite bond) I have yet to see shrapnel of any description. I would not reuse a bearing that had been heated while installed in a rotor, it sort of crushes itself and looses some diameter, so there will never be an adequate diameter to maintain the press fit.



A bit of a chamfer on the "in" side of the rotor hole done with a small sanding drum will all but eliminate the scrapings of plating left over after installing a new bearing. If there was a reason for not using the Locktite, it would be that over heating the oil, destroys the Locktite bond.



I have never lost a main bearing, and they require indexing, so the tab stays on them, and no Locktite is involved.



Lynn E. Hanover

Lynn E. Hanover 12-17-2004 08:34 PM

93BlackFD,Dec 17 2004, 08:05 AM



wouldn't that bypass your secondary oil pressure regulator?







Correct. The outer gallery is not used at all. No banjo fitting, no regulator nothing.





Lynn E. Hanover

93BlackFD 12-18-2004 08:53 AM


Originally Posted by Lynn E. Hanover' date='Dec 17 2004, 06:29 PM
I know I shouldn't say anything more about Locktite, and I am talking about Locktite not some other product.





I think this sum's up why Lynn and I have different experiences, and as long as we're talking about two different products, the discussion is going to be lacking. I have no direct experience with locktite, I was merely relaying the general opinion I've come upon with the engine builders that I look up to.



I think the main discussion here was the dowel pinnin, and it seems that lynn and I have both described both the problem and the remedy, I hope that answers some of the questions some people had on the subject.



I'm hung over, and tired https://www.nopistons.com/forums/pub...IR#>/smile.png

93BlackFD 12-18-2004 09:01 AM


Originally Posted by GMON' date='Dec 17 2004, 04:24 PM
Also, is there really a need to dowel all the way through the rotor housing. Why not just use the same thing thats on the back of the rear iorn used to pin the tranny in place??




which is going to fail first? something braced in aluminum, or something braced in iron on both ends and happens to "filt" the aluminum hole?



This method would work with two pieces of iron, but you have to take into account the materials being used.



Why not dowel around the stock dowels? You're not addressing the issue of there being an "apex" between the two dowels in which most of the force/pressure is exerted.



You could put dowel pins all over the place, but, these are the "best" placement

RETed 12-21-2004 07:06 PM

Be careful with "Loctite"...

There are three (easily) available "colors" of Loctite.

Red, blue, green

Red and blue are recommended pre-assembly.

Green is recommended post-assembly.

If you're so paranoid about pre-assembly Loctite (I've never seen any damage myself either, so I concur with Lynn...), you can always use the green stuff.

This stuff is also called "sleeve bearing retaining" locker for a reason.





-Ted

Kaboom! 12-22-2004 04:49 PM

I have dowelled quite a few engines.

My 4 rotor engine is dowelled and the method I have used is the same as the method on my dowelled 13b engines.

I actually make new through bolts that are 14mm diameter and then all of the relevant holes in ALL of the side plates and rotor housings are opened up to match.

It works a treat.

My 4 rotor is dowelled on every through bolt at 14mm,the engine probably could be a structural member of the car.(Wouldn't like to test it though!)

I usually dowell with 8 of these through bolts with one near the top stock dowell which is still used and then through spark plug and combustion phase area of the housings.

Regards

Carl


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