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-   -   Rebuild With Rotary Aviation Seals (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/rebuild-rotary-aviation-seals-38252/)

'79rx7 05-03-2004 06:21 PM

How many miles and what rpms are you guys recommending...



I was told 1,000 miles change the oil, and take it up to 5,000 rpm then at 1,500 miles drive it the way i normally would...



what do you guys reconmend?....



Thanks

Shay

mazdaspeed7 05-03-2004 06:27 PM

Thats a good bit longer than what I do. First 500 miles, staying under 4500 rpm(no boost if turbo), change the oil/filter, and gradually raise the redline until 1000 miles.

'79rx7 05-03-2004 08:07 PM

Oh yeah and with 450 miles on it the compression number are in the lowwer 5's

mazdaspeed7 05-03-2004 10:07 PM


Originally Posted by '79rx7' date='May 3 2004, 09:07 PM
Oh yeah and with 450 miles on it the compression number are in the lowwer 5's

Those seals are very hard, and take a long time to fully wear in, especially on used housings.

Kathy Atkins 05-03-2004 10:34 PM

Low 5's are real low, how's she starting???? Ours are usually in the 8.9 - 10's even with used housings...

mazdaspeed7 05-03-2004 10:36 PM


Originally Posted by Kathy Atkins' date='May 3 2004, 11:34 PM
Low 5's are real low, how's she starting???? Ours are usually in the 8.9 - 10's even with used housings...

With your apex seals? They are considerably softer than the RA ones.



The numbers are still low, but give it another 1000 miles, and see how it fares from there.

'79rx7 05-03-2004 11:27 PM

The housing were in great shape, about a 9 on a 1-10 scale, the rotary doctor assembled the engine i trust his work... He had said these seals don't show the higher compression numbers for about 3,000-5,000 miles. and that's the compression on a factory mazda compression tester i'm not sure what you guys are using, but only once have i seen an engine with compression even in the 9's

jspecracer7 05-04-2004 03:22 AM

scarthart did some testing on the these seals for compression and found that they have the best compression after 3000 miles(if memory serves me correct).

scathcart 05-04-2004 03:45 AM

It was 5000 miles, actually. I have done a few tests on these seals and a couple others for personal information, and so far, I have been very pleased with the results from the RWS seals.

They have held 200 hp nitrous shots for 25+ seconds intervals for me (at 11.8:1 AFR and timing appropriately retarded), so I can't understand any issues being brought up about warping when the seals are properly fitted.

scathcart 05-04-2004 04:02 AM

Keep in mind that is when I tend to achieve peak compression, with testing done very 500 miles. You can vary your break-in periods and styles however your engine builder sees fit.



When using these seals, i use this:

-Start the engine and let it idle for 30 minutes.

-Change the oil and filter (this removes any bearing wear from new bearings, if used, and any material that was left in the oil passages after sonic cleaning, etc).

- Idle the engine to 2000 for 90 minutes.

- Initial tune for cruising load, 13.2-13.5 AFR under cruising load.

- Drive 1000 miles with carry load, using lots of starts and stops, no hard launches, no WOT, no boost, and no engine rpms over 4000 rpm.

- Change the oil and filter.

- Drive 2000 miles, highway miles work fine, no hard launches, no WOT, no boost, and no engine rpms over 4500 rpms.

- Change oil and filter.

- Drive 2000 miles, highway is fine, easy launches, no WOT, boost under 5 psi, no engine rpms over 5000

-Change oil and filter, retune car for WOT and cruise AFR.

The Ultimate 7 05-04-2004 04:56 AM

Yep they take forever to break-in.



Scathcart, the seals that warped were factory defects. The detects were inadvertantly cut thinner than 2mm making them very loose in the rotor grove. Thats why they warped.

Drago86 05-04-2004 07:03 AM

These seals shouldnt take longer to break in then stock mazdas due to there hardness. RWS does not claim there seals are harder then stock Mazda seals. They cannot be, they are through hardend (says so on the site and in the pamphlet they send you with the seals). Stock seals are a bainite structure with a chill hardend 2mm deep section at the tip. If RWS seals were as hard a stock seals all the way through, they would be incredibly brittle and shatter easily. Based on the fact that the RWS seals are much more ductile then stock and are through hardend they must be considerably less hard then the wear are of the stock seals, thus should less time to break in then stock mazda seals. I suspect the extra break in time is due to the RWS's seal design with the wide apex tip. While this design reduces wear on the housings (as per hurley and rws claims) and makes instalation easier, it is not the best design for overall sealing ability. Because two piece seals run zero lateral clearance; when they are cold they are exactly the right length, but as they start to expand the corner piece slides down to acomidate the expansion and keep the seal the right length. with stock seals this compromises the sealing ability in a very small area. With wide corner pieces a much larger area is compromised, thus lower compression then a stock seal design motor. the long break in is most likley the seals slowly wearing their end clearence down over the 5kmiles so that when hot they the side piece isnt pushed down as much, thus more compression. I believe atkins now has an option for small corner pieces on there seals now just for this reason (may be wrong on that, but i think i heard it somewhere). I am in no way knocking the RWS seals, as i myself am using them in my rebuild, they just compromise some sealing ability for other benifits, and a more ductile, softer seal then stock can have benifits (improved overall durability, less wear on housings etc). If you were to clearence the seals end clearence before installation (Judge Ito does this on Atkins seals i think) i think you would avoid this long break in period. Heres a picture of what im talking about so you guys dont call me insain, its kinda hard to explain. I'd like to acknoledge that RETed origonally enlightend me on this issue.

mazdaspeed7 05-04-2004 09:23 AM

I *completely* disagree with the apex seal clearanceing thing. The coefficient of thermal expansion for aluminum is much greater than that of iron or steel. Therefore, it side length of the apex seals are set for cold housings, when it heats up, the aluminum rotor housing will expand more than the iron seals, and the seals will be slightly shorter than the width of the rotor housing at operating temp.



I havent seen any comparison numbers between RA and OEM, but I know the Atkins and hurley seals are much softer than stock, and the RA seals are considerably harder than the Atkins and Hurley seals.

Drago86 05-04-2004 10:23 AM

true, but the apex seals run much hotter then the water cooled housing. A quick look up in the SAE papers ive posted before (recent-tech84) shows apex seal idle temps of 120 degrees C and WOT temps above 5k at over 240 degrees C. using a housing temp of 90 degrees C we come out with a housing expansion of .173mm for a theoretical total housing width of 80.173mm. For a seal at 120 degrees c we come up with an expansion of.115, for a total theoretical seal lenght at idle of 80.115mm. At 240 degrees C the seal undergoes an expansion of .230mm, for a total theoretical seal length of 80.230mm. As you can see this is .0574 more expansion at 5k rpm then the housing. Add this to the fact that all 2-piece seals are slightly oversized from the factory ~.05mm





so, final sizes are:

Housing @90 degrees C: 80.173

Apex seal at idle: 80.165

apex seal at 5k:80.280



the seal will be to large at anything but idle.



I'm going to measure my rotary aviation sels right now to get an exact length on them,..

TURBOX2 05-04-2004 10:36 AM

^^I must say this is very interesting reading..thanks guys!

Drago86 05-04-2004 12:20 PM

It's hard to get an exact measurement because i dont want to glue them together, but it appears to be more like .025 oversize.

mazdaspeed7 05-04-2004 02:12 PM


Originally Posted by Drago86' date='May 4 2004, 11:23 AM
true, but the apex seals run much hotter then the water cooled housing. A quick look up in the SAE papers ive posted before (recent-tech84) shows apex seal idle temps of 120 degrees C and WOT temps above 5k at over 240 degrees C. using a housing temp of 90 degrees C we come out with a housing expansion of .173mm for a theoretical total housing width of 80.173mm. For a seal at 120 degrees c we come up with an expansion of.115, for a total theoretical seal lenght at idle of 80.115mm. At 240 degrees C the seal undergoes an expansion of .230mm, for a total theoretical seal length of 80.230mm. As you can see this is .0574 more expansion at 5k rpm then the housing. Add this to the fact that all 2-piece seals are slightly oversized from the factory ~.05mm





so, final sizes are:

Housing @90 degrees C: 80.173

Apex seal at idle: 80.165

apex seal at 5k:80.280



the seal will be to large at anything but idle.



I'm going to measure my rotary aviation sels right now to get an exact length on them,..

Good stuff.

FikseRxSeven 05-04-2004 08:44 PM

does the 5000miles breakin go for 3mm apex seals for 12a's or does that go for 2mm seals also... im not looking forward to my breakin..... maybe ill put the car on jackstands and let her fun there with a brick on the gas

Cheers! 05-04-2004 09:58 PM


Originally Posted by mazdaspeed7' date='May 4 2004, 09:23 AM
I *completely* disagree with the apex seal clearanceing thing. The coefficient of thermal expansion for aluminum is much greater than that of iron or steel. Therefore, it side length of the apex seals are set for cold housings, when it heats up, the aluminum rotor housing will expand more than the iron seals, and the seals will be slightly shorter than the width of the rotor housing at operating temp.



I havent seen any comparison numbers between RA and OEM, but I know the Atkins and hurley seals are much softer than stock, and the RA seals are considerably harder than the Atkins and Hurley seals.

ya but the aluminum housing has much greater mass, and thus will take longer to heat up when compared to an object with much smaller mass


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