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New rotor housings, using old irons?

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Old Feb 18, 2011 | 12:24 PM
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New rotor housings, using old irons?

Is that going to work well? I just split the engine, and there was chrome flaking on the housings. Irons are ok but they need some lapping.
Sorry for newb question.
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Old Feb 18, 2011 | 03:26 PM
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Well, if the irons need lapping, they should be lapped.

But if you are asking if you can mix new housings with old irons, then yes. The engine will have more blowby due to worn irons.
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Old Feb 19, 2011 | 10:30 AM
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From: Voss
What do you mean by "blowby"? Also is there any manual or something that mentions how much that can be lapped off, and can all irons be lapped without the engine becoming too short?
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Old Feb 19, 2011 | 10:49 AM
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You didn't mention any year or model, but check the Factory Service Manual. IIRC, the specs for the FD are in the the FSM. I assume the others as well.
As for re-using irons, that's common. Mine were re-used with new housings at about 90k miles durng a rebuild for a failed coolant seal and they didn't even need lapping. It's not unheard of to even re-use side seals if they're within spec, as long as you use new side seal springs and put them back in the exact position and on the same rotor. But I personally wouldn't recommend re-using any other hard seals.
This might also be of interest....
http://www.rotaryresurrection.com/3r...ear_guide.html
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Old Feb 19, 2011 | 11:58 AM
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From: Voss
It's an 89 Turbo II. And I've checked the manuals I have, and I didnt find any info on how much that can be lapped off.
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Old Feb 20, 2011 | 01:22 AM
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Ya can take a fair bit of the plates but i would only hand lap them,derpends how bad they are.

If your plates are not real bad like dont have dep groves in them no need.

And yes ya can mix old plates with new houseings.
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Old Feb 20, 2011 | 06:27 AM
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They have some stripes that I can feel with my nails, otherwise they seem ok.
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Old Feb 20, 2011 | 07:43 AM
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Arrow

http://www.rebuildingrotaryengines.c...ousings_Plates
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Old Feb 20, 2011 | 10:25 AM
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The FSM contains minimum thickness specs for the irons. The older irons could be lapped a lot. So much so that on assembly, the stationary gears might have needed to be spaced out in order to fit the engine together.

But newer irons can only be lapped about twice (depending on how much needs to be removed) before the water o-ring grooves are too shallow.

Check the FSM for specs on how to measure iron wear. You'll need a straight edge, a set of feeler gauges and a dial indicator with stand. Primarily you are measuring the "football" pattern of wear lines.

Hand lapping for an iron that has significant wear is just a waste of time. Hand lapping is a fine tuning measure after the major wear has been ground away by machine.

"Blowby" refers to combustion gasses and the air/fuel mix bypassing the rotor seals (or piston rings in those piston engines) and ending up in the crankcase. This leads to smoking and oil pollution.
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