How bad can the housing and rotor be to be useable?The scoring is not to deep,and no flaking.

 

Not sure on the housing, but TOSS THAT ROTOR. Or make it into a clock.

See that little indent in the apex seal path? Yeah, its useless now. The entire slot must be free from "indents". Knicks and such are O.K., but that is protruding in the path of the apex seal, which needs to be able to spring up and down freely.

 

wow, must have chucked a seal around in there?

 

wow...that looks just like my rotors and housings off my cosmo, that I bought off www.enginelandinc.com <---Bastards, before the rebuild. Those rotors and housing are totally screwed IMO because your apex seals aren't going to be working effieciently compared to a undefected rotor and for the apex seals to keep on rubbing on a nicked or slightly uneven surface is going to wear the seals out and potentially break off , but you can always do what the cheapo people in Florida sand down smooth the housing and fill in the gaps in the rotors with whatever it takes to make one run.

 

Rotor is no good.

Damage on the rotor housing depends on location.
If it's above the exhaust port, then if you really need to resuse it...go ahead.


-Ted

 

I dont think I'd use either. However, it doesnt look like that rotor is too bad off. You could mill it back to 2mm or even go out to 3mm (along with your other) and call it an upgrade. You could very possibly use a long file to straighten the slot back out, using an apex seal to test the slot for clearance as you go. Using the file takes a long time and you must be meticulous not to open the top of the slot more than the bottom (V shape).

So long as there is no damage adjacent to corner and side seal slots, and all those seals still move freely in the rotor, the tips aren't hard to salvage. More often than not, there is damage across the entire rotor, not just in the middle. And since the rotor tip is very weak adjacent to the corner seal, it usually gets pushed way down and makes the corner seal slot bind up. Then the rotor is absolutely not saveable, because you cant repair the corner or side seal slots.

On the rotorhousing, if the damage is around the exhaust port, you can use it, but I dont like to. IF the damage is up on the top half where compression is generated, toss it, else you'll always have very low compression due to blowby. Also, if you use it, be SURE that the marks and gouges are ground down to a LOW SPOT and that there is no HIGH SPOT sticking up at all. I use a flat razor blade for this test, and sweep it along the housing surface at about a 45 degree angle. IF it catches or raises up at all, there is a high spot that needs to be ground down (die grinder or dremel tool with stone bit).

IF you leave a high spot, it will cause the apex seals to have a gap worn into them, which will then lower compression across the board.

 

Thanks for the info.I think Im going to get a better housing.Rotor doesnt seem to have anything restricting that would get in the way of the new seals.

 

is that stock gap, if it is get it machined to fit 3mm seals

 

I wouldn't touch the rotor with a 10 foot pole.
Damage apex seal grooves like that fatigue the metal.
Even machining them out to 3mm would still compromise the strength due to the "grain" being already misaligned.
Remember, the apex seal groove handles the majority of combustion blow-by.
The apex seals already tend to vibrate in the slot.
All this stress on an already weakened apex seal groove means poor reliabiliy for the engine.
Used rotors are plentiful and relatively cheap.


-Ted

 

From what I know, it is commonplace for many builders to salvage mildly damaged rotors by milling out to 3mm provided they meet the criteria I specified above (no distortion of corner or side seal slots). I have done it myself quite a bit, though I dont build a whole lot of 3mm motors. I have yet to have one of these 3mm setups fail (obviously a 3mm motor is intended to be abused, so this is when a failure would show up). However I am not able to track what happens with most of the motors once they leave, so I cant be sure.

I agree that it is always better to use the best parts you can, but there are times when time or cash is a limiting factor, and it's not like we're building a rocket ship here.

 

pitch em both, seriously...the rotor is not worth the effort when you can pick up a good used one for $75 or less and the housing surface looks too scored to me, even if the marks are in a safe no compression zone they still would have to be perfectly even to prevent damage to the seal and that just does not look like a surface i would want to reuse.

 

That housing and rotor would never in any circumstance be atempted in my shop EVER to be reused. Nor will any 86+ motor be built or modifyd for 3mm seals.