sevenracer

I need to a 12a motor for SCCA improved touring racing (no porting).

I'm struggling to find good housings for my best parts, and I am wondering how bad the results would be if I built up a motor in the interim with parts I have lying around.

Basically, I have these parts:

1. Rotor housings that are overall in good shape but have a bit of chrome flaking, maybe 1/8" wide by about 1-2" long along one edge.
2. Apex seals - taken from various stock engines, all would be at least 7.5mm (vs 8.5 mm stock and min spec of 7mm per factory manual). Probably would buy new springs - the ones I have seem past it.
3. Side seals - I should be able to get a full set with less than .0035" clearance to corner seals.
4. Irons - have a good set that measure out ok per FSM.
5. Rotors - good shape, should be in spec.
6. All other parts used but good condition: corner seals, springs, eshaft, oil control rings, etc.

Can anyone comment on what to expect based on similar experience? Hard starts, low power - by how much, longevity? From what I read on rotary resurrection it is not unthinkable for to get a reasonable motor from such parts.

Also, one specific question, if the apex seals described above are a bad idea, will carbon seals survive with those housings? I have heard they chip easily.

Overall goal is to get back out there with a reasonable motor for minimal investment while I search for better parts.

Thanks for your help.

heretic

You should be fine.

The most critical things, I've found, are the apex seal springs, the apex seal to rotor clearance, and the condition of the oil rings and O-rings. Side seal springs and oil control springs don't really show issue from any of the engines I've torn down.

Apex seal springs - Replace with new. They degrade from the start, and it doesn't take very much high RPM use to make them hockeystick shaped.
Apex seal to rotor groove clearance - The tighter the better. It's very hard for me to find good rotors in the field. Loose tolerances here will cause rapid rotor housing chatter wear.
Oil control bits - Go by the service manual guidelines for ring wear, and replace the O-rings. I've had very good luck with the aftermarket O-rings that Atkins sells.

If at all possible, get new corner seals. Most of the increase in side seal gap seems to come from the corner seals getting notched. For your application, I wouldn't worry about going with FD corner seal springs, the wire ones will work plenty good enough and for your limited application, every bit of reduction in friction will help.

sevenracer

Thanks, heretic. Good info.

Any comment on using carbon seals with housings that have some chrome flaking (about 1/8" wide but up to 2" long)? Will the seals get damaged? Never used carbon before, heard they are fragile.