Guys:
I am at a point where I am not sure what to do. I have a rear rotor for a 12A with stuck side seals. I have tried soaking in carb cleaner, heating, beating, etc and cannot get the side seals removed... I am totally frustrated with this rotor.

Can anyone please help with suggestions? I have to get that 12A rebuilt. It's been in pieces for way too long!

The engine came from a 1980. If I get another set of rotors from a 79 or 80 can I just drop them in? Anyone have a set?

Thanks

 

Try oven cleaner - it dissolves carbon by design. Wear gloves and goggles, as it's fairly caustic. Works best hot, usually; follow instructions on the can.

If that won't do it, you're better off replacing it.

You want rotors to be matched-weight pairs to maintain balance.

 

there are many ways to go at it.

1. try soaking in other things (DD's oven cleaner idea is a great one)
2. find something strong and thin enough to go at them from the corner seal slots ... maybe notch an old side seal and use it as a pick.
3. i once went as far as putting rotor in the freezer overnight. you can try that.

 

PB Blaster has a nice peppermint scent and I haven't found a stuck metal to metal problem yet that it hasn't done well with. Definitely try that before you get medieval on it.

 

the 76-82 rotors are the same. easy ID, they are stamped either F or R, for front or rear. the 83-85 are FN or RN

 

I recall a slight difference in the pre 80's and post 80's non "N" rotors . The compression ratio on both are the same but the compression chambers on the rotors have a slightly different shape. I don't know if it affects weight but would I definitely avoid using one of each.

 

I have tried PB blaster, carb cleaner (soaking B-12 now), beating using a sheet rock spatula in the groove, WD-40...

I'll try freezing and oven cleaner.

Thanks

Oh, and I do have another set of rotors. I thought they were 83-84 but they are stamped F and R. I can use those OK with all other 80 parts? Same counter weight and all?

 

I use a small flat head screwdriver thru the corner seal slots . The thinner ones that are for eye glasses they fits inside of the side seal groove. Stick it under the seal and pry it up the seal will break and you can work it out one piece at a time. Be careful not to damage the groove . You can also try to break off a piece of the seal on both ends and grab on to the side seal spring with pliers on both end and pull up. Sometime it gets it free sometime the spring just breaks but it's worth a shot plus if you get the spring out of there it give you a little more room to wedge under the seal itself.

 

I use a blade from a box cutter. You have to break it into a smaller length. The slanted end and get down under the side seal and the broken off straight end can be tapped with a really small hammer. Works great to get extremely stuck side seals out due to rust and/or carbon that have already gotten broken using other methods. Also WD40 tends to help.

 

Looks super clean.

 

I'd be careful of the oven cleaner. It can have negative effects on some metals. Your oven is ceramic or enamel coated, which is why it's safe to use there. I've seen it eat aluminum, and etch other metals. Just my two cents.

 

Have you tried a tub of ATF?

 

the tub of ATF trick can take a very long time to work lol.

 

I've left rotors in ATF for as long as a week with poor results . It's just to thick to penetrate efficiently. Works just not great.

 

...it takes longer than a week.

 

Yeah, but at least you aren't beating on an engine part with a screwdriver.

I dunno, I've only ever rebuilt 13B's and if I run into such issues its as simple as run to a junkyard and find a ricey FC and rip a motor.

 

Hey my screwdriver works great . Gets the seals out the same day. And I don't even have to beat it.

 

ok, so it looks like the set of rotors for the 82-83 is good. Can I use those as a pair with all of the 1980 parts?

I've tried the screw driver and all tricks except ATF. This things are really stuck!

 

I think there are flywheel differences between the 83 and 80 parts.

 

I normally don't approve of interchanging parts in the rotating assembly without balancing ,but if both sets of rotors are close enough in weight to each other you will not have problem.

 

1. you can use any set of rotors in the '80 engine as long as it complies with the basic rules: (a) they are from the same vintage, (b) in that vintage, that they are no more than 2 letters apart, and (c) you use the appropriate front counterweight and flywheel with the set.

2. 82-83 should not be a set because they are of different vintage. so unless that's a typo, you should double-check what you have. 82 rotors belong to the older vintage (76-82) and then of course there is 83-85.

 

I think In a previous post he states he really doesn't know what year they are from but are definitely not 83-85 "N" rotors so definitely 76-82 rotors. What year exactly? Who really knows?

What weight stamp is on the good rotors and what weight stamp the rotors with the stick seals? . Also if you have a scale you could even get away with changing around just one rotor. But like I stated in a previous post I'm pretty sure there was more then one casting for the earlier rotors . So make sure the combustion chambers are the same.

 

Where is the weight stamp? Thanks

 

It's a letter imprinted on the gear side of the rotor A-E . Basically you can use anything within one letter . AA BB CC and so on or AB BC CD but not AC BD CE. Also wanna keep it within a 50g difrence front and rear .

 

My front had a D and an E stamped on two opposite sides of the gear end. The rear has a C.
Came off the same engine.
Thanks