Have a peek, guys. I'd like your comments on this.

http://forum.teamfc3s.org/showpost.p...&postcount=399

B

 

How did your rotorhousings look after those RA seals rode against them?

 

As far as the cleanliness of it goes, I'd say alky is a small part. A member around me who has ran his FD engine for nearly 3 years on a single (GT35R) tore it down recently and it was nearly as spotless. He runs straight 93. However he also premixes.....

I dunno if its the *only* reason, but I'd say the cleanliness of your internals vs. his are very very close and he doesn't have any form of AI.

Nice documentation though, and you have a PM

edit: just noticed, I can't comment on the shape of his intakes since I didn't see them, only the housings/irons/rotors/seals. I'd bet the AI is what's keeping those spotless for sure.

 

I haven't taken a real close look but they look like they're worn some. I saw/felt some chatter on them.

B

 

I've pretty much concluded that it's the alcohol given the specifics. I'll get to your PM shortly.

B

 

My feelings are that if it's a motor that just gets started up on weekends and take hellraising trips with buddies to show them what the car will do...then the rotors will stay spotless due to the large volume of fuel and air shooting in. If you daily drive in traffic and take short (easy) trips to the store/whatever, then you will build carbon like no other from all the idle time. This covers most of the stock motors I take apart.

 

Good point. The engine I mentioned was by no means babied....

 

C16 also keeps engines clean

 

I just broke down my motor that was daily driven and raced for ~20,000 miles.

3mm RA seals and 50:1 premix, no emmisions.

First thing I was amazed by was how spotless the motor was inside. No carbon on the rotors, no carbon even in the exhaust ports untill the diffuser, no carbon in the intake- just no carbon.


The junk rotor housings I had used had actually had most of the broken apex seal gouges in the chrome worn back out to flat by the RA seals. They looked/felt about .003" deep when the motor went together- so lots of wear.

The lengthwise striations everyone is getting with RA seals are present to the eye, buy you can just feel them with your fingernail. So, lots of premix helps but can't fix the incompatibility of the materials.

Much less chatter marking then when the motor went together with the RA seals, but I kept the redline down to 8,000rpm this time.

It is going back together as is with 2mm RA Super Seals for the Hillclimb as I build a motor out of good parts for next season.

Rear (unblown) rotor housing had 90 psi compression cold. Wait, these ports are gonna have MORE power with a decent compression motor next season?

BTW, Cause of motor death- the rear EGT probe broke/melted off and was pushed into the front rotor housing where it impacted into the corner of the rotor and pinched a cornerseal and one of its sideseals.

EGTs were 800-900 C in lean cruise and below 800 C under load.

It was likely because the last blown engine had impacted the probe with some apex seals and spring and bent it slightly. I cleaned it, inspected it for scoring/collapse and left it bent to avoid stressing it, but apparently it was already weakened. DOH!

Also, I had thought the Mcmaster Carr encapulated inner coolant seals had started to split last rebuild, but it was very thin flashing where it had been sqeezed between the rotor housing and sidehousing on the combustion chamber side. I rubbed it off with my fingers back then and they look fine after ~20,000 miles in this engine.