Howdy all, just gearing up to put my engine back together, my RWS apex seals should be here in just over a week, as well as my other springs (including some S6 corner springs... )



Now what about my side seals/corner seals and their clearances? How much clearance do they have stock? and what is their maximum you should let them have?



Also if I acidentally made the clearance to big (I hope I don't..) then what bad effects would that have? Would I get markadly worse compression? or would I just get some blow by?



Does blow by cause any damage to the seals over a period of time? what about the oil control rings?



Any thoughts/inputs are appreciated.

 

too much clearance between the corner and sideseals will have no ill effect on the apex seals but will lower the compression drastically, maybe even to the point of a no start situation. Compression on engines with too much clearance there will have usually less than the minimum 85psi when hot.



that is from personal experience. Try to set the clearnances to the factory specs and you will have no probs.



Judge Ito posted the clearances he uses for different engine setups, like for example nitrous and turbo app, vs n/a use. Try to search for that article.

 

For racing I use zero clearance for the side seals. The side seal is pushed along by the corner seal in operation. The end of the side seal quickly wears into the corner seal and produces some clearance soon after start up. So long as the oiled corner and side seals come back up when depressed, that is enough clearance. Remember they all move together. Don't push a side seal down and not the corner at the same time, or it will stick. If it comes back up when both or all are depressed together, then all is well, and you have enough clearance.



Cover them with a coat of grease to keep them in the rotor during assembly.



For a street engine I would think (I have no experience at all with street engines)

that so long as the break in period was extended to some extent, that zero or close to zero would work just fine.



You are after zero leakage to be the ideal. The factory has to build an engine that some idiot will be running at the red line one hour after the car gets to the dealership. If you take it real easy for a while, you could run close to zero.



Lynn E. Hanover

lehanover@aol.com

 

Wow! great info! thanks Lynn E. Hanover



I've got another question I hope you might be able to answer..

I've got an o-ring in my rebuild kit i don't know what to do with.



Its about 1-1/2in or 1-3/4 inch diameter on the outside...

its _noticibly_ thicker than any other o-ring in the kit.



Any ideas?

 

the CAS o ring?