What would be the clearence for the side seals?

 

I have had two failures of corner seals. Both the ones with the rubber plug. One turned back into the powdered iron it was made from. The engine stopped but it didn,t do much damage.



The other was just cracked into 2 pieces and found on disassembly.



I now only use solid corner seals.



I use zero side seal clearance. So long as they will pop back up when both the side seal and the corner seal is released as a unit, it will work fine. The centrifugal load will add a bit of clearance, and the the advancing side of the corner seal drives the side seal around, so that junction will wear in quickly and provide even more clearance. Instant hot starts after a heat soak.



If you can wear out a new set of solid corner seals in 400 miles, there is some untold story there.



Lynn E. Hanover

 

0 side seal clearance ? I'm rebuilding my engine right now. I followed the side seal to corner seal clearance told by the haynes. Should I use new side seals to have 0 side seal clearance. I probably will use stock corner seals without the rubber plug since I want to port the intake.

 

I didn't want to write up a long story like I first intended to. I'll say that they both work great depending on application(low boost vs high boost.... small nitrous shot vs a big nitrous shot) When using none solids corner seals, try and keep the engine away from detonations. They do not like detonation at all(they will crack down the middle) If your going to build an engine and go for extreme boost or nitrous shot I highly recommend solid corner seals. Basically solid vs none solids is up to the type of application your going to use the engine under. Stock rebuilds and light to medium mods= none solids... serious mods,high boost(30 to 40lbs of boost and/or 200+ nitrous oxide shot use solids).. hope this helped a little.

 

Sorry I didn't see this sooner.



There is no problem with the stock clearance specs you see in manuals. There is nothing quite like the insanity of racing to show up a problem with any piece of equipment.





A fresh engine has about 20 minutes to break in. Near the end of that time it will be turning up max revs. Maybe 9,600 RPM. So we get the clearance we need for near perfect sealing in short order. The clearance required to seal well is just that amount that cannot bind up the side and corner seals and prevent them from moving. There is a tiny amount of side clearance in the side seal groove. The centrifugal load on the seals tends to force them against the outside of the groove when unloaded. So zero static clearance still produces some clearance. They were at the drive end of the seal eats into the corner seal, and some of the side seal wears away to produce additional clearance. So zero becomes two or three thousandths on teardown. Still, once the extra clearance is established and some oil can get between the parts, the gap will not increase dramatically over a great amount of time.



These are like the gaps in a piston ring. The difference is that the piston is iron and changes shape at about the same rate as the seal. So huge amounts of clearance are not required. In my 3.31" bore Fiat pistons I ran .009" end gap on the top ring and .008" on the second ring. That would produce zero leakdown after a dyno run. And that with 245 pounds of cranking compression.



Extra clearance is not a problem, but it will not produce zero leakage, and zero is what you are looking for.





The picture is the chassis for the 95 RX-7. 135 pounds of SAE 4130 total. The idiot on the right is me. The idiot on the left is Craig Rhine the engineer.





Lynn E. Hanover

 

Something came to me as I re-read this thread...

If expense was not an issue, could RX8 corner seals be used in a large streetport application? After all the rubber plug has been replaced by a what appears to be a carbon aluminum plug that anchors from inside the Corner seal.

I also understand that the plug will have to be milled due to the apex seal height of the regular 13B and the Renesis.



Just a thought lets see what yall think about it.

 

Your theory here makes sense, but what happens with the side seal expands when it's exposed to the heat of combustion? What about combustion itself pushing down on the seal? I would expect that to easily overpower the centripetal forces on the seal from the spinning rotor. Perhaps Mazda's thinking of 2 or 3 thou static would become zero under the forces of compression and combustion.

 

So in my s4 13b block instead of replacing my corners because of lost rubbers i should put them in without? Its a large extended port?

 

sorry bout the crap photo but should i reassemble like this?

 

How thick do may corner seals need to be rx8 2pc can not find this anywere