Help my 13b today started knocking lightly. I filled up my tank today with 93 gas. I always ever since I rebuilt the motor I have been putting 93. The car doesn't knock while revving, but when I let go of the gas I can hear knock on the back rotor. Motor only has around 3000 miles on it...

 

You want to run through what you have checked so far? Primaries inj both working? Is it 'combustion' knock, or more 'mechanical sounding? I guess a compression test would be a good starter, just so you end up on the right 'path' to find the solution. Jeremy

 

Well it's running carbutator I cheked the compression couple days ago before I heard the knock it was at 95 both rotors

 

knocking on let off from the rear rotor???

1. how are you determining this?
2. what generation?
3. what's your ignition setup?
4. what's your exhaust setup?
5. what carbie and AFRs?

 

It's a 13b 6 port, s5 supposly, running carb, racing beat headers all the way to a racing beat muffler,. At let go of gas you can hear the back rotor like something rattling inside. It happened to me the last 2 12a I had and the bearings broke... Help I don't wanna break this one its not doing it loud but if I let it keep going I am afraid that it will break. It's my daily driver..

 

Have you checked to make sure something in the engine bay isn't rattling?

Are any of the clutch components loose?

Did you build the 2 12As that failed in the same way?! If so, then are you checking bearing clearances? Did you press in new bearings correctly? Correct end play set?

If you really do suspect the rear bearing, then you can pull the transmission, flywheel and then remove the stationary gear and check. This of course is a huge pain in the *** so it's bes to rule out everything else first.

Rear bearing failures are NOT typical with rotary engines unless something was done wrong during the build or there are oil starvation issues.

 

this.

what kind of oil pressures are your getting? does it start off strong and the drop regardless of RPM? my guess: you (or your builder) is not building with an adequate seal at the front cover main oil port.

 

I get around 60 while starting then Goss down to 35 when heated up. When the rpm rises out goes up and up , max I seen it go is only 64 oil pressure ...

 

How tight did you get the massive Flywheel nut? I had one come loose on me, knocked like crazy...

 

Thing is It doesn't knock when revving just off throttle when rpm is going down you can hear cluttering noise on the back rotor maybe is bearing messing up?

 

And there is no metal on the oil pan I drained it no metal

 

I'm Quite Confused. S5's Don't Have Carbs... And If It Was Put On... ...Why?

 

no need for confusion. youre right carbs are not OEM on S5s. however there are several choices for those that want to run a carburetor. as for why, it's completely up to the owner.

 

My the housings have the two hose to put the injectors but my dad block them. I don't know how maybe welding, but they are blocked. .

 

bang on the cat with a dead blow hammer, does it rattle?

sometimes the exhaust port sleeves will also come loose and rattle, you can check them by removing the header and see if either is loose in the housing.

aside from those 2 things i can't give you any further ideas, these engines simply don't make much internal noise even if there is a huge issue present. even spun bearings are as quiet as a mouse.

 

that same exact noise happened in my fd. it was bearing failure do to oil starvation

 

I am sure it a spun bearing but what you guys think , is it stationary bearing or the rotor bearing what should I replace.

 

U gotta diassemble but almost fir sure its ur bearings

 

common sense, some people have it and some people don't..


here, let me get out my crystal ball:

replace all the bearings if one of them spun.

but do we know if one did? sorry, my x-ray vision isn't working today so i suppose you're just going to have to start stripping things off the engine until you find out.