christopherdeanerogers

Hey guys,

I drove my car (2001 FD3S RX7 Type RS) to a friends place for this weekend and was going to follow up with a track day next week.

Well that idea is shattered now, I think.

I was driving my car along the freeway today when a noise started which I initially thought was the flapping of a flat tyre. So I went to pull over, slipping it into neutral and I noticed the flapping slowed. I then realised that the frequency of the flapping matched engine rpm rathan than speed.

The frequency of this tapping noise at idle (900-1000RPM) is about 4 taps per second. It doesn't go away when you rev it or give it some power it just goes faster.

The noise is comming from the rear of the engine, behind the inlet manifold and it is fairly loud.

The power FC hand controller says that all is normal. I have no loss of power and it is not blowing smoke either at idle or under power.

Does anyone have any clue what this could be?

I would suggest it would be something in the clutch hitting the casing, but the frequency is too low.

Thoughts?

oyvindjs

iTrader: (4)

Any chance of getting it on a lift, start the car on the lift and go underneath to listen, with for ex. a stetoscope on the engine, clutch-house and gearbox to locate the strongest knocknoise?
My money is on clutch area.

christopherdeanerogers

Yeah, I tried that just then, cant work it out exactly, but I think it is near that area. It is hard to pin point because the noise is so loud.

What are you thinking it could be?

Im about to upload a video, just figuring out how to compress the file size.

christopherdeanerogers

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/fYs0fulsQK4?hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/fYs0fulsQK4?hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

christopherdeanerogers

http://www.youtube.com/watch?v=fYs0fulsQK4

twinsinside

iTrader: (34)

Lift it and remove the clutch access panels and have a look in there.

christopherdeanerogers

Do you mean the thin inspection covers?

christopherdeanerogers

I opened and looked in the inspection cover.

Nothing out of the ordinary.

Ran car with inspection cover off and the noise was not amplified and was not coming from within the clutch area.

Had a listen to the starter motor while the car was running and it seemed ok.

Any other thoughts?

What is around there that could be tapping anyway?

twinsinside

iTrader: (34)

I dunno man, all I can say is it sounds like something in the rotating parts, or something hititng the rotating parts since it increases with RPMs.

I've seen pressure plate bolts come loose and make a sound like that.

oyvindjs

iTrader: (4)

my thoughts went to a loose or semiloose counterweight..?
he has compression and apparently starts the car without hassle..?
Or can we have another case of shifted centre axle?

K-Tune

iTrader: (26)

Sounds like it could be a stationary gear issue...when was the last oil change? Drain the oil and look for metal pieces...

christopherdeanerogers

Hey guys,

Well, I took my car to a few motor mechanics and no one had any idea.

So I took it to my mechanic who is 2 hours drive away.

His name is Joe Signorelli and he owns Gas Motorsport and Rotormaster.
As soon as I started the car he knew exactly what it was.

He says the 2001 and 2002 model RX7's are prone to this issue and he has seen it a number of times. He said that the rear rotor has had a minor knock caused by a minor overboost. This produces a high spot on the rotor. This high spot is just high enough to touch the rotor housing every time it gets to that spot.

4.5K for a rebuild and it will be fixed in a week. Great huh?

I will keep you guys updated with how it goes and follow it up with some pics of the issue. Well, I hope that he is right!

The guys at Gas/Rotormaster are really helpful and knowledgeable, I would recommend them to anyone.

Although the cost of the rebuild is high, included is the installation of my single turbo set up and a port job. So it is not all bad. Should come out of this with 340 rwkw.

twinsinside

iTrader: (34)

Sorry to hear that, but that isn't bad including ports and turbo work.

Did you figure out what caused the boost problem?

christopherdeanerogers

Ports were an extra $300.

From what I can gather, there is no big cause for the knock in the first place. Joe was saying that this model has the fault and that other models, given the same occurance, would easily handle it.

Must have been an issue in the manufacturing process for these rotors.


But , hopefully, with the newset up (GFB 50mm wastegate and electronic boost controller) I shouldn't get any boost spikes (hopes).

I will keep this thread updated.

christopherdeanerogers

Ok,

So we pulled the engine down and found the problem. It was nothing to do with an overboost at all.

One of the eccentric shaft oil jets, which feed the rotor bearings, had come loose. Aparantly the Loctite used on my model car was a bit of a manufacturing probem.

One of the jets let go while cruising at around 3K rpm and flung outwards into the rotor itself. The force was that great that it created an impression on the outside of the rotor. There is even a crack on the rotor surface where it hit. This impression was hitting the housing on each revolution.

Car should be back together by the end of this week.

Hope that helps others out there with a similar problem.