Mazda Rotary Club

Cars by Model Type => 3rd generation RX-7's => Topic started by: Sideways_Steve on December 27, 2008, 06:53:31 PM

Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 27, 2008, 06:53:31 PM
As above folks, Ive not managed to find anything usefull searching so far so ...

what are the normal symptoms of rotor tip failure ??
Title: Tip Failure Symptoms ?
Post by: Timmy on December 27, 2008, 07:03:46 PM
hard to start, vibration, lack of power, boost gauge fluttering, lumoy idle.
Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 27, 2008, 07:46:26 PM
ok heres some more questions then.

If it does still start albeit slightly lumpier than normal, does idle, and drives faultlessly above 1200rpm is it still likely it could be a cracked tip ?

When you do the chuff test would you notice anything or would it only show on a proper compression test ?
Title: Tip Failure Symptoms ?
Post by: matt p on December 27, 2008, 07:59:09 PM
Chuff test proved my front rotor was down.

Still starts from cold fine and even drives, just a ....er to start from hot.

HTH

Matt
Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 27, 2008, 08:09:08 PM
OK mine starts the same both cold and hot, chuff test sounded even across both rotors with 3 close together chuffs on each rotor done seperatly over and over

So am i right in saying that if it had a cracked tip it would be fairly noticeable when you do the chuff test ??

If thats the case then what the heck is wrong with my baby!!!!!!!! LOL

Ite like its misfiring on idle but is perfect above 1200 rpm. Im so confused! LOL could it be plugs ?

I thought usually with plugs that are duff you get a misfire under load not at idle ?
Title: Tip Failure Symptoms ?
Post by: matt p on December 27, 2008, 08:20:22 PM
Im guessing so dude, but i dont know enough about these yet,

Have you had the plugs out?, are the gapped correctly?, always worth checking the simple stuff before thinking the engine may be goosed bud.

My one just has a moody tip, not sure as it could be a side seal according to laeeq who i picked it up from, diamond bloke by the way lol.

Wont know properly till i pull it to bits:yes
Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 27, 2008, 08:23:32 PM
Nah you cant gap the plugs on these bud due to the style of them, there weird looking and not adjustable. I know that sounds odd but when you remove one you will see what I mean :)

Im thinking it could be plugs as they do look a bit worse for wear but I really dont want to spend £40 on plugs to discover it still wont run right LOL!
Title: Tip Failure Symptoms ?
Post by: HaywardRotary on December 27, 2008, 08:42:40 PM
Try changing the plugs,they should be done pretty regularly anyway,and can still be used even if you have to rebuild the engine.
If you have a tip that has just lost a very small part on the end then that can behave like you have said,but you usually notice  that the engine does not want to drive hard and under boost very well.
regards
Carl
Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 28, 2008, 10:37:41 AM
Thanks for the replys, I got my compression tester back this morning so Ill get it checked out tomorrow, as doing the family thing today lol!

Fingers crossed it turns out to be something silly though!

It runs excellently on boost though and certainly doesnt have any problems with being driven hard !
Title: Tip Failure Symptoms ?
Post by: interloper393 on December 28, 2008, 01:23:38 PM
vac hose leaks would cause similar probs bud
Title: Tip Failure Symptoms ?
Post by: FDAsh on December 28, 2008, 02:35:12 PM
http://uk.youtube.com/watch?v=0NXwlDcglgA&feature=related

Sound anything like that? Stuck side seal...
Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 29, 2008, 12:33:08 AM
Nah she doesnt sound like that Ash
Title: Tip Failure Symptoms ?
Post by: FDAsh on December 29, 2008, 01:51:15 AM
Glad to hear it. :)
Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 29, 2008, 04:33:05 PM
Well today I had a better look at the car, nothing visibly wrong however now that ive had a chance to check for codes etc from the ecu I know its not a sensor.

Also im running non sequential so was able to check out the vac piping easily and cant find any problems there either.

After checking over everything I took it for a spin. From cold it started up fairly easily and done the usual cold fast idle then dropped to about 1500rpm for a bit before finally reducing down to the more "normal" idle speed of about 8-900rpm.

as stated before it idles good above 1000rpm but below than and you can hear that its certainly not running on both rotors fully.

Went for a drive and again drives fairly good above 1000-1200rpm but below that and its certainly misfiring. Also any time you change gear it pops as if its overfuelling too.

When you rev it right up and come on boost it pulls strongly, again popping on gear changes and overfuelling but when you then lift off there are puffs of blue smoke. It only does this after being on boost though.

Once fully hot it still idles really badly and the boost gauge does flutter a bit too. Also when accelerating lightly the gauge flutters a fair bit.

If you turn it off and start it again when hot it starts up no problem.

Now im thinking the worst here but still the fact it starts ok both hot and cold and does drive on boost doesnt tie up with what others have said when they have dropped a tip ?

Also again the chuff test sounds even enough on both rotors to me too.

Im thinking its probably not a good idea to drive it anymore untill I get to the bottom of this incase it causes more damage ?

Any thoughts on it folks ? I really dont want to go pulling the engine to bits unless i really have to. Is there any more checks I can do at all to confirm if its deffo a tip ?
Title: Tip Failure Symptoms ?
Post by: Carl on December 29, 2008, 04:36:31 PM
It certainly seems like you have a small chip on the end of a tip.
I would not drive it anymore untill you get it properly compression tested.
Regards
Carl
Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 29, 2008, 04:44:50 PM
Quote from: Carl;569377It certainly seems like you have a small chip on the end of a tip.
I would not drive it anymore untill you get it properly compression tested.
Regards
Carl

balls..................... LOL

Oh well, looks like its going off the road for a bit. Too skint to fix her till I get paid again so guess i better find a runabout, certainly dont want to be driving about on my motorbike for the rest of the month in this weather! :eek:

Thanks for the info Carl, will a proper compression test show a chipped tip up ?

Also if you do chip a tip am I likely to require a rotor housing as well as new tips ?
Title: Tip Failure Symptoms ?
Post by: Carl on December 29, 2008, 04:46:28 PM
Quote from: Sideways_Steve;569379balls..................... LOL

Oh well, looks like its going off the road for a bit. Too skint to fix her till I get paid again so guess i better find a runabout, certainly dont want to be driving about on my motorbike for the rest of the month in this weather! :eek:

Thanks for the info Carl, will a proper compression test show a chipped tip up ?

Also if you do chip a tip am I likely to require a rotor housing as well as new tips ?

Hi Steve,
A proper rotary compression tester should show it up.
Regards
Carl
Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 29, 2008, 04:54:01 PM
Cheers Carl,

Do mazda dealerships have one ? Just i only have a normal compression tester and there is nowhere up here in scotland that I know of that has one :(
Title: Tip Failure Symptoms ?
Post by: HaywardRotary on December 29, 2008, 06:38:30 PM
Some do have,but they aren\'t cheap to get the test done and also they seem to be a bit poor at doing the test,ring around.
Title: Tip Failure Symptoms ?
Post by: Sideways_Steve on December 29, 2008, 06:47:58 PM
cheers folks, living in scotland really does suck at times :(