Running noise like catching on something

[SiH]

I also have a slight rattle on the clutch release bearing (it goes when you depress the clutch) so was thinking could these be connected possibly, although they do sound like 2 different noises??

That\'s not clutch release bearing, that\'s the input shaft bearing on the box.
Clutch release bearing noise shows itself when you depress the clutch, but isn\'t there when it\'s up. Input shaft/layshaft/whatever you want to call  it bearing does it when the clutch is up, and is most prominent when the car\'s in neutral.
I seem to be plauged by it, whatever car I buy! My FD sounds like it\'s got a straight cut box sometimes, it\'s that bad.

[bumpstart]

i have just assembled an engine doing basically the same thing,, "chink" ing in the same place every 360 degree rotation

with endfloat/ front stack loose,, no clashing,, upon tightening front pulley bolt,, motor has a "chink" and a tight spot every rotation

so,, process of elimination has discovered it doesnt do it when the rear counterweight is not attached
 ( and endfloat set and pulley bolt tightened )

inspection of the inside surface of the counterweight reveals its clashing on part of the rear stat bearing

this is due to the counterweight ( and the others i have ) sitting too far up the taper on the crank


this is due ( in my example ) to a previous builder having linished the crank on the taper

however,, on yours ,, likely due to the flywheel having come loose,, and both the taper in the flywheel,, and that on the crank are possibly both worn


-- which brings me to this post --- and handy pic showing the surface in question
http://www.mazdarotaryclub.com/forums/showthread.php?t=63141


myself,, i am having that inside face of the counterweight milled back 1mm
( it isnt supposed to ride on the underside of the stat )

you may have to investigate if you have similar clash,, and may have to mill the flywheel in similar location to fix

[SiH]

Are yo 100% sure of the origin of the counterweight? I had something very similar - turned out that the person on here who basically jsut breaks cars and replies to wanted ads had sold me a counterweight that didn\'t fit, and didn\'t even appear to be from an FD. I still have it as he point blank refused to accept that there was anything wrong with it.
In my case it was worse though, as it completely bound up the e-shaft.

[bumpstart]

100% certain,,,,, there is only one factory marked counterweight
-- rx4

the rest are unmarked,, but i also know how to differentiate them by measuring the machined rim flats


rx4,, luckily has the rear mass marked 1029A ( or 1029,,or just 29 )
and the front mass marked 1757
( the only factory marked counterweights out of all of them, mazda got lazy )


-- and i have tried 2 different 1029A masses on the same crank,, same issue

it\'s definitely to far up the taper due to previous crank polishing, and the clash is visible on the underside of the rear weight
 simple lathe work will clearance it OK,, and will be in action soon

[Looney]

Right, uploading the video of the rattling is not going to happen with mobile broadband and propper broadband aint happening till the end of the month.
 
So I have decided to remove the gearbox again in a couple of weekends when I\'m next off.
 
It could be the fly wheel is not seating correctly on the shaft as I have noticed play in the fly wheel when I was under the car the other day inspecting what I could. The only leverage I could get was an up and down motion, which seemed to seat it better for the run I took it on after, but its back to normal since that run.
 
If the rear bearing has gone, I\'m thinking a replacement is needed obviously.
 
I have been on rotary art who seem to have these but I canna make heads or tails atm of what the differences are:
T=1.980mm yellow or T=1.983mm green or T=1.986mm brown or T=1.989mm black or T=1.992mm blue
T=1.988mm yellow or T=1.991mm green or T=1.994mm brown or T=1.997mm black and T=2.000mm blue
 
What is T? Is it thickness of bearing? Is there a quick way of telling once the fly is off with out removing the bearing?
 
 
This issue can only be one of the above two other than gearbox failure, but the sound appears to come from the fly end after using the metal bar method of a stethoscope to pin point where the sound is origonating.
 
I am hoping to find out what bearing I need by midday on the first day strip down, so I can order it and have it in the post asap to be refitted with out have the rex on axle stands for too long.
 
 
 
Also on another note, are there any rotary specialists in south wales? Even just for parts at the least?

[Looney]

Quick update:
 
All sorted now, this noise was the flywheel being slightly loose on the shaft and catching on part of the gearbox housing.
 
The main bearing is not how I expected as it is a metal cylinder sheath with oil holes with oil running thourgh it constantly.
 
The T above stands for the thickness of the sheath.
 
You can change these with out having to dismantle the engine for anyone that would like to know! lol.
 
I is happy again!!!!

[HaywardRotary]

You can only really change the rear one relatively easily once gearbox is off,the front one requires quite a bit of parts removal including front cover.
Regards
Carl