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-   -   REBUILD TIME! First timer has some questions. (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/rebuild-time-first-timer-has-some-questions-591359/)

Longshoe 10-27-06 04:00 PM

REBUILD TIME! First timer has some questions.
 
Alright, most of the internals look good except ive got a few strange things going on. I will put up pics later as my buddy's camera is too complex for me to get any fine detail.

First, the e-shaft has burn marks around it. There are two rings one on both sides of the shaft where the lobes that the rotors ride on meet the twist in the middle.

Second, the front iron is not in spec- there is a pretty deep groove that my fingernail can catch on so im wondering what to do about it... Should I send it off to get lapped? Should I replace the iron? If I replace it should I replace the rear iron at the same time just so everything is even?

Finally, what constitutes a bad bearing? I see no copper on my rotor bearings but on one of them it looks like a piece of metal got in there and scored it up a little (however there is no such scoring on the e-shaft?).

Also what do you recommend I use to clean all of these parts? Can I use just about anything or are there things I should avoid that would damage the surface on the rotor housings?

Pics will be up a little later.

Aaron Cake 10-27-06 04:13 PM


Originally Posted by Longshoe
First, the e-shaft has burn marks around it. There are two rings one on both sides of the shaft where the lobes that the rotors ride on meet the twist in the middle.

That's normal. I think it has something to do with how Mazda manufactures the shaft. Burns are bad when they are on the bearing surface.


Second, the front iron is not in spec- there is a pretty deep groove that my fingernail can catch on so im wondering what to do about it... Should I send it off to get lapped? Should I replace the iron? If I replace it should I replace the rear iron at the same time just so everything is even?
If it's badly out of spec (confirm with a dial indicator) then either replace it or get it lapped. If you have a convenient and cheap way of getting it lapped, then go ahead. Otherwise, used irons are cheap.


Finally, what constitutes a bad bearing? I see no copper on my rotor bearings but on one of them it looks like a piece of metal got in there and scored it up a little (however there is no such scoring on the e-shaft?).
Scored bearing should be replaced. The babbit surface should be totally smooth.


Also what do you recommend I use to clean all of these parts? Can I use just about anything or are there things I should avoid that would damage the surface on the rotor housings?
I use Gunk degreaser to clean things initially, then I wash in water with dish soap and rinse with warm water and dry immediately. This is great for the housings, irons and rotors.

For things like the eccentric shaft, stationary gears, oil pump and chain, etc. I just use brake cleaner to hose them down.

brent clement 10-27-06 04:54 PM

The marks on the eshaft are from the heat treating process.

eriksseven 10-27-06 05:08 PM


Originally Posted by Longshoe
Second, the front iron is not in spec- there is a pretty deep groove that my fingernail can catch on so im wondering what to do about it... Should I send it off to get lapped? Should I replace the iron? If I replace it should I replace the rear iron at the same time just so everything is even?

Every motor that I've ever torn apart has had the 'corner-seal' trace line on the iron-faces, even engine's with as few as 60k miles and IIRC most of them were deep enough to catch a nail on... Resurfacing can be kinda expensive (I suppose it depends on who does it), so I've just reused what I've had... How many miles are on your irons?

calrx7 10-27-06 05:10 PM

basically, anything u can catch ur finger on, get it replaced. like for the irons, yeah.. lapping works but id rather get a good condition iron.

brent clement 10-27-06 05:46 PM

The only thing that compares to a resurfaced iron is a new one. If your fingernail catches it imagine what it's doing to your engine at 7k. Get it resurfaced whether it be lapping or grinding. I never build an engine without resurfacing the irons. Of course, I do my own so it's cost effective. You should be able to get all 3 irons done for $200-$300. Considering the time and effort that goes into a build it's well worth it.

HAILERS 10-27-06 07:45 PM

http://www.mazdatrix.com/s.htm


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