BlackWorksInc

I was flipping through the archives trying to get an idea of what parts I would need and how much it would cost if I went ahead and rebuilt my engine...

I did a few searches on rebuilding and found a lot of mixed answers and few websites to look at.


So I was wondering what are good places to find new seals and such? and about how much am I looking at here?

Thanks in advance for all your help guys.

slate84

do you want to just replace the gaskets? or are you going to go all out and replace the seals springs and housings? it really depends what you want to replace.

BlackWorksInc

Do I really need to replace the whole housings? Could I just replace the side,apex, and other seals?

slate84

ya but the housings you'll want to consider since chrome chipping can be pretty bad on 12a's being so old with so many miles. its something to consider. i'm just swapping into a 13b when my seals decide to call it quits. if you want to replace everything but the housing, irons, and rotors your looking about 800 bucks. atkins and mazdatrix both sell pretty good complete rebuilds as well.

BlackWorksInc

Hmm... Okay then, thanks that's what I was looking for.

Bridge it baby

hey there, you won't know if you need to replace your housings untill the motor is apart. If they have grooves/scratchs in them, or some of the chrome has peeled off, then yes you will, if you want the rebuild to be worth while. As for parts needed, isnt it worth it to replace all seals and gaskets while its apart? Its better doing it once the right way, than having to strip it later on because a spring or seal etc that wasn't replaced, has failed?...
As far as price goes, it'll be a bit different for you (I'm in NZ), but for my rebuild kit (for a 12a), consisting of new apex/side seals and new springs for both, new o-rings (water and oil) and springs, gaskets for complete engine, and new rotor bearings, cost me NZ $1200, which i thought was a damn good deal, considering what some other places around were going to charge me.

Hope this helps, long live the 12a!!!

slate84

if the seals and springs are within tollerence, theres nothing wrong with using them. i'd rather use parts that are broken it. saves money too. as long as your not dragging it. theres quite an argument about replaceing the bearings too since your more likely to spin one after its replaced. you shouldn't pay over a k for a rebuild with springs and seals.

djessence

I got my kit from atkins. I ended up getting new rotor housings as well because one was iffy and the other was toast.

As slate said not over 1k. I paid about 900 for everything, except housings.


Demon....do you even have a seven to stick an engine in anymore?

BlackWorksInc

Low blow.

Nothing concrete yet, but I am working on sourcing a shell... another fourm member offered his so we're going back and forth...

... I don't know now if I may rebuild the engine though, it sounds a little too expensive for me right now...

Jeezus

iTrader: (4)

I got some stuff about tolerances and clearances if you need me to PM them to ya. Rebuilding is fun, I have taken some engines apart and mock put them together. Nothing seriously rebuilt... yet

djessence

Sorry wasnt meant as a low blow, was more wondering if you'd found a shell.

If you think its time for a rebuild, tear it apart and see. could be you only need a few new parts and a gasket kit. Who knows till it comes apart

rx7learner

+1^

Tear it apart, make sure you have micrometers and a dial indicator, and a whole bunch of cleaning supplies... and get to checking specs.

Got over 1k on my rebuild consisting of parts that were well in spec with all for the cost of new soft gaskets and spings (using FD corner springs) and she's running great... about 250$ (plus the cost of tools above... from Harbor Freight < 75$) plus the cost of a rebuild DVD about 40$.

Also crushed the ROPR and shimmed the front oil reg and ported while I was in there for free.

You dont really know till you pull it apart. I had 2 85 12A's and one had just within tolerance apex seals while the other had 95%... So much history behind these cars that they are almost like a box of chocolates.... You never know who did what in the past...

Good luck...

slate84

see, if it ain't broke, don't replace it. you can get away cheaper than you think.

BlackWorksInc

Hmm... I'm just hesitant to take it apart and when trying to reuse some stuff it leaks...

Though the idea of porting it and cleaning her up sounds good....

I'll let you guys know when I can tear out the motor...

Jobro

iTrader: (2)

I disagree wholeheartedly about using used apex seals in a fresh motor. You can't measure the thing and say for 100% certainty that it has not suffered from detonation in the past and it is not brittle. If them or any other seals inside the combustion chamber chip or crack then you will be up for a lot more.

I believe worn chrome has something to do with spiting and cracking apex seals, you won't want to leave that inside a nice new engine. I did everything I could afford during my build. All I mist out on was a new oil pump waterpump and irons and rotors. My pumps and irons were iffy but I decided everything else was more important. I've since upgraded the waterpump and I will upgrade the oil pump to a high flow part in the near future.

Don't take any chances, with the amount of time it will take a beginner to do all this stuff it is stupid economically to not put new housings and seals in it.

BlackWorksInc

That's the problem... the money.

I probably will put new seals, but I'm kind of debating on the housings and rotors...

j9fd3s

iTrader: (3)

having taken apart a bunch of 12a's here's what ive found.

irons: usually look great. if the engines got really high miles or ran out of oil or something then maybe its bad?

e shaft: usually looks new

stat gears/bearings: the gears are usually fine, unless the engines seen a ton of rpms. bearings used to last, but lately it seems like they arent. lack of zinc in the oil?

rotors: if an apex seal broke, then it usually destroys a rotor. also high mile rotors have worn out grooves. how worn out is acceptable is up to you.

rotor housings: in the 90's it was taking 5 engines to get a good pair of rotor housings. i would expect them to be bad on tear down. the chrome falls off...

apex seals: these like to break into 3rds, and it seems to just randomly happen, bad idea to reuse these in spec or not.

all the other seals, just measure out to spec and replace as needed.

i think in the us, with the falling dollar, prices are going up.

BlackWorksInc

Here's a stupid question...

Is it rather inefficient if we have to replace practically all the components of the engine when rebuilding?

i.e. The housings, rotors, and ect?

Wouldn't that be the equivalent of buying a new block each time you rebuilt it?

Just wondering if I am going to go through that much trouble, may I should just buya new one? Stupid question I know...

j9fd3s

iTrader: (3)

i think 2 rotor housings + bearings + seals is equivalent to rebuilding a piston engine with new pistons and valves.

BlackWorksInc

Hmm... I guess.

What am I looking for if I decide to raid junkyards? I may do that this weekend just to scope out some housings in case?

Because I have never really seen chrome flaking on a housing... only on old bumpers.

IanS

iTrader: (4)

The chrome is on the inside, so you dont ever know how bad it is until you tear it down and then even if it was al good you would want to replace the springs and soft seals minimum.

BlackWorksInc

Oh I plan on doing the apex seals at least... I was just curious what "excessive chrome flaking" meant? At what point does the loss of chrome become most counterproductive to the engine?

djessence

If you look at mazdatrix faqs page they have an extensive thing on chrome flaking.

I dont recommend buying a used engine for parts to rebuild yours before youve torn it apart to see whats needed. Even then its iffy. I needed 1 housing for sure and couldve used 2 so i bought a very low mileage engine (like 100k kms) and it turned out pretty much everything in there was toast. Good thing I only paid 150 bucks for it but you can just never tell.

If you want to do a rebiuld or buy another engine at least tear yours apart first and see whats going on. Worst case scenario (or best?) you buy a gasket kit for 100 and stick it back together.

It starts to be the most counterproductive part of the engine when it starts to affect compression and destroys seals. When the chrome is gone it is extremely rough underneath.

If you autox it might be worth signing up to mazda Motorsports becuase you get parts at dealer cost.

rx7learner

+1 for djessence

It's allways easy to say new is better... especially if you have the money...

But for those that will always opt for new please pm me when your getting ready to trash in tolerance seals.

If I cant use them at the time... I can definately sell them on E-Bay to one of us "economically stupid" people that opt to reuse 95% apex seals and dont ignore oiling system upgrades.