RAWRX7

if my water seals are blown but everything else is fine can i tear my engine apart and replace the seals or do i have to do a complete rebuild? the only reason im not doing a complet rebuild is due to money.

stylEmon

iTrader: (2)

it'll probably blow again soon after.
If one thing is fuct, there is likely much else that needs repair.
Unless you know exactly what 'in-spec' and ; out of spec' means, it's a pretty hell-acious task.

RB_eater

iTrader: (1)

You'll have to change all soft seals since they are not reusable. A blown seal could also be the result of iron damage in which case you'll also have to replace the iron.

RAWRX7

well it over heated the other day that has been the only issue i have had

thebigbluecan

Well Don't drive it thats for sure.

RAWRX7

cant the car wont start and the coolent smells like gas thats how i knew it had a blown seal. oh by the way this is a S4 N/A

RotaryResurrection

iTrader: (8)

...and people wonder why rebuilt rotaries have a bad name.

TehMonkay

iTrader: (-1)

If that is what you need to do then do it, just measure the length of all of the ceals and check all clearances while you're at it, mazda created the fsm as a tool that lets us not have to open the damn thing and say, well, gotta replace everything!

texFCturboII

iTrader: (17)

if you are going to go through the trouble to rip the engine apart to replace the coolant seals, why are you not going to take the time to replace all the other seals as well?

Aaron Cake

iTrader: (1)

Basically what everyone else says. In addition, if you intend to rebuilding the engine you will want to pull it apart now and clean everything up. If you leave it assembled, you'll have a rusted mess when you finally do get around to rebuilding it.

TehMonkay

iTrader: (-1)

yes the water will rust and destroy the irons if you dont do this now.

thebigbluecan

+1 Got a good point there.

RotaryResurrection

iTrader: (8)

I took apart an overheated/coolant seal motor that was let to sit a few months just last night:

http://www.rotaryresurrection.com/builds/musgrove/

Do not let the engine sit.

Either continue to start it regularly (do not drive it far or at all in this condition) to keep rust from forming,

OR

drain the radiator and block entirely of coolant, start the engine and let it run for about 15-30 seconds to burn off any internal coolant puddles, and then inject it with motor oil/atf/mmo/whatever liberally to coat all internal surfaces and displace water, to preserve internals for a later rebuild,

OR

go ahead and tear it apart right now.

At a very minimum you will be replacing coolant seals, apex seals, and oil control ring inserts. These are the MAJOR wear items in the engine that you absolutely would not want to reuse. These parts at retail will cost you around 400 bucks. For a few dollars more you should also do front and rear main seals, thermal pellet replacement for the e-shaft, and 93+ corner seal springs.

IF you are careful and lucky everything else inside the enigne will be reuseable. So, here we have established a baseline for the minimum requirements to successfully open an old, worn, original rotary engine and reseal it and expect it to last more than a few months.

Now, if you compare this parts list to my "base" rebuild parts list on my site, you'll notice they are identical. This is the bare minimum you can expect to do and have a decent engine rebuild; of course there are other parts that may be damaged or worn, or that you could replace to gain better longevity or compression.

RAWRX7

I called a junk yard and found a used engine off a 88SE for $188 so i think im going to put that in for the mean time.

new question.
i think i will have the plates resurfaced and ported while its out and do a complete rebuild.
now are the plates and housings the same on a S4 N/A and a S4 turbo? and the only dif is the high and low compression rotars? is that correct?

if so than i should get me some turbo rotars and slap them in with my newly rebuilt/ painted motor.
PS dont the rotars have to be etched out to take 3mm apex seals?

Aaron Cake

iTrader: (1)

No. A glance at the FSM/Haynes manual will show you all the differences.

Why? Do you intend on turbocharging the engine?

If you want to run 3MM seals (why?) then the rotors will need to be milled to accept them.

RAWRX7

86-88 nonturbo:

chrome flake and compression surface wears moderately, most of these aren't in very good condition if they have over 100k miles. They're usually fine to reuse in a street nonturbo engine, but not for something like a modded t2 or an FD. They have the noise diffusers in the exhaust, so you can either cut them out or swap sleeves entirely. The port itself is identical. Plug timing is different from 89+, and these do not have the casting above the T plug for the knock sensors. Required 4 oil injectors for lube.

87-88 turbo:

same as above, except with smooth exhaust port. Also they have an additional coolant passage where the LIM bolts up, on FC's this feeds water to the stock turbo through the LIM which has a drilled passage. To use this housing on a nonturbo engine or an FD engine you have to block off this coolant passage, usually by tapping and plugging.

yes, well maybe.

Aaron Cake

iTrader: (1)

The turbo engines are 4 port, the NA engines are 6 port. That's the biggest difference. Entirely different intake manifolds. Just browse through some of the pictures in the pictures forum to see what I mean.

If you only may turbocharge the engine, stick with the higher compression NA rotors.